Recently amateur radio hobbyist WB20SZ wrote in to us to let us know about his work with creating an easy to build receive only APRS internet gateway (IGate) with a Raspberry Pi and RTL-SDR dongle. The process involves using WB20SZ’s “Dire Wolf” software which is a free Linux based APRS encoder/decoder. He writes that it can be used to observe APRS traffic, as a digipeater, APRStt gateway or Internet Gateway (IGate). Setting up the APRS IGate is a simple matter of piping the received APRS audio from rtl_fm into the direwolf software. Instructions for installing direwolf can be found here.
APRS stands for Automatic Packet Reporting System and is a packet radio protocol used by radio amateurs to broadcast real time data such as messages, announcements, weather station reports and sometimes the location of vehicles. If an APRS station has a GPS attached to it, the broadcasts will also contain the GPS coordinates. Internet Gateways or IGates are repeaters that are used to receive messages from a local radio and pass them on via the internet to a transmit capable IGate repeater anywhere in the world. To run an IGate you should be a radio amateur with a callsign. A global aggregation of APRS broadcasts received by IGates can be seen at aprs.fi.