Hey there, everyone! This Tuesday, tomorrow 6th of May, I’ll be attempting to pick up a signal from a satellite I’m involved with at the hackerspace. If you’ve ever wondered how to do this, come along & find out! The demonstration will start at around 5:30pm, with the target orbital pass occurring at 6:18pm. This may be a little early for some but this is a close, almost-directly-overhead pass only 340km away AND it’s on a Tuesday night, which is too good to ignore.
I’m by no means an expert on this & I’m doing everything on the cheap (I’m not even using name-brand duct-tape to hold it together, just the cheap stuff) so this may not be the “best” way to do it, but it’s a way that works. And where would all the hacking fun be if the ground station isn’t hacked together?
I have everything I need & I do all the noise cancellation in software in post-processing, so another SDR wouldn’t be of any use to my setup. Although depending on what model SDR you have, you’re part of the way to building your own receiver! You just need a very-low-noise amplifier & a high-gain antenna matched to your target frequency.
(he says “you just need” and then lists big things… )
The pass I’ll be picking up starts at 6:14, peaks at 6:18 and ends at 6:21 so you wouldn’t have missed it all at 6:20. I’ll have my stuff with me the entire night, and naturally I can answer any questions as best I can. There’s always something passing overhead though, especially cubesats (but they’re usually pretty weak). We can hunt down something else that transmits in the 70cm band for a second demonstration later on if people are interested.
My antenna is tuned for 430-440MHz, my amplifier is from 174MHz-860MHz, and the SDR is from 140KHz to just under 2.1GHz. Cost was around $400 but keep in mind the components were selected to be as cheap as possible while performing exceedingly well in a very narrow target frequency band. I can pick up strong signals outside 430-440MHz with this equipment but it’s not designed for it.
We managed to get a blip! Not as strong as I was hoping, but the signal was getting attenuated by everyone crowding around too close to and standing in front of the antenna. I should’ve asked people to step back a little, my fault there. This means the signal wasn’t strong enough to decode its contents, but hey, it’s a 1-watt radio transmitter that’s 600km away moving at a speed of 7.5km/s - it amazes me I can pick up anything. You can easily hear it over the background static. Here’s one I prepared earlier!
(I had no idea Discourse auto-embedded links to audio files like that. Cool!)
I know a bunch of people took photos of the event, it’d be great if people could post them.
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