Listening To Space

Several times now, I’ve managed to pick up on the ISS’s VHF/UHF repeater while they passed overhead, and it’s honestly one of the coolest things I’ve done with radio so far. Even if there are no astronauts on the air, you’re hearing somebody’s voice, bounced off a floating space station moving hundreds of miles per hour above your head, thousands of miles away, I don’t see how you couldn’t find that neat.

Picking up on the signal is actually fairly easy, for the ISS as very least – I’ve been less fortunate with other stations, but that could just be from inactivity. You can find the frequencies for the ISS on this website, and you can use a tracker tool to know where it is, and when it’ll pass overhead. I use a desktop utility called gPredict and on my iPhone I use an app called ISS Detector on the App Store, but regardless the app or software you use, just find the ISS and wait until you see a good event. To find a list of active satellite you might be able to hit/hear, check out the AMSAT Website. Make sure to lookup the satellite and see what modes it supports, for example, I can only do AM/FM RX, and FM TX, limiting me to about four satellites in my region.

I ideally wait for an event with at least a thirty degree inclination, any lower and I don’t have any shot of picking it up, but that depends on your area – basically, hold your arms straight in front of you, that’s 0 degrees, now raise them up until you can point at the skyline without pointing at any buildings. That’s your minimum inclination. Once you get this all programmed in, it should tell you when your Acquisition of Signal (AOS) event will be – that’s when you should be outside on the radio with a clear view of the sky.

If your radio has a satellite mode or Doppler tuning, you can use that to correct for the Doppler effect of the space station whizzing past far above, but you don’t actually need this for monitoring the ISS. It may make it a little easier to pick up on something, especially in a worse signal area, but most my receptions of the pass were just tuned to the posted frequencies.

As I write this, (several days before posting the final revision) I’m tracking an ISS pass overhead at FM19 at 22:33 GMT, approximately five minuets out. I’m configuring my radio to tracker mode, connecting my tablet to my PC to watch GPredict plot its path, and bundling up to stand outside for five minuets in 7C weather, hoping to hear contacts – still getting over radio anxiety, have yet to make a satellite contact myself. I also happen to live in an area not really suited for making contacts, with buildings all over. Just got back in from the event, didn’t managed to pick up much for long, but I clearly heard some callsigns. Location, height, and antenna do all really help here.