Lorenz beam

The Lorenz beam was blind-landing radio navigation system developed by C. Lorenz AG in Berlin. The first system had been installed in 1932 at Berlin-Tempelhof Central Airport, followed by Dübendorf in Switzerland (1934) and others all over the world. The Lorenz company referred to it simply as the Ultrakurzwellen-Landefunkfeuer, German for "ultra-short-wave landing radio beacon", or LFF. Prior to the World War II the Germans had deployed the landing aid system at many Luftwaffe airfields in and outside Germany and equipped most of their bombers with the radio equipment needed to use it. The RAF continued using the system as late as 1955, under the name Standard Beam Approach (SBA).

The basic idea behind the short-range LFF system was later developed into a long-range system for air navigation known as Elektra. Further development produced a system that worked over very long distances, hundreds or thousands of kilometres, known as Sonne (or often, Elektra-Sonnen) that allowed aircraft and U-Boats to take fixes far into the Atlantic. The British captured Sonne receivers and maps and started to use it for their own navigation under the name Consol.

The blind approach navigation system was developed starting in 1932 by Dr. Ernst Kramar of the Lorenz company. It was adopted by Deutsche Lufthansa in 1934 and sold around the world. The Lorenz company was founded in 1880 by Carl Lorenz and is now part of ITT.

Lorenz used a single radio transmitter at 33,33 MHz (Anflugfunkfeuer) and three antennas placed in a line parallel to the end of the runway. The center antenna was always powered, while the other two were short circuited by a mechanical rotary switch turned by a simple motor. This resulted in a "kidney" shaped broadcast pattern centered on one of the two "side" antennas depending on which antenna had been short-circuited. The contacts on the switch were set so that one antenna was shorted for the time to be considered a "Dot" by a morse operator and the other as a "Dash". The signal could be detected for some distance off the end of the runway, as much as 30 km. The Lorenz obtained a sharper beam than could be created by an aerial array by having two lobes of signal.

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