If you’re a real hacker, you’re interested in all sorts of tech, from computers and the internet to radio to airplanes. The intersection of all of these interests is ADS-B, the protocol used by aircraft to share data like position and speed. Widespread availability of cheap software-defined radio (SDR) receivers and cheap computers like the Raspberry Pi makes it easy for anyone to join a global network sharing ADS-B data. Read on to learn how to build your own ADS-B receiver for under $100 and get involved!