A fixed radio transmitter, (now rarely used) usually identifying itself by a
Morse code signal, on which a bearing can be taken with a Radio
direction-finder. Marine radio beacons are sited specifIcally to assist sea
vessels, but a small-boat skip­per can also make use of aero beacons if they
are sited near the coast. (But some aero beacons transmit on VHF, whereas
marine beacons are usually in the low frequency band.)