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 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.

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.

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.

* 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

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. 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: Minicircuits ZX60-242GLN-S+ - 28dB Gain @ 0.9dB NF
Low cost, acceptable performance: 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

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.

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 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

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

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

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.

For more details see this wiki page:Ryde Receiver

OpenTuner

PC based software developed by Tom ZR6TG

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

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/

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/ - 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
SDRangel 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.

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.

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 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 - 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.

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: 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.

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