It began with buying an old Datatrak navigation receiver, and ended in the reverse-engineering of an entire navigation system -- one that had been dead since 2014. A demonstration of how a 1980s navigation receiver was reverse-engineered to component level, and the structure of the network analysed to protocol level, using the data stored in the receiver's battery-backed RAM.
Includes sections on how land (not satellite) radio navigation works, PCB reverse engineering, how old recordings of the signals were recovered, and the design of an Arduino shield to generate new Datatrak signals.
An ongoing project of interest to PCB and software reverse engineers, and radio enthusiasts.