81-526: [REDACTED] Look up CH , Ch , ch , cH , or .ch in Wiktionary, the free dictionary. CH , Ch , cH , or ch may refer to: Arts and entertainment [ edit ] Television channel (sometimes abbreviated as "ch." for television and cable stations) Chaos;Head , a video game Clone Hero , a clone game version of popular rhythm game series Guitar Hero . CollegeHumor ,
162-436: A BBC short wave transmitter and flying an aircraft around the area. Using commercial short wave radio hardware, Watt's team built a prototype pulsed transmitter and by June 1935 it detected an aircraft that happened to be flying past. Basic development was completed by the end of the year, with detection ranges on the order of 100 mi (160 km). In 1936 attention was focused on a production version, and early 1937 saw
243-479: A German newspaper with an image of a large radio antenna that had been installed on Feldberg in the same area. Although highly skeptical about claims of engine-stopping rays and death rays, the Air Ministry could not ignore them as they were theoretically possible. If such systems could be built, it might render bombers useless. If this were to happen, the night bomber deterrent might evaporate overnight, leaving
324-548: A World War II radar array Heavy cruiser (U.S. Navy ship code CH, standing for "Cruiser, Heavy") In other sciences [ edit ] Clay of high plasticity (USCS soil type CH) Cassini-Huygens Places [ edit ] Confoederatio Helvetica , the formal name for Switzerland, Latin in origin ISO country code for Switzerland .ch , the Internet country code top-level domain for Switzerland CH postcode area ;
405-659: A breezy interview, Watson-Watt and Jock Herd stated the job was his if he could sing the Welsh national anthem . He agreed, but only if they would sing the Scottish one in return. They declined, and gave him the job. Starting with the BBC transmitter electronics, but using a new transmitter valve from the Navy, Bowen produced a system that transmitted a 25 kW signal at 6 MHz (50 metre wavelength), sending out 25 μs long pulses 25 times
486-591: A championship at a conformation show, prefixed "Ch." Christ's Hospital , Horsham, West Sussex Companion of Honour , a British and Commonwealth honour Chaudhary , an honorific used in the Indian and Pakistani Punjab regions Metres above the Sea (Switzerland) , an elevation reference system The logo for the Montreal Canadiens ice hockey team Adobe Character Animator , an Adobe software Topics referred to by
567-532: A comedy website CH (television system) , a defunct Canadian television system later known as E! Businesses [ edit ] Bemidji Airlines (IATA code CH) Carolina Herrera , a fashion designer based in New York Columbia Helicopters , an aircraft manufacturing and operator company based in Aurora, Oregon, United States In language [ edit ] Ch (digraph) , considered
648-462: A complete radar could be built. While such a system could determine the angle to a target, it could not determine its range and provide a location in space. To do so, two such measurements would have to be made from different locations. Watt's huff-duff technique solved the problem of making rapid measurements, but the issue of coordinating the measurement at two stations remained, as did any inaccuracies in measurement or differences in calibration between
729-409: A considerable number of mast and aerial systems". Several members of the team went on scouting trips with Watt to the north of Orfordness but found nothing suitable. Then Wilkins recalled having come across an interesting site about 10 mi (16 km) south of Orfordness, some time earlier while on a Sunday drive. He recalled it because it was some 70–80 ft (21–24 m) above sea level, which
810-453: A containment hierarchy of classes of formal grammars Continuum hypothesis , in set theory Hyperbolic cosine , in mathematics, a hyperbolic function, ch(x) = cosh(x) Curry–Howard correspondence , the relationship between computer programs and mathematical proofs CH register , the high byte of an X86 16-bit CX register Ch (computer programming) , a cross-platform C/C++ interpreter Contraction hierarchies , in computer science,
891-439: A distance of 5 kilometres (3.1 mi) from 98 to 105 °F (37 to 41 °C). To Watt's bemusement, Wilkins immediately surmised this was a question about a death ray. He made a number of back-of-the-envelope calculations demonstrating the amount of energy needed would be impossible given the state of the art in electronics. According to R. V. Jones , when Wilkins reported the negative results, Watt asked, "Well then, if
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#1732848856510972-512: A few months of his joining the Committee, what had previously been an innovative and forward-looking group became riven with strife. It was strictly Lindemann versus the rest, with his hostility to radar and his insistence on totally impractical ideas about intercepting enemy aircraft by means of wires dangled from balloons, or by infrared, which at that time simply did not have the sensitivity to detect aircraft at long range. Churchill's backing meant
1053-586: A joint AMES-GPO group. The Treasury gave approval for full-scale deployment in August, and the first production contracts were sent out for 20 sets in November, at a total cost of £380,000. Installation of 15 of these sets was carried out in 1937 and 1938. In June 1938 a London headquarters was established to organize the rapidly growing force. This became the Directorate of Communications Development (DCD), with Watt named as
1134-400: A receiver to give an early indication of approaching aircraft. Watt wrote back to the committee saying the death ray was extremely unlikely, but added: Attention is being turned to the still difficult, but less unpromising, problem of radio detection and numerical considerations on the method of detection by reflected radio waves will be submitted when required. The letter was discussed at
1215-538: A second. Meanwhile, Wilkins and L.H. Bainbridge-Bell built a receiver based on electronics from Ferranti and one of the RRS CRTs. They decided not to assemble the system at the RRS for secrecy reasons. The team, now consisting of three scientific officers and six assistants, began moving the equipment to Orfordness on 13 May 1935. The receiver and transmitter were set up in old huts left over from World War I artillery experiments,
1296-447: A signal detectable at about 10 miles (16 km). They went on to suggest that the output power could be increased as much as ten times if the system operated in pulses instead of continuously, and that such a system would have the advantage of allowing range to the targets to be determined by measuring the time delay between transmission and reception on an oscilloscope . The rest of the required performance would be made up by increasing
1377-444: A single letter in several Latin-alphabet languages Chamorro language : ISO 639 alpha-2 language code (ch) Science and technology [ edit ] Chemistry [ edit ] The methylidyne radical (a carbyne); CH (or •CH), CH (or ⫶ CH) The methylidyne group ≡CH The methine group (methanylylidene, methylylidene) =CH− Mathematics and computing [ edit ] Chomsky hierarchy , in computer science,
1458-584: A speech on "The threat of Nazi Germany" in which he pointed out that the Royal Navy could not protect Britain from an enemy who attacked by air. Through the early 1930s, a debate raged within British military and political circles about strategic airpower. Baldwin's famous speech led many to believe the only way to prevent the bombing of British cities was to make a strategic bomber force so large it could, as Baldwin put it, "kill more women and children more quickly than
1539-630: A speed-up technique for finding shortest paths in a graph Medicine [ edit ] Cholesterol Cluster headache Congenital hypothyroidism , a condition of thyroid hormone deficiency present at birth Cerebellar hypoplasia , characterized by reduced cerebellar volume Cerebellar hypoplasia (non-human) French catheter scale (Charrière), a scale for medical catheters, also abbreviated as Fr Children's hospital Military technology [ edit ] Cargo helicopter (U.S. military helicopter alpha-numeric prefix) Chain Home ,
1620-412: A suitable pulsed transmitter. An engineer familiar with these concepts was needed. Edward George Bowen joined the team after responding to a newspaper advertisement looking for a radio expert. Bowen had previously worked on ionosphere studies under Appleton, and was well acquainted with the basic concepts. He had also used the RRS' RDF systems at Appleton's request and was known to the RRS staff. After
1701-504: A system was becoming increasingly pressing. In 1932, Winston Churchill and his friend, confidant and scientific advisor Frederick Lindemann travelled by car in Europe, where they saw the rapid rebuilding of the German aircraft industry. It was in November of that year that Stanley Baldwin gave his famous speech, stating that " The bomber will always get through ". In the early summer of 1934,
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#17328488565101782-704: Is different from Wikidata All article disambiguation pages All disambiguation pages CH">CH The requested page title contains unsupported characters : ">". Return to Main Page . Chain Home Chain Home , or CH for short, was the codename for the ring of coastal early warning radar stations built by the Royal Air Force (RAF) before and during the Second World War to detect and track aircraft. Initially known as RDF , and given
1863-467: The Tizard Committee asked radio expert Robert Watson-Watt to comment on the repeated claims of radio death rays and reports suggesting Germany had built some sort of radio weapon. His assistant, Arnold Wilkins , demonstrated that a death ray was impossible but suggested radio could be used for long-range detection. In February 1935, a successful demonstration was arranged by placing a receiver near
1944-405: The acoustic mirror systems that had been in development for a decade were still limited to only 5 mi (8.0 km) range under most conditions, and were very difficult to use in practice. Work on mirror systems ended, and on 19 December 1935, a £60,000 contract for five RDF stations along the south-east coast was sent out, to be operational by August 1936. The only person not convinced of
2025-465: The bearing of any reflections. Such a system saw patents issued to Germany's Christian Hülsmeyer in 1904, and widespread experimentation with the basic concept was carried out from then on. These systems revealed only the bearing to the target, not the range, and due to the low power of radio equipment of that era, they were useful only for short-range detection. This led to their use for iceberg and collision warning in fog or bad weather, where all that
2106-521: The gain of the antennas by making them very tall, focusing the signal vertically. The memo concluded with an outline for a complete station using these techniques. The design was almost identical to the CH stations that went into service. The letter was seized on by the Committee, who immediately released £4,000 to begin development. They petitioned Hugh Dowding , the Air Member for Supply and Research , to ask
2187-420: The 1950s. Only a few of the original sites remain. From the earliest days of radio technology, signals had been used for navigation using the radio direction finding (RDF) technique. RDF can determine the bearing to a radio transmitter, and several such measurements can be combined to produce a radio fix , allowing the receiver's position to be calculated. Given some basic changes to the broadcast signal, it
2268-486: The British military with claims of having perfected some form of the fabled electric or radio " death ray ". Some turned out to be frauds and none turned out to be feasible. Around the same time, a series of stories suggested another radio weapon was being developed in Germany. The stories varied, with one common thread being a death ray, and another that used the signals to interfere with an engine's ignition system to cause
2349-659: The Chester postcode area in the UK Chihuahua (state) , the State of Chihuahua, Mexico Conservation Halton , in Ontario, Canada China (FIPS and NATO country code CH) Chandigarh , a union territory of India Chapel Hill, North Carolina Other uses [ edit ] Chain (length) , a unit of linear measure in the Imperial system Championship (dog) , a dog qualifying for
2430-541: The GPO testing team's observation that aircraft flying near the receiver caused the signal to change in intensity, an annoying effect known as fading . The stage was now set for the development of radar in the UK. Using Wilkins' knowledge that shortwave signals bounced off aircraft, a BBC transmitter to light up the sky as in Appleton's experiment, and Watt's RDF technique to measure angles,
2511-705: The Met Office and NPL, were combined to form the Radio Research Station (with the same acronym, RRS), run by the NPL with Watt as the Superintendent. This provided Watt with direct contact to the research community, as well as the chief signals officers of the British Army , Royal Navy and Royal Air Force . Watt became a well-known expert in the field of radio technology. This began a long period where Watt agitated for
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2592-478: The NPL to take a more active role in technology development, as opposed to its pure research role. Watt was particularly interested in the use of radio for long-range aircraft navigation, but the NPL management at Teddington was not receptive and these proposals went nowhere. In 1931, Arnold Frederic Wilkins joined Watt's staff in Slough. As the "new boy", he was given a variety of menial tasks to complete. One of these
2673-514: The RAF carried out large-scale exercises with up to 350 aircraft. The forces were split, with bombers attempting to attack London, while fighters, guided by the Observer Corps , attempted to stop them. The results were dismal. In most cases, the vast majority of the bombers reached their target without ever seeing a fighter. To address the one-sided results, the RAF gave increasingly accurate information to
2754-481: The RRS team, along with Rowe representing the Tizard Committee. Watt was so impressed he later claimed to have exclaimed: "Britain has become an island again!" Rowe and Dowding were equally impressed. It was at this point that Watt's previous agitation over development became important; NPL management remained uninterested in practical development of the concept, and was happy to allow the Air Ministry to take over
2835-454: The RRS. The system consisted of several parallel dipoles separated vertically on the receiver masts. Normally the RDF goniometer was connected to two crossed dipoles at the same height and used to determine the bearing to a target return. For height finding, the operator instead connected two antennas at different heights and carried out the same basic operation to determine the vertical angle. Because
2916-540: The Treasury for another £10,000. Dowding was extremely impressed with the concept, but demanded a practical demonstration before further funding was released. Wilkins suggested using the new 10 kW, 49.8 m BBC Borough Hill shortwave station in Daventry , Northamptonshire as a suitable ad hoc transmitter. The receiver and an oscilloscope were placed in a delivery van the RRS used for measuring radio reception around
2997-487: The UK open to attack by Germany's ever-growing air fleet. Conversely, if the UK had such a device, the population could be protected. In 1934, along with a movement to establish a scientific committee to examine these new types of weapons, the RAF offered a £1,000 prize to anyone who could demonstrate a working model of a death ray that could kill a sheep at 100 yards; it went unclaimed. The need to research better forms of air defense prompted Harry Wimperis to press for
3078-465: The addition of height finding. The first five stations, covering the approaches to London, were installed by 1937 and began full-time operation in 1938. Over the next two years, additional stations were built while the problem of disseminating the information to the fighter aircraft led to the first integrated ground-controlled interception network, the Dowding system . By the time the war started, most of
3159-500: The changing wavelengths. The application of this technique to a detection system was not lost on those working in the field, and such a system was prototyped by W. A. S. Butement and P. E. Pollard of the British Signals Experimental Establishment (SEE) in 1931. The War Office proved uninterested in the concept and the development remained little known outside SEE. At the same time, the need for such
3240-478: The countryside. On 26 February 1935, they parked the van in a field near Upper Stowe and connected it to wire antennas stretched across the field on top of wooden poles. A Handley Page Heyford made four passes over the area, producing clearly notable effects on the CRT display on three of the passes. A memorial stone was placed at the site of the test. Observing the test were Watt, Wilkins, and several other members of
3321-414: The death ray is not possible, how can we help them?" Wilkins recalled the earlier report from the GPO, and noted that the wingspan of a contemporary bomber aircraft , about 25 m (82 ft), would be just right to form a half-wavelength dipole antenna for signals in the range of 50 m wavelength, or about 6 MHz. In theory, this would efficiently reflect the signal and could be picked up by
CH - Misplaced Pages Continue
3402-431: The defenders, eventually telling the observers where and when the attacks would be taking place. Even then, 70 per cent of the bombers reached their targets unhindered. The numbers suggested any targets in the city would be destroyed. Squadron Leader P. R. Burchall summed up the results by noting that "a feeling of defencelessness and dismay, or at all events of uneasiness, has seized the public." In November, Churchill gave
3483-524: The direction to be determined before the signal disappeared. In 1922, he solved this by connecting a cathode-ray tube (CRT) to a directional Adcock antenna array, originally built by the RRS but now unused. The combined system, later known as huff-duff (from HF/DF, high frequency direction finding), allowed the almost instantaneous determination of the bearing of a signal. The Met Office began using it to produce storm warnings for aviators. During this period, Edward Appleton of King's College, Cambridge
3564-539: The east and south coasts had radar coverage. Chain Home proved important during the Battle of Britain in 1940. CH systems could detect enemy aircraft while they were forming over France, giving RAF commanders ample time to marshal their aircraft in the path of the raid. This had the effect of multiplying the effectiveness of the RAF to the point that it was as if they had three times as many fighters, allowing them to defeat frequently larger German forces. The Chain Home network
3645-521: The enemy." Even the highest levels of the RAF came to agree with this policy, publicly stating that their tests suggested that "'The best form of defence is attack' may be all-too-familiar platitudes, but they illustrate the only sound method of defending this country from air invasion. It is attack that counts." As it became clear the Germans were rapidly rearming the Luftwaffe , the fear grew RAF could not meet
3726-455: The engine to stall. One commonly repeated story involved an English couple who were driving in the Black Forest on holiday and had their car fail in the countryside. They claimed they were approached by soldiers who told them to wait while they conducted a test, and were then able to start their engine without trouble when the test was complete. This was followed shortly thereafter by a story in
3807-469: The expected reflectivity of an aircraft. The received signal would be only 10 times as strong as the transmitted one, but such sensitivity was considered to be within the state of the art. To reach this goal, a further improvement in receiver sensitivity of two times was assumed. Their ionospheric systems broadcast only about 1 kW, but commercial shortwave systems were available with 15 amp transmitters (about 10 kW) that they calculated would produce
3888-465: The face of such a threat is inexcusable until it has definitely been shown that all the resources of science and invention have been exhausted." In 1923–24 inventor Harry Grindell Matthews repeatedly claimed to have built a device that projected energy over long ranges and attempted to sell it to the War Office, but it was deemed to be fraudulent. His attempts spurred on many other inventors to contact
3969-464: The first official meeting of the Tizard Committee on 28 January 1935. The utility of the concept was evident to all attending, but the question remained whether it was actually possible. Albert Rowe and Wimperis both checked the maths and it appeared to be correct. They immediately wrote back asking for a more detailed consideration. Watt and Wilkins followed up with a 14 February secret memo entitled Detection and Location of Aircraft by Radio Means . In
4050-517: The formation of a study group to consider new concepts. Lord Londonderry , then Secretary of State for Air , approved the formation of the Committee for the Scientific Survey of Air Defence in November 1934, asking Henry Tizard to chair the group, which thus became better known to history as the Tizard Committee . When Wimperis sought an expert in radio to help judge the death-ray concept, he
4131-405: The new memo, Watson-Watt and Wilkins first considered various natural emanations from the aircraft – light, heat and radio waves from the engine ignition system – and demonstrated that these were too easy for the enemy to mask to a level that would be undetectable at reasonable ranges. They concluded that radio waves from their own transmitter would be needed. Wilkins gave specific calculations for
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#17328488565104212-457: The new system recently completed at Bawdsey failed. The next day, Robert Hanbury-Brown and the new recruit Gerald Touch started up the Orfordness system and were able to run the demonstrations from there. The Orfordness site was not closed until 1937. The system was deliberately developed using existing commercially available technology to speed introduction. The development team could not afford
4293-455: The objective of winning such a tit-for-tat exchange and many suggested they invest in a massive bomber building exercise. Others felt advances in fighters meant the bomber was increasingly vulnerable and suggested at least exploring a defensive approach. Among the latter group was Lindemann, test pilot and scientist, who noted in The Times in August 1934 that "To adopt a defeatist attitude in
4374-410: The official name Air Ministry Experimental Station Type 1 ( AMES Type 1) in 1940, the radar units were also known as Chain Home for most of their life. Chain Home was the first early warning radar network in the world and the first military radar system to reach operational status. Its effect on the war made it one of the most powerful systems of what became known as the "Wizard War". In late 1934,
4455-418: The other experiments at the RRS at Slough, and expressing their gratitude that the Air Ministry had granted them access to unused land at Orfordness to continue their efforts. Bowen continued increasing the voltage in the transmitter, starting with the 5000 volt maximum suggested by the Navy, but increasing in steps over several months to 12,000 V, which produced pulses of 200 kW. Arcing between
4536-461: The other members' complaints about his behaviour were ignored. The matter was eventually referred back to Lord Swinton , the new Secretary of State for Air. Swinton solved the problem by dissolving the original Committee and reforming it with Appleton in Lindemann's place. As the development effort grew, Watt requested a central research station be established "of large size and with ground space for
4617-402: The range was continually pushed out. During a 24 July test, the receiver detected a target at 40 mi (64 km) and the signal was strong enough that they could determine the target was actually three aircraft in close formation. By September the range was consistently 40 miles, increasing to 80 miles (130 km) by the end of the year, and with the power improvements Bowen worked into
4698-639: The rapid movement of the aircraft during the measurement would make coordination difficult. Since 1915, Robert Watson-Watt had been working for the Met Office in a lab that was colocated at the National Physical Laboratory 's (NPL) Radio Research Section (RRS) at Ditton Park in Slough . Watt became interested in using the fleeting radio signals given off by lightning as a way to track thunderstorms , but existing RDF techniques were too slow to allow
4779-401: The same term [REDACTED] This disambiguation page lists articles associated with the title CH . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=CH&oldid=1255805873 " Category : Disambiguation pages Hidden categories: Short description
4860-424: The shorter wavelength produced no loss of performance. This led to a further reduction to 13 m, and finally the ability to tune between 10 and 13 m, (roughly 30-20 MHz) to provide some frequency agility to help avoid jamming. Wilkins' method of height-finding was added in 1937. He had originally developed this system as a way to measure the vertical angle of transatlantic broadcasts while working at
4941-594: The site on 15 June to examine the team's progress. Watt secretly arranged for a Vickers Valentia to fly nearby, and years later insisted that he saw the echoes on the display, but no one else recalls seeing these. Watt decided not to return to the RRS with the rest of the Tizard group and stayed with the team for another day. With no changes made to the equipment, on 17 June the system was turned on and immediately provided returns from an object at 17 mi (27 km). After tracking it for some time, they watched it fly off to
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#17328488565105022-408: The south and disappear. Watt phoned the nearby Seaplane Experimental Station at Felixstowe and the superintendent stated that a Supermarine Scapa flying boat had just landed. Watt requested the aircraft return to make more passes. This event is considered the official birth date of radar in the UK. Aircraft from RAF Martlesham Heath took over the job of providing targets for the system, and
5103-407: The team. Days later, the Treasury released £12,300 for further development, and a small team of the RRS researchers were sworn to secrecy and began developing the concept. A system was to be built at the RRS station, and then moved to Orfordness for over-water testing. Wilkins would develop the receiver based on the GPO units, along with suitable antenna systems. This left the problem of developing
5184-685: The time to develop and debug new technology. Watt, a pragmatic engineer, believed "third-best" would do if "second-best" would not be available in time and "best" never available at all. This led to the use of the 50 m wavelength (around 6 MHz), which Wilkins suggested would resonate in a bomber's wings and improve the signal. Unfortunately, this also meant that the system was increasingly blanketed by noise as new commercial broadcasts began taking up this formerly high-frequency spectrum . The team responded by reducing their own wavelength to 26 m (around 11 MHz) to get clear spectrum. To everyone's delight, and contrary to Wilkins' 1935 calculations,
5265-437: The transmitter antenna was a single dipole strung horizontally between two 75 foot (23 m) poles, and the receiver a similar arrangement of two crossed wires. The system showed little success against aircraft, although echoes from the ionosphere as far as 1,000 miles away were noted. The group released several reports on these effects as a cover story , claiming that their ionospheric studies had been interfering with
5346-399: The transmitter antenna was deliberately focused vertically to improve gain, a single pair of such antennas would only cover a thin vertical angle. A series of such antennas was used, each pair with a different center angle, providing continuous coverage from about 2.5 degrees over the horizon to as much as 40 degrees above it. With this addition, the final remaining piece of Watt's original memo
5427-403: The transmitter, was over 100 mi (160 km) by early 1936. In August 1935, Albert Rowe , secretary of the Tizard Committee, coined the term "Radio Direction and Finding" (RDF), deliberately choosing a name that could be confused with "Radio Direction Finding", a term already in widespread use. In a 9 September 1935 memo, Watson-Watt outlined the progress to date. At that time the range
5508-603: The two stations. The missing technique that made radar practical was the use of pulses to determine range by measuring the time between the transmission of the signal and reception of the reflected signal. This would allow a single station to measure angle and range simultaneously. In 1924, two researchers at the Naval Research Laboratory in the United States, Merle Tuve and Gregory Briet, decided to recreate Appleton's experiment using timed pulsed signals instead of
5589-464: The utility of RDF was Lindemann. He had been placed on the Committee at the insistence of his friend, Churchill, and proved unimpressed with the team's work. When he visited the site, he was upset by the crude conditions, and apparently, by the box lunch he had to eat. Lindemann strongly advocated the use of infrared systems for detection and tracking and numerous observers have noted Lindemann's continual interference with radar. As Bowen put it, Within
5670-400: The valves required the transmitter to be rebuilt with more room between them, while arcing on the antenna was solved by hanging copper balls from the dipole to reduce corona discharge . By June the system was working well, although Bainbridge-Bell proved to be so skeptical of success that Watt eventually returned him to the RRS and replaced him with Nick Carter. The Tizard Committee visited
5751-405: Was about 40 mi (64 km), so Watson-Watt suggested building a complete network of stations 20 mi (32 km) apart along the entire east coast. Since the transmitters and receivers were separate, to save development costs he suggested placing a transmitter at every other station. The transmitter signal could be used by a receiver at that site as well as the ones on each side of it. This
5832-481: Was accomplished and the system was ready to go into production. Industry partners were canvassed in early 1937, and a production network was organized covering many companies. Metropolitan-Vickers took over design and production of the transmitters, AC Cossor did the same for the receivers, the Radio Transmission Equipment Company worked on the goniometers, and the antennas were designed by
5913-638: Was carrying out experiments that would lead to him winning the Nobel Prize in Physics . Using a BBC transmitter set up in 1923 in Bournemouth and listening for its signal with a receiver at Oxford University , he was able to use changes in wavelength to measure the distance to a reflective layer in the atmosphere then known as the Heaviside layer . After the initial experiments at Oxford, an NPL transmitter at Teddington
5994-547: Was continually expanded, with over 40 stations operational by the war's end, including mobile versions for use overseas. Late in the war, when the threat of Luftwaffe bombing had ended, the CH systems were used to detect V2 missile launches. UK radar systems were wound down after the war but the start of the Cold War led to the Chain Home radars being pressed into service in the new ROTOR system until replaced by newer systems in
6075-434: Was naturally directed to Watt. He wrote to Watt "on the practicability of proposals of the type colloquially called 'death ray'". The two met on 18 January 1935, and Watt promised to look into the matter. Watt turned to Wilkins for help but wanted to keep the underlying question a secret. He asked Wilkins to calculate what sort of radio energy would be needed to raise the temperature of 8 imperial pints (4.5 L) of water at
6156-470: Was possible for the receiver to determine its location using a single station. The UK pioneered one such service in the form of the Orfordness Beacon . Through the early period of radio development it was widely known that certain materials, especially metal, reflected radio signals. This led to the possibility of determining the location of objects by broadcasting a signal and then using RDF to measure
6237-461: Was quickly rendered moot by the rapid increases in range. When the Committee next visited the site in October, the range was up to 80 mi (130 km), and Wilkins was working on a method for height finding using multiple antennas. In spite of its ad hoc nature and short development time of less than six months, the Orfordness system had already become a useful and practical system. In comparison,
6318-484: Was required was the rough bearing of nearby objects. The use of radio detection specifically against aircraft was first considered in the early 1930s. Teams in the UK, US, Japan, Germany and others had all considered this concept and put at least some amount of effort into developing it. Lacking ranging information, such systems remained of limited use in practical terms; two angle measurements could be used, but these took time to complete using existing RDF equipment and
6399-520: Was to select a new shortwave receiver for ionospheric studies, a task he undertook with great seriousness. After reading everything available on several units, he selected a model from the General Post Office (GPO) that worked at (for that time) very high frequencies. As part of their tests of this system, in June 1932 the GPO published a report, No. 232 Interference by Aeroplanes . The report recounted
6480-553: Was unusual in that area. The large manor house on the property would have ample room for experimental labs and offices. In February and March 1936, the team moved to Bawdsey Manor and established the Air Ministry Experimental Station (AMES). When the scientific team left in 1939, the site became the operational CH site RAF Bawdsey . While the "ness team" began moving to Bawdsey, the Orfordness site remained in use. This proved useful during one demonstration when
6561-453: Was used as a source, received by Appleton in an out-station of King's College in the East End of London. Watt learned of these experiments and began conducting the same measurements using his team's receivers in Slough. From then on, the two teams interacted regularly and Watt coined the term ionosphere to describe the multiple atmospheric layers they discovered. In 1927 the two radio labs, at
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