I created a little web game which I'm going to use for a future video explaining how aircraft used to navigate by radio before VORs. No special equipment needed, just listen to morse code tones, if you're on one of the 4 beams then you'll hear a continuous tone, so find a beam, stay on it and get to the destination, then it gets harder, removing the map, and eventually just relying on the audio alone:
illectro.github.io
(Not mobile friendly currently)