Pictures from Space (by alaric)
So the International Space Station (ISS) contains some equipment that's part of a project called ARISS, or Amateur Radio on the ISS.
One of the ARISS projects is occasional transmissions of images via SSTV, or Slow-scan television - basically colour faxes sent via radio.
Anyway, a few days ago, I saw that there was an SSTV transmission scheduled, and the ISS would be passing over England at times I would be able to try and pick it up, so I gave it a go... My setup was simple:
To receive the signal, I used a Kenwood TH-D72 handheld transceiver with its supplied little rubber antenna (although I'm sure a cheaper Baofeng transceiver would have done just fine, I wasn't sure how good a signal I'd get and didn't want to take any chances, so went for the fancier radio).
To decode the picture, I installed an Android app called Robot36.
Lacking a cable to feed the audio from the radio direct to the microphone socket on my phone, I was forced to just hold the phone next to the radio's speaker, so I didn't have high hopes!
At the appointed time, I went into the garden and listened on 144.8MHz with the radio... and got nothing but noise. I tried again at the next pass later in the day, and also got nothing, when a friend I was lamenting with pointed out that I'd gotten completely incorrect timings for the passes. I quickly installed gpredict on my computer and worked out there would be a pass at just after 7pm that evening, so I headed out again.
This time, I heard the sound of SSTV rising rapidly out of the noise as soon as the station cleared the horizon. I hit the start button on the SSTV decoder and the following partial image emerged:
You can see how the image quality improves as you go down the image, as the ISS rose above the horizon and the signal got stronger!
There was then a short pause, before I received the next image, now with only clear sky between me and the ISS. The signal was great, even with my little antenna, so the picture came out well:
The line of noise across the middle was a gust of wind, and there was a bit of traffic noise in the background throughout!
Then after a pause, I caught another one, but the ISS was starting to drop below the other horizon by now, so the image decayed towards the bottom:
Well, now I have some pictures of smiling cosmonauts in my collection!
This is hardly useful, although it was definitely cool to be receiving a picture direct from the ISS. However, with similar setups you can receive photos from weather satellite cameras, which might be handy. I should definitely get the right cable to connect my smartphone to the radio without using speaker and microphone and the air, and give it another try sometime!
Fri 2nd Oct 2020 3:19 pm 
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