Many aircraft today carry ADS-B beacons that transmit their location along with other identifying information. This is transmitted on 1090 mhz and can be decoded by an SDR radio and software on a Raspberry Pi computer. The team at FlightAware uses this data for aircraft tracking and displays it on an annotated map that’s accessed from the Pi.  We’ve set up such a station at the GCARC clubhouse and the map can be viewed by pointing a web browser (cell phone, computer, etc.) to 192.168.50.151 once you’re on the clubhouse wifi. This shows planes whose ADS-B beacons have been received by the SDR receiver in the satellite/VHF room, and you can look up in the sky at the clubhouse, spot a plane and locate it on the ADS-B map. You can also click on the plane ID and get a link to information about that flight. Pretty cool – not exactly ham radio but hopefully still cool to see a local implementation of this system.