BATC Wiki - User contributions [en-gb]

Ryde Receiver

2026-01-16T17:14:06Z

G8GTZ: /* Ryde Hardware */

The BATC Ryde receiver is a stand-alone receiver or Set Top Box (STB) designed specifically for Digital Amateur TV with similar functionality to a consumer STB.

It is controlled by an IR remote and has a "point and shoot" interface - simply enter frequency and SR and the Ryde will look for DVB-S or DVB-S2 DATV signals without the need to enter Bouquets, transponders or scan across a range of frequencies. It will also receive DVB-T signals when used with a Knucker tuner.
[[File:Ryde_With_Menu_Small.jpg|500px|center]]

* The Ryde is a standalone receiver controlled by an infra-red remote with on-screen menus
* The Ryde directly drives an external HDMI or composite video (PAL/NTSC) monitor
* The Ryde does not require any additional hardware such as a PC
* The Ryde provides a lock indication output for use at DATV repeater sites.

==Ryde Hardware==

The Ryde receiver is simple to construct and is built from a standard Raspberry Pi 4 and either [[[[PicoTuner]]|Pico Tuner USB receiver hardware]] for DVB-S2 reception or [[Knucker]] hardware connected via USB. .

Full hardware details are described on this page: [[Ryde Hardware]].

[[File:Ryde1 boxed.jpg|500px|center]]

The above shows the four of the main parts of the Ryde:-

1. Raspberry Pi 4

2. GPIO breakout PCB

3. 12V input 5.2V 5A output DC to DC converter

4. Switch and IR sensor PCB

All parts are mounted in a Eddystone 26827PSLA Diecast box (Farnell Ordercode 301589) with room for future expansion.

The BATC MiniTiouner or Knucker tuner are mounted in a separate box connected by USB to the Raspberry Pi.

====IR remote control====

More details on how to connect an IR sensor to the Ryde, which remote control to use and how to program your own control are here: [[Ryde remote controls]]

====RF input band switching====

The Ryde has been designed to control the Portsdown 4 and 8 way RF switches https://wiki.batc.org.uk/8-Band_RF_Output_Switch The RF switch should be built leaving out the MMIC stage U1 which is bypassed with a short circuit or a 1nf capacitor.

This switching is enabled in Ryde software version 202111051 and later. The default GPIO pins are specified in the [[Ryde_GPIO_Connections]], but can be changed by manually editing the /home/pi/ryde/config.yaml file. Note that the numbers in the config file refer to the Broadcom port numbers in the second column of the GPIO table.

====GPIO connection====

A GPIO breakout PCB is available from the BATC shop - NOTE, this PCB is intended to be mounted to go outside the Pi4 profile as shown above.

More details here: [[Ryde GPIO breakout|https://wiki.batc.org.uk/Ryde_GPIO_breakout]]

'''Note that the Raspberry Pi 4 GPIO connections are different to the Raspberry Pi 3'''

Full details of the Ryde GPIO connections are here: [[Ryde_GPIO_Connections]]

==Ryde Software==

There are 2 ways to get the Ryde Software. As with Portsdown, you can buy a pre-programmed SD Card from the [https://batc.org.uk/category/usb-receivers/ BATC Shop]; or you can build your own card.

===Building Your Own SD Card===

The instructions on this page [https://github.com/BritishAmateurTelevisionClub/ryde-build BATC GitHub Ryde Build Page] (scroll down) take you step-by-step through building your own Ryde SD Card. No great computer expertise is required. The process will be familiar to anyone who has built a Portsdown SD Card.

Once you have bought or built your card, please read this information about using the [[Ryde Software]].

===Ryde presets===

There are 10 presets in the default build. You can modify each of them from the on-screen menu, but these on-screen changes are volatile and will be lost when you close the application or reboot.

You can modify the detail of each preset permanently from the ssh console menu (reached by entering 'menu' at the command prompt). However, you cannot modify the preset names. This was too complicated to handle in the Menu.

Each preset has frequency, SR and band defined. Frequencies and SRs can be multiple for scanning.
I have defined 8 bands. Each band has LO Frequency, LO side, LNB voltage, Tuner port and Band GPIO setting defined. Note that Band GPIO setting does not have any effect yet. You cannot modify the band names, but can modify all the other band parameters.

You can select which preset channel the receiver starts up on. It does not have to be the QO-100 beacon.

You can also manually edit the presets as described here [[Ryde_Software#Manually_Editing_the_Presets]].

===Ryde scanning modes===

Primarily designed for use in at repeater sites, the Ryde can be set to scan multiple SRs on a single frequency or multiple SRs on multiple frequencies. Set these up as follows:

* Log in via SSH

* For a repeater go to menu 2 and define which preset to use on start up.

* Then go to menu 4 and customise your preset - enter frequency (or frequencies) followed by up to 4 symbol rates. Restart your Ryde and it will use the start up preset and scan Frequencies and Symbol rates as entered.

Note under menu 3 you set which LNB F type port is used on which band so you can have 70cms use the top port and 23cms use the bottom port.

===Customising the Ryde===

You change what information is displaed on the screen - details in this forum post: https://forum.batc.org.uk/viewtopic.php?f=130&t=7502&hilit=customising+ryde

You change the words on the Red splash screens - details here: https://forum.batc.org.uk/viewtopic.php?f=130&t=8054

==The Ryde as a Repeater Receiver==

As well as a dedicated shack receiver without the need for a PC, the Ryde is also designed for use at repeater sites.

* Reliable lock indicator output from the RPi GPIO connector.
* Status banner showing station ID, MER and D number displayed after signal lock (Display period adjustable in config menu)
* Symbol rate search across a number of presets. Feature would enable a single Ryde receiver to listen on 437MHz and receive 2Ms, 1Ms, 333ks and 125ks signals

==The Ryde as a DVB-T Receiver==

The Ryde is also capable of receiving DVB-T signals in conjunction with the Knucker receiver.

In the config file, the DVB-T tuner must be selected when the band is defined. The default config file has 2 DVB-T channels, 146.5 MHz, 333 kHz bandwidth and 437 MHz 333 kHz bandwidth.

==The Ryde DVB-S/S2 Watchdog==

The Ryde is perfect for use at Exhibitions to the public, but sometimes when auto-tuning on QO-100 it will come across a station with illegal parameters and crash. The Ryde watchdog, described here [[Ryde Watchdog]] restarts the Ryde application when this happens.

==FAQ==

If you are having problems with your Ryde Receiver, please check these FAQs before posting any questions on the BATC Forum. [[Ryde FAQ]]

==Original Requirement Specification==

The original requirement specification for the Ryde Receiver, written in April 2020 by G8GTZ, can be found here: [[Ryde Requirement Specification]].

29 MHz

2025-12-07T17:19:49Z

G8GTZ: /* Introduction */

==Introduction==

The 2022 RSGB band plan http://rsgb.org/main/files/2022/02/220126_2022-Band-Plans_RadCom-web.pdf identifies 29000 - 29510 kHz segment as available for experimental wide bandwidth operation on a non-interference basis to other stations, including the amateur satellite service segment at 29300 -
29510 kHz. It is recommended that stations use a center frequency of 29.250 MHz to avoid causing interference to the weak-signal satellite downlinks of OSCAR 7 and CAMSAT satellites.

In practice, this means we can experiment with reduced bandwidth DATV on 10m. The 10m band opens for worldwide DX around solar maximum, so theoretically and now in practice it is possible to transmit video worldwide.

These pages are intended cover the experiments, noting they are experiments, that may require significant effort in construction of equipment, development of software and quite a but patience in order to participate. So far, signals have been sent across the Atlantic by several amateurs using very low symbol rates. There is much still to do to improve performance and reliability. If that interests you, you are in the right place.

==Propagation Effects and multipath==

The F2 and E skip that provides good DX on 10m usually comes at the cost of multipath distortion. In practice this means our usual phase modulated signals (e.g. Quadrature Phase Shift keying (QPSK)) of above a few kHz bandwidth can't be decoded. Success so far has used relatively low bandwidth 18ks/s QPSK in a bandwidth of ~20kHz but even this is too wideband and does not deliver particularly good video. Here are three narrow band signals received by a networked radio in Pennsylvania. They are Gareth G4XAT, Rob M0DTS and Mike G0MJW. All were about 100W, with Mike and rob using beams and Gareth a vertical. The multipath distortion is very apparent, as is the difference in propagation paths.

[[File:Multipath1.jpg|400px]]

Despite the good signal strengths, none of these signals were decodable except very briefly whenever a single path became sufficiently dominant.

The solution to multipath for digital audio broadcasting at HF and VHF and terrestrial television at VHD/UHF is to use a modulation mode, called Orthogonal Frequency Division Multiplexing (OFDM) where many narrow bandwidth signals are stacked next to each other.

[https://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing Wikipedia - OFDM]

Each narrow bandwidth carrier is less impacted by multipath and clever algorithms can be used to compensate and even take advantage of the multiple paths to either increase data throughput (as in MIMO) or improve the signal to noise ratio.

Some form of OFDM is likely to be the best technique, but requires software development to enable it.

==Equipment for 29MHz DATV==

Generally, we can generate DATV signals in the same way we do for higher frequencies using software defined radios (SDR).

The popular SDRs that are used to transmit DATV at higher frequencies are the Adlam-pluto and Lime Mini. The pluto does not work below 70MHz and while the Lime Mini does cover 29MHz natively, in practice the spectrum it generates in this region is not sufficiently clean to use on the air. Consequently, to use either device for transmitting it is best to down-convert from a higher frequency, for example with a 2m to 10m transmit downconverter.

Similarly on receive, the popular minitiouner used at higher frequencies does not tune down to 29 MHz. An upconverter is needed to translate the signal to an IF within the range of the tuner.

A better option for receive may be to use an HF SDR, e.g. an Airspy, RFSpace SDRIQ/CloudSDR or an RTL dongle and decode the signal in a software package like GnuRadio or SDRAngel. Both of these software packages can also be used to transmit.

Information on a simple 2m to 10m frequency transverter is [[29MHz transverter]]

Information on building power amplifiers for 29 MHz DATV is [here]

Information on suitable antennas for 29 MHz is [here]

==Software for 29MHz DATV==

ffmpeg - for generating the encoded video stream
SDRAngel - for receiving

==Generating a low rate transport stream==

There isn't much bandwidth available on 10m which means relatively low symbol rates are needed, probably occupying no more than 100kHz of bandwidth, ideally less. This means we need to use the most efficient video compression readily available to us, at the time of writing this is H265 which can produce good video in 100kb/s and fair video in less. The ffmpeg software package can encode video and generate low data rates mpeg transport streams. Using ffmpeg requires a complex set of command line options that must be tuned to get the best quality. For example the following developed by Rob, M0DTS takes input from OBS and uses an Nvidia graphics card to generate a transport stream for a Pluto running Evariste F5OEO's firmware:

ffmpeg -f dshow -i video="OBS-Camera" -vcodec hevc_nvenc -g 8 -s 213x120 -bf 0 -pix_fmt yuv420p -b:v 10k -bufsize 30k -r 2 -preset fast -profile:v main -rc cbr_hq -rc-lookahead 5 -an -f mpegts -streamid 0:256 -metadata service_provider="YourCall" -metadata service_name="YourName" -max_delay 2500000 -pcr_period 80 -pat_period 0.4 "udp://192.168.2.1:8282?pkt_size=1316"

This is pretty complex and breaking this down is out of scope and might reveal many liberties being taken but it did actually work. Here is an example received trans-atlantic using SDRAngel.

[[File:SDRAngel1.jpg|400px]]

The above parameters need to be tweaked for each required but rate, which will depend on the transmissions bandwidth, modulation and forward error correction.

HAMTV from the ISS - How to build a ground station

2025-12-06T17:02:49Z

G8GTZ: /* MiniTiouner Mk1 PCB */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

'''The MiniTiouner has been replaced by the PicoTuner, which was released in April 2024 and is the recommended solution for new builders'''.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV but is no longer available for new builds.

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

The original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The PicoTuner hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

It is possible to run SDR software which does not need any special hardware, such as PicoTuner, as it uses the Pluto SDR hardware.

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

=== SDR Software ===

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS - How to build a ground station

2025-12-06T17:01:35Z

G8GTZ: /* SDR (Software-Defined Radio) Receivers */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

'''The MiniTiouner has been replaced by the PicoTuner, which was released in April 2024 and is the recommended solution for new builders'''.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV but is no longer available for new builds.

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The PicoTuner hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

It is possible to run SDR software which does not need any special hardware, such as PicoTuner, as it uses the Pluto SDR hardware.

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

=== SDR Software ===

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS - How to build a ground station

2025-12-06T17:00:43Z

G8GTZ: /* SDR Software */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

'''The MiniTiouner has been replaced by the PicoTuner, which was released in April 2024 and is the recommended solution for new builders'''.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV but is no longer available for new builds.

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The PicoTuner hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

=== SDR Software ===

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS - How to build a ground station

2025-12-06T17:00:05Z

G8GTZ: /* SDR Software */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

'''The MiniTiouner has been replaced by the PicoTuner, which was released in April 2024 and is the recommended solution for new builders'''.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV but is no longer available for new builds.

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The PicoTuner hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

=== SDR Software ===

It is possible to run SDR software which does not need any special hardware, such as PicoTuner, as it uses the Pluto SDR hardware.

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS - How to build a ground station

2025-12-06T16:27:11Z

G8GTZ: /* Software for use with the USB receiver */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

'''The MiniTiouner has been replaced by the PicoTuner, which was released in April 2024 and is the recommended solution for new builders'''.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV but is no longer available for new builds.

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The PicoTuner hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

==== SDR Software ====

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS - How to build a ground station

2025-12-06T16:26:35Z

G8GTZ: /* Mark 2 MiniTiouner PCB */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

'''The MiniTiouner has been replaced by the PicoTuner, which was released in April 2024 and is the recommended solution for new builders'''.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV but is no longer available for new builds.

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

==== SDR Software ====

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS - How to build a ground station

2025-12-06T16:25:41Z

G8GTZ: /* USB Receiver hardware */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

'''The MiniTiouner has been replaced by the PicoTuner, which was released in April 2024 and is the recommended solution for new builders'''.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

==== SDR Software ====

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS - How to build a ground station

2025-12-06T16:25:05Z

G8GTZ: /* USB Receiver hardware */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

'''The MiniTiouner has been replaced with the PicoTuner, which was released in April 2024, is the recommended solution for new builders'''.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

==== SDR Software ====

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS - How to build a ground station

2025-12-06T16:24:34Z

G8GTZ: /* USB Receiver hardware */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note: the MiniTiouner has been replaced with the PicoTuner, which was released in April 2024, is '''the recommended solution for new builders'''.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

==== SDR Software ====

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS - How to build a ground station

2025-12-06T16:23:16Z

G8GTZ: /* USB Receiver hardware */

== Introduction ==

Firstly you should to set yourself the goal of what you want to achieve. It is relatively easy to build a station that will receive 30 seconds of video when the ISS is passing directly over at high elevation, it is very difficult (and often expensive) to build a station that will receive 8 minutes of video for a similar pass as the decreasing signal strength at low elevation becomes increasingly demanding of station performance.

We suggest that you work out your average minimum elevation that you'll see the ISS at, and use that to provide an upper bound as to the performance you need. Note that 2395MHz does not penetrate thick trees or structures, so your effective horizon will likely be higher than it is for VHF/UHF.

A high minimum horizon means that it's not worth spending extra effort or money on a high performance station. A low minimum horizon leaves the choice open to you.

Rough suggestions of levels of station (these may evolve over time):

* High performance (>20 deg horizon): Well-calibrated G-5500 or better, 1.2m+ dish, <1dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Medium performance (>30 deg horizon): G-5500 / other motorised, 90cm dish, <3dB Noise Figure LNA, Optional downconverter, High-specification SDR or Minitiouner receiver.
* Low performance (>45 deg horizon): Hand-steered 60cm, <5dB Noise Figure LNA, Downconverter, SDR receiver.

* Experimental (>70 deg horizon, very short passes): Directional helix antenna, <5dB Noise Figure LNA, Downconverter, SDR receiver

=== Pitfalls ===

Setting up a ground station can be a time-consuming and expensive endeavour so we want to be up-front about potential pitfalls. Without expensive test equipment or alternative components to compare, fault-finding can be difficult and frustrating.

* Pointing Calibration - a 1 meter dish needs to be pointed within +/- 3 degrees, this needs to include calibration of the rotator, mounting of the dish, and any instability / wind-bend of your mast. Larger dishes will be more demanding.
* RF Interference (RFI) - WiFi is only 5MHz away and can easily overload high-gain amplifiers or unfiltered receivers. Some regions (e.g. UK) also have a very strong 4G band which requires filtering to avoid overloading even the best receivers.
* Falsely-advertised amplifiers - Some cheap amplifiers may have less gain or more noise than specified.
* Poor coax cabling - RG58 and RG213 are simply not suitable for 2395MHz. Also cheap SMA patch cables can be of very low construction quality, with the loss varying by several dB depending on the bending of the cable!
* Receivers - an overloaded receiver, particularly by something intermittent such as WiFi, can display a strong signal but just not lock reliably. Identifying the cause of the issue can often take iteration of the station setup.
* Software - the software can be complex, not widely tested, and not easy to install or configure. You may need to ask for help, and be patient in finding a solution.

__TOC__

== Technical ==

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is Right-Hand Circular Polarisation (RHCP), so if you're using a dish then the feed must be LHCP (Left-Hand ..) as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

S-band is high demand spectrum for ground communications and so it's extremely likely that you'll have strong local signals, '''requiring''' good filtering in your system.

2.4GHz WiFi is the most common issue, as shown on the right in the spectrum capture below. The WiFi signal is intermittent so can be hard to detect on some systems, but a strong un-filtered 'data-burst' can cause receivers to lose lock for several seconds.

In the UK we have an additional problem of a 4G/LTE band in 2350-2390MHz, shown here on the left. This is a more constant signal but the very strong power can overload amplifiers/receivers in your system and so degrade your HamTV reception, particularly when pointing at low elevation angles.

[[File:ISS_13-9-25_1940_ends-low-angle_annotated.png|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by other local signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

==== SDR Software ====

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable. You will need the 'nightly' build as the latest stable (v1.2.2) does not contain the DVB-S processor.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDR Television / SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

==== Portsdown + Lime SDR ====

* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

==== GNUradio + [PlutoSDR, Lime SDR, USRP, etc.] ====

Download an IQ file from the ARISS Media store, for example from the UK Contact in late 2025: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/2025-10-18%20Radford%20Semele%20UK/ https://live.ariss.org/media/HAMTV Recordings/IQ Files/2025-10-18 Radford Semele UK/]

The files are (g)zipped complex samples, these will need decompressing (unzipping) before use. (.cf32.gz -> .cf32)

Then these can be played back in GNUradio as 'complex' data type, for example using a PlutoSDR with the [https://wiki.gnuradio.org/index.php/PlutoSDR_Sink PlutoSDR Sink Block]:

[[File:PlutoSDR HAMTV IQ Playback.png|500px]]

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

At this time only the [[MiniTiouner hardware Version 1|MiniTiouner Version 1]] and [[MiniTiouner hardware Version 2|MiniTiouner Version 2]] are approved for use with the Merger. We are working to validate Satdump for SDR reception. The Techno-Trend 1600 and 3200 receivers are not suitable.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

HAMTV from the ISS

2025-08-28T20:03:40Z

G8GTZ: /* How to receive HAMTV? */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018. The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

Reports from stations receiving HamTV, including details of their stations, are on the BATC forum: https://forum.batc.org.uk/viewtopic.php?f=117&t=9197

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 64kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagramV2.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so '''good filtering is essential''' to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

July 2025 update - UK stations are reporting that 4G cellular signals in the 2350 to 2390MHz band are VERY strong and causing issues receiving HamTV. This makes a good channel filter with maximum 6 MHz bandwidth even more important to receive HamTV.

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

==== SDR Software ====

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

File:Hamtv diagramV2.jpg

2025-08-28T20:02:57Z

G8GTZ: File uploaded with MsUpload

File uploaded with MsUpload

HAMTV from the ISS

2025-08-28T19:52:13Z

G8GTZ:

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018. The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

Reports from stations receiving HamTV, including details of their stations, are on the BATC forum: https://forum.batc.org.uk/viewtopic.php?f=117&t=9197

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 64kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. A good LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Medium cost, good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF]
* Low cost, acceptable performance: [https://www.nooelec.com/store/lana.html Nooelec LaNA - 12dB gain @ 1.5dB NF]

Note that very high gain units such as the Kuhne LNAs (60dB gain) can be easily overloaded by WiFi and other RFI without a filter placed in front, which will reduce their performance.

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so '''good filtering is essential''' to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

July 2025 update - UK stations are reporting that 4G cellular signals in the 2350 to 2390MHz band are VERY strong and causing issues receiving HamTV. This makes a good channel filter with maximum 6 MHz bandwidth even more important to receive HamTV.

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box DVB receiver, and the more affordable SDR receivers and so may require a frequency downconverter. Placing a downconverter at the masthead also allows lower grade coax cable to be used to bring the IF signal back to the shack.

For the BATC Minitiouner DVB receivers, the Mark 2 or Picotuner equipped with the Serit 4434 NIM can tune up to 2450MHz so does not require a downconverter. It may still be useful to use one to reduce loss stations with on long coax feeders.
For earlier Minitiouners (using the Sharp or Eardatek tuner) or other DVB receivers you will need a downconverter to place the HAMTV signal between 950 and 2150MHz.

Most downconverters will still require an LNA in front to receive the weak HamTV signals.

For hardware it is often possible to find suitable used "S-band" downconverters from manufacturers such as California Microwave.

On the market products such as [https://www.nooelec.com/store/ham-it-down.html Nooelec's "Ham It Down"] are also likely to be suitable - but you need to check the output frequency and IF power level, to ensure compatibility with your receiver.

== Receivers for HAMTV ==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Megasymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

NB there is currently no software for Apple macOS to run the Minitiouner USB receivers.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

Several previous versions can be downloaded from the ARISS website: https://live.ariss.org/hamtv/software/

[[File:20160507 Walbury GW8VPG.jpg|300px]]

=== SDR (Software-Defined Radio) Receivers ===

An SDR receiver with a sample rate of >= 2.4Msps (>= 2.4Mhz bandwidth) can be used with a software demodulator to receive and decode the HamTV DVB-S signal.

This solution will require a reasonably powerful PC/Laptop.

==== SDR Hardware ====

Cheaper receivers tend to have less dynamic range, this means that they will be very sensitive to the correct RF input levels, and will easily degrade in the presence of RFI such as WiFi and Cellular signals.
More expensive SDR receivers tend to be better but can easily exceed the cost of the hardware DVB receivers above.

In order of increasing cost:

* RTL-SDR - works but not recommended for reliable reception, the limited dynamic range is easily impacted by RFI.
* Airspy SDR
* ADALM-PLUTO PlutoSDR
* HackRF One
* Lime Microsystems LimeSDR
* Ettus USRP

==== SDR Software ====

* SatDump [https://www.satdump.org/ https://www.satdump.org/] - Most reliable.
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/] - Less reliable.

SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and the author has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-08-21T13:18:23Z

G8GTZ: /* Band pass Filter */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018. The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

Reports from stations receiving HamTV, including details of their stations, are on the BATC forum: https://forum.batc.org.uk/viewtopic.php?f=117&t=9197

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 64kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so '''good filtering is essential''' to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

July 2025 update - UK stations are reporting that 4G cellular signals in the 2350 to 2390MHz band are VERY strong and causing issues receiving HamTV. This makes a good channel filter with maximum 6 MHz bandwidth even more important to receive HamTV.

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-08-21T13:18:10Z

G8GTZ: /* Band pass Filter */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018. The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

Reports from stations receiving HamTV, including details of their stations, are on the BATC forum: https://forum.batc.org.uk/viewtopic.php?f=117&t=9197

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 64kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so '''good filtering is essential''' to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

July 2025 update - UK stations are reporting that 4G cellular signals in the 2350 to 2390MHz band are VERY strong and causing issues receiving HamTV. This makes a good channel filter with maximum 6 MHz bandwidth even more important to receive HamTV.

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-08-21T13:17:39Z

G8GTZ: /* Band pass Filter */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018. The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

Reports from stations receiving HamTV, including details of their stations, are on the BATC forum: https://forum.batc.org.uk/viewtopic.php?f=117&t=9197

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 64kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so '''good filtering is essential''' to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

July 2025 update - UK stations are reporting that 4G cellular signals in the 2350 to 2390MHz band are VERY strong and causing issues receiving HamTV. This makes a good channel filter with maximum 6 MHz bandwidth even more important to receive HamTV.

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-08-21T13:17:07Z

G8GTZ: /* Band pass Filter */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018. The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

Reports from stations receiving HamTV, including details of their stations, are on the BATC forum: https://forum.batc.org.uk/viewtopic.php?f=117&t=9197

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 64kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

July 2025 update - UK stations are reporting that 4G cellular signals in the 2350 to 2390MHz band are VERY strong and causing issues receiving HamTV. This makes a good channel filter with maximum 6 MHz bandwidth even more important to receive HamTV.

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-08-21T13:13:24Z

G8GTZ:

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018. The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

Reports from stations receiving HamTV, including details of their stations, are on the BATC forum: https://forum.batc.org.uk/viewtopic.php?f=117&t=9197

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 64kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-08-21T13:11:47Z

G8GTZ:

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

Reports from stations receiving HamTV, including details of their stations, are on the BATC forum: https://forum.batc.org.uk/viewtopic.php?f=117&t=9197

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 64kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-07-30T19:19:08Z

G8GTZ: /* TS format */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 64kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-07-30T19:18:39Z

G8GTZ: /* OpenTuner */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 364kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-07-30T19:18:05Z

G8GTZ: /* OpenTuner */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 364kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

See this page on how to use OpenTuner to receive HamTV from the ISS [[OpenTuner for HamTV|https://wiki.batc.org.uk/OpenTuner_for_HamTV]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-07-30T19:17:42Z

G8GTZ: /* OpenTuner */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 364kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

See this page on how to use OpenTuner to receive HamTV from the ISS [[OpenTuner for HamTV|https://wiki.batc.org.uk/OpenTuner_for_HamTV]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

OpenTuner

2025-07-30T19:16:28Z

G8GTZ: /* Download and more information */

=OpenTuner Windows software for MiniTiouner hardware=
Unfortunately, due to a family bereavement F6DZP is currently not developing the MiniTioune software – MiniTioune has become the go-to Windows software for DATV reception and the ATV community wishes Jean Pierre well for the future.

However, all is not lost as coincidently Tom ZS6RTG released the first version of his Windows OpenTuner software in March 2023 which uses the same standard MiniTiouner hardware. Tom has used the LongMynd receiver developed by M0MHO as the basis for this capability and his C# source code is published on his GitHub repository. Other users have already demonstrated that the software can be modified and recompiled.

The software has been developed primarily for use on QO-100 and includes a click and tune waterfall display and a window showing the QO-100 chat facility.

[[File:OT1.png|400px]]

==Features==

Features include Transport recording, a UDP output and the ability to customise the user interface in a foreign language. New features are being added every week.
For non QO-100 use, tick disable QO-100 and then enter the frequency, LNB offset and symbol rate in the tuner control box and press change. Note for terrestrial use put 0000 in the LNB offset box.

==Receiving HamTV from the ISS with Opentuner==

See this page on how to use OPentuner to receive the ISS [[OpenTuner for HamTV|https://wiki.batc.org.uk/OpenTuner_for_HamTV]]
==Download and more information==
For more details on the software and how to download it go to https://www.zr6tg.co.za/open-tuner/

There are already active discussions on the BATC forum – look there for answers to your questions:
https://forum.batc.org.uk/viewforum.php?f=142

HAMTV from the ISS

2025-07-30T19:13:10Z

G8GTZ: /* ISS HAMTV antenna */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 364kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to antenna 41 on the ISS which is a simple patch antenna.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-07-30T19:11:26Z

G8GTZ:

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. Unfortunately a lengthy "topology reassessment" was then required due to space issues in the Columbus module.

'''29th July 2025 - Following years of work by the ARISS team, the HamTV module has been successfully reinstalled and is active. No video source is currently connected so only a black screen is transmitted.'''

You can see live video from the ISS as received by a chain of stations using the BATC merger here https://live.ariss.org/hamtv/

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1.5 Mbits/s, PID 256
* MP2 Audio, approx 364kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:HamTV_OT_11.PNG|300px]]

For general details see this wiki page: [[OpenTuner]]

Instructions on how to set OpenTuner up for receiving HamTV (updated 30 July 2025) are here: [[OpenTuner for HamTV]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-05-10T14:12:18Z

G8GTZ: /* SDR Television software */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take months to complete.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will '''NOT''' receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-05-10T14:12:04Z

G8GTZ: /* SDR Television software */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take months to complete.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
SDRTV by Simon Brown G4ELI will NOT receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-05-10T14:11:29Z

G8GTZ: /* PC software receivers */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take months to complete.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

====SDR Television software====
'''SDRTV by Simon Brown G4ELI will NOT receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.
'''

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-05-10T14:10:45Z

G8GTZ: /* PC software receivers */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take months to complete.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

'''Note SDRTV by Simon Brown G4ELI will NOT receive the DVB-S HAMTV signal and Simon has confirmed the capability will NOT be added to any future release.
'''

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-05-02T15:06:49Z

G8GTZ:

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take months to complete.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-05-02T15:03:15Z

G8GTZ: /* BATC TS (transport stream) merger system */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete.

Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-05-02T15:00:47Z

G8GTZ: /* Social media */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete.

Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

=Social media=

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-05-02T15:00:31Z

G8GTZ: /* Actually receiving HamTV */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete.

Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

==Actually receiving HamTV==
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

===Social media===

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2025-05-02T15:00:05Z

G8GTZ: /* Social media */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete.

Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

===Social media===

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

2022 6cm Activity Ladder

2024-12-01T11:02:47Z

G8GTZ:

1. '''Introduction'''. The main object of the 6cm Activity Ladder is to promote ATV activity on 5.6GHz. Anyone interested in ATV, whether they are members of the British Amateur Television Club or not, are welcome to take part.

2. '''Eligibility'''. BATC Contests are open to all licensed radio amateurs who are equipped to transmit pictures by analogue or digital Fast Scan. There is no receive only section.

'''To encourage all Microwave activity, entries from stations running FM voice on 5665MHz will be accepted for the ladder contest from October 1st 2022 to December 31st 2022.'''

3. '''Dates and Times'''. The competition will run from 0000hrs UTC on 1st January 2022 to 2359hrs UTC on the 31st December 2022.

4. '''Location'''. Operating locations must be within the terms of your licence. If operating away from your main station, please get the permission of the landowner. Any (legal) location may be used, but contacts between two licensees operating from unchanged locations may only be claimed a maximum of twice per week. For example, if you have a daily sked, you may claim for it twice per week.

5. '''Frequencies and Modes'''. This Ladder is restricted to the 6cm band, using either FM voice, FM ATV or digital ATV modes. Contacts using Narrow band voice (SSB), CW and data modes are not valid for the activity ladder.

6. '''Power'''. Output power must not exceed that set out in the terms of your licence.

7. '''Exchange'''. Both a CALL SIGN and a FOUR-FIGURE code number must be conveyed and received by another station. Reception of the transmitted signal can only be via the RF link. Reception via a streamer is not permitted.

For a video contact only, confirmation of reception is required by transmitting the sum of the code numbers (not the actual transmitted number) on the talk-back channel. Stations are encouraged to use amateur radio for talkback, but use of mobile phones or internet is permitted.

Please note that the contest number should be four random chosen digits. The digits shall neither be the same (e.g. 2222) nor consecutive (e.g. 4567 or 5432).

8. '''On-line logging'''. Use the 6cm Activity Ladder page on the BATC website here: https://batc.org.uk/6cm-ladder and fill in the boxes for each contact as appropriate. The website will calculate the points awarded for the contact and add them to your total. You can add contacts made since the 1st January 2022 retrospectively. '''Entries will only be accepted via the on-line Activity Ladder web page'''.

9. '''Disputes'''. The decision of the contest manager and/or the BATC Committee is final.

10. '''Spirit of the Contest'''. Don’t leave your video transmission on any longer than necessary and don't hog the ATV calling channel 144.75 MHz; move off to another channel once the contact is established. Contests mean activity and good fun, join in and, even if you only work one or two stations, please use the Ladder to record your activity.

11. '''Declaration of Interest'''. Although acting as contest manager, I reserve the right to take part.

12. '''Contact Address'''. Queries can be submitted to: C. Reynolds, 49 Westborough Way, Anlaby Common, East Riding of Yorkshire HU4 7SW. Email: contests@batc.tv

Clive Reynolds G3GJA / G8EQZ BATC Contest Manager 24 March 2022

70cm Activity Ladder

2024-12-01T11:01:48Z

G8GTZ:

1. '''Introduction'''. The main object of the 70cm Activity Ladder is to promote ATV activity on 70cm. Anyone interested in ATV, whether they are members of the British Amateur Television Club or not, are welcome to take part.

2. '''Eligibility'''. BATC Contests are open to all licensed radio amateurs who are equipped to transmit pictures by analogue or digital Fast Scan. There is no receive only section.

3. '''Dates and Times'''. The competition will run from 0000hrs UTC on 1st January 2022 to 2359hrs UTC on the 31st December 2022.

4. '''Location'''. Operating locations must be within the terms of your licence. If operating away from your main station, please get the permission of the landowner. Any (legal) location may be used, but contacts between two licensees operating from unchanged locations may only be claimed a maximum of twice per week. For example, if you have a daily sked, you may claim for it twice per week.

5. '''Frequencies and Modes'''. This Ladder is restricted to the 70cm band, using AM or Digital ATV modes.

6. '''Power'''. Output power must not exceed that set out in the terms of your licence.

7. '''Exchange'''. Both a CALL SIGN and a FOUR-FIGURE code number must be conveyed via video and received by another station. Reception of the transmitted signal can only be via the RF link. Reception via a streamer is not permitted.

Confirmation of reception is by transmitting the sum of the code numbers (not the actual transmitted number) on the talk-back channel. Stations are encouraged to use amateur radio for talkback, but use of mobile phones or internet is permitted.

Please note that the contest number should be four random chosen digits. The digits shall neither be the same (e.g. 2222) nor consecutive (e.g. 4567 or 5432).

8. '''On-line logging'''. Use the 70cm Activity Ladder page on the BATC website here: https://batc.org.uk/contests/70cm-ladder/ and fill in the boxes for each contact as appropriate. The website will calculate the points awarded for the contact and add them to your total. You can add contacts made since the 1st January 2022 retrospectively. Entries will only be accepted via the on-line Activity Ladder web page.

9. '''Disputes'''. The decision of the contest manager and/or the BATC Committee is final.

10. S'''pirit of the Contest'''. Don’t leave your video transmission on any longer than necessary and don't hog the ATV calling channel 144.75 MHz; move off to another channel once the contact is established. Contests mean activity and good fun, join in and, even if you only work one or two stations, please use the Ladder to record your activity.

11. '''Declaration of Interest'''. Although acting as contest manager, I reserve the right to take part.

12. '''Contact Address'''. Queries can be submitted to: C. Reynolds, 49 Westborough Way, Anlaby Common, East Riding of Yorkshire HU4 7SW. Email: contests@batc.tv

Clive Reynolds G3GJA / G8EQZ BATC Contest Manager 24 March 2022

HAMTV from the ISS

2024-09-19T10:45:35Z

G8GTZ:

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In summer 2024, some work still needed to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete.

Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-09-18T08:46:42Z

G8GTZ: /* USB Receiver hardware */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In mid-July 2024, some work still needs to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete. Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-09-18T08:46:29Z

G8GTZ: /* USB Receiver hardware */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In mid-July 2024, some work still needs to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete. Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components. Note from 2024 the MiniTiouner has been replaced with the PicoTuner see below.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-09-18T08:45:09Z

G8GTZ: /* What is HAMTV used for? */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In mid-July 2024, some work still needs to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete. Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is initially recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-09-18T08:44:47Z

G8GTZ: /* What is HAMTV used for? */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In mid-July 2024, some work still needs to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete. Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is recommissioned in 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-08-13T11:13:11Z

G8GTZ: /* Do I need a downconverter? */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In mid-July 2024, some work still needs to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete. Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is recommissioned in Spring / Summer 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Serit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-08-13T10:24:13Z

G8GTZ:

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival.

In mid-July 2024, some work still needs to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete. Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is recommissioned in Spring / Summer 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-08-13T10:23:20Z

G8GTZ:

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it was hoped that it would be recommissioned by a visiting astronaut within a few weeks of its arrival. Presently, mid-July 2024, some work still needs to be completed to enable the placement of the HamTV in the Columbus module. Technically this is known as a “topology reassessment” and this may take a further three months to complete. Therefore the expected commencement of operations remains “TBD” but will not be before Autumn 2024.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is recommissioned in Spring / Summer 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-07-09T20:04:58Z

G8GTZ: /* Decoding a local signal */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was recently returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is recommissioned in Spring / Summer 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-07-09T20:04:41Z

G8GTZ: /* Decoding a local signal */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was recently returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.

==HAMTV specifications==

Whilst the transmitter has a number of settings listed below, it is anticipated that most transmissions will be:

2395 MHz, 2.0 Msymbols/second, QPSK, DVB-S, FEC 1/2, MPEG-2 video with MP2 audio

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is recommissioned in Spring / Summer 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC MiniTiouner and PicoTuner are PCBs which host the Serit FTS-4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Raspberry Pi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO-100 satellite.

The PicoTuner was released in April 2024 and is '''the recommended solution for new builders'''.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit FTS-4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Raspberry Pi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

==Decoding a local signal==

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not currently have a DATV system there are a couple of methods you can use to generate a local signal:

'''The recommended method is to use a Raspberry Pi 4 with the Portsdown 4 software and a Pluto SDR'''. Follow the simple instructions on this page to set this up [[Testing a HamTV Receiver using the Portsdown]]. A LimeSDR is a suitable alternative to the Pluto.

There are more difficult, less reliable, methods using just a Raspberry Pi as described here: [[UglyDATV01]]

===Playing out a local IQ file===

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv

HAMTV from the ISS

2024-06-28T19:47:50Z

G8GTZ: /* Decoding a local signal */

[[File:HAMTV 1.jpg|400px|center]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.

The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.

The unit failed in 2019, and was brought back to earth for repair. It was recently returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024 and it is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.

==HAMTV specifications==

====Ham Video RF Transmission====
*2395 MHz (main operating frequency)
*2369 MHz
*2422 MHz
*2437 MHz

The HAMTV transmitter produces 10 watts RF, however this is then fed through a series of interconnecting cables and bandpass filter before passing through the ISS Columbus module external wall.

Estimated power at the antenna is approx. 2 watts.

Polarisation is RHCP.

====DVB-S modulation====
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
* FEC : ½
* Rolloff: 35%

====TS format====
* MPEG-2 Video, approx. 1 Mbits/s, PID 256
* MP2 Audio, approx 360kb/s, PID 257
* Null padding, PID 8191
* NTSC
* SIF resolution: 352×240 or D1:720×480, 29.97fps
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.

MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]

==== ISS HAMTV antenna ====
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

[[File:HamTV patch.png|400px]]

This patch antenna is located on the earth facing side of the ISS but there are many other items that project below the antenna and may cause reflections. These include the solar panels, thermal radiator panels, sometimes, two or more visiting vehicles and robotic arms. Depending upon your location in respect to the ISS, these projections may result in strong reflected signals as well as the one from the patch antenna itself. They may cause disturbances to the signal level you receive.

The ISS also “flies” slightly nose down to protect the cupola windows from space debris and so the RF performance, particularly when it is rising from the west, is slightly unpredictable.

The transmissions are right hand circular polarised (RHCP)

==What is HAMTV used for?==

The primary use is for ARISS schools contacts, when the astronaut will use a camera to show live video of himself and the inside of the ISS to the school during the VHF radio contact.

[[File:HAMTV 2.jpg|400px]]

It is hoped in the future that test patterns, including JPEG images, will be transmitted when the cameras are not in use. Note this will NOT happen when HAMTV is recommissioned in Spring / Summer 2024.

==When will HAMTV be "on the air"?==

Once re-commissioned, HAMTV will be tested before school contacts are undertaken, however it is unlikely that the transmitter will be left on air 24/7.

During the first flight on the ISS between 2014 and 2018 it was used primarily for ARISS schools contacts but transmitter was left on at other times but no video was transmitted. This did allow ground stations to test their receive equipment and it is hoped a test signal generator will eventually be included, perhaps in 2025.

HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.

=How to receive HAMTV?=

There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the elements shown in the diagram.

[[File:Hamtv diagram.jpg|800px|center]]

* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
* The upper blue-boxes option is the preferred solution for new builders.
* In the blue-boxes option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used to avoid the RF level being too low at the receiver.
* The satellite line amplifiers are required to ensure there is enough signal at the receiver input - these may be placed at masthead or in the shack
* The filters are essential, not nice to have!
* The Minitiouner V2 / Pico tuner USB receiver can be connected to '''EITHER''' a PC running OpenTuner or Minitiouner software or a Pi4 based Ryde set top box receiver.

See the sections below for a full description of the elements in the diagram.

===Ground station antennas===

[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]

The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.

This means an antenna with reasonable gain is required to receive the signal and whilst it is possible to receive the signal on a simple antenna when the ISS is overhead, to enable more than 5 minutes of reception, a higher gain antenna such as a dish with an efficient feed system is required.

It will be difficult to receive HamTV DATV picture when ISS is at a low elevation at your ground station location. Generally, a minimum of 20 degrees elevation is required to begin receiving DATV pictures.

A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work at high elevations when the path length is short and have the advantage of a wider beamwidth making it easier to track the ISS, but they are unlikely to work at low elevations due to the significantly longer path.

Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes when installing, but are generally less available and more expensive.

===Rotator (mechanical tracking) ===

Perhaps the most challenging aspect of receiving HamTV is that, unlike the QO-100 satellite available in the Europe and Africa, the ISS is not geo-stationary and orbits the earth every 96 minutes and is visible at any location for a maximum of 11 minutes, often less.

Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead, increasing demands on the mechanical tracking.

The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but with this size it will require careful azimuth and elevation calibration and may lose tracking intermittently during the fast (high) parts of the pass. A 1-1.2m dish on a G-5500 is a lot easier to handle and is recommended.

SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.

* 1m dish: 8 degrees beamwidth (+/-4 degrees)
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)

Software - Just like for other spacecraft in low earth orbit, there is a choice of software available to control the rotator system. [https://www.pstrotator.com/ PSTrotator] which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them.

===Dish feeds===
The transmission is RHCP, so the feed on a dish must be LHCP as the polarity is reversed when the signal is bounced off the dish surface into the feed. Any antenna used to receive the signal directly will need to be RHCP.

A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html

There are a number of dish feeds around for QO100 satellite uplink - these are suitable for HamTV reception as they work at the same frequency in the 2.3GHz amateur band.

https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.

http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm

https://www.amsat.org/amsat/articles/g3ruh/116.html

It should be possible to use the POTY patch dish feed designed for QO100 uplink. http://www.hybridpretender.nl/poty.html Note - it may be possible to receive HamTV on a dish aligned on QO100 when the ISS passes in front of Eshail-2!

===LNA and Pre-amp===

A low noise pre-amp (LNA) should be connected directly to the antenna feed point via very high quality feeder to minimise losses. The LNA should have noise figure (NF) less than 1db and a gain of at least 15 dB.

===== Commercial LNA Options =====
* Best and most expensive: [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+220240+A++Super+Low+Noise+Amplifier/?card=1794 KU LNA 220240 A - 0.4dB NF], [https://www.kuhne-electronic.com/funk/en/shop/industrial/prof-low-noise-ampli/KU+LNA+222+AH++Super+Low+Noise+Amplifier/?card=359 KU LNA 222 AH - 0.5dB NF]
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]

===Band pass Filter===

Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent strong, local WiFi signals from getting into the wide band satellite tuner and causing interference or de-sense. Phil M0DNY has a video on Youtube showing just how much stronger wi-fi can be than the HAMTV signal: https://www.youtube.com/watch?v=ZFvXjWo-MoY

[[File:HamTV wi-fi.jpg|600px]]

It is desirable to put the filter AFTER the LNA so the noise figure of the system is not degraded by filter loss. However, you must ensure the LNA is not driven into compression (overloaded) by the local WiFi signals - if this is happening then the filter should be placed before the LNA at masthead as otherwise the HamTV signal may not decode.

If you are using a downconverter, the filter can be at the IF frequency as long as the downconverter is not overloaded by the WiFi.

Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.

More information on transmit and receive filters can be found on this wiki page: [[Filters]]

Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.

===Receive co-ax cable===

It is recommended to use professional grade satellite co-ax. If you are using a long cable run you must check the received signal level at the receiver - see below.

===Receive Line amplifier===

Satellite TV receivers need a high level of RF signal - they are designed for use with satellite LNBs which have ~55dB gain. Your masthead pre-amp must be followed by at least one satellite TV line amplifier with greater than 30 dB gain.

[[File:Inline sat amp-800x800.jpg|200px]]
Your masthead LNA/LNB MUST have enough gain to overcome your co-ax cable loss. The satellite line amplifier can be placed at masthead if needed to help overcome the feeder loss or in the shack. To hear more about the importance of noise figure and gain distribution in a DATV receive system watch https://youtu.be/lfSi7vTQK44?si=wn_wLBjxco3_RnAf

You can check if you have enough gain in your receive system by checking the RF signal level on the Ryde, OpenTuner, MiniTiouner or Portsdown DATV receivers - the noise floor should sit between -30 to -70dBm when not receiving any signals.

If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.

===Do I need a downconverter?===

The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.

Unless you are using the BATC MiniTiouner Mark 2 or PicoTuner USB receiver equipped with the Serit 4434 NIM, which can tune up to 2450MHz, you will need a frequency down converter to place the HAMTV signal between 950 and 2150MHz which is within the range of a standard satellite receiver.

Note: The MiniTiouner Mk1 PCB with a Sharp or Eardatek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardatek units.

The downconverter should be placed between the low noise amplifier and satellite receiver – placing it at the masthead will mean that lower grade feeder can be used to bring the IF signal back to the shack.

Previous suppliers of suitable downconverters, such as Kuhne Electronics, no longer market suitable items and BATC '''strongly recommends''' purchasing a new USB tuner hardware kit using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.

==Digital receivers for HAMTV==

The HamTV transmissions can be received using a DVB-S receiver capable of decoding 2 Msymbol / second MPEG2 transmission. This means that a standard consumer Set Top Box (STB) can be used. However, because the signal is only available during the ISS pass it is essential to use a receiver that can be set to both the frequency and symbol rate before the pass.

A receiver, such as a typical consumer STB, that needs to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.

===Receivers designed for DATV===

For optimum performance, a receiver designed for receiving narrow band DATV signals should be used. The Amateur TV community has developed a number of receive solutions based around a USB connected tuner hardware.

This USB hardware connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 sets the frequency and symbol rate of the USB receiver hardware and decodes and displays the received signal.

===USB Receiver hardware===

The BATC Minitiouner and PicoTuner are PCBs which host the Serit 4334 satellite tuner and a USB interface. This unit is designed to be built at home, requiring only intermediate skills and does not use surface mount components.

====Mark 2 MiniTiouner PCB====

[[File:Serit complete.jpg|300px]]

This is the USB hardware which has been available for 7 years and will work well for HAMTV.

For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]

====PicoTuner PCB====

[[File:Picotuner Mk1.png|300px]]

The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.

It replaces the FTDI USB interface on the original PCB with a Rpi Pico module. The Pico is not only significantly cheaper (£5 vs £32) but enables 2 stations to be received at once when used on the QO100 satellite.

The PicoTuner was released in April 2024 and is the recommended solution for new builders.

For more details see this wiki page [[PicoTuner]]

====MiniTiouner Mk1 PCB====

[[File:IMAG0218.jpg|300px]]

As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardatek tuner '''DOES NOT''' cover 2395MHz and will require a downconverter.

As well as covering the HAMTV frequency without a down converter, the Serit 4334 has much better RF performance than the original Sharp and Eardatek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.

===Software for use with the USB receiver===

The USB hardware described above connects to either a PC or Raspberry Pi 4 via a USB port - software on the PC or Pi4 controls the USB receiver hardware and decodes and displays the received signal.

When the original HamTV was on the air, due to a problem with the DVB tables in the transmission, the MiniTiouner software by F6DZP running on Windows had to be used.

However, during the last few years several developments have taken and so we now have a choice of software to use with the Mk2 Serit 4334 based USB tuner hardware.
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.

Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.

===Ryde===

Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.

[[File:Ryde_With_Menu_Small.jpg|300px]]

For more details see this wiki page:[[Ryde Receiver]]

===OpenTuner===

PC based software developed by Tom ZR6TG

[[File:OT1.png|300px]]

For more details see this wiki page: [[OpenTuner]]

===Portsdown===

The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal

[[File:Pdown rxr.jpg|300px]]

For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]

===MiniTiouner===

The MiniTiouner software is still available however the author F6DZP is no longer involved in the amateur radio community so is not providing support or enhancements and you can no longer register on the Viva DATV forum to download the software.

[[File:20160507 Walbury GW8VPG.jpg|300px]]

===PC software receivers===

There are a number of software receivers that can use an SDR such as the ADALM Pluto and Hack RF to receive the RF/IF, and then perform the DVB-S demodulation in software. Those reported to work are listed below.

* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]
* SatDump [https://www.satdump.org/ https://www.satdump.org/]
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]

Do note that any software-based receiver is likely to be less sensitive (1dB+) than a hardware receiver and will require a more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.

=Receiving the Signal=

First - always check the HamTV transmitter status before attempting to align your system as it is unlikely that it will be left on 24/7 and it certainly will not be available when EVAs (space walks) and docking of space craft are happening.

It is likely but not confirmed that the status will be published on the ARISS international website and Twitter account – the ISSfanclub website may also have the status updates.

[[File:Amsat status.png|500px]]

https://www.amsat.org/status/

=Testing your system=

As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.

There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.

===Measuring sun noise===

The most useful is to measure the sun noise received on your system. This will not only measure your system performance but if you leave it running for a few hours with your rotator control system set to track the sun, it will confirm the accuracy of your tracking system. Systems known to receive HamTV when it was previously running detected between 2.0 and 2.5 dB of Sun Noise.

====Portsdown DATV test system====

The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise.

* Connect the signal from your LNA / downconverter to the rx port on a Lime SDR or a Pluto SDR and select Menu 2 > test equipment > Noise power meter.

* In setting menu, adjust the Lime gain so that the noise floor sits at around -60dBm.

*From the main menu, select differential in the mode settings and then touch the right side of the "analogue" meter display on the main menu to set it to display -5 to +5dB.

* As you turn your antenna through the sun you should see a hump on the the time / gain display as the meter reads the level of sun noise - expect to see approximately 2dB on an average HamTV system.

[[File:Noise meter for Ham TV.png|400px]]

The peak on the right hand side of the history plot (bottom right) in this screenshot shows about 2 dB of Sun noise as the antenna was rotated through the sun.

For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]

The Portsdown DATV transceiver has a number of very useful RF test modes including a noise figure meter and a noise power meter. A very simple system can be built from a Raspberry Pi 4 running the free to download software and a LimeSDR or Pluto SDR - [[Portsdown_Test_Equipment|see this wiki page for a complete list]]

====SDR continuum mode====

Measuring sun noise can be done using SDR software running in continuum mode and running a program such as spectra view on the audio output – a Google search for sun noise measurement will show several techniques.

====MiniTiouner Noise power measurement====

F6DZP developed a suite of programs to help test a HamTV receive system which included a Noise Power Measurement program (see CQ-TV253 page 27 for more details). This was available as part of the MiniTiouner v0.8 package but appears to have been dropped in later releases. The program can be used to measure the noise power received by a Serit 4334 tuner over a period of time and requires no extra software or equipment to make sun noise measurements – the picture shows the sun noise recording from a RFHams 1.2 m mesh dish used to receive HamTV for the Principia mission in 2016.

[[File:NPM.JPG|400px]]

===Decoding a local signal===

Once you have checked your system sun noise and tracking accuracy it is worth checking that your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz.

If you do not have a DATV system there are several methods you can use to generate a local signal.

====Rpi Ugly mode====

A very basic DATV generator on 437MHz can be made by just using a RPi 2!

See [[UglyDATV01]]

====Portsdown based test signal generator====

If you already have a Lime Mini or Pluto you can download the free Portsdown software to a RPi 4 and use the web interface to control the system.

====Playing out a local IQ file====

You can use the Portsdown Raspberry Pi 4 based system with a Lime SDR to generate this signal. To do this:
* Connect the Portsdown to the internet and attach a LimeSDR. On Menu 1, select "Freq" and select the frequency that you want the signal to be generated on; you can use the keyboard key to enter 2395 MHz.
* Select Menu 2, File Menu, Download HamTV IQ File. Note that this is a 2 GB file which takes at least 5 minutes to download, and another 5 minutes to unzip.
* Once the file has downloaded, select Menu 2, File Menu again and then "Select IQ File". Touch the file SDRSharp_20160423_121611Z_731000000Hz_IQ.wav so that it is highlighted and press select.
* Then press "Play IQ File". The file will be played out on the frequency that you selected in the first step.

For full details see here: [[Portsdown IQ File Player]].

If you don't have a Portsdown, but have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings from 2016 that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]
* 5Ms/s Complex Samples
* WAV (SDRsharp) format
* Please note that these were recorded on a 0.6m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!

If these tests are successful you should be set to receive HamTV!

=Actually receiving HamTV=
All that remains is to wait until it is confirmed that the HamTV transmitter has been turned on then set your tracking program to follow the ISS and wait for the magic signs on the spectrum display (BandViewer?) or lock indicator that you are receiving the signal!

Once you have successfully received the HamTV transmission, the Dsave button in MiniTioune can be used to record data such as RF level, MER and Vber to show how well and for how long you received the pass.

=BATC TS (transport stream) merger system=

Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the MPEG-TS UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to the school, reducing the pressure on the school ground station.

Despite several large capable stations in the system, ground-station-specific blockage is common on the ISS due to docked spacecraft and other equipment, so more geographically-diverse smaller stations are always wanted.

[[File:TSmerger.png|600px]]

Once you have your system up and running please post on the BATC forum asking for more details.

In the meantime - here is a webpage that shows GHY6 dish at Goonhilly https://status.ghy6.goonhilly.org/camera/ If you look to the left of the 32 metre dish you can just see a small dish. It is actually a 5 metre dish! When not otherwise in use, this is already tracking the ISS and is receiving on 2395MHz. When a DATV signal is received it will automatically appear here https://live.ariss.org/hamtv/

==Social media==

Follow ARISS international on twitter for the latest status updates

https://twitter.com/ARISS_Intl

==BATC forum==

BATC have setup a new forum thread to discuss receiving HamTV.

Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398

A lot of information is available on the BATC forum:

https://forum.batc.org.uk/viewtopic.php?t=4389

==Youtube videos==

Colin G4KLB made a video on how he received HamTV in 2014

https://www.youtube.com/watch?v=9keVA21DPBc

Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.

https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN

G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=4J_JA3Syv6Y

Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023

https://www.youtube.com/watch?v=MQvRdG1FBo4

==Comments on this wiki page==

If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv