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| − | [[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. | + | __NOTOC__ |
| | + | [[File:HAMTV 1.jpg|400px|right]] HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It is a DVB-S digital audio and video transmitter, normally on 2395MHz (13cm band). |
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| − | The original HamTV unit was installed on the ISS in 2013 and commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018. | + | The HamTV unit was first installed on the ISS in 2013, commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018. |
| | + | The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. It was finally installed and first powered on again on 29th July 2025. |
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| − | 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.
| + | == Purpose == |
| | | | |
| − | | + | The primary use of HAMTV 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. |
| − | ==HAMTV specifications==
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| − | ====Ham Video downlink frequencies====
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| − | *2395 MHz (main operating frequency)
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| − | *2369 MHz
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| − | *2422 MHz
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| − | *2437 MHz
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| − | ====DVB-S modulation====
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| − | *Symbol rates: 1.3 Ms/s or 2.0 Ms/s (2.0 Ms/s is normally used)
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| − | *FEC : ½
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| − | ====RF output====
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| − | 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. | |
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| − | Estimated power at the antenna is ~ 2 watts.
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| − | ====HAMTV antenna====
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| − | The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.
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| − | [[File:HamTV patch.png|400px]]
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| − | 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.
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| − | 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.
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| − | The transmissions are right hand circular polarised (RHCP)
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| − | ====Video format====
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| − | * MPEG-2 Video, approx. 1 Mbits/s
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| − | * MP2 Audio, approx 360kb/s
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| − | * NTSC
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| − | * SIF resolution: 352×240 or D1:720×480, 29.97fps
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| − | * Note that non-square pixels are used, the 4:3 picture has to be stretched to 16:9 for correct visual aspect ratio.
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| − | ==What is HAMTV used for?==
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| − | 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.
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| | [[File:HAMTV 2.jpg|400px]] | | [[File:HAMTV 2.jpg|400px]] |
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| − | 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.
| + | Outside of school contacts the transmitter is often left switched on to enable experimentation and self-education in the building of ground stations. |
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| − | ==When will HAMTV be "on the air"?==
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| − | 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.
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| − | 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.
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| − | HamTV will be added to the AMSAT status page https://www.amsat.org/status/ - always check there before doing any receive tests.
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| − | =How to receive HAMTV?=
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| − | 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.
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| − | [[File:Hamtv diagram.jpg|800px|center]]
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| − | * The LNA / Downconverter should placed as close as possible to the dish feed and high quality microwave cable must be used.
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| − | * The upper blue-boxes option is the preferred solution for new builders.
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| − | * 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.
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| − | * 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
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| − | * The filters are essential, not nice to have!
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| − | * 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.
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| − | See the sections below for a full description of the elements in the diagram.
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| − |
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| − | ===Ground station antennas===
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| − | [[File:dish.jpg|400px]] [[File:M0DNY HamTV Antenna.jpg|225px]]
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| − | The HamTV transmission runs relatively low power on 2395MHz to a simple patch antenna on the ISS.
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| − | 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.
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| − | 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.
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| − | 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.
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| − | 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.
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| − | ===Rotator (mechanical tracking) ===
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| − | 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.
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| − | 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.
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| − | 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.
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| − | | |
| − | SPID rotators are a lot more capable and can track more precisely, however are significantly more expensive.
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| − | * 1m dish: 8 degrees beamwidth (+/-4 degrees)
| + | == Transmission Details == |
| − | * 1.8m dish: 4.5 degrees beamwidth (+/-2.2 degrees)
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| − | 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.
| + | Whilst the transmitter has a number of possible configurations, it is anticipated that most transmissions will be: |
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| − | ===Dish feeds===
| + | * 2395 MHz, RHCP, 2W power at the patch antenna pointing down from the ISS. |
| − | 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.
| + | * Modulation: 2.0 Msymbols/second, DVB-S (QPSK), FEC 1/2 |
| | + | * Content: MPEG-2 video with MP2 audio. |
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| − | A suitable helical design for deep dishes was described by G3RUH here https://www.amsat.org/amsat/articles/g3ruh/116.html
| + | '''More details can be found at: [[HAMTV from the ISS - HAMTV Transmitter Information]]''' |
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| − | 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.
| + | == How can I watch HAMTV? (without a ground station) == |
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| − | https://dc8pat.darc.de/rc3/referrers/qrz_dc8pat.html - helical antenna design is at the bottom of the page.
| + | A network of ARISS ground stations contribute to a central feed using the BATC Merger to enable high-quality reception for School Contacts. You can watch the video output whenever ground stations are receiving the signal. |
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| − | http://f5ad.free.fr/Liens_coupes_ANT/G/PA3FYM%20Helice%202300.htm
| + | '''ARISS / BATC HAMTV Ground Station Network: https://live.ariss.org/hamtv/''' |
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| − | 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!
| + | == How can I build my own ground station to receive HAMTV? == |
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| − | ===LNA and Pre-amp===
| + | Building a ground station to receive HAMTV from the ISS is challenging. |
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| − | 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.
| + | The link budget is a lot less forgiving of non-optimal stations than VHF/UHF, the high 'microwave' frequency brings lots of pitfalls, the equipment can be expensive and/or hard to source, and the limited visibility and fast movement of the space station across the sky can make it time-consuming and frustrating to troubleshoot any problems that occur. |
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| − | ===== Commercial LNA Options =====
| + | The result however is being able to receive live video from an Astronaut (during school contacts), with your own S-band ground station! You could also talk to ARISS Ops about joining the ground station network and using your antenna to contribute directly to School Contacts. |
| − | * 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]
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| − | * Lower cost (relative), good performance: [https://www.minicircuits.com/WebStore/dashboard.html?model=ZX60-242GLN-S%2B Minicircuits ZX60-242GLN-S+ - 0.9dB NF]
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| − | ===Band pass Filter=== | + | === Components of a typical ground station === |
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| − | 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
| + | * Antenna - Typically a dish of 0.6-1.2 meters in diameter, with a helix or patch feed. |
| | + | * Pointing Mechanism - to follow the ISS across the sky. Can be motorised, or manual for smaller antennas. |
| | + | * LNA - Required, and mounted as close as possible to the antenna feed to minimise coax loss at microwave frequencies. |
| | + | * Filter - May be required to prevent overload if you have strong WiFi (2400MHz+) or 5G (2380MHz-) nearby. |
| | + | * Downconverter - Optional, allows use of non-microwave capable receivers, also reduces loss in long coax runs. |
| | + | * Receiver - Needs to be capable of receiving 2.4MHz-wide DVB-S. A good receiver can be more tolerant of issues elsewhere in the ground station. |
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| − | [[File:HamTV wi-fi.jpg|600px]] | + | '''For more information read: [[HAMTV from the ISS - How to build a ground station]]''' |
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| − | 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.
| + | == Can I help support HAMTV downlinks for ARISS Educational Contacts? == |
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| − | 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.
| + | To assist our volunteer teams with providing a reliable HAMTV experience for the participants at Educational Contact events, a Ground Station Merger facility has been developed to crowd-source the HAMTV data in realtime from geographically diverse ground stations. |
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| − | Multi-pole interdigital filters work well for this, and should ideally be tuned to provide a low-pass roll-off above 2396MHz.
| + | Before getting involved you'll need to have a reliable station up and running, however there are also some requirements on the equipment involved that can be found at the link below. |
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| − | More information on transmit and receive filters can be found on this wiki page: [[Filters]]
| + | '''[[HAMTV from the ISS - How to contribute to the ARISS Merger]]''' |
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| − | Note - in some countries 2395MHz may be allocated to other services which may cause problems to receive HamTV transmissions.
| + | =Social media= |
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| − | ===Receive co-ax cable===
| + | ARISS international on Twitter/X: https://twitter.com/ARISS_Intl |
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| − | 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.
| + | ARISS International on Bluesky: https://bsky.app/profile/arissintl.bsky.social |
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| − | ===Receive Line amplifier===
| + | Join and ask questions in the ARISS Discord: https://discord.gg/dQUEE48C |
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| − | 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.
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| − | [[File:Inline sat amp-800x800.jpg|200px]]
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| − | 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
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| − | 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.
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| − | If you are powering the LNA at masthead up the co-ax, you will need to place the DC inserter AFTER the filter.
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| − | ===Do I need a downconverter?===
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| − | The HAMTV frequency on 2395MHz is outside the frequency range of a standard consumer set top box or satellite tuner.
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| − | 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.
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| − | 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.
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| − | 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.
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| − | 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.
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| − | ==Digital receivers for HAMTV==
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| − | 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.
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| − | 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.
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| − | ===Receivers designed for DATV===
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| − | 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.
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| − | 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.
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| − | ===USB Receiver hardware===
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| − | 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.
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| − | ====Mark 2 MiniTiouner PCB====
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| − | [[File:Serit complete.jpg|300px]]
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| − | This is the USB hardware which has been available for 7 years and will work well for HAMTV.
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| − | For full details of the USB tuner hardware, including parts list and construction details see this wiki page: [[MiniTiouner hardware Version 2]]
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| − | ====PicoTuner PCB====
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| − | [[File:Picotuner Mk1.png|300px]]
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| − | The PicoTuner is an enhanced version of the Mk2 MiniTiouner PCB launched in Spring 2024.
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| − | 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.
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| − | The PicoTuner will be released in April 2024 and it will become the recommended solution for new builders.
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| − | For more details see this wiki page [[PicoTuner]]
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| − | ====MiniTiouner Mk1 PCB====
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| − | [[File:IMAG0218.jpg|300px]]
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| − | 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.
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| − | 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.
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| − | ===Software for use with the USB receiver===
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| − | 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.
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| − | 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.
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| − | 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.
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| − | Note Open Tuner, Ryde and Portsdown receivers DO NOT support the Mk1 MiniTiouner hardware.
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| − | Any desktop PC since approx. 2014, or any mid+ laptop since approx 2017 should be capable of running the required software.
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| − | ===Ryde===
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| − | Raspberry Pi 4 based set-top box software with IR handset remote control designed specifically for receiving narrow band DATV signals.
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| − | [[File:Ryde_With_Menu_Small.jpg|300px]]
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| − | For more details see this wiki page:[[Ryde Receiver]]
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| − | ===Opentuner===
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| − | PC based software developed by Tom ZR6TG
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| − | [[File:OT1.png|300px]]
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| − | For more details see this wiki page: [[OpenTuner]]
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| − | ===Portsdown===
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| − | The BATC designed DATV transceiver system based on a Rpi 4 has a receiver which has been tested and decodes the HAMTV signal
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| − | [[File:Pdown rxr.jpg|300px]]
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| − | For more details see this wiki page [[The_Portsdown_DATV_transceiver_system#Portsdown_DATV_receiver]]
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| − | ===MiniTiouner===
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| − | 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.
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| − | [[File:20160507 Walbury GW8VPG.jpg|300px]]
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| − | ===PC software receivers===
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| − | 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.
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| − | For more details see https://www.sdrangel.org/
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| − | 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.
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| − | =Receiving the Signal=
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| − | 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.
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| − | 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.
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| − | [[File:Amsat status.png|500px]]
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| − | https://www.amsat.org/status/
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| − | =Testing your system=
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| − | As the ISS is only above your horizon for short periods, it will be difficult to see if your HAMTV receive system is working.
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| − | There are a number of tests you can do to ensure your system is optimised before HAMTV comes back on the air.
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| − | ===Measuring sun noise===
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| − | 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.
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| − | ====Portsdown DATV test system====
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| − | 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.
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| − | For more details see this wiki page [[Portsdown_Noise_Meter|https://wiki.batc.org.uk/Portsdown_Noise_Meter]]
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| − | [[File:Noise_Meter.png|400px]]
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| − | ====SDR continuum mode====
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| − | 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.
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| − | ====MiniTiouner Noise power measurement====
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| − | 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.
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| − | [[File:NPM.JPG|400px]]
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| − | ===Decoding a local signal===
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| − | | |
| − | 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.
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| − | | |
| − | You can use the Portsdown Pi4 based system with a Lime SDR to generate this signal.
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| − | | |
| − | 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/]
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| − | * 5Ms/s Complex Samples
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| − | * WAV (SDRsharp) format
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| − | * 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!
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| − | | |
| − | If these tests are successful you should be set to receive HamTV!
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| − | | |
| − | =Actually receiving HamTV=
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| − | 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!
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| − | | |
| − | 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.
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| − | | |
| − | =BATC TS (transport stream) merger system=
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| − | | |
| − | 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.
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| − | | |
| − | 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.
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| − | [[File:TSmerger.png|600px]]
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| − | Once you have your system up and running please post on the BATC forum asking for more details.
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| − | | |
| − | =Further information=
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| − | | |
| − | ==Social media==
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| − | Follow ARISS international on twitter for the latest updates
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| − | https://twitter.com/ARISS_Intl | |
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| | ==BATC forum== | | ==BATC forum== |
| Line 341: |
Line 70: |
| | Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398 | | Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398 |
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| − | A lot of information is available on the BATC forum: | + | A lot of information is available on the BATC forum: https://forum.batc.org.uk/viewtopic.php?t=4389 |
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| − | https://forum.batc.org.uk/viewtopic.php?t=4389 | |
| − | | |
| − | ==Youtube videos==
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| − | | |
| − | Colin G4KLB made a video on how he received HamTV in 2014
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| − | https://www.youtube.com/watch?v=9keVA21DPBc
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| − | Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016. | + | == Relevant Presentations and Video == |
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| − | https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN | + | Colin G4KLB on how he received HamTV in 2014: [https://www.youtube.com/watch?v=9keVA21DPBc YouTube] |
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| − | G8GTZ presentation on receiving HAMTV at the AMSAT UK conference in October 2023
| + | Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016: [https://youtu.be/DnJmxNCX4V4?si=RySuD0ft1Bcl1nTN YouTube] |
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| − | https://www.youtube.com/watch?v=4J_JA3Syv6Y | + | G8GTZ on receiving HAMTV at the AMSAT UK conference in October 2023: [https://www.youtube.com/watch?v=4J_JA3Syv6Y YouTube] |
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| − | Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023 | + | Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023: [https://www.youtube.com/watch?v=MQvRdG1FBo4 YouTube] |
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| − | https://www.youtube.com/watch?v=MQvRdG1FBo4 | + | HamTV Ground Stations presentation by Phil M0DNY in October 2024: [ YouTube (coming soon)] [https://wiki.batc.org.uk/images/c/cd/M0DNY_-_HAMTV_-_AMSAT-UK_2025.pdf Slides] |
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| | ==Comments on this wiki page== | | ==Comments on this wiki page== |
| | | | |
| | If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv | | If you have any comments on this wiki page or if you think we should add more information to it, please email them to wiki @ batc.tv |
HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS). It is a DVB-S digital audio and video transmitter, normally on 2395MHz (13cm band).
The HamTV unit was first installed on the ISS in 2013, commissioned in April 2014 and was used for a number of ARISS school contacts in 2016 - 2018.
The unit failed in 2019, and was brought back to earth for repair. It was returned to the ISS on the SpaceX SpX-30 flight on March 21st 2024. It was finally installed and first powered on again on 29th July 2025.
Purpose
The primary use of HAMTV 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.
Outside of school contacts the transmitter is often left switched on to enable experimentation and self-education in the building of ground stations.
Transmission Details
Whilst the transmitter has a number of possible configurations, it is anticipated that most transmissions will be:
- 2395 MHz, RHCP, 2W power at the patch antenna pointing down from the ISS.
- Modulation: 2.0 Msymbols/second, DVB-S (QPSK), FEC 1/2
- Content: MPEG-2 video with MP2 audio.
More details can be found at: HAMTV from the ISS - HAMTV Transmitter Information
How can I watch HAMTV? (without a ground station)
A network of ARISS ground stations contribute to a central feed using the BATC Merger to enable high-quality reception for School Contacts. You can watch the video output whenever ground stations are receiving the signal.
ARISS / BATC HAMTV Ground Station Network: https://live.ariss.org/hamtv/
How can I build my own ground station to receive HAMTV?
Building a ground station to receive HAMTV from the ISS is challenging.
The link budget is a lot less forgiving of non-optimal stations than VHF/UHF, the high 'microwave' frequency brings lots of pitfalls, the equipment can be expensive and/or hard to source, and the limited visibility and fast movement of the space station across the sky can make it time-consuming and frustrating to troubleshoot any problems that occur.
The result however is being able to receive live video from an Astronaut (during school contacts), with your own S-band ground station! You could also talk to ARISS Ops about joining the ground station network and using your antenna to contribute directly to School Contacts.
Components of a typical ground station
- Antenna - Typically a dish of 0.6-1.2 meters in diameter, with a helix or patch feed.
- Pointing Mechanism - to follow the ISS across the sky. Can be motorised, or manual for smaller antennas.
- LNA - Required, and mounted as close as possible to the antenna feed to minimise coax loss at microwave frequencies.
- Filter - May be required to prevent overload if you have strong WiFi (2400MHz+) or 5G (2380MHz-) nearby.
- Downconverter - Optional, allows use of non-microwave capable receivers, also reduces loss in long coax runs.
- Receiver - Needs to be capable of receiving 2.4MHz-wide DVB-S. A good receiver can be more tolerant of issues elsewhere in the ground station.
For more information read: HAMTV from the ISS - How to build a ground station
Can I help support HAMTV downlinks for ARISS Educational Contacts?
To assist our volunteer teams with providing a reliable HAMTV experience for the participants at Educational Contact events, a Ground Station Merger facility has been developed to crowd-source the HAMTV data in realtime from geographically diverse ground stations.
Before getting involved you'll need to have a reliable station up and running, however there are also some requirements on the equipment involved that can be found at the link below.
HAMTV from the ISS - How to contribute to the ARISS Merger
Social media
ARISS international on Twitter/X: https://twitter.com/ARISS_Intl
ARISS International on Bluesky: https://bsky.app/profile/arissintl.bsky.social
Join and ask questions in the ARISS Discord: https://discord.gg/dQUEE48C
BATC forum
BATC have setup a new forum thread to discuss receiving HamTV.
Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398
A lot of information is available on the BATC forum: https://forum.batc.org.uk/viewtopic.php?t=4389
Relevant Presentations and Video
Colin G4KLB on how he received HamTV in 2014: YouTube
Video of HamTV in action during the Tim Peake Principia mission contact with Norwich schools in 2016: YouTube
G8GTZ on receiving HAMTV at the AMSAT UK conference in October 2023: YouTube
Next generation HamTV presentation by Phil M0DNY at the AMSAT UK conference in October 2023: YouTube
HamTV Ground Stations presentation by Phil M0DNY in October 2024: [ YouTube (coming soon)] Slides
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
