I wanted to know what's flying around up there, so I first applied for a free Flightradar24 receiver kit. They rejected me. So I dug out an old RTL-SDR dongle, plugged in a piece of wire as an emergency antenna and put it by the window. It worked surprisingly well; even with this makeshift setup I was able to track planes up to ~150km out.
This blew me away so much that I ordered a bigger antenna. It arrived a few days later and is now sitting temporarily outside on the terrace. The range immediately doubled to ~300km.
When I have time I'll mount it on the roof and connect it directly to the server in the basement.
In the Grafana dashboard you can clearly see when I switched from the wire antenna to the proper antenna. The activity immediately doubled.
The setup
The whole thing receives ADS-B on 1090 MHz with an RTL-SDR dongle. A GPS receiver provides the position for MLAT (multilateration). tar1090 shows everything in the browser, and the data goes to both Flightradar24 and ADSBExchange. For that I get a contributor account with business features.
An InfluxDB logger stores everything for Grafana dashboards. The complete setup is managed via Ansible, so I can re-provision the Pi at any time without manually typing configs.
The rabbit hole goes deeper
This project totally got me hooked. Now I want to get myself a better antenna, a splitter and even more SDR dongles to listen in on other frequencies as well. With RTL-SDR you can receive a whole lot:
- Air band (118-137 MHz) - pilots talking to air traffic control
- ACARS (131.550 MHz) - aircraft automatically transmit weather and status messages
- NOAA weather satellites (137 MHz) - receive live satellite images
- Marine VHF (156-162 MHz) - ship communication
- ISM band (433 MHz) - garage doors, weather stations, all kinds of IoT stuff
An RTL-SDR dongle costs ~55€ and receives from 100 kHz to 1.75 GHz. That's quite a spectrum for little money.
Build it yourself
If you feel like building something like this yourself: ADSBExchange and Flightradar24 both have detailed guides with shopping lists and step-by-step instructions. A Raspberry Pi 5 4GB for ~€120 is plenty, but you can also use an old 3B+ like I did if you want to save money. I got myself the Nooelec RTL-SDR v5 for ~€55 and the AirNav Radar ADS-B 1090 MHz antenna for ~€75, both work great.
Tech stack: Raspberry Pi 3B+, RTL-SDR, readsb, tar1090, gpsd, Ansible, InfluxDB, Grafana
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