NavList:

Earhart has been discussed here before, so I apologize if this link has also been posted in the past.

I am a ham radio operator and also a marine radio operator (recreational not commerical).  I also used RDF as a tool at sea before the days of GPS.  In the Southern Hemisphere we did not have the Decca and Loran systems that parts of the Northern Hemisphere enjoyed, so coastal radio beacons were a thing.  To a lesser and limited extent, even commerical broadcast signals could be useful.  I have always found the radio-related aspects of the story interesting.

https://www.usni.org/magazines/naval-history-magazine/1993/december/amelia-didnt-know-radio

The writer of the linked item knew radio and also somehat knew Noonan.

Murray.