Difference between revisions of "HAMTV from the ISS"

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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 schools contacts in 2016 - 2018. The unit failed in 2019 and was shipped back to Kaiser Italia for repair.  
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[[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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[[File:HAMTV 1.jpg|400px|]]
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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.
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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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== Purpose ==
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Following repairs carried out last year it now looks likely that the original HAMTV unit will be returned to the ISS with potential commissioning by a visiting astronaut during Spring 2024.
 
  
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==What is HamTV==
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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.
  
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HAMTV is the name of the Digital Amateur Television (DATV) transmitter on board the Columbus module of the International Space Station (ISS).
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[[File:HAMTV 2.jpg|400px]]
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[[File:HamVideo1.jpg|400px]]
 
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It transmits Digital video and audio in MPEG-2 format using the DVB-S protocol in the 13cms band.
 
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===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 and 2.0 Ms/s
 
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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.  Estimated power at the antenna is ~ 2 watts.
 
  
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====HAMTV antenna====
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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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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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== Transmission Details ==
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This patch antenna is located on the earth side of the ISS but is surrounded by solar panels, thermal radiator panels, two or more visiting vehicles and robotic arms. 
 
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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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*NTSC
 
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*SIF resolution: 352×240 or D1:720×480
 
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==What is HAMTV used for?==
 
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The primary use is during ARISS schools contacts, when the astronaut will use a camera to show himself and the inside of the ISS during the VHF radio contact.
 
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[[File:HAMTV 2.jpg|400px]]
 
  
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It is hoped that test patterns, including JPEG images, will be transmitted when the cameras are not in use.
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Whilst the transmitter has a number of possible configurations, it is anticipated that most transmissions will be:
  
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==When will HAMTV be "on the air"?==
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* 2395 MHz, RHCP, 2W power at the patch antenna pointing down from the ISS.
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* Modulation: 2.0 Msymbols/second, DVB-S (QPSK), FEC 1/2
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* Content: MPEG-2 video with MP2 audio.
  
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It is unlikely that the HamTV transmitter will be on air 24/7. 
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'''More details can be found at: [[HAMTV from the ISS - HAMTV Transmitter Information]]'''
  
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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 groud stations to test their receive equipment and it is hoped a test signal generator will be included when it is re commissioned in 2024.
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== How can I watch HAMTV? (without a ground station) ==
  
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Once re-commissioned it will be tested before contacts and will be added to the Amsat status page https://www.amsat.org/status/
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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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==How to receive HAMTV?==
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'''ARISS / BATC HAMTV Ground Station Network: https://live.ariss.org/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 following elements
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== How can I build my own ground station to receive HAMTV? ==
  
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A typical groundstation system block diagram
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Building a ground station to receive HAMTV from the ISS is challenging.
  
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===Ground station antenna===
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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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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 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.
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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.
  
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[[File:dish.jpg|400px]]
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=== Components of a typical ground station ===
  
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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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* Antenna - Typically a dish of 0.6-1.2 meters in diameter, with a helix or patch feed.
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* Pointing Mechanism - to follow the ISS across the sky. Can be motorised, or manual for smaller antennas.
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* LNA - Required, and mounted as close as possible to the antenna feed to minimise coax loss at microwave frequencies.
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* Filter - May be required to prevent overload if you have strong WiFi (2400MHz+) or 5G (2380MHz-) nearby.
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* Downconverter - Optional, allows use of non-microwave capable receivers, also reduces loss in long coax runs.
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* 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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A 1mt 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.
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'''For more information read: [[HAMTV from the ISS - How to build a ground station]]'''
  
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===Pre-amp and filter===
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== Can I help support HAMTV downlinks for ARISS Educational Contacts? ==
  
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A low noise pre-amp with band pass filter tuned to 2395MHz should be connected directly to the antenna feed point to minimise co-ax losses.
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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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Note that 2395MHz is only 5MHz below the 2.4GHz WiFi Channel 1, so good filtering will be needed to prevent WiFi from getting into the wide band satellite tuner.
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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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If you are powering the LNA at masthead up the co-ax, you will need to place the DC inseerter AFTER the filter.
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'''[[HAMTV from the ISS - How to contribute to the ARISS Merger]]'''
  
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===Do I need a downconverter===
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=Social media=
  
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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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ARISS international on Twitter/X: https://twitter.com/ARISS_Intl
  
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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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ARISS International on Bluesky: https://bsky.app/profile/arissintl.bsky.social
  
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Note: The MiniTiouner Mk1 PCB with a Sharp or Eardertek tuner does NOT cover 2395MHz and will require a downconverter.
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Join and ask questions in the ARISS Discord: https://discord.gg/dQUEE48C
  
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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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==BATC forum==
  
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Previous suppliers of a suitable down converter, such as Kuhne Electronics, no longer market suitable downconverters and BATC '''strongly recommends''' purchasing a new USB tuner hardware using the Serit 4334 tuner rather than building or sourcing a down converter - see next section on HamTV receivers.
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BATC have setup a new forum thread to discuss receiving HamTV.
  
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===Digital receivers for HAMTV===
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Please post any questions, comments and status updates here: https://forum.batc.org.uk/viewtopic.php?f=2&t=8398
  
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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 lot of information is available on the BATC forum: https://forum.batc.org.uk/viewtopic.php?t=4389
  
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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.
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== Relevant Presentations and Video ==
  
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===Receivers designed for DATV===
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Colin G4KLB on how he received HamTV in 2014: [https://www.youtube.com/watch?v=9keVA21DPBc YouTube]
  
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=====Hardware=====
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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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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.
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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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The hardware is connected to either a PC or Raspberry Pi 4 using the USB 2 connection.
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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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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.
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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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=====Software=====
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==Comments on this wiki page==
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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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During the last 8 years many developments have taken
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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

Latest revision as of 14:31, 11 October 2025

HAMTV 1.jpg

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.

HAMTV 2.jpg

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

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

Retrieved from ‘https://wiki.batc.org.uk/index.php?title=HAMTV_from_the_ISS&oldid=11971’