The prototype system was mounted on the light cruiserHMSDido in October 1940.[1] This radar used a frequency of 90MHz, a beamwidth of 35°, and a wavelength of 3.5m (3.8yd). It required separate transmitting and receiving antennas that were rotated by hand. For long-range warning the radar used a 15 microsecond pulse at a power level of 350kW that gave a detection range up to 110 nautical miles (200km; 130mi) for aircraft. For tracking surface targets it used a 2–3 microsecond pulse at 1 MW that gave a range up to 12 nautical miles (22km; 14mi). A second set was installed in January 1941 aboard the battleshipHMSPrince of Wales and production began of another 57 sets with the first deliveries occurring the following month.[2][3] This set also had a secondary aerial and surface gunnery capability and used a Precision Ranging Panel. The Type 281 ranging system allowed the user to select either a 2,000 yards (1,830m) to 14,000 yards (12,800m) or a 2,000 yards (1,830m) to 25,000 yards (22,860m) range display with range accuracies of 50 yards (50m) or 75 yards (70m) RMS, respectively. Aerial target ranges were passed directly to the HACS table (fire control computer).[4]
Type 281B consolidated the transmission and receiving antennas while the Type 281BP radar had the short-pulse feature removed. It was fitted with improved receivers that increased the maximum detection range for an aircraft at 20,000 feet (6,100m) to 120 nautical miles (220km; 140mi). At lower altitudes, ranges declined to 90 nautical miles (170km; 100mi) at 10,000 feet (3,050m) and 65 nautical miles (120km; 75mi) at 5,000 feet (1,520m). The Type 281BQ was a Type 281BP fitted with power rotation, at 2 or 4 rpm, and equipped with a plan position indicator. After the end of the war, the Type 281 was replaced by the Type 960 radar.[5]
Brown, Louis (1999). A Radar History of World War II: Technological and Military Imperatives. Bristol and Philadelphia: Institute of Physics Publishing. ISBN0-7503-0659-9.
Friedman, Norman (1981). Naval Radar. London: Conway Maritime Press. ISBN0-85177-238-2.
Pout, H.W. (1995). "Weapon Direction in the Royal Navy". In Kingsley, F.A. (ed.). The Application of Radar and other Electronic Systems in the Royal Navy in World War 2. London: Macmillan. ISBN0-333-62748-2.
Mitchell, Alastair (1980). "The Development of Radar in the Royal Navy (1935–45), Part I". In Roberts, John (ed.). Warship IV. London: Conway Maritime Press. ISBN0-85177-205-6.
Swords, Sean S. (1986). Technical History of the Beginnings of Radar. London: IEE/Peter Peregrinus. ISBN0-86341-043-X.
Watson, Raymond C. Jr. (2009). Radar Origins Worldwide: History of Its Evolution in 13 Nations Through World War II. Trafford. ISBN978-1-4269-2111-7.
In aviation, distance measuring equipment (DME) is a radio navigation technology that measures the slant range (distance) between an aircraft and a ground station by timing the propagation delay of radio signals in the frequency band between 960 and 1215 megahertz (MHz). Line-of-visibility between the aircraft and ground station is required. An interrogator (airborne) initiates an exchange by transmitting a pulse pair, on an assigned 'channel', to the transponder ground station. The channel assignment specifies the carrier frequency and the spacing between the pulses. After a known delay, the transponder replies by transmitting a pulse pair on a frequency that is offset from the interrogation frequency by 63 MHz and having specified separation.
The history of radar started 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. However, it was not until the early 20th century that systems able to use these principles were becoming widely available, and it was German inventor Christian Hülsmeyer who first used them to build a simple ship detection device intended to help avoid collisions in fog. True radar, such as the British Chain Home early warning system provided directional information to objects over short ranges, were developed over the next two decades.
HNoMS Svenner was a Royal Norwegian Navy destroyer during the Second World War. She was built for the Royal Navy as the S-class destroyer HMS Shark but on completion was lent to the Norwegian Armed Forces in exile. Svenner was sunk off Sword, one of the Allied landing zones in Normandy, at dawn on 6 June 1944 while supporting the British Army Normandy landings. It was the only Allied ship to be sunk by the Kriegsmarine during the morning of the invasion.
HMS Seneschal was a S-class submarine of the third batch built for the Royal Navy during World War II. She survived the war and was sold for scrap in 1965.
HMS Shakespeare was an S-class submarine built for the Royal Navy during the Second World War, and part of the Third Group built of that class. She was built by Vickers-Armstrongs and launched on 8 December 1941.
The AN/FPS-17 was a ground-based fixed-beam radar system that was installed at three locations worldwide, including Pirinçlik Air Base in south-eastern Turkey, Laredo, Texas and Shemya Island, Alaska.
The AN/FPQ-6 is a fixed, land-based C-band radar system used for long-range, small-target tracking. The AN/FPQ-6 Instrumentation Radar located at the NASA Kennedy Space Center was the principal C-Band tracking radar system for Apollo program.
HMS Clacton was a Bangor-class minesweeper built for the Royal Navy during the Second World War.
HMS Ardrossan was a Bangor-class minesweepers built for the Royal Navy during the Second World War.
Radar mile or radar nautical mile is an auxiliary constant for converting a (delay) time to the corresponding scale distance on the radar display.
Radar in World War II greatly influenced many important aspects of the conflict. This revolutionary new technology of radio-based detection and tracking was used by both the Allies and Axis powers in World War II, which had evolved independently in a number of nations during the mid 1930s. At the outbreak of war in September 1939, both the United Kingdom and Germany had functioning radar systems. In the UK, it was called RDF, Range and Direction Finding, while in Germany the name Funkmeß (radio-measuring) was used, with apparatuses called Funkmessgerät . By the time of the Battle of Britain in mid-1940, the Royal Air Force (RAF) had fully integrated RDF as part of the national air defence.
HMIS Rohilkhand (J180) was a Bangor-class minesweeper built for the Royal Navy, but transferred to the Royal Indian Navy during the Second World War.
The Type 79 radar was a British naval early-warning radar developed before World War II. It was the first radar system deployed by the Royal Navy.
HMSSaltburn was a Hunt-class minesweeper built for the Royal Navy during World War I. Named after the town of Saltburn-by-the-Sea in North Yorkshire, she was not completed until after the end of the war. The ship saw no active service during World War II as she spent the war as a training ship. Saltburn was sold for scrap in 1946, but was wrecked while under tow.
The Type 271 was a surface search radar used by the Royal Navy and allies during World War II. The first widely used naval microwave-frequency system, it was equipped with an antenna small enough to allow it to be mounted on small ships like corvettes and frigates, while its improved resolution over earlier radars allowed it to pick up a surfaced U-boat at around 3 miles (4.8 km) and its periscope alone at 900 yards (820 m).
The Type 965 radar was VHF long-range aircraft warning radar used by warships of the Royal Navy from the 1960s onwards. The Type 965M, Type 965P, Type 965Q and Type 965R were improved versions; the Type 960, 965M and 965Q used the single bedstead AKE(1) aerial, whilst the Type 965P and 965R used the double bedstead AKE(2) aerial.
The Type 277 was a surface search and secondary aircraft early warning radar used by the Royal Navy and allies during World War II and the post-war era. It was a major update of the earlier Type 271 radar, offering much more power, better signal processing, new displays, and new antennas with greatly improved performance and much simpler mounting requirements. It allowed a radar with performance formerly found only on cruisers and battleships to be fitted even to the smallest corvettes. It began to replace the 271 in 1943 and was widespread by the end of the year.
HMS Swift was an S-class destroyer built for the Royal Navy in the Second World War. The ship belonged to the January 1941 order of the Royal Navy from the War Emergency program. The destroyer was launched from the shipyard J. Samuel White in Cowes on 15 June 1943 and was put into service on 12 December 1943.
The AN/APS-20 was an airborne early warning, anti-submarine, maritime surveillance and weather radar developed in the United States in the 1940s. Entering service in 1945, it served for nearly half a century, finally being retired in 1991. Initially developed at Massachusetts Institute of Technology (MIT) under Project Cadillac, the radar was developed to be carried by aircraft to extend the sensor range of ships by placing a radar at altitude. Although developed for carrier-borne operation, first being installed in the single-engined General Motors TBM-3W Avenger, it was also used in larger four-engined airframes, the last being a fleet of Avro Shackleton AEW.2 which were converted from maritime patrol aircraft. Similarly, although developed for detecting aircraft, it saw extensive service in anti-submarine and maritime patrol roles and was one of the first radars to be used in researching extreme weather like hurricanes by agencies like the Environmental Science Services Administration (ESSA). As well as the United States, the radar was used by a large number of services in other countries, including the French Navy, Japan Maritime Self-Defense Force (JMSDF), Royal Air Force (RAF) and Royal Canadian Air Force (RCAF). Early versions of the radar could see a low-flying aircraft at 65 nautical miles and a ship at 200 nautical miles. This was improved, so that later versions had a range against aerial targets of 115 nautical miles.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
