Build this 8.6 dBi 1090MHz Vertical Dipole Array for under $20. Automatic Dependent Surveillance-Broadcast, or ADS-B, is a surveillance technology in which an aircraft determines its position via satellite navigation or other sensors and broadcasts it, enabling it to be tracked. There are several smartphone apps available that allow users to monitor aircraft positions, flight numbers, speed, altitude and several more parameters. A receiving system can be built with a Raspberry Pi, a receiver dongle, and an antenna. This article is based on using Flightradar24 and FlightAware apps.
