The transmitted carrier wave frequency of ALL Marker Beacons is 75 MHz.

Each MKR BCN carries an audio frequency for Ident purposes.

Outer Marker 400 Hz Morse Letter O _ _ _ Transmitted at 2 dashes per second

Middle Marker 1300 Hz Morse Letter C _ . _ . Transmitted as alternating dashes and dots at a rate of 2 dashes and 6 dots per second

Inner Marker 3000 Hz Morse Letter I . . Transmitted at 6 dots per second