USB with passband tuning and CW filter (250Hz)
http://www.lazygranch.com/sound/temp/aec_cw.wav

AM with 2.1khz filter
http://www.lazygranch.com/sound/temp/aec_am.wav

Note the beacon is 400 miles away and I'm recording from an urban
environment, hence all the noise. Beacon Morse code AEC. Frequency
209Khz.

The marine RDFs assume you are in the ocean, so the only noise source
would be your boat.