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73-504: The Helmore / GEC Turbinlite was a 2,700 million candela (2.7 Gcd) searchlight fitted in the nose of a number of British Douglas Havoc night fighters during the early part of the Second World War and around the time of The Blitz . The Havoc was guided to enemy aircraft by ground radar and its own radar. The searchlight would then be used to illuminate attacking enemy bombers for defending fighters accompanying

146-511: A force multiplier , allowing the husbanding of resources, both human and material, and only needing to scramble when attack was imminent. This greatly reduced pilot and aircraft fatigue. Very early in the battle, the Luftwaffe made a series of small but effective raids on several stations, including Ventnor , but they were repaired quickly. In the meantime, the operators broadcast radar-like signals from neighbouring stations in order to fool

219-505: A demonstration in which operators were attempting to locate an "attacking" bomber, he noticed that the primary problem was not technological, but information management and interpretation. Following Watson-Watt's advice, by early 1940, the RAF had built up a layered control organization that efficiently passed information along the chain of command, and was able to track large numbers of aircraft and direct interceptors to them. Immediately after

292-618: A development project was started in great secrecy on the Orford Ness Peninsula in Suffolk . E. G. Bowen was responsible for developing the pulsed transmitter. On 17 June 1935, the research apparatus successfully detected an aircraft at a distance of 17 miles. In August, A. P. Rowe , representing the Tizard Committee, suggested the technology be code-named RDF, meaning Range and Direction Finding . In March 1936,

365-452: A major advance in radar capability. The resulting magnetron was a small device that generated high-power microwave frequencies and allowed the development of practical centimetric radar that operated in the SHF radio frequency band from 3 to 30  GHz (wavelengths of 10 to 1 cm). Centimetric radar enables the detection of much smaller objects and the use of much smaller antennas than

438-527: A mixer for the receiver were essential. These were targeted developments, the former by R W Sutton who developed the NR89 reflex klystron , or "Sutton tube". The latter by H W B Skinner who developed the 'cat's whisker' crystal. At the end of 1939 when the decision was made to develop 10 cm radar, there were no suitable active devices available - no high power magnetron, no reflex klystron, no proven microwave crystal mixer, and no TR cell. By mid-1941, Type 271,

511-485: A passing airplane. This was officially reported by Taylor. Hyland, Taylor, and Young were granted a patent (U.S. No. 1981884, 1934) for a "System for detecting objects by radio". It was recognized that detection also needed range measurement, and funding was provided for a pulsed transmitter. This was assigned to a team led by Robert M. Page , and in December 1934, a breadboard apparatus successfully detected an aircraft at

584-637: A project in Doppler-beat detection. Following Page's success with pulse-transmission, the SCL soon followed in this area. In 1936, Paul E. Watson developed a pulsed system that on December 14 detected aircraft flying in New York City airspace at ranges up to seven miles. By 1938, this had evolved into the Army's first Radio Position Finding (RPF) set, designated SCR-268 , Signal Corps Radio , to disguise

657-474: A radio-based detection apparatus that was not further pursued by the Army. When war started and Air Ministry activities were relocated to Dundee , the Army detachment became part of a new developmental centre at Christchurch in Dorset . John D. Cockcroft , a physicist from Cambridge University , who was awarded a Nobel Prize after the war for work in nuclear physics, became Director. With its greater remit,

730-452: A range of 15 miles. Types 282 and Type 285 were used with Bofors 40 mm guns . Type 283 and Type 284 were other 50-cm gunnery director systems. Type 289 was developed based upon Dutch pre-war radar technology and used a Yagi-antenna. With an improved RDF design it controlled Bofors 40 mm anti-aircraft guns (see Electric listening device ). The critical problem of submarine detection required RDF systems operating at higher frequencies than

803-527: A range of one mile. The Navy, however, ignored further development, and it was not until January 1939, that their first prototype system, the 200-MHz (1.5-m) XAF , was tested at sea. The Navy coined the acronym RAdio Detection And Ranging (RADAR), and in late 1940, ordered this to be exclusively used. Taylor's 1930 report had been passed on to the U.S. Army's Signal Corps Laboratories (SCL). Here, William R. Blair had projects underway in detecting aircraft from thermal radiation and sound ranging, and started

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876-658: A successful programme, started in 1936 by Edward George Bowen , developed a miniaturized RDF system suitable for aircraft, the on-board aircraft interception radar (AI) set (Watson-Watt called the CH sets the RDF-1 and the AI the RDF-2A). Initial AI sets were first made available to the RAF in 1939 and fitted to Bristol Blenheim aircraft (replaced quickly by Bristol Beaufighters ). These measures greatly increased Luftwaffe loss rates. Later in

949-524: A surfaced submarine at 13 miles range. At Portsmouth, the team continued development, fitting antennas behind cylindrical parabolas (called "cheese" antennas) to generate a narrow beam that maintained contact as the ship rolled. Designated Type 271 radar , the set was tested in March 1941, detecting the periscope of a submerged submarine at almost a mile. The set was deployed in August 1941, just 12 months after

1022-560: A twin-engine design. However, the early radar-equipped Bristol Blenheims lacked the necessary speed advantage over the German Heinkel He 111s and Dornier Do 17 bombers then raiding the UK to be truly effective. The Blenheims could find the bombers but were often not fast enough to shoot them down. Non-radar-equipped single-engined fighters, whilst being fast enough to catch the bombers, simply could not find them. In addition, there

1095-449: A useful addition to the evolution of radar. This slow-to-fade display tube was used by air traffic controllers from the very beginning of radar. The Luftwaffe took to avoiding intercepting fighters by flying at night and in bad weather. Although the RAF control stations were aware of the location of the bombers, there was little they could do about them unless fighter pilots made visual contact. This problem had already been foreseen, and

1168-465: The Battle of Britain , and was critical in enabling the RAF to defeat the much larger Luftwaffe forces. Whereas the Luftwaffe relied on, often out of date, reconnaissance data and fighter sweeps, the RAF knew with a high degree of accuracy Luftwaffe formation strengths and intended targets. The sector stations were able to send the required number of interceptors, often only in small numbers. CH acted as

1241-714: The Bristol Beaufighter and the later de Havilland Mosquito , although one of the latter, the Mosquito II, serial W4087 , was itself experimentally fitted with a Turbinlite installation. Over Germany the Luftwaffe used Wilde Sau (wild boar) with illumination provided by searchlight batteries and the fires created by British bombing. The following units are known to have used the Havoc I Turbinlite and Havoc II Turbinlite operationally: In September 1942

1314-748: The GL3B sets were manufactured, it was the American version that was most numerous in the defense of London during the V-1 attacks. The Experimental Department of His Majesty's Signal School (HMSS) had been present at early demonstrations of the work conducted at Orfordness and Bawdsey Manor. Located at Portsmouth in Hampshire , the Experimental Department had an independent capability for developing wireless valves (vacuum tubes), and had provided

1387-505: The Soviet Union . Operational research found that anti-aircraft guns using GL averaged 4,100 rounds fired per hit, compared with about 20,000 rounds for predicted fire using a conventional director . In early 1938, Alan Butement began the development of a Coastal Defence ( CD ) system that involved some of the most advanced features in the evolving technology. The 200 MHz transmitter and receiver already being developed for

1460-677: The Tizard Mission visited the United States. The cavity magnetron was demonstrated to Americans at RCA, Bell Labs, etc. It was 100 times more powerful than anything they had seen. Bell Labs was able to duplicate the performance, and the Radiation Laboratory at MIT was established to develop microwave radars. The magnetron was later described by American military scientists as "the most valuable cargo ever brought to our shores". In addition to Britain, Germany, and

1533-748: The duplexers for VHF were destroyed by the new higher-powered transmitter. This problem was solved in early 1941 by the transmit-receive (T-R) switch developed at the Clarendon Laboratory of Oxford University , allowing a pulse transmitter and receiver to share the same antenna without affecting the receiver. The combination of magnetron, T-R switch, small antenna and high resolution allowed small, powerful radars to be installed in aircraft. Maritime patrol aircraft could detect objects as small as submarine periscopes , allowing aircraft to track and attack submerged submarines, where before only surfaced submarines could be detected. However, according to

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1606-473: The 135 kW and 1,200 Amp searchlight was sufficient for about two minutes of operation. The Havoc's own armament was removed from the nose. The radar fitted was the AI Mk.IV , with broad "arrow head" aerials protruding from the both sides of the aircraft nose with additional side-mounted, and upper- and lower-wing mounted, dipoles . The modifications were carried out at Burtonwood Aircraft Repair Depot and

1679-551: The AI and ASV sets of the Air Defence were used, but, since the CD would not be airborne, more power and a much larger antenna were possible. Transmitter power was increased to 150 kW. A dipole array 10 feet (3.0 m) high and 24 feet (7.3 m) wide, was developed, giving much narrower beams and higher gain. This "broadside" array was rotated 1.5 revolutions per minute, sweeping a field covering 360 degrees. Lobe switching

1752-477: The Blenheim, also having a considerable performance advantage, and it was decided to conduct experiments with these. The Havoc nightfighter was already fitted with aircraft interception radar. The searchlight, developed and built by GEC , was fitted into the nose of the Havoc behind a flat transparent screen with power for the light coming from heavy lead-acid batteries in the Havoc's bomb bay. Battery power for

1825-720: The British Army in Malta and Egypt in 1939–40. Seventeen sets were sent to France with the British Expeditionary Force ; while most were destroyed at the Dunkirk evacuation in late May 1940, a few were captured intact, giving the Germans an opportunity to examine British RDF kit. An improved version, GL Mk. II , was used throughout the war; some 1,700 sets were put into service, including over 200 supplied to

1898-651: The British were without peer. The result of the Tizard Mission was a major step forward in the evolution of radar in the United States. Although both the NRL and SCL had experimented with 10–cm transmitters, they were stymied by insufficient transmitter power. The cavity magnetron was the answer the U.S. was looking for, and it led to the creation of the MIT Radiation Laboratory (Rad Lab). Before

1971-401: The Germans that coverage continued. The Germans' attacks were sporadic and short-lived. The German High Command apparently never understood the importance of radar to the RAF's efforts, or they would have assigned these stations a much higher priority. Greater disruption was caused by destroying the teletype and landline links of the vulnerable above-ground control huts and the power cables to

2044-465: The Havoc to shoot down. In practice the Turbinlite was not a success, and the introduction of higher performance night fighters with their own radar meant they were withdrawn from service in early 1943. The then-state-of-the-art metre- wavelength aircraft interception (AI) radar was bulky and, due to the operator workload, generally unsuited to carriage by single-engined fighters — and so required

2117-692: The RDF research and development effort was moved to the Bawdsey Research Station located at Bawdsey Manor in Suffolk. While this operation was under the Air Ministry, the Army and Navy became involved and soon initiated their own programs. At Bawdsey, engineers and scientists evolved the RDF technology, but Watson-Watt, the head of the team, turned from the technical side to developing a practical machine/human user interface. After watching

2190-596: The Radio Research Station, Slough, was asked to investigate a radio-based "death ray". In response, Watson-Watt and his scientific assistant, Arnold F. Wilkins , replied that it might be more practical to use radio to detect and track enemy aircraft. On 26 February 1935, a preliminary test, commonly called the Daventry Experiment , showed that radio signals reflected from an aircraft could be detected. Research funds were quickly allocated, and

2263-595: The TRU had two vans for the electronic equipment and a generator van; it used a 105-ft portable tower to support a transmitting antenna and two receiving antennas. A prototype was tested in October 1937, detecting aircraft at 60-miles range; production of 400 sets designated GL Mk. I began in June 1938. The Air Ministry adopted some of these sets to augment the CH network in case of enemy damage. GL Mk. I sets were used overseas by

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2336-482: The U.S. Navy Aircraft Radio Laboratory, noticed that a ship crossing the transmission path of a radio link produced a slow fading in and out of the signal. They reported this as a Doppler-beat interference with potential for detecting the passing of a vessel, but it was not pursued. In 1930, Lawrence A. Hyland . working for Taylor at the Naval Research Laboratory (NRL) noted the same effect from

2409-442: The U.S. Navy in 1940, and the term "radar" became widely used. While the benefits of operating in the microwave portion of the radio spectrum were known, transmitters for generating microwave signals of sufficient power were unavailable; thus, all early radar systems operated at lower frequencies (e.g., HF or VHF ). In February 1940, Great Britain developed the resonant-cavity magnetron , capable of producing microwave power in

2482-399: The United States, the technology was demonstrated during December 1934. However, it was only when war became likely that the U.S. recognized the potential of the new technology, and began the development of ship- and land-based systems. The U.S. Navy fielded the first of these in early 1940, and a year later by the U.S. Army . The acronym RADAR (for Radio Detection And Ranging) was coined by

2555-481: The United States, wartime radars were also developed and used by Australia , Canada , France , Italy , Japan , New Zealand , South Africa , the Soviet Union , and Sweden . Research leading to RDF technology in the United Kingdom was begun by Sir Henry Tizard 's Aeronautical Research Committee in early 1935, responding to the urgent need to anticipate German bomber attacks. Robert A. Watson-Watt at

2628-691: The advent of the Havoc II Turbinlite , of which a further 39 were built, this time as conversions from the Havoc II. There was one confirmed Turbinlite intercept and shootdown of a Heinkel He 111 bomber on the night of 30 April 1942, by a 253 Squadron Hurricane and a 1459 Flight Havoc. The concept behind the Turbinlite-equipped Havoc was rendered obsolete with the introduction of higher frequency centimetric radar along with suitable high-performance night fighters such as

2701-405: The antenna was rotated mechanically, followed by the display on the operator's console. That is, instead of a single line across the bottom of the display from left to right, the line was rotated around the screen at the same speed as the antenna was turning. The result was a 2-D display of the air space around the station with the operator in the middle, with all the aircraft appearing as dots in

2774-454: The bottom of the screen – would give target range. By rotating the receiver goniometer connected to the antennas, the operator could estimate the direction to the target (this was the reason for the cross shaped antennas), while the height of the vertical displacement indicated formation size. By comparing the strengths returned from the various antennas up the tower, altitude could be gauged with some accuracy. CH proved highly effective during

2847-633: The development of the GL3B . All of the equipment, including the power generator, was contained in a protected trailer, topped with two 6-foot dish transmitting and receiving antennas on a rotating base, as the transmit-receive (T-R) switch allowing a single antenna to perform both functions had not yet been perfected. Similar microwave gun-laying systems were being developed in Canada (the GL3C ) and in America (eventually designated SCR-584 ). Although about 400 of

2920-426: The earlier, lower frequency radars. A radar with a wavelength of 2 meters (VHF band, 150 MHz) cannot detect objects that are much smaller than 2 meters and requires an antenna whose size is on the order of 2 meters (an awkward size for use on aircraft). In contrast, a radar with a 10 cm wavelength can detect objects 10 cm in size with a reasonably sized antenna. In addition a tuneable local oscillator and

2993-416: The even higher-frequency American-created H2X , allowed new tactics in the strategic bombing campaign . Centimetric gun-laying radars were much more accurate than older technology; radar improved Allied naval gunnery and, together with the proximity fuze , made anti-aircraft guns much more effective. The two new systems used by anti-aircraft batteries are credited with destroying many V-1 flying bombs in

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3066-521: The exchange began, the British were surprised to learn of the development of the U.S. Navy's pulse radar system, the CXAM , which was found to be very similar in capability to their Chain Home technology. Although the U.S. had developed pulsed radar independently of the British, there were serious weaknesses in America's efforts, especially the lack of integration of radar into a unified air defense system. Here,

3139-571: The existing Chain Home. Consequently, CD was also adopted by the RAF to augment the CH stations; in this role, it was designated Chain Home Low ( CHL ). When the cavity magnetron became practicable, the ADEE co-operated with TRE in utilising it in an experimental 20 cm GL set. This was first tested and found to be too fragile for army field use. The ADEE became the ADRDE in early 1941, and started

3212-513: The existing sets because of a submarine's smaller physical size than most other vessels. When the first cavity magnetron was delivered to the TRE, a demonstration breadboard was built and demonstrated to the Admiralty. In early November 1940, a team from Portsmouth under S. E. A. Landale was set up to develop a 10-cm surface-warning set for shipboard use. In December, an experimental apparatus tracked

3285-659: The facility became the Air Defence Research and Development Establishment (ADRDE) in mid-1941. A year later, the ADRDE relocated to Great Malvern , in Worcestershire . In 1944, this was redesignated the Radar Research and Development Establishment (RRDE). While at Bawdsey, the Army detachment developed a Gun Laying ("GL") system termed Transportable Radio Unit ( TRU ). Pollard was project leader. Operating at 60 MHz (6-m) with 50-kW power,

3358-438: The first Naval S-band radar, was in operational use. The cavity magnetron was perhaps the single most important invention in the history of radar. In the Tizard Mission during September 1940, it was given free to the U.S., along with other inventions, such as jet technology, in exchange for American R&D and production facilities; the British urgently needed to produce the magnetron in large quantities. Edward George Bowen

3431-453: The first apparatus was demonstrated. On November 16, the first German submarine was sunk after being detected by a Type 271. The initial Type 271 primarily found service on smaller vessels . At ASE Witley, this set was modified to become Type 272 and Type 273 for larger vessels. Using larger reflectors, the Type 273 also effectively detected low-flying aircraft, with a range up to 30 miles. This

3504-683: The ground without "seeing" the reflection of the ground or water – known as clutter . Unlike the larger CH systems, the CHL broadcast antenna and receiver had to be rotated; this was done manually on a pedal-crank system by members of the WAAF until the system was motorised in 1941. Systems similar to CH were later adapted with a new display to produce the Ground-Controlled Intercept (GCI) stations in January 1941. In these systems,

3577-526: The idea of an airborne searchlight for night-fighters, that he termed "aerial target illumination" (ATI). He enlisted the help of William Helmore , and they jointly took out patents on the techniques. Helmore, a serving RAF officer, then sponsored the development of what became known as Turbinlite. At around this time the Bostons converted to night duties (and known as Havoc) then entering limited service as nightfighters and intruders offered an alternative to

3650-468: The kilowatt range, opening the path to second-generation radar systems. After the Fall of France , Britain realised that the manufacturing capabilities of the United States were vital to success in the war; thus, although America was not yet a belligerent, Prime Minister Winston Churchill directed that Britain's technological secrets be shared in exchange for the needed capabilities. In the summer of 1940,

3723-455: The late summer of 1944. During Air Ministry RDF development in Bawdsey, an Army detachment was attached to initiate its own projects. These programmes were for a Gun Laying (GL) system to assist aiming antiaircraft guns and searchlights and a Coastal Defense (CD) system for directing coastal artillery. The Army detachment included W. A. S. Butement and P. E. Pollard who, in 1930, demonstrated

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3796-513: The latest reports on the history U.S. Navy periscope detection the first minimal possibilities for periscope detection appeared only during 50's and 60's and the problem was not completely solved even on the turn of the millennium. In addition, radar could detect the submarine at a much greater range than visual observation, not only in daylight but at night, when submarines had previously been able to surface and recharge their batteries safely. Centimetric contour mapping radars such as H2S , and

3869-475: The major RDF/radar equipment used by the Air Ministry is briefly described. All of the systems were given the official designation Air Ministry Experimental Station (AMES) plus a Type number; most of these are listed in this link. Shortly before the outbreak of World War II, several RDF (radar) stations in a system known as Chain Home (or CH ) were constructed along the South and East coasts of Britain, based on

3942-517: The masts than by attacking the open latticework towers themselves. To avoid the CH system, the Luftwaffe adopted other tactics. One was to approach the coastline at very low altitude. This had been anticipated and was countered to some degree with a series of shorter-range stations built right on the coast, known as Chain Home Low ( CHL ). These systems had been intended for naval gun-laying and known as Coastal Defence (CD), but their narrow beams also meant that they could sweep an area much closer to

4015-409: The numbered flights were incorporated with their own fighter aircraft into new squadrons Typically during operations, 1453 Flt operated in conjunction with No. 151 Squadron RAF and No. 486 Squadron RNZAF , illuminating targets for the fighters to attack, with each flight / squadron of Turbinlite Havocs being associated with fighter squadrons in their vicinity. The Turbinlite was later considered in

4088-423: The proper location in space. Called plan position indicators (PPI), these simplified the amount of work needed to track a target on the operator's part. Philo Taylor Farnsworth refined a version of his picture tube ( cathode ray tube , or CRT) and called it an "Iatron". It could store an image for milliseconds to minutes (even hours). One version that kept an image alive about a second before fading, proved to be

4161-709: The pulse width. With steerable antennas, it was also used for Gun Control. This was first used in combat in March 1941 with considerable success. Type 281B used a common transmitting and receiving antenna. The Type 281 , including the B-version, was the most battle-tested metric system of the Royal Navy throughout the war. In 1938, John F. Coales began the development of 600-MHz (50-cm) equipment. The higher frequency allowed narrower beams (needed for air search) and antennas more suitable for shipboard use. The first 50-cm set

4234-424: The radar generated strong returns from ships and docks. This was due to the vertical sides of the objects, which formed excellent partial corner reflectors , allowing detection at several miles range. The team focussed on this application for much of 1938. The Air-to-surface-vessel (ASV) Mark I, using electronics similar to those of the AI sets, was the first aircraft-carried radar to enter service, in early 1940. It

4307-491: The resulting aircraft was known as the Havoc I Turbinlite . The unarmed Havoc Turbinlite was intended to find the enemy bomber using its radar and then use the Turbinlite to illuminate the target for the accompanying Hawker Hurricanes to find and shoot down. Approximately 31 Havoc I Turbinlites were so modified, using the Havoc I or Havoc L.A.M . (long aerial mine), which had themselves originally been Boston II 's, before

4380-656: The search for a method of illuminating surfaced enemy U-boats at night, but was supplanted by the competing Leigh light . William Helmore Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.237 via cp1104 cp1104, Varnish XID 198201247 Upstream caches: cp1104 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 07:58:01 GMT Radar in World War II#Centimetric In

4453-484: The successful model at Bawdsey. CH was a relatively simple system. The transmitting side comprised two 300-ft (90-m)-tall steel towers strung with a series of antennas between them. A second set of 240-ft (73-m)-tall wooden towers was used for reception, with a series of crossed antennas at various heights up to 215 ft (65 m). Most stations had more than one set of each antenna, tuned to operate at different frequencies . Typical CH operating parameters were: CH output

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4526-417: The technology. It operated at 200 MHz 1.5 m, with 7-kW peak power. The received signal was used to direct a searchlight . In Europe, the war with Germany had depleted the United Kingdom of resources. It was decided to give the UK's technical advances to the United States in exchange for access to related American secrets and manufacturing capabilities. In September 1940, the Tizard Mission began. When

4599-722: The tubes used by Bowden in the transmitter at Orford Ness. With excellent research facilities of its own, the Admiralty-based its RDF development at the HMSS. This remained in Portsmouth until 1942, when it was moved inland to safer locations at Witley and Haslemere in Surrey . These two operations became the Admiralty Signal Establishment (ASE). A few representative radars are described. Note that

4672-534: The type numbers are not sequential by date. The Royal Navy's first successful RDF was the Type 79Y Surface Warning , tested at sea in early 1938. John D. S. Rawlinson was the project director. This 43-MHz (7-m), 70-kW set used fixed transmitting and receiving antennas and had a range of 30 to 50 miles, depending on the antenna heights. By 1940, this became the Type 281 , increased in frequency to 85 MHz (3.5 m) and power to between 350 and 1,000 kW, depending on

4745-749: The war began in September 1939, the Air Ministry RDF development at Bawdsey was temporarily relocated to University College, Dundee in Scotland. A year later, the operation moved to near Worth Matravers in Dorset on the southern coast of England, and was named the Telecommunications Research Establishment (TRE). In a final move, the TRE relocated to Malvern College in Great Malvern . Some of

4818-455: The war, British Mosquito night intruder aircraft were fitted with AI Mk VIII and later derivatives, which with Serrate allowed them to track down German night fighters from their Lichtenstein signal emissions, as well as a device named Perfectos that tracked German IFF . As a countermeasure, the German night fighters employed Naxos ZR radar signal detectors. While testing the AI radars near Bawdsey Manor, Bowen's team noticed

4891-420: Was Type 282. With 25-kW output and a pair of Yagi antennas incorporating lobe switching, it was trialed in June 1939. This set detected low-flying aircraft at 2.5 miles and ships at 5 miles. In early 1940, 200 sets were manufactured. To use the Type 282 as a rangefinder for the main armament, an antenna with a large cylindrical parabolic reflector and 12 dipoles was used. This set was designated Type 285 and had

4964-406: Was attached to the mission as the RDF lead. This led to the creation of the Radiation Laboratory (Rad Lab) based at MIT to further develop the device and usage. Half of the radars deployed during World War II were designed at the Rad Lab, including over 100 different systems costing US$ 1.5 billion. When the cavity magnetron was first developed, its use in microwave RDF sets was held up because

5037-414: Was incorporated in the transmitting array, giving high directional accuracy. To analyze system capabilities, Butement formulated the first mathematical relationship that later became the well-known "radar range equation". Although initially intended for detecting and directing fire at surface vessels, early tests showed that the CD set had much better capabilities for detecting aircraft at low altitudes than

5110-404: Was quickly replaced by the improved Mark II, which included side-scanning antennas that allowed the aircraft to sweep twice the area in a single pass. The later ASV Mk. II had the power needed to detect submarines on the surface, eventually making such operations suicidal. The improvements to the cavity magnetron by John Randall and Harry Boot of Birmingham University in early 1940 marked

5183-406: Was read with an oscilloscope . When a pulse was sent from the broadcast towers, a visible line travelled horizontally across the screen very rapidly. The output from the receiver was amplified and fed into the vertical axis of the scope, so a return from an aircraft would deflect the beam upward. This formed a spike on the display, and the distance from the left side – measured with a small scale on

5256-495: Was some doubt as to the best way to find, intercept and shoot down attacking bombers at night. The idea was put forward that an aircraft that carried a searchlight, as well as AI radar, could light up the attacking bombers after locating them for accompanying fighters to shoot them down, the single-engine fighters having a considerable performance advantage over the German twin-engine bombers. In September 1940, Sidney Cotton pursued

5329-577: Was the first Royal Navy radar with a plan-position indicator . Further development led to the Type 277 radar , with almost 100 times the transmitter power. In addition to the microwave detection sets, Coales developed the Type 275 and Type 276 microwave fire-control sets. Magnetron refinements resulted in 3.2-cm (9.4-GHz) devices generating 25-kW peak power. These were used in the Type 262 fire-control radar and Type 268 target-indication and navigation radar. In 1922, A. Hoyt Taylor and Leo C. Young , then with

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