./backlog: Charlie's blog

meanderings through tidbits of mathsy computery stuff

A Christmas Present from the International Space Station

This year, the Russian cosmonauts aboard the International Space Station are transmitting Slow-Scan TV (SSTV) images to Earth via Amateur radio.

The images are Russian (from one of the Russian cosmonauts currently on board the ISS) - and apparently (according to a Russian friend of a friend) the images are to do with celebrating Yuri Gagarin's 80th birthday. There are 12 in total being transmitted - the image I captured happens to be the 12th!

So, how did I get into doing this? I have dabbled in amateur radio for a while, and I heard about the SSTV images from the ISS. I set out one evening while the ISS was passing over to see if I could pick up any signal on my handheld radio. It was quite an eerie experience - if you haven't heard SSTV transmissions before, they're kind of an unearthly whistle/screeching noise. Couple this with the isolation (I was standing in a field), the cold evening, and the fact that it was pitch black and deserted outside, and you have the ingredients for a pretty surreal experience.

I was lucky enough to capture the most part of an image that evening, and here's the (partial - poor quality) image I managed to get. It doesn't look like much - but that picture came from space! I'm still a little starstruck (no pun intended) and today will go down in my memory as one of the highlights of

  1. ISS SSTV image

Want to receive your own? Read on.

Receiving SSTV from the ISS

Well, all you need is a £10 DVB stick (RTL2832U chipset), a little bit of open-source software (GQRX and QSSTV), and a lot of luck.

In GQRX, set your monitoring frequency to 145.800MHz (the downlink frequency for the ISS and a few other radio satellites). Make sure you adjust the squelch value properly - you don't want an SSTV transmission that's full of static! The SSTV image encoding from the ISS is PD180 (this is important if you only receive a partial image).

Then it's just a question of waiting for the ISS to fly overhead and recording when you can!

Good luck.