Over on his blog, cynicalGSD has written a detailed post about how he extended his home ADS-B flight tracking setup to also decode ACARS. His existing system runs an RTL-SDR dongle on a Raspberry Pi feeding a database and Flask web app. Adding ACARS required a second RTL-SDR and a separate VHF dipole antenna tuned for 129–131 MHz.

ACARS (Aircraft Communications Addressing and Reporting System) is a text-based datalink that has been in use since 1978, carrying short messages between aircraft and ground stations. It includes messages such as OOOI events (Out of gate, Off ground, On ground, Into gate), pilot weather reports, maintenance fault codes, and gate and fuel data. The key feature of their implementation is cross-referencing ACARS messages with existing ADS-B records via aircraft registration and ICAO hex address, enriching flight records with precise departure and arrival timestamps from the airline's own reporting system.

The full write-up covers the database schema, Python integration using acarsdec, gain tuning tips, and the Flask web interface. cynicalGSD mentions that the code is available for anyone interested, but we didn't see a link, so please comment on his post if you are interested.