Ramark

A Ramark is a type of radar beacon occasionally used to mark maritime navigational hazards. The word is an acronym for RAdar MARKer.

They are wide-band beacons which transmit either continuously or periodically on the radar bands. The transmission forms a line of Morse characters on a plan position indicator radar display which radiates from the centre of the display to its edge.

Periodic transmissions every few seconds are usually used so that important radar targets behind the ramark beacon are not masked by the Morse characters. Ramark beacons are less commonly used than Racon beacons which give the location as well as the bearing of the hazard and do not clutter the display so much.