NDB BFO RNAV
The BFOBFO —Beat Frequency Oscillator (Beat Frequency Oscillator) is switched on in the aircraft to hear the morse code identification ("Ident") of older, N0N A1A beacons. This happens automatically in modern passenger aircraft. You are not required to know the technical details behind the working of the BFOBFO —Beat Frequency Oscillator. There are very few of these A1A beacons left in the world now as they are being replaced by more modern navigational aids.