https://wiki.batc.org.uk/api.php?action=feedcontributions&user=M0DNY&feedformat=atomBATC Wiki - User contributions [en-gb]2024-03-29T15:51:01ZUser contributionsMediaWiki 1.35.6https://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=11015HAMTV from the ISS2024-03-24T13:02:25Z<p>M0DNY: /* PC software receivers */</p>
<hr />
<div>[[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.<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It 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.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video RF Transmission====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
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. <br />
<br />
Estimated power at the antenna is approx. 2 watts.<br />
<br />
====DVB-S modulation====<br />
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
* FEC : ½<br />
* Rolloff: 35%<br />
<br />
====TS format====<br />
* MPEG-2 Video, approx. 1 Mbits/s, PID 256<br />
* MP2 Audio, approx 360kb/s, PID 257<br />
* Null padding, PID 8191<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]<br />
<br />
==== ISS HAMTV antenna ====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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<br />
<br />
[[File:HamTV wi-fi.jpg|600px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
====MiniTiouner Mk1 PCB====<br />
<br />
[[File:IMAG0218.jpg|300px]]<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===OpenTuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
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.<br />
<br />
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]<br />
* SatDump [https://www.satdump.org/ https://www.satdump.org/]<br />
** Demonstration from Author using 2016 IQ recording: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]<br />
<br />
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.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==Social media==<br />
<br />
Follow ARISS international on twitter for the latest status updates<br />
<br />
https://twitter.com/ARISS_Intl<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV in 2014<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.<br />
<br />
https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN<br />
<br />
G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=4J_JA3Syv6Y<br />
<br />
Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=MQvRdG1FBo4<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=11014HAMTV from the ISS2024-03-24T12:59:01Z<p>M0DNY: /* PC software receivers */</p>
<hr />
<div>[[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.<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It 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.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video RF Transmission====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
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. <br />
<br />
Estimated power at the antenna is approx. 2 watts.<br />
<br />
====DVB-S modulation====<br />
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
* FEC : ½<br />
* Rolloff: 35%<br />
<br />
====TS format====<br />
* MPEG-2 Video, approx. 1 Mbits/s, PID 256<br />
* MP2 Audio, approx 360kb/s, PID 257<br />
* Null padding, PID 8191<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]<br />
<br />
==== ISS HAMTV antenna ====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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<br />
<br />
[[File:HamTV wi-fi.jpg|600px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
====MiniTiouner Mk1 PCB====<br />
<br />
[[File:IMAG0218.jpg|300px]]<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===OpenTuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
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.<br />
<br />
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]<br />
* SatDump [https://www.satdump.org/ https://www.satdump.org/]<br />
** Example from Author: [https://twitter.com/aang254/status/1771869215776985466 https://twitter.com/aang254/status/1771869215776985466]<br />
<br />
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.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==Social media==<br />
<br />
Follow ARISS international on twitter for the latest status updates<br />
<br />
https://twitter.com/ARISS_Intl<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV in 2014<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.<br />
<br />
https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN<br />
<br />
G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=4J_JA3Syv6Y<br />
<br />
Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=MQvRdG1FBo4<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=11013HAMTV from the ISS2024-03-23T18:23:11Z<p>M0DNY: /* HAMTV specifications */</p>
<hr />
<div>[[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.<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It 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.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video RF Transmission====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
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. <br />
<br />
Estimated power at the antenna is approx. 2 watts.<br />
<br />
====DVB-S modulation====<br />
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
* FEC : ½<br />
* Rolloff: 35%<br />
<br />
====TS format====<br />
* MPEG-2 Video, approx. 1 Mbits/s, PID 256<br />
* MP2 Audio, approx 360kb/s, PID 257<br />
* Null padding, PID 8191<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
MPEG-TS Recordings of previous transmissions can be found at [https://live.ariss.org/media/HAMTV%20Recordings/ live.ariss.org/media/HAMTV Recordings/]<br />
<br />
==== ISS HAMTV antenna ====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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<br />
<br />
[[File:HamTV wi-fi.jpg|600px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
====MiniTiouner Mk1 PCB====<br />
<br />
[[File:IMAG0218.jpg|300px]]<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===OpenTuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
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.<br />
<br />
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]<br />
* SatDump [https://www.satdump.org/ https://www.satdump.org/]<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver and will require a significantly more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==Social media==<br />
<br />
Follow ARISS international on twitter for the latest status updates<br />
<br />
https://twitter.com/ARISS_Intl<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV in 2014<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.<br />
<br />
https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN<br />
<br />
G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=4J_JA3Syv6Y<br />
<br />
Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=MQvRdG1FBo4<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=11012HAMTV from the ISS2024-03-23T18:22:01Z<p>M0DNY: /* DVB-S modulation */</p>
<hr />
<div>[[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.<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It 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.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video RF Transmission====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
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. <br />
<br />
Estimated power at the antenna is approx. 2 watts.<br />
<br />
====DVB-S modulation====<br />
* Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
* FEC : ½<br />
* Rolloff: 35%<br />
<br />
====TS format====<br />
* MPEG-2 Video, approx. 1 Mbits/s, PID 256<br />
* MP2 Audio, approx 360kb/s, PID 257<br />
* Null padding, PID 8191<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==== ISS HAMTV antenna ====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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<br />
<br />
[[File:HamTV wi-fi.jpg|600px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
====MiniTiouner Mk1 PCB====<br />
<br />
[[File:IMAG0218.jpg|300px]]<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===OpenTuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
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.<br />
<br />
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]<br />
* SatDump [https://www.satdump.org/ https://www.satdump.org/]<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver and will require a significantly more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==Social media==<br />
<br />
Follow ARISS international on twitter for the latest status updates<br />
<br />
https://twitter.com/ARISS_Intl<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV in 2014<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.<br />
<br />
https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN<br />
<br />
G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=4J_JA3Syv6Y<br />
<br />
Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=MQvRdG1FBo4<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=11011HAMTV from the ISS2024-03-23T18:20:01Z<p>M0DNY: /* HAMTV specifications */</p>
<hr />
<div>[[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.<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It 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.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video RF Transmission====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
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. <br />
<br />
Estimated power at the antenna is approx. 2 watts.<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====TS format====<br />
* MPEG-2 Video, approx. 1 Mbits/s, PID 256<br />
* MP2 Audio, approx 360kb/s, PID 257<br />
* Null padding, PID 8191<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==== ISS HAMTV antenna ====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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<br />
<br />
[[File:HamTV wi-fi.jpg|600px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
====MiniTiouner Mk1 PCB====<br />
<br />
[[File:IMAG0218.jpg|300px]]<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===OpenTuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
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.<br />
<br />
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]<br />
* SatDump [https://www.satdump.org/ https://www.satdump.org/]<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver and will require a significantly more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==Social media==<br />
<br />
Follow ARISS international on twitter for the latest status updates<br />
<br />
https://twitter.com/ARISS_Intl<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV in 2014<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.<br />
<br />
https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN<br />
<br />
G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=4J_JA3Syv6Y<br />
<br />
Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=MQvRdG1FBo4<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=11010HAMTV from the ISS2024-03-23T14:47:37Z<p>M0DNY: /* PC software receivers */</p>
<hr />
<div>[[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.<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It 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.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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<br />
<br />
[[File:HamTV wi-fi.jpg|600px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
====MiniTiouner Mk1 PCB====<br />
<br />
[[File:IMAG0218.jpg|300px]]<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===OpenTuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
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.<br />
<br />
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]<br />
* SatDump [https://www.satdump.org/ https://www.satdump.org/]<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver and will require a significantly more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==Social media==<br />
<br />
Follow ARISS international on twitter for the latest status updates<br />
<br />
https://twitter.com/ARISS_Intl<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV in 2014<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.<br />
<br />
https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN<br />
<br />
G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=4J_JA3Syv6Y<br />
<br />
Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=MQvRdG1FBo4<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=11009HAMTV from the ISS2024-03-23T14:46:58Z<p>M0DNY: /* PC software receivers */</p>
<hr />
<div>[[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.<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It 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.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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<br />
<br />
[[File:HamTV wi-fi.jpg|600px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
====MiniTiouner Mk1 PCB====<br />
<br />
[[File:IMAG0218.jpg|300px]]<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note OpenTuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===OpenTuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
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 known are listed below.<br />
<br />
* SDRangel [https://www.sdrangel.org/ https://www.sdrangel.org/]<br />
* SatDump [https://www.satdump.org/ https://www.satdump.org/]<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver and will require a significantly more powerful computer to run. For this reason the BATC recommends to use a hardware receiver.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==Social media==<br />
<br />
Follow ARISS international on twitter for the latest status updates<br />
<br />
https://twitter.com/ARISS_Intl<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV in 2014<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016.<br />
<br />
https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN<br />
<br />
G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=4J_JA3Syv6Y<br />
<br />
Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023<br />
<br />
https://www.youtube.com/watch?v=MQvRdG1FBo4<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10981HAMTV from the ISS2024-03-22T12:00:11Z<p>M0DNY: /* Ground station antennas */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10980HAMTV from the ISS2024-03-22T11:58:49Z<p>M0DNY: /* Rotator (mechanical tracking) */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10979HAMTV from the ISS2024-03-22T11:58:18Z<p>M0DNY: /* Rotator (mechanical tracking) */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10978HAMTV from the ISS2024-03-22T11:56:36Z<p>M0DNY: /* Rotator (mechanical tracking) */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10977HAMTV from the ISS2024-03-22T11:56:08Z<p>M0DNY: /* Rotator (mechanical tracking) */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
SPID rotators are a lot more capable and can more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10976HAMTV from the ISS2024-03-22T11:55:59Z<p>M0DNY: /* Rotator (mechanical tracking) */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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 calibratio, 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.<br />
<br />
SPID rotators are a lot more capable and can more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
More information on transmit and receive filters can be found on this wiki page: [[Filters]]<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see this wiki page [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this wiki page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software.<br />
<br />
For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
If these tests are successful you should be set to receive HamTV!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.<br />
<br />
=Further information=<br />
<br />
==BATC forum==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
==Youtube videos==<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
==Comments on this wiki page==<br />
<br />
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</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10958HAMTV from the ISS2024-03-21T23:17:52Z<p>M0DNY: /* Ground station antennas */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable and can more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=File:M0DNY_HamTV_Antenna.jpg&diff=10957File:M0DNY HamTV Antenna.jpg2024-03-21T23:17:11Z<p>M0DNY: </p>
<hr />
<div>M0DNY HamTV Antenna</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10956HAMTV from the ISS2024-03-21T23:15:11Z<p>M0DNY: /* BATC TS (transport stream) merger system */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable and can more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
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.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10955HAMTV from the ISS2024-03-21T23:14:26Z<p>M0DNY: /* BATC TS (transport stream) merger system */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable and can more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
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.<br />
<br />
Despite several large capable stations in the system, direction-specific blockage is common on the ISS and so more geographically-diverse smaller stations are always wanted.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10953HAMTV from the ISS2024-03-21T23:12:08Z<p>M0DNY: /* Decoding a local signal */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable and can more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* 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!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10952HAMTV from the ISS2024-03-21T23:10:30Z<p>M0DNY: /* Ground station antennas */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
Either offset- or prime-focus dishes can be used. Prime focus will be easier to visually align with the rotator axes, but are generally less available and more expensive.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable and can more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10951HAMTV from the ISS2024-03-21T23:09:07Z<p>M0DNY: /* Rotator (mechanical tracking) */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable and can more precisely, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10950HAMTV from the ISS2024-03-21T23:08:24Z<p>M0DNY: /* Rotator (mechanical tracking) */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
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.<br />
<br />
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.<br />
<br />
The Yaesu G-5500 rotator is commonly used. It can handle up to approx. 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable and can track with larger antennas, however are significantly more expensive.<br />
<br />
* 1m dish: 8 degrees beamwidth (+/-4 degrees)<br />
* 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)<br />
<br />
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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10949HAMTV from the ISS2024-03-21T23:03:11Z<p>M0DNY: /* Tracking the ISS */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead.<br />
<br />
A Yaesu G-5500 rotator can handle up to about a 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable, albeit more expensive.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10948HAMTV from the ISS2024-03-21T23:02:53Z<p>M0DNY: /* Rotator (mechanical pointing) System */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Rotator (mechanical tracking) ===<br />
<br />
Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead.<br />
<br />
A Yaesu G-5500 rotator can handle up to about a 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable, albeit more expensive.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10947HAMTV from the ISS2024-03-21T23:01:40Z<p>M0DNY: /* Software for use with the USB receiver */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Rotator (mechanical pointing) System ===<br />
<br />
Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead.<br />
<br />
A Yaesu G-5500 rotator can handle up to about a 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable, albeit more expensive.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10946HAMTV from the ISS2024-03-21T22:59:11Z<p>M0DNY: /* Receive Line amplifier */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Rotator (mechanical pointing) System ===<br />
<br />
Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead.<br />
<br />
A Yaesu G-5500 rotator can handle up to about a 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable, albeit more expensive.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10945HAMTV from the ISS2024-03-21T22:58:38Z<p>M0DNY: /* Band pass Filter */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Rotator (mechanical pointing) System ===<br />
<br />
Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead.<br />
<br />
A Yaesu G-5500 rotator can handle up to about a 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable, albeit more expensive.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10943HAMTV from the ISS2024-03-21T22:56:51Z<p>M0DNY: /* Ground station antennas */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Rotator (mechanical pointing) System ===<br />
<br />
Larger-aperture antennas will result in a stronger signal but require finer steps and more accurate pointing at the ISS as it passes overhead.<br />
<br />
A Yaesu G-5500 rotator can handle up to about a 1.8m dish, but 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.<br />
<br />
SPID rotators are a lot more capable, albeit more expensive.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10942HAMTV from the ISS2024-03-21T22:50:48Z<p>M0DNY: /* How to receive HAMTV? */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The upper blue-boxes option is the preferred solution for new builders.<br />
* 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.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work 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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10941HAMTV from the ISS2024-03-21T22:49:54Z<p>M0DNY: /* How to receive HAMTV? */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue-boxes option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work 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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10940HAMTV from the ISS2024-03-21T22:49:18Z<p>M0DNY: /* What is HAMTV used for? */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
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.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work 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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10939HAMTV from the ISS2024-03-21T22:48:45Z<p>M0DNY: /* Video format */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kb/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work 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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10938HAMTV from the ISS2024-03-21T22:48:34Z<p>M0DNY: /* Video format */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2 Video, approx. 1 Mbits/s<br />
* MP2 Audio, approx 360kbps<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work 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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10937HAMTV from the ISS2024-03-21T22:47:55Z<p>M0DNY: /* Band pass Filter */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 2 Mbits/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work 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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10936HAMTV from the ISS2024-03-21T22:46:02Z<p>M0DNY: /* LNA and Pre-amp */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 2 Mbits/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work 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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
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.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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 defense.<br />
<br />
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 swamped by the local wi-fi signals - if this is happening then the filter should be placed before the LNA at masthead.<br />
<br />
If you are using a downconverter, the filter can be at the IF frequency.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10935HAMTV from the ISS2024-03-21T22:45:34Z<p>M0DNY: /* LNA and Pre-amp */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 2 Mbits/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work 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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
A low noise pre-amp (LNA) with bandpass filter tuned to 2395MHz 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.<br />
<br />
Filters should be tuned to best reject WiFi at >2400MHz while minimising insertion loss at 2395MHz. A 3-pole or greater interdigital filter is suitable.<br />
<br />
===== Commercial LNA Options =====<br />
* 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]<br />
* Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]<br />
<br />
===Band pass Filter===<br />
<br />
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 defense.<br />
<br />
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 swamped by the local wi-fi signals - if this is happening then the filter should be placed before the LNA at masthead.<br />
<br />
If you are using a downconverter, the filter can be at the IF frequency.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10934HAMTV from the ISS2024-03-21T22:37:20Z<p>M0DNY: /* Ground station antennas */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 2 Mbits/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum. Smaller antennas such as flat plate or patch antennas will work 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.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
A low noise pre-amp (LNA) with bandpass filter tuned to 2395MHz 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.<br />
<br />
===Band pass Filter===<br />
<br />
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 defense.<br />
<br />
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 swamped by the local wi-fi signals - if this is happening then the filter should be placed before the LNA at masthead.<br />
<br />
If you are using a downconverter, the filter can be at the IF frequency.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10933HAMTV from the ISS2024-03-21T22:36:11Z<p>M0DNY: /* Digital receivers for HAMTV */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 2 Mbits/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum but smaller antennas such as flat plate or patch antennas will work and have the advantage of a wider beamwidth making it easier to track the ISS but they are unlikely to work at low elevations.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
A low noise pre-amp (LNA) with bandpass filter tuned to 2395MHz 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.<br />
<br />
===Band pass Filter===<br />
<br />
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 defense.<br />
<br />
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 swamped by the local wi-fi signals - if this is happening then the filter should be placed before the LNA at masthead.<br />
<br />
If you are using a downconverter, the filter can be at the IF frequency.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
Do note that any software-based receiver is likely to be several dB less sensitive than a hardware receiver, and will require a significantly more powerful computer.<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10932HAMTV from the ISS2024-03-21T22:34:52Z<p>M0DNY: /* Decoding a local signal */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 2 Mbits/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum but smaller antennas such as flat plate or patch antennas will work and have the advantage of a wider beamwidth making it easier to track the ISS but they are unlikely to work at low elevations.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
A low noise pre-amp (LNA) with bandpass filter tuned to 2395MHz 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.<br />
<br />
===Band pass Filter===<br />
<br />
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 defense.<br />
<br />
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 swamped by the local wi-fi signals - if this is happening then the filter should be placed before the LNA at masthead.<br />
<br />
If you are using a downconverter, the filter can be at the IF frequency.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable even with the best receiver!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10931HAMTV from the ISS2024-03-21T22:34:31Z<p>M0DNY: /* Decoding a local signal */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 2 Mbits/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum but smaller antennas such as flat plate or patch antennas will work and have the advantage of a wider beamwidth making it easier to track the ISS but they are unlikely to work at low elevations.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
A low noise pre-amp (LNA) with bandpass filter tuned to 2395MHz 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.<br />
<br />
===Band pass Filter===<br />
<br />
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 defense.<br />
<br />
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 swamped by the local wi-fi signals - if this is happening then the filter should be placed before the LNA at masthead.<br />
<br />
If you are using a downconverter, the filter can be at the IF frequency.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you 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/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10930HAMTV from the ISS2024-03-21T22:34:00Z<p>M0DNY: /* Decoding a local signal */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 2 Mbits/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum but smaller antennas such as flat plate or patch antennas will work and have the advantage of a wider beamwidth making it easier to track the ISS but they are unlikely to work at low elevations.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
A low noise pre-amp (LNA) with bandpass filter tuned to 2395MHz 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.<br />
<br />
===Band pass Filter===<br />
<br />
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 defense.<br />
<br />
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 swamped by the local wi-fi signals - if this is happening then the filter should be placed before the LNA at masthead.<br />
<br />
If you are using a downconverter, the filter can be at the IF frequency.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings available that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/ live.ariss.org/media/HAMTV Recordings/IQ Files/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10929HAMTV from the ISS2024-03-21T22:32:56Z<p>M0DNY: /* Decoding a local signal */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 21st 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)<br />
*FEC : ½<br />
<br />
====RF output====<br />
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. <br />
<br />
Estimated power at the antenna is ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
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.<br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 2 Mbits/s<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
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.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
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. <br />
<br />
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.<br />
<br />
HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.<br />
<br />
=How to receive HAMTV?=<br />
<br />
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.<br />
<br />
<br />
[[File:Hamtv diagram.jpg|800px|center]]<br />
<br />
* The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.<br />
* The Blue option is the preferred solution for new builders.<br />
* In the blue option the line amplifier and filters are at 2.4Ghz and GOOD (not cheap) quality satellite co-ax must be used.<br />
* 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<br />
* The filters are essential, not nice to have!<br />
* 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.<br />
<br />
See the sections below for a full description of the elements in the diagram.<br />
<br />
===Ground station antennas===<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
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.<br />
<br />
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. <br />
<br />
A 1 meter or larger dish is optimum but smaller antennas such as flat plate or patch antennas will work and have the advantage of a wider beamwidth making it easier to track the ISS but they are unlikely to work at low elevations.<br />
<br />
===Dish feeds===<br />
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.<br />
<br />
A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html<br />
<br />
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.<br />
<br />
https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.<br />
<br />
http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm<br />
<br />
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!<br />
<br />
===LNA and Pre-amp===<br />
<br />
A low noise pre-amp (LNA) with bandpass filter tuned to 2395MHz 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.<br />
<br />
===Band pass Filter===<br />
<br />
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 defense.<br />
<br />
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 swamped by the local wi-fi signals - if this is happening then the filter should be placed before the LNA at masthead.<br />
<br />
If you are using a downconverter, the filter can be at the IF frequency.<br />
<br />
===Receive co-ax cable===<br />
<br />
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. <br />
<br />
===Receive Line amplifier===<br />
<br />
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 in the shack.<br />
<br />
[[File:Inline sat amp-800x800.jpg|200px]]<br />
Your masthead 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.<br />
<br />
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.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter. The Seit NIM also has better RF performance than the Sharp or Eardertek units.<br />
<br />
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.<br />
<br />
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.<br />
<br />
==Digital receivers for HAMTV==<br />
<br />
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. <br />
<br />
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.<br />
<br />
===Receivers designed for DATV===<br />
<br />
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.<br />
<br />
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.<br />
<br />
===USB Receiver hardware===<br />
<br />
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.<br />
<br />
====Mark 2 MiniTiouner PCB====<br />
<br />
[[File:Serit complete.jpg|300px]]<br />
<br />
This is the USB hardware which has been available for 7 years and will work well for HAMTV.<br />
<br />
Full details of the USB tuner hardware, including parts list and construction details are available here: [[MiniTiouner hardware Version 2]]<br />
<br />
====PicoTuner PCB====<br />
<br />
[[File:Picotuner Mk1.png|300px]]<br />
<br />
The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024. <br />
<br />
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. <br />
<br />
The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.<br />
<br />
For more details see [[PicoTuner]]<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB (available from 2015 to 2017) with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner, Ryde and Portsdown DATV receive systems.<br />
<br />
===Software for use with the USB receiver===<br />
<br />
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.<br />
<br />
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.<br />
<br />
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. <br />
Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.<br />
<br />
===Ryde===<br />
<br />
Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.<br />
<br />
[[File:Ryde_With_Menu_Small.jpg|300px]]<br />
<br />
For more details see this page:[[Ryde Receiver]]<br />
<br />
===Opentuner===<br />
<br />
PC based software developed by Tom ZR6TG <br />
<br />
[[File:OT1.png|300px]]<br />
<br />
For more details see this wiki page: [[OpenTuner]]<br />
<br />
===Portsdown===<br />
<br />
The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal<br />
<br />
[[File:Pdown rxr.jpg|300px]]<br />
<br />
<br />
See [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]<br />
<br />
===MiniTiouner===<br />
<br />
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.<br />
<br />
<br />
[[File:20160507 Walbury GW8VPG.jpg|300px]]<br />
<br />
<br />
===PC software receivers===<br />
<br />
SDR Angel is PC software that receives DATV signals using SDR hardware such as the ADALM Pluto and Hack RF - at this time we do not have any experience of using SDR Angel to receive HamTV. <br />
For more details see https://www.sdrangel.org/<br />
<br />
=Receiving the Signal=<br />
<br />
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. <br />
<br />
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.<br />
<br />
[[File:Amsat status.png|500px]]<br />
<br />
https://www.amsat.org/status/<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
=Testing your system=<br />
<br />
As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.<br />
<br />
===Measuring sun noise===<br />
<br />
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.<br />
<br />
====Portsdown DATV test system====<br />
<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. <br />
<br />
You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
If you have an SDR capable of transmitting IQ files, there are a couple of small on-air HamTV RF recordings available that you can use for local playback: [https://live.ariss.org/media/HAMTV%20Recordings/IQ%20Files/]<br />
* 5Ms/s Complex Samples<br />
* WAV (SDRsharp) format<br />
* Please note that these were recorded on a 0.8m hand-steered dish, so the signal in the recordings will fade in and out of being decodable!<br />
<br />
=Actually receiving HamTV=<br />
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!<br />
<br />
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.<br />
<br />
=Further information=<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. <br />
<br />
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
=BATC TS (transport stream) merger system=<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]<br />
<br />
Once you have your system up and running please post on the BATC forum asking for more details.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&diff=10786HAMTV from the ISS2024-03-04T22:26:12Z<p>M0DNY: /* Video format */</p>
<hr />
<div>HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).<br />
<br />
It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.<br />
<br />
[[File:HAMTV 1.jpg|400px|]]<br />
<br />
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. <br />
<br />
The unit failed in 2019, and was returned to earth for repair. It is expected to be returned to the ISS on the SpaceX SpX-30 flight currently scheduled for March 12th 2024. It is hoped that it will be recommissioned by a visiting astronaut within a few weeks of its arrival.<br />
<br />
<br />
==HAMTV specifications==<br />
<br />
====Ham Video downlink frequencies====<br />
*2395 MHz (main operating frequency)<br />
*2369 MHz<br />
*2422 MHz<br />
*2437 MHz<br />
<br />
====DVB-S modulation====<br />
*Symbol rates: 1.3 Ms/s or 2.0 Ms/s<br />
*FEC : ½<br />
<br />
====RF output====<br />
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 ~ 2 watts.<br />
<br />
====HAMTV antenna====<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. <br />
<br />
[[File:HamTV patch.png|400px]]<br />
<br />
This patch antenna is located on the earth facing side of the ISS but is surrounded by solar panels, thermal radiator panels, two or more visiting vehicles and robotic arms. <br />
<br />
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.<br />
<br />
The transmissions are right hand circular polarised (RHCP)<br />
<br />
====Video format====<br />
* MPEG-2, approx. 800kbps<br />
* NTSC<br />
* SIF resolution: 352×240 or D1:720×480, 29.97fps<br />
* Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.<br />
<br />
==What is HAMTV used for?==<br />
<br />
The primary use is for ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.<br />
<br />
[[File:HAMTV 2.jpg|400px]]<br />
<br />
It is hoped that test patterns, including JPEG images, will be transmitted when the cameras are not in use.<br />
<br />
==When will HAMTV be "on the air"?==<br />
<br />
It is unlikely that the HamTV transmitter will be on air 24/7. <br />
<br />
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 be included when it is re commissioned in 2024.<br />
<br />
Once re-commissioned it will be tested before contacts and will be added to the AMSAT status page https://www.amsat.org/status/<br />
<br />
==How to receive HAMTV?==<br />
<br />
There are a number of challenges to receive HAMTV from the ISS and a typical ground station is made up of the following elements<br />
<br />
A typical groundstation system block diagram<br />
<br />
===Ground station antenna and feed===<br />
<br />
The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS. This patch antenna is located on the earth facing side of the ISS but is surrounded by solar panels, thermal radiator panels, two or more visiting vehicles and robotic arms. 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.<br />
<br />
[[File:dish.jpg|400px]]<br />
<br />
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.<br />
<br />
A 1 meter or larger dish is optimum but smaller antennas such as flat plate or patch antennas will work and have the advantage of a wider beamwidth making it easier to track the ISS. They are unlikely to work at low elevations.<br />
<br />
===Suitable feeds===<br />
<br />
===Pre-amp and filter===<br />
<br />
A low noise pre-amp with bandpass filter tuned to 2395MHz should be connected directly to the antenna feed point to minimise co-ax losses. <br />
<br />
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 desense.<br />
<br />
If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.<br />
<br />
If you are using a downconverter, a bandpass filter at the IF frequency in L band is possible.<br />
<br />
===Do I need a downconverter?===<br />
<br />
The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner. <br />
<br />
Note: place image of Minitiouner here<br />
<br />
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.<br />
<br />
Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter.<br />
<br />
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.<br />
<br />
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.<br />
<br />
===Digital receivers for HAMTV===<br />
<br />
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. <br />
<br />
A receiver, such as a typical consumer STB, that need to scan the frequency is unlikely to lock to the signal in the time available during the pass. This solution is therefore not recommended.<br />
<br />
===Receivers designed for DATV===<br />
<br />
=====Hardware=====<br />
<br />
Ideally a receiver designed for receiving DATV signals should be used. 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.<br />
<br />
The hardware is connected to either a PC or Raspberry Pi 4 using the USB 2 connection.<br />
<br />
As mentioned above, the original BATC MiniTiouner Mk1 PCB launched in 2015 with a Sharp or Eardertek 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 Eardertek units and has been integrated into the OpenTuner and Portsdown DATV receive systems.<br />
<br />
=====Software=====<br />
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.<br />
<br />
During the last 8 years many developments have taken and so we expect now to have a choice of software:<br />
<br />
* Ryde - Raspberry Pi 4 based set-top box software designed specifically for DATV <br />
<br />
* Portsdown - <br />
<br />
* Opentuner<br />
<br />
* 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.<br />
<br />
==Finding the signal==<br />
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.<br />
<br />
==Tracking the ISS==<br />
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.<br />
<br />
In order to track the ISS, an azimuth and elevation rotator system is required. The most commonly used system is the Yaesu G5500, which is capable of rotating a 1.2m dish with a 5 degree beam width to track the ISS. When choosing/designing your system remember the ISS does go north of 50 degrees and so any system will need to be capable of flip mode to track it when it goes overhead.<br />
<br />
Just like for other spacecraft in low earth orbit, software is available to control the rotator system – there are a number of different programs available. PSTrotator which is a very versatile system with almost unlimited number of interfaces to control rotators is one of them..<br />
<br />
==Testing your system==<br />
<br />
As the ISS is not visible every day at a given location and then only for short periods, it is difficult to see if your HAMTV receive system is working.<br />
<br />
There are a number of tests you can do to ensure your system is optimised but 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.<br />
<br />
===Measuring sun noise===<br />
====Portsdown DATV test system====<br />
The Portsdown DATV transceiver incorporates a test function that has a continuous noise measurement facility designed to measure sun noise. It is very easy to use. Simply connect the signal from your LNA to the rx port on a Pluto or Lime SDR and run the software - see [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]<br />
<br />
[[File:Noise_Meter.png|400px]]<br />
<br />
====SDR continuum mode====<br />
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.<br />
<br />
====MiniTiouner Noise power measurement====<br />
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.<br />
<br />
[[File:NPM.JPG|400px]]<br />
<br />
===Decoding a local signal===<br />
Once you have checked your system sun noise and tracking accuracy it is worth testing you’re your system can receive a locally generated 2Ms DVB-S signal on 2395 MHz. You can use the Portsdown Pi4 based system with a Pluto or Lime SDR to generate this signal.<br />
<br />
If this is successful you should be set to receive HamTV!<br />
<br />
==Receiving HamTV==<br />
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!<br />
<br />
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.<br />
<br />
==Further information==<br />
<br />
BATC have setup a new forum thread to discuss receiving HamTV. Please post any questions, comments and status updates here:<br />
<br />
https://forum.batc.org.uk/posting.php?f=2&mode=post&sid=9c1b12a07706567454ebeca685548796 (NOT SURE THIS LINK IS CORRECT!)<br />
<br />
Receivers compatible with HamTV:<br />
<br />
[[Ryde_Receiver|Ryde Receiver]]<br />
<br />
[[DVB-S/S2_Reception|Portsdown DATV transceiver]]<br />
<br />
[[MiniTioune|MiniTioune]]<br />
<br />
A lot of information is available on the BATC forum:<br />
<br />
https://forum.batc.org.uk/viewtopic.php?t=4389<br />
<br />
Colin G4KLB made a video on how he received HamTV<br />
<br />
https://www.youtube.com/watch?v=9keVA21DPBc<br />
<br />
==BATC TS (transport stream) merger system==<br />
<br />
Once HamTV is active from ISS, BATC will be running the TS merger system. This is a server which combines the UDP outputs from several ground stations and enables continuous video stream from the ISS to be presented to a web page.<br />
<br />
It typically gives 25 mins of continuous video over Europe and we will be looking for ground stations to join the network.<br />
<br />
[[File:TSmerger.png|600px]]</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=EMFcamp_2024&diff=10634EMFcamp 20242024-02-08T11:14:18Z<p>M0DNY: </p>
<hr />
<div><br />
'''AMSAT-UK''' represents the amateur satellite community in the UK whose members not only operate amateur satellites but also help to design, build and fund them. <br />
'''BATC''' The British Amateur Television Club (BATC) actively promotes the hobby of Amateur Television and covers all aspects of Television from making and editing programmes to transmitting television on the amateur radio bands. During EMF Camp, presentations will be given on the subjects, in addition to making video contacts via the QO-100 geostationary satellite.<br />
operations.<br />
'''UKuG''' The UK Microwave Group is the body who represent Amateur activities and developments in the high UHF and microwave parts of the radio spectrum.<br />
<br />
There is a wide cross-over in the activities and interests of these three groups. And regularly work together to further the many projects and issues that affect Amateur Radio in the UK.<br />
At EMF-2024 these three organisations will be demonstrating various aspects of the hobby. Including low earth orbiting and geostationary satellite communications and possibly deep space reception. Microwave contest operation. Digital television via terrestrial links and via the QO100 transponder, aboard a geostationary satellite. And a random selection of other interests, which members would like to showcase.<br />
<br />
'''GB4EMF''' We will be APPLYING for this Amateur Radio Special Event callsign during EMF for all contacts.<br />
'''G0AUK''' The AMSAT-UK (Club) callsign will also be in use.<br />
<br />
=== Inhabitants ===<br />
<br />
If you want your name added to the list but don't want to edit the wiki, give Dave a shout. On-site coordination: 144.750MHz, 432.750MHz, bring an H/T!<br />
<br />
{| class="wikitable" <br />
|- style="font-weight:bold;"<br />
! Name<br />
! Callsign<br />
! Ticket<br />
! Arrival<br />
! Departure<br />
! Bringing<br />
|-<br />
| Dave Johnson<br />
| G4DPZ<br />
| <br />
| Friday<br />
| Sunday<br />
| GB4EMF callsign (we can use G0AUK too), QO-100 Khune GS & 90cm Dish, complete LEO GS, LoRa TinyGS, 433/868 Lora GS for HAPS, Starlink and Switch, large mains extension<br />
|-<br />
| Phil Crump + 1<br />
| M0DNY<br />
| yes<br />
| <br />
| <br />
| QO-100 DATV Uplink Chain (BATC Streaming PC, Modulator, PA) + Downlink Chain (PC, Minitiouner). Long network cabling. Possibly HamTV RX.<br />
|-<br />
| Jason Flynn + ?<br />
| G7OCD<br />
|<br />
| <br />
| <br />
| 2.4m dish, mount & feed. Tools for dish. <br />
|-<br />
| Jules Smith<br />
| G0NZO<br />
| yes<br />
| Thursday<br />
| Monday<br />
| Mains cabling (16A 5-way dist + misc), mech toolbox, soldering iron, POTS phones and fax. Long ETH cable. 1200bd packet system. Portsdown with PAs for 146&432MHz. Possibly contest stations for 23&13cm. Small pole mast and antennas.<br />
Fridge, gas stove, kettle, water carrier (~10L), washing up bowl, microwave oven, <br />
|-<br />
| Iain Young<br />
| G7III<br />
| yes<br />
| <br />
| <br />
| <br />
|-<br />
| John Cariss<br />
| G7ACD<br />
| <br />
| <br />
| <br />
| Event shelter. 2.4m prime dish. Camp kitchen(stand).<br />
|-<br />
| Dave Akerman<br />
| M0RPI<br />
| <br />
| Thursday<br />
| Monday<br />
| Probably will be in my campervan in which case I'll have a fridge that can be used. Will also bring a portable fridge. Can also bring gas stoves (3) + gas. I'll also bring long CAT6 leads, 16A --> 4-way lead.<br />
|-<br />
| Paul Marsh<br />
| M0EYT<br />
|<br />
| <br />
| <br />
| 2.4GHz DATV<br />
|-<br />
| Prospectively ? others<br />
|<br />
|<br />
|<br />
|<br />
|}<br />
<br />
'''NB: label your stuff folks!'''<br />
<br />
== Village Setup ==<br />
<br />
* 6x6m Marquee with flooring, tables (x?), chairs (x?) for stations, workshops, demonstrations. Includes interior lighting and power strip. [Rented from EMF]<br />
<br />
* 4.5x4.5m Event shelter for mess use [G7ACD], camp kitchen, kettles, fridges, lighting as above.<br />
<br />
* 2.4m dish on trailer (trailer to stay on site). Use unassigned. QO100 NB ? [G7ACD]<br />
<br />
* 2.4m Dish for QO-100 WB DATV uplink [G7OCD, via small cargo trailer]<br />
<br />
* LEO GS (G4DPZ)<br />
<br />
* QO-100 COTS GS (G4DPZ)<br />
<br />
* Starlink and network<br />
<br />
== Village Happenings ==<br />
<br />
'''TBD:''' as we sort out a plan around the main EMF schedule! Will include some talks on what AMSAT do and how, live TV transmissions via QO-100 geostationary satellite...<br />
<br />
== QO-100 satellite dish bearing ==<br />
<br />
[[File:amsat-village-qo-100-heading.png]]<br />
<br />
OfCOM Compliance<br />
<br />
Satellite Uplink (70cm) 2022 figures<br />
<br />
[[https://wiki.emfcamp.org/wiki/File:AMSAT-UK-70cm-emf.pdf]] <br />
<br />
Satellite Uplink (2m) 2022 figures<br />
<br />
[[https://wiki.emfcamp.org/wiki/File:Amsat-2m-emf.pdf]]<br />
<br />
Satellite Uplink (13cm) - Below Ofcom limits for EMF assessment<br />
<br />
<br />
[[Category:Villages]]</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=ARISS_Digital_Communication_System&diff=10583ARISS Digital Communication System2023-10-31T13:06:56Z<p>M0DNY: sp.</p>
<hr />
<div>A team from the BATC and AMSAT-UK are developing a next-generation "Digital Communication System" for the ARISS suite of equipment on the ISS. Experience gained from the technologies involved will inform the choice of technologies for future Amateur payloads on Lunar missions.<br />
<br />
The project is being run in a number of phases:<br />
* Phase 0 was simple demonstration to the ARISS International Meeting in Noordwijk NL on 18 - 20 April 2023. Full details are available in CQ-TV 280 pp 10 - 12.<br />
* Phase 1 is the demonstration that our proposed hardware can achieve the spectral purity required for installation on the ISS. The target date for completion of this phase is 1 December 2023.<br />
* Phase 2 is the exhibition and demonstration of the proposed hardware modules at the ARISS 40th Anniversary Meeting in February 2024 in the USA.<br />
<br />
Subsequent phases will involve delivery of hardware designs and software builds to the ARISS US team for assembly into enclosures for certification for flight on the ISS. <br />
<br />
Documentation for the project will be published on pages linked from here.</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=File:Screenshot_2022-03-28_22-56-46.png&diff=9758File:Screenshot 2022-03-28 22-56-46.png2022-05-05T11:23:09Z<p>M0DNY: Phil Test Upload</p>
<hr />
<div>== Summary ==<br />
Phil Test Upload</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=BATC_Wiki&diff=9715BATC Wiki2022-04-14T16:02:18Z<p>M0DNY: </p>
<hr />
<div>'''Welcome to the British Amateur Television Club Wiki''' - the place to find information on all Amateur Television related equipment and projects. For details on how to join the BATC, the member's shop and CQ-TV archive and download visit the BATC website https://batc.org.uk/<br />
<br />
This is your site, developed by the BATC for use by the worldwide ATV community - any information which you feel is of use to others can be put on the Wiki but please observe any copyright restrictions on the material you use. <br />
<br />
* New to Amateur TV - Get the basics on our [[Getting Started|Getting Started page]]<br />
<br />
* For details on the Portsdown DATV transmit and receive system go to [[The Portsdown DATV transceiver system|the Portsdown pages]]<br />
<br />
* For information on the MiniTiouner USB DATV receiver go to [[MiniTioune|MiniTiouner]]<br />
<br />
* For the DATV equipment capability list go to [[DATV equipment capability|https://wiki.batc.org.uk/DATV_equipment_capability]]<br />
<br />
<br />
== Contents ==<br />
* [[Registering]] on the BATC wiki<br />
<br />
== New to Amateur TV? ==<br />
* Get the basics on our [[Getting Started|Getting Started page]]<br />
<br />
== BATC Information and services==<br />
* The [[BATC archive]] Collection of photos and documents from BATC's past<br />
* The [[new BATC website]]<br />
* [[Joining the BATC]]<br />
* [[Renewing your membership]]<br />
* The [[BATC Privacy statement and data protection policy]] <br />
* The original [[BATC.TV video streaming service]] - pre May 2018<br />
* The [[BATC video archive]]<br />
* The [[BATC forum]]<br />
* The [[BATC shop]]<br />
<br />
== BATC projects ==<br />
* [[The Portsdown Transmitter]] - the BATC's Raspberry Pi-based DATV Transmitter<br />
* [[MiniTioune]] - the DATV DVB-S / S2 receiver project<br />
* [[Ryde Receiver]] - Dedicated DATV set top box project<br />
* [[Knucker]] - Variable bandwidth DVB-T project<br />
* [[Advanced receiver hardware]] - Details of the BATC advanced receiver hardware.<br />
* [[WinterHill Receiver Project]] - Multi-channel DVB-S / S2 project<br />
* [[BATC Video Source]] - The Raspberry Pi-based composite video source described in CQ-TV 270<br />
* [[Digilite]] - The original home build DATV construction project<br />
* [[Repeater Controller]] - The BATC ATV Repeater Controller using a Raspberry Pi 4<br />
<br />
== CQ-TV Magazine ==<br />
* [[Index of articles]]<br />
* [[Archive edition|Archive editions]] download<br />
* [[BATC_Software_Library]] for project downloads<br />
<br />
==BATC Event Streaming Equipment==<br />
* [[Equipment Description]]<br />
<br />
== BATC Conventions ==<br />
* [[CAT 21]] Presentations from CAT 21 which was conducted as a Zoom Meeting.<br />
* [[CAT 20]] Presentations from CAT 20 which was conducted as a Zoom Webinar.<br />
* [[CAT 19 South|CAT 19 South (Didcot)]] Presentations from the 2019 regional convention at Didcot.<br />
* [[CAT 19 Finningley]] Presentations from the 2019 regional convention at Finningley.<br />
* [[CAT 19 Bristol]] Presentations from the 2019 regional convention at Bristol.<br />
* [[CAT 18|CAT 18 Coventry]] Presentations and links to the videos from the 2018 convention.<br />
* [[CAT 17|CAT 17 Finningley|]] Antenna test range results, presentations and links to the videos from the 2017 convention.<br />
* [[Presentations from CAT 16|CAT 16 Cosford]] Presentations and links to the videos from the 2016 convention.<br />
* Video Recordings from previous ATV Conventions can be found on the [https://www.youtube.com/channel/UCUWLnUZllytlcCFd93tnBzw BATC YouTube Channel].<br />
<br />
==International Events==<br />
<br />
* [[ HAM RADIO 2018 ]] ATV Presentations from HAM RADIO 2018 at Friedrichsafen.<br />
<br />
* [[ HAM RADIO 2019 ]] ATV Presentations from HAM RADIO 2019 at Friedrichsafen.<br />
<br />
== Getting on the air with ATV ==<br />
===The ATV bands===<br />
* [[71 MHz]]<br />
* [[146 MHz RB-TV]]<br />
* [[70cms Analogue TV]]<br />
* [[70cm DATV]]<br />
* [[23cms ATV]]<br />
* [[13cms]]<br />
* [[3.4 GHz DATV]]<br />
* [[5.6 GHz]]<br />
* [[10 GHz]]<br />
* [[:Media:ATV on 5.6 10 and 24 Ghz.pdf|April 2018 Presentation to MMRT about ATV on 5.6 10 and 24 GHz]]<br />
<br />
===The different ATV modes===<br />
* [[Reduced bandwidth TV]] (RB-TV)<br />
* [[The Effect of FEC]]<br />
<br />
===Equipment Options===<br />
* [[DATV transmitting Equipment]]<br />
<br />
==Advanced encoding / input options==<br />
<br />
Details of advanced transmission configurations, primarily for H265,and video production software.<br />
<br />
* [[Feeding Video to Portsdown from vMix|Vmix output in to Portsdown IPTS input]]<br />
* [[OBS - Open Broadcast Studio|OBS output in to Portsdown IPTS input]]<br />
* [[Using GTX10xx Graphics card encoder with OBS]]<br />
* [[Custom_DATV_Firmware_for_the_Pluto|Using the Pluto for DATV]]<br />
* [[Jetson_Nano|Using the Jetson Nano with Portsdown]]<br />
<br />
== Operating ==<br />
* [[DATV equipment capability]] - Wiki page documenting the capabilities of common DATV transmit and receive equipment.<br />
* [[ATV standards]] - a list of standards used by ATV operators including FM bandwidths, DATV PIDs, symbol rates and FEC<br />
* [[EMF Compliance]] - information about EMF compliance for ATV and Microwave Operation<br />
* [[Directory of portable sites]] suitable for ATV and microwave operation<br />
* [https://www.google.com/maps/d/u/0/edit?mid=1VeLnRRbLwloDTL2i9-HE2sxqL0c&ll=52.95536632179757%2C-0.49709419999999227&z=7 Google map] showing possible portable operating sites<br />
* [[Mapping tools]] including finding the QRA locator of a site, UK postcode to Lat and Long conversion and a topographic overlay for Google maps<br />
* [[Propagation tools]]<br />
* [[UK ATV DX Records]] - a list of Known DX Records for the UK<br />
* [[2022 Activity Weekends]]<br />
* [[Christmas 2021 BATC Repeater Activity Contest and Activity Challenge]]<br />
* [[2021 5.6GHz Activity Ladder]]<br />
* [[IARU ATV contest]] - How to enter the annual international TV contest<br />
* [[IARU ATV contest 2021 International Results]] - International Results for the June 2021 IARU Contest<br />
* [[IARU ATV contest 2020 International Results]] - International Results for the June 2020 IARU Contest<br />
* [[IARU ATV contest 2019 International Results]] - International Results for the June 2019 IARU Contest<br />
* [[IARU ATV contest 2018 Results]] - UK Results for the June 2018 IARU and BATC Contests<br />
* [[IARU ATV contest 2018 International Results]] - International Results for the June 2018 IARU Contest<br />
* [[September 2019 BATC Low Band Contest]]<br />
<br />
==ATV repeaters==<br />
* [[UK ATV repeaters]]<br />
* [[USA ATV repeaters]]<br />
* [[Australian TV repeaters]]<br />
<br />
* [[Technical topics for ATV repeater builders]]<br />
<br />
==Es'hail-2==<br />
* [[Es'hail-2 Basic Information|Getting started, LNBs and aligning a dish]]<br />
<br />
* [[Es'hail-2 Ground Station|Es'hail-2 BATC WebSDR & DATV Spectrum Monitor]]<br />
<br />
* [[Es'hail-2 DATV Bandplan]]<br />
<br />
* [[Es'hail-2_LNBs_and_Antennaes|Es'hail-2_LNBs]]<br />
<br />
* [[Transmitting_Oscar_100_DATV_signals|Es'hail-2 Transmitters]]<br />
<br />
* [[Es'hail-2 Antennaes]]<br />
<br />
* [[Es'hail-2 conference transmissions]]<br />
<br />
<br />
==ATV projects==<br />
* [[The MacGuffin Project]] - Collection of tools used to create an automated multi-band ATV system <br />
* [[Receiver upconverters]] - Details of upconverters to receive 146 and 437 MHz on STB and MiniTioune<br />
* [[Jetson Nano]] - Third generation computer-based DATV Transmitter<br />
* [[DTX1 TS]] - interface board to take in TS streams to the DTX1<br />
* [[RpiDATV]] - software for the Rpi<br />
* [[RBTVMOD]] - variable rate RB-TV mdulator for the Rpi<br />
* [[DATVExpress]] - SDR hardware based DATV transmitter covering 70 - 2450 MHz<br />
* [[PE4302]] - PE4302 variable attenuator project<br />
* [[ADF435x PIC]] - PIC controllers for Chinese ADF4350/4351 boards<br />
* [[DigiTwist]] - an experimental 2 axis satellite tracker<br />
* [[G4WIM PA controller]] - an advanced PA controller design by G4WIM published in CQ-TV 265<br />
* [[WinterHill Receiver Project]]<br />
<br />
== Deutschsprachiges Wiki ==<br />
<br />
* Portsdown DATV Projekt - Deutschsprachiges Wiki<br />
* Minitioune(r) - Deutschsprachiges Wiki<br />
<br />
== Useful Circuits and notes ==<br />
* [[Antenna changeover relays]] - Notes on suitable antenna change over relays for ATV use.<br />
* [[Filters]] - Collection of links and designs for that most critical but over looked component!<br />
* [[Pre-amps]] - Notes, suppliers and circuits of pre-amplifiers suitable for ATV<br />
* [[Power amplifiers]] - Notes, suppliers and circuits of power amplifiers suitable for ATV<br />
* [[Video circuits]] - Notes and circuits for video processing<br />
* [[Satellite receiver tuning offsets]] - Note on how to set up a satellite receiver to directly receive L band signals.<br />
* [[Using ex-satellite dishes]] - Notes on how to find the feed point of a dish and designs for feeds to use<br />
<br />
== ATV Equipment manuals and schematics ==<br />
* [[Bob Platts G8OZP]] Circuits and documentation for the Bob Platts range of equipment<br />
* [[Comtech module]] - 23cms and 13cms ATV Tx and Rx circuits and guides<br />
* [[Solent ATV units]] - Tx and Rx circuits and information<br />
* [[Wood & Douglas FM TV equipment]] - Circuits, pcb layouts and information<br />
* [[LMW Electronics]] - Circuits, pcb layouts and information<br />
* [[Fortop]] - Circuits, pcb layouts and information<br />
* [[Glencom]] - VC-510 VHF to L band up converter circuit diagram and modifications<br />
* [[Global communications]] - Hand drawn circuit of tuneable 70 / 140 MHz to L band block up converter<br />
* [[Jaybeam]] - Details of many Jaybeam aerials<br />
<br />
== Ex commercial broadcast equipment manuals ==<br />
* [[NDS System 3000]]<br />
* [[NDS Alteia rx]]<br />
<br />
== Test equipment manuals ==<br />
For HP and Agilent equipment see the [https://groups.yahoo.com/neo/groups/hp_agilent_equipment/info Yahoo group]<br />
<br />
== Other equipment information related to ATV ==</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=CAT_20&diff=7634CAT 202020-10-27T14:41:02Z<p>M0DNY: /* Afternoon */</p>
<hr />
<div>[[File:CAT20_Prog.JPG|543px]]<br />
<br />
===Videos===<br />
<br />
Videos of all the CAT 20 Presentations are on the BATC Youtube Channel here: https://www.youtube.com/playlist?list=PLhLAVxsCvzNBj4tMuiR9Yv_CuZ9rjG7sK<br />
<br />
==Presentations==<br />
<br />
===Morning===<br />
<br />
[[:Media:CAT20_Portsdown.pdf|Portsdown 4]] Dave, G8GKQ<br />
<br />
[[:Media:CAT20_Ryde.pdf|Introduction to the Ryde Receiver]] Tim, MW0RUD<br />
<br />
[[:Media:CAT20_GB3KM.pdf|GB3KM - An all-digital Repeater]] Rob, M0DTS<br />
<br />
[[:Media:Bursary.pdf|BATC bursary scheme]] Noel, G8GTZ<br />
<br />
===Afternoon===<br />
<br />
[[:Media:CAT20-ampleon.pdf|Ampleon Pallet Amplifiers on 2.4 GHz]] Michel, HB9DUG<br />
<br />
[[:Media:CAT20-Video_Production.pdf|Video Production for online streaming]] David, G4NRT<br />
<br />
[[:Media:CAT20_MCR21.pdf|MCR21 ex-BBC Outside Broadcast Unit]] Brian, G8GQS<br />
<br />
[[:Media:Multi-channel DATV Receiver.pdf|Multi-channel DATV Receiver]] Brian, G4EWJ<br />
<br />
[[:Media:CAT20 - BATC Streamer after Flash.pdf|BATC Streamer after Flash]] Phil, M0DNY</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=File:CAT20_-_BATC_Streamer_after_Flash.pdf&diff=7633File:CAT20 - BATC Streamer after Flash.pdf2020-10-27T14:40:16Z<p>M0DNY: </p>
<hr />
<div></div>M0DNYhttps://wiki.batc.org.uk/index.php?title=Es%27hail-2_DATV_Bandplan&diff=7027Es'hail-2 DATV Bandplan2020-04-01T20:55:49Z<p>M0DNY: Add redirect.</p>
<hr />
<div>#REDIRECT [[QO-100 WB Bandplan]]<br />
<br />
This bandplan has now been replaced with the [[QO-100 WB Bandplan]]<br />
<br />
<br />
===Old Bandplan - NOT VALID===<br />
<br />
The Es'hail-2 Digital ATV operating guidelines and bandplan can be found here: [[:Media:Eshail2 DATV Bandplan V1c.pdf|Es'hail-2 DATV Bandplan Version 1c]].<br />
<br />
The bandplan can also be represented graphically:<br />
<br />
[[File:Bandplan Graphic4.JPG|808px]]<br />
<br />
Here is a simple list of channels:<br />
<br />
{| class="wikitable"<br />
|-<br />
! Designator !! Uplink Freq MHz !! Downlink Freq MHz !! IF Freq MHz<br />
|-<br />
| 2MS1||2403.000||10492.500||742.500<br />
|-<br />
| 2MS2||2406.000||10495.500||745.500<br />
|-<br />
| 1MS1||2402.250||10491.750||741.750<br />
|-<br />
| 1MS2||2403.750||10493.250||743.250<br />
|-<br />
| 1MS3||2405.250||10494.750||744.750<br />
|-<br />
| 1MS4||2406.750||10496.250||746.250<br />
|-<br />
| 333KS1||2407.750||10497.250||747.250<br />
|-<br />
| 333KS2||2408.250||10497.750||747.750<br />
|-<br />
| 333KS3||2408.750||10498.250||748.250<br />
|-<br />
| 333KS4||2409.250||10498.750||748.750<br />
|-<br />
| 125KS1||2407.625||10497.125||747.125<br />
|-<br />
| 125KS2||2407.875||10497.375||747.375<br />
|-<br />
| 125KS3||2408.125||10497.625||747.625<br />
|-<br />
| 125KS4||2408.375||10497.875||747.875<br />
|-<br />
| 125KS5||2408.625||10498.125||748.125<br />
|-<br />
| 125KS6||2408.875||10498.375||748.375<br />
|-<br />
| 125KS7||2409.125||10498.625||748.625<br />
|-<br />
| 125KS8||2409.375||10498.875||748.875<br />
|-<br />
| <br />
|}<br />
<br />
You can print this list as a .pdf:[[:media:Bandplan Channels.pdf|Printed Channel Sheet]]<br />
<br />
Or enter your own local oscillator frequency into this spreadsheet and print a customised copy. [[:File:Bandplan Channels Calculator.xls]]</div>M0DNYhttps://wiki.batc.org.uk/index.php?title=QO-100_WB_Bandplan&diff=7026QO-100 WB Bandplan2020-04-01T20:53:26Z<p>M0DNY: </p>
<hr />
<div>The QO-100 Wideband Transponder Digital ATV operating guidelines and bandplan were revised in March 2020 and can be found here: [[:Media:QO-100 WB Bandplan V2.0.pdf|QO-100 Bandplan V2.0]].<br />
<br />
The bandplan can also be represented graphically:<br />
<br />
[[File:V2.0 Graphic Final 2.JPG|800px]]<br />
<br />
===Recommended Frequencies===<br />
<br />
Narrow DATV transmissions should be confined to the “Narrow DATV” section, but may use the “Wide and Narrow DATV” section if the Narrow DATV section is fully occupied.<br />
<br />
The recommended Narrow DATV frequencies in the new bandplan are all now at 250 kHz spacing, with alternate channels (*.250 and *.750) designated for 333 kS and 250 kS. <br />
<br />
[[File:Bandplan V2.0 Table.JPG|552px]]<br />
<br />
===Power Levels===<br />
<br />
During March 2020, the beacon bandwidth was reduced to leave more bandwidth for users on the transponder. However, to maintain the data rate, the FEC was increased from 2/3 to 4/5. This meant that to leave the same signal margin for signal decoding, the beacon power density had to be increased by just over 1 dB.<br />
<br />
What this means is that user signal power densities (for QPSK) should now be limited to 1 dB lower than the beacon. This can clearly be seen on the spectrum monitor, and the overpower indication trigger limit has been adjusted. For signals of 333 kS and below (only), it is acceptable to exceed this marging if 8PSK, 16 APSK or 32 APSK modes are being used.</div>M0DNY