A few summers ago my project was to build an ADS-B receiver and use the data collected to upload to an aircraft tracking website. If you want to see what I see then go to:

360 Radar

I don’t remember the details about how I found this but the project was good fun and I got the Raspberry Pi in the loft with a decent aerial, filter and pre-amp, and it was all working fine. I was using a lovely piece of software called Virtual Radar Server and was able to use this as a web server and people could see the aircraft on web pages served by the Pi.

360 Radar is good because it using multi-lateration to detect the positions on military aircraft. This is pretty handy for spotters like me and it also works well when I take cadets to RAF Wittering for some Air Experience Flying, I can see where my cadets are in the air.

Over the last few months I’d been receiving outage warnings from the 360 guys. It would appear that my Pi had stopped sending them data and while I live in a flight-busy area of the country and there’s plenty of contributors here every little helps. I had the occasional outage and this seemed to be when the router reset and the Pi wouldn’t re-find the existing wi-fi network. I just had to power cycle the Pi and everything worked fine. The outages seemed to be occurring more over the last while with the Pi stopping feeding every few days.

At first I thought it was a wi-fi issue so I bought some new ethernet-over-power adapters and linked the system into the route via a wired connection. This also meant I could ssh in to the Pi even if wifi was the original problem. I tried to work out how to turn the wifi connection off entirely but just ended up changing the SSID the Pi looked for as a simle way of ensuring the wired connection took preference.

After a week of testing I was still getting outages and my initial thought was that the VRS software was making the Pi work too much. I’m not sure why I thought that but I looked up ways to remove VRS. This was not the easiest as I had installed it years ago and couldn’t remember how it ran within the OS. I eventually managed to remove the Mono service and this stopped VRS running.

It was at this point I worked out how to use the log file of the MLAT client and I could see that all the software seemed to be working fine it was the Dump1090 program that didn’t seem to be sending data internally. I figured that Dump1090 had somehow stopped receiving the signal from the aerial. It all worked fine after a reboot and so I decided to replace the USB dongle that was decoding the ADS-B signals. I ordered a FlightAware USB stick and at the same time decided I would rebuild the Pi OS from scratch to have a “clean” build.

Once the new USB stick arrived I turned off all the systems and followed the excellent instructions from the 360 Radar guys to rebuild the OS of the Pi and just run a lite version of what I had been doing before. This took a while as I mistakenly thought the Pi wasn’t uploading to 360 because I was looking at the wrong server details. After an email to the support chaps it turned out I was contributing and a couple of hours of troubleshooting by me hadn’t been worth it!

So, the Pi sits in the loft, chugging away supplying data to 360 Radar, in return for which I get free access to their excellent tracking site. I’m running dump1090-mutability along with the MLAT-Client from 360. I’d really like to be able to allow you all to see the output of this but Mutability doesn’t have an external feed and I am not opening up my 80 port for the world.

Output of dump1090-mutability
Output of dump1090-mutability