Raspi + SDR + ADS-B = awesome

A lot of people have combined a RasPi and a SDR dongle to get a low power consumption ADS-B tracker. Tomasz Miklas has created an image for the Raspberry Pi, that has everything that is needed to run your own aircraft tracking "service" already set up. I've finally had a chance to experiment with it and this will be my short review.

First of all, I have to say I'm really sorry to Tomasz, because he send me the image at the 10th of October to test it out before releasing it publicly and I'm posting this two months later. Sorry mate.

Tomasz, has a well written post explaining how the image works , so I'll skip the details. All tests were performed using a dongle with a R820T chip and the stock omnidirectional antenna. Since I moved recently, I didn't have the time to construct a proper antenna, yet even with such an antenna the result were pretty good.

So, you download the image, dd it to a SD card, plug your SDR dongle, power it on, point your browser to the IP the RasPi obtained through DHCP and … and everything simply works out of the box. At least it did for me.

I was really surprised by how lightweight the whole setup was. After one and a half hours of uptime, two clients connected to the server and, receiving messages from two planes, the RasPi reported that it only used 30 megs of RAM and the CPU was pinned at 35% the whole time, with 4-5% of it being htop itself. The process using the CPU was of course dump1090, which does all the heavy lifting. Unfortunately, due to the time I tested the image (4 AM) and my location, there weren't many planes (two simultaneously at max), so I don't know how dump1090 behaves under a lot of load/traffic.

As mentioned above, I was using the stock antenna that came with the SDR dongle, but I was still able to get a signal from planes that were 72km away on average! On some of my previous tests under Windows and ADSB#, I only got 28km of range. A lot of things have changed since then though, mainly my new house and my antenna placement, or perhaps the old one was a Faraday cage? Either way, for the time being, I'll leave the RasPi running and further report on its performance after a bit of testing.

If you own a RasPi and a SDR dongle, give the image a try. It may not be something you haven't seen or done already, but it certainly is the easiest way to monitor ADS-B traffic, at least to my knowing. I know, I'll be keeping a copy of the image in a SD card because it's so handy.