The BFO (Beat Frequency Oscillator) on an ADF receiver is used to:

Increase the signal strength

Improve bearing accuracy

Filter out interference

Make the Morse code ident of an unmodulated CW NDB carrier audible

Correct

Explanation

The BFO generates an internal tone that, when mixed with the unmodulated carrier of a CW NDB, produces an audible beat frequency for identification.

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