In this paper the author sketches the historical development of radar beacons: the different types are classified in relation to code and frequency employed and the benefits and drawbacks of more recently proposed types of beacon are discussed.

The paper was presented at a Marine Electronics Symposium sponsored by the Society of Electronic and Radio Technicians at the University of Southampton in July 1976.

The military use of responder beacons before 1945 led to secondary radar systems, such as Rebecca-Eureka, Oboe, and IFF, giving facilities for target location at long range with an accuracy and identification not available from a primary radar system. The desirability of these advantages in civilian systems was recognized but the absence of military urgency and considerations of cost led to delay. Although responder beacons became an essential part of the Air Traffic Control System, extension into the marine field did not succeed until the U.K. Ministry of Transport Safety of Navigation Committee set up a Technical Committee and Working Party in 1962 to investigate the conditions governing the marine installation of responder beacons as a navigational aid. This committee recommended that responder beacons (alternatively called racons) should be set up to an agreed specification at selected sites around the UK coast, to become the first civil marine navigational racon system. The co-operation of the Admiralty Surface Weapons Establishment, Trinity House, and Kelvin Hughes made possible the installation and operation of three racons—on the Liverpool Bar LV, the Kish LV, and St. Abb's Head LH—to provide operational experience on which the committee's recommendations were based, followed by the setting up of the complete system.