Range and Direction Finding
Encyclopedia
Range and Direction Finding (RDF) was the initial technique and hardware in Great Britain that eventually came to be called 'radar.'
Since the earliest days of radio (wireless), the signals had been used in direction finding
on land, sea, and in the air. This was accomplished by rotating the antenna at a receiving station and noting the direction of rotation that gave the maximum signal, thus showing the direction to the transmitting station. The abbreviation DF was often applied to this technique, as well as the receiving equipment. Since radio was being used, the abbreviation RDF came to be commonly used for Radio Direction Finder
equipment.
Radio direction finding was a passive technique – the receiving station simply detected the signal from the emitting station. If two receiving stations separated by some known distance were used, the method of triangulation
might be applied – with restrictions – to give an approximation of the distance to the transmitting station.
Starting in the mid-1930s, active techniques were developed in a number of nations to give precise measures of range (distance) from the transmitter to a given reflecting target. These techniques were developed in great secrecy, and various cover names were applied. (See History of radar
)
In Great Britain, the development of this active technology was concentrated in a technical group under the Air Ministry
and initially working at Orford Ness
, an isolated location on the North Sea coast. Albert Percival Rowe
, a physicist from the Air Ministry, was stationed on site, and in August 1936, suggested that RDF – an initialism for Range and Direction Finding – be used for reference. This was a good ‘cover’ for the work, since to an outsider it would seem to be the original Radio Direction Finder.
In the United States, the cover name was RADAR, an acronym for RAdio Detection And Ranging. This was coined by S. M. Tucker and F. R. Furth of the U.S. Navy, and in November 1940, this designation was officially ordered to be used for all unclassified references to this technology. By early 1941, the work on such systems in Great Britain and America was basically combined, and the name 'radar' quickly replaced RDF.
Since the earliest days of radio (wireless), the signals had been used in direction finding
Direction finding
Direction finding refers to the establishment of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication...
on land, sea, and in the air. This was accomplished by rotating the antenna at a receiving station and noting the direction of rotation that gave the maximum signal, thus showing the direction to the transmitting station. The abbreviation DF was often applied to this technique, as well as the receiving equipment. Since radio was being used, the abbreviation RDF came to be commonly used for Radio Direction Finder
Radio direction finder
A radio direction finder is a device for finding the direction to a radio source. Due to low frequency propagation characteristic to travel very long distances and "over the horizon", it makes a particularly good navigation system for ships, small boats, and aircraft that might be some distance...
equipment.
Radio direction finding was a passive technique – the receiving station simply detected the signal from the emitting station. If two receiving stations separated by some known distance were used, the method of triangulation
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly...
might be applied – with restrictions – to give an approximation of the distance to the transmitting station.
Starting in the mid-1930s, active techniques were developed in a number of nations to give precise measures of range (distance) from the transmitter to a given reflecting target. These techniques were developed in great secrecy, and various cover names were applied. (See History of radar
History of radar
The history of radar starts with experiments by Heinrich Hertz in the late 19th century that showed that radio waves were reflected by metallic objects. This possibility was suggested in James Clerk Maxwell's seminal work on electromagnetism...
)
In Great Britain, the development of this active technology was concentrated in a technical group under the Air Ministry
Air Ministry
The Air Ministry was a department of the British Government with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964...
and initially working at Orford Ness
Orford Ness
Orford Ness is a cuspate foreland shingle spit on the Suffolk coast in Great Britain, linked to the mainland at Aldeburgh and stretching along the coast to Orford and down to North Wier Point, opposite Shingle Street. It is divided from the mainland by the River Alde, and was formed by longshore...
, an isolated location on the North Sea coast. Albert Percival Rowe
Albert Percival Rowe
Albert Percival Rowe was a British physicist and senior research administrator who had a major role in the development of Radar before and during World War II....
, a physicist from the Air Ministry, was stationed on site, and in August 1936, suggested that RDF – an initialism for Range and Direction Finding – be used for reference. This was a good ‘cover’ for the work, since to an outsider it would seem to be the original Radio Direction Finder.
In the United States, the cover name was RADAR, an acronym for RAdio Detection And Ranging. This was coined by S. M. Tucker and F. R. Furth of the U.S. Navy, and in November 1940, this designation was officially ordered to be used for all unclassified references to this technology. By early 1941, the work on such systems in Great Britain and America was basically combined, and the name 'radar' quickly replaced RDF.
General references
- Brown, Louis; Radar History of World War II, Inst. of Physics Publishing, 1999
- Guerlac, Henry E,; Radar in World War II,Tomash Publishers for Am. Inst. of Physics, 1987
- Swords, S. S.; Technical History of the Beginnings of Radar; Peter Peregrinus Ltd, 1986
- Watson, Raymond C. Watson, Jr.; Radar Origins Worldwide, Trafford Publishing, 2009