This reminds me of a Claude hobby project from a while back that listens on public KiwiSDR receivers (on-demand, politely, never taking the last slot) and decodes ships’ DSC radio signals: https://research.datadesk.eco/skywave/

These are mostly quite boring, but I did manage to make some progress in triangulating position between multiple receivers using the delay, which would be useful as a method for tracking AIS-dark vessels.