When the big annual meteor showers come around, you can often find us driving up to a mountaintop to escape light pollution and watching the skies for a while. But what to do when it’s cloudy? Or when you’re just too lazy to leave your computer monitor? One solution is to listen to meteors online! (Yeah, it’s not the same.)
Meteors leave a trail of ionized gas in their wake. That’s what you see when you’re watching the “shooting stars”. Besides glowing, this gas also reflects radio waves, so you could in principle listen for reflections of terrestrial broadcasts that bounce off of the meteors’ tails. This is the basis of the meteor burst communication mode.
[Ciprian Sufitchi, N2YO] set up his system using nothing more than a cheap RTL-SDR dongle and a Yagi antenna, which he describes in his writeup (PDF) on meteor echoes. The trick is to find a strong signal broadcast from the earth that’s in the 40-70 MHz region where the atmosphere is most transparent so that you get a good signal.
This used to be easy, because analog TV stations would put out hundreds of kilowatts in these bands. Now, with the transition to digital TV, things are a lot quieter. But there are still a few hold-outs. If you’re in the eastern half of the USA, for instance, there’s a transmitter in Ontario, Canada that’s still broadcasting analog on channel 2. Simply point your antenna at Ontario, aim it up into the ionosphere, and you’re all set.
We’re interested in anyone in Europe knows of similar powerful emitters in these bands.
As you’d expect, we’ve covered meteor burst before, but the ease of installation provided by the SDR + Yagi solution is ridiculous. And speaking of ridiculous, how about communicating by bouncing signals off of passing airplanes? What will those ham radio folks think of next?