Receiving SSTV images from ISS

Several times per year, the International Space Station transmits pictures using SSTV (Slow Scan Television) on 145.800 MHZ. It can be fun to receive them, and (if desired) upload your pictures to the online portal, for a nice confirmation certificate. https://www.spaceflightsoftware.com/ARISS_SSTV/

Receiving these pictures is its own art. Many online guides already exist for how to tell when these pictures are sent out, and how to receive them. But, having done this a few times, here is what I have learned and what my suggestions are for starting out.

  • You’ll want to set up everything and leave it alone while passes occur. I usually set things up a day or two in advance – and sometimes ISS starts transmitting earlier than they publish, and you might get some bonus passes.
  • If at all possible, use a direct connection to the radio, using the radios onboard sound card, or an external device like a Signalink. Less noise in the channel = better picture. SSTV programs exist for every OS platform – MSSTV for Windows, QSSTV for Linux. Even Android and IOS have receiving apps that can work. (consider a cable like this to directly connect to your phone to a radio)
  • It can help to have more than one radio receiving the signals – often two antennas even 20 feet apart can have different results. I also use different software on the two – sometimes one SSTV application gets confused, while the other one does not.
  • Make sure if your radio has multiple FM settings, to be using the wide FM setting, not NFM. At 145.800, many normal 2M/440 radios could be used, as well as many HF/VHF/UHF rigs.
  • The common wisdom is to avoid high-gain antennas, because they have more gain towards the horizon and less sensitivity overhead – but, I have found that high gain antennas can work well. For one thing, if ISS is overhead it’s only 300 miles away, where it can be 1500 miles away for low passes. Also, there tend to be more passes closer to the horizon than directly overhead anyway (and overhead passes still spend most of their time either climbing or descending – both benefiting from the higher gain. ) I have seen perfect reception passes at 20 degrees above the horizon. You probably are best off with a medium gain antenna that has some gain, but doesn’t overdo it.
  • Be prepared to get few “good” images – most passes will have some noise interference or may get cut off by the orbit of ISS either entering or leaving your sky.
  • Operating system updates are the BANE of the SSTV receiver’s existence. Many times I’ve had everything set up for receiving pictures, only to find that windows updates installed, and all of the SSTV passes after the installation were missed. It’s best to set your system to prompt for updates, and/or make sure all updates are installed before the passes.
  • Testing, testing, testing. I like to transmit a SSTV signal on lowest possible power on 145.800 when ISS is not overhead, just to make sure all of my receivers are working. Most times, if my test works, so will ISS. Accidentally leaving on a tone squelch or something, will prevent the receive from working.

If money is no object, there is also always the option of a sky-tracking rotator like the Yaesu G-5500DC.

Receiving SSTV images from ISS is a fun aspect of the hobby to do once in a while. You can see my past archive of images (and hopefully, improving skills over time) at my ISS SSTV google album.

Hope you have fun and stay safe.

-Tim KC0LQL

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