We are receiving you - My experiences getting Slow Scan TV pictures from the International Space Station. (Part 2)
Part 2: The first attempt
Author’s note: This is written from the point of view of what I knew at the time of attempting to receive. It will become clear that some of the information I have here is wrong. Later on I will write a more in depth precise how to. Also please read Part 1 first, as this article will make more sense.
So here I was now very aware that the satellite would be spitting these pictures out every so often. Looking into it, two minutes of broadcast, and then two minutes of silence. But how do you know when the station passes you?
I first did some research. I found a list of frequencies for the ISS. UHF Packet Uplink and Downlink: 437.550 MHz? That sounds like SSTV would come from that.
But how do I know when the ISS can be reached? Is this available at all times? Do I just…. Go outside and point an antenna? A bit of searching brought me to Heavens Above. This is a site that will tell you when the ISS is in range to be received. What you need is your latitude and longitude, which can be gained from Google Maps (though that was a bit fiddly to do), and your elevation (allegedly also doable from google maps, but there are various apps on phone that will just tell you straight away). You can also use your gridsquare, which appears to just be an easy way to communicate a location over ham air waves.
Once you have this entered in (I advise just creating an account with them), you can see when the station is passing. Now the selection “visible” is a misnomer, even though to me “Line of sight” would say something needs to be visible. The first pass I only selected visible, because Heavens Above presumes you are going to be looking at the station, and you can’t really see it during the day, and sometimes not at night. Selecting all will give you a wider variety of passes, and try to select a pass 4 minutes or longer when you go out. (I didn’t know that anything but visible worked day one, but had figured it out by day 2!)
I had from Christmas, December 25th, to the 5th of January. I started on Christmas. I went out at night with my Radtel, that has the Nagoya 771 antenna attached. It’s a longer antenna than the standard rubber duck, which I had read that some people had luck receiving with. In my experiences, it is an improvement over the stock rubber duck antenna. I also read that keeping it simple for your first Sat pass is best, and to hold the radio broadside when receiving (kind of on it’s back), preferably aiming in the direction the space station is going to be. I had also heard that some people had heard the sstv on things as simple as a Baofeng and the stock “rubber duck” antenna, but we won’t be needing that, right? (Right??).
I didn’t get anything from that pass. Not a single beep, nothing. I would have to try again tomorrow. That’s the thing about this. You only get so much of a window to do it, then you’re looking up your next pass.
And then I did some more research. That frequency I had, the 437.550 MHz? Well it’s precisely as it said, for packet radio. There’s a different frequency, 145.8 MHZ. I never considered that SSTV wouldn’t count as packet radio. So at this point, I was off to trying again on the 26th. We’ll pick up from there in the next article.
- Reed