History of Radar
During the 1930s, efforts to use radio echoes for aircraft detection were initiated independently and almost simultaneously in eight countries that were concerned with the prevailing military situation and that already had practical experience with radio technology. The United States, Great Britain, Germany, France, the Soviet Union, Italy, the Netherlands, and Japan all began experimenting with radar within about two years of one another and embarked, with varying degrees of motivation and success, on its development for military purposes. Several of these countries had some form of operational radar equipment in military service at the start of World War II.
USA Radars development history
Summary
The development of radio electronics in the United States in the prewar years allowed the creation of a wide range of radar devices at the very beginning of the Second World War. Radars were equipped with air defense forces, aviation and navy. An important role in the development of American radars was played by the exchange of information with the United Kingdom, which enabled the Americans to receive information about the latest developments of both allies and Germany. Unqualified leadership in the development of shipborne and airborne radar during the Second World War belonged to the United States. Developers of US radars were the first to massively use the microwave range, and also made a great contribution to signal processing technology.
Implement of the first rad
In 1922 two engineers of Naval Aircraft Radio Laboratory (Washington, D.C.) Albert H. Taylor and Leo C. Young placed both transmitter and receiver on different sides of river to make some communication experiments. During such experiments, they casually noticed some wooden ship that was interfering with their signals. Due to randomness of this observation, they did not make a research about that possible way to detect an object and just continued to work on another projects in Naval Research Laboratory (NRL) created in 1923 and headed by Albert H. Taylor. Then in 1930 one of Taylor’s assistant, Lawrence A. Hyland, was testing an antenna and observed an interference from a passing through aircraft. Reminded of the 1922 observation of a similar nature, Taylor and Young submitted a report titled “Radio-Echo Signals from Moving Objects,” and with Taylor and Young had demonstrated the first continuous wave interference detector. They had a patent (U.S. No. 1981884, 1934) granted for a “System for detecting objects by radio”.
A.Taylor during experiments
Leo Young with radio transmitter
Lack of success by early 1934, however, led Young to suggest to try a pulsed transmitter, that would provide timing between the transmitted and received pulse, that in turn, could be used to determine the distance to the target. Robert Morris Page was assigned by Taylor to construct such experimental system. It consisted of pulse transmitter, an antenna, a receiver, modified to pass pulsed signals and an oscilloscope displayed both the transmitted and received signals. Starting from testing it on the roof of NRL’s building, in December 1934 Page achieved significant result: the system could successfully detected an aircraft at distances up to one mile. This was a proof of the basic concept and was a demonstrating the world's first true radar (Which could not only detect objects but also measured the distance (range) to the target)
US Navy Radar production
“XAF” is one of the most important inventions in the field of military technology after the advent of radio.The commander of the Atlantic squadron, U.S. Navy
In January 1939 a prototype of a shipboard surveillance radar system operating at frequency of 200 MHz (1.5 m), called “XAF”, was demonstrated. XAF was installed on battleship New York and was able to detect aircraft at a distance of 185 km, and ship - at a distance of 28 km. In addition, it was determined that the radar could be useful in navigation, could observe explosion of missiles, as well as to track large caliber missiles during their flight. The captain of battleship New York made an enthusiastic response about the use of radar, after reading which the leadership of U.S Navy recommended to install radar in all major ships and aircraft carriers.
NRL’s XAF radar on the battleship USS New York, 1938-1939.
U.S. Army's Radar production
Engineer of U.S. Army's Signal Corps Laboratories (SCL) often called the “Father of American Radar” William R. Blair was initially involved in projects of detecting aircraft from thermal radiation and sound ranging. In SCL also worked Harold Zahl who’s initial project was about detecting aircraft using thermal radiation from their engines. After Page's success with pulse-transmission the SCL was also directed towards this area of research. In 1931, Blair initiated Project 88, “Position Finding by Means of Light.” Here “light” was used in the general sense of electromagnetic radiation, including infrared and the very-short radio waves with line-of-sight transmission characteristics (microwaves).
Image of searchlight
In 1935 Blair proposed pulse-echo technique (on which was based a patent titled “Object Locating System” applied by SCL in 1945, because of secrecy, however, it was not allowed to apply for a patent until after the end of World War II, U.S. Patent No. 2,803,819 was granted in 1957) In December 1936, SCL’s engineer Paul E. Watson developed a pulsed system capable to detect aircraft flying in New York City airspace at ranges up to 11 km. By 1937 Watson's team had developed a proto-type “Search Light Control Radar” (SCR) apparatus and successfully demonstrated it.
Radio Set SCR-270 set up for operation
SCR-270 operations van components
By 1938, this system had evolved into the first radar developed by the U.S. Army named the SCR-268 (worked at a frequency of 205 MHz) for controlling anti-aircraft gunfire and the SCR-270 (mobile configuration) and the SCR-271 (fixed-site) radar systems for detecting and positioning aircraft. SCR-270 and SCR-271 used a common antenna for both transmitting and receiving, were formed of gas-discharge device, called a duplexer, invented by Zahl. SCR-270 and SCR-271 worked at frequency 106 Mhz (2, 83m ) and with power 100 Kw provided range detection of 230 km. These systems started to be fielded in 1940, and were used throughout the war.
Non portable version: the SCR-271 at Camp Evans
SCR-271-D Range Scope
Tizard Mission
“When the members of the Tizard Mission brought one cavity magnetron to America in 1940, they carried the most valuable cargo ever brought to our shores”.
James Phinney Baxter III, Official Historian of the Office of Scientific Research and Development. Baxter III 1946, p. 142.
Being involved in war with Germany, the United Kingdom proved a significant lack of resources. By Tizard Mission started in 1940 it was decided to give the UK's technical advances to the United States in exchange for their manufacturing capabilities and some related American technologies. One of the leading roles in this operation was played by the developments of radar. For example, the SCR-270 versions were eventually replaced by newer microwave units based on cavity magnetron that was introduced to the US during Tizard Mission.
Radars for artillery and anti-aircraft fire control
Bell Telephone Laboratories (BTL) was the first to develop a centimeter range radar for artillery fire control systems, (A fire-control system is a number of components working together, usually a gun data computer, a director, and radar, which is designed to assist a weapon system in hitting its target. It performs the same task as a human gunner firing a weapon, but attempts to do so faster and more accurately.)
Image showing guns on ship.
while NRL and SCL developers were working on radars operating in the meter wave range. BTL, according to the Tizard plan, obtained access to UK developments, based on the UK radar “Type 284”, developed FA Mark 1, the first radar of fire control for the US Navy. Later on base of FA MARk 1 was developed the prototype “FB Mark 2” and went to the series FC Mark 2 for use against surface targets, and “FD Mark 3” for the control of anti-aircraft weapons, worked on a frequency 750 MHz (60 cm),it began to be produced serially and went into service in the autumn of 1941. During the Battle for Guadalcanal, the American battleship Washinghton was able to partecipate in targeted fire fighting during a night battle on the Japanese battleship Hiei due to the use of the radar “FD Mark 3”. On the basis of “Mark 3” was created a compact 3-cm radar fire control Mark 27, which was also installed on battleships of the U.S. Navy.
Mark 3 Range Scope showing target signal.
Microwave radars for controlling anti-aircraft fire were also originally developed in the UK, and then, according to the Tizard plan, all materials were transferred to the United States. As a result, in May 1942, a 10 cm SCR-584 radar was created, which was equipped with an automatic tracking system based on an analog computer “M-9”, created in BTL.
Exterior view of the SCR-584.
The Radar Mark 8 (FH) was developed by BTL, it operated in the X-band (10 cm) and had a system with electronic scanning and fire control through an analog computer. “Mark 8” operate on power of 15-20 kW and had a detection range of 36 km. In the postwar years, a version with a parabolic antenna was also produced, having the Mark 13 index.
Mark 8 Fire Control Radar.
Shipborne Radar
In 1939, XAF was produced by Radio Corporation of America (RCA). The pre-series versions, designated "CXAM", were installed in 1940 on aircraft and battleships. The improved version, “CXAM-1”, with a simplified antenna, was produced serially and when the United States entered World War II in December 1941, the use of these radars in the US Navy was massive.
CXAM-I Antenna on Battleship.
U.S. Navy aircraft carrier USS Ranger (CV-4) on 8 November 1942, showing the CXAM-1 radar antenna
On the basis of the CXAM radars in September 1942 the SA radars were produces, they had improved resolution characteristics, were equipped with a IFF system and at a wavelength of 1.36 m at a power of 100 kW they were able to detect a bomber at a distance of 70 km and a heavy ship 20 km.
The type “SC” radars became the further development of the “CXAM” radars but were sreplaced with more advanced models isnce they had a manual antenna drive and inconvenient indicators. The radars “SC-2” and “SC-3”, working at a wavelength of 1.5 m and at a power of 20 kW, capable of detecting ships at a distance of 40 km, and planes at 160 km are much more convenient in application. Their main difference was the use of a circular indicator and use of an antenna with an electric drive from the radar “CXAM-1”. “SC-2” and “SC-3” were in service from 1943.
US, Radar, Type SC-2
The SD type radars were the first non-directional radars installed on submarines in 1942. They worked on a wave length of 2.65 m and at a power of 100 kW they were able to detect the aircraft at a distance of 37 km. The “SD” radars could only perform the early warning function, because they could not determine the direction to the target. Later, they were replaced by microwave SV radars, equipped with a rotating antenna and a circular view indicator. The range of detection by a “SV” type radar of a single aircraft or submarine at periscope depth was 12 km, the ship - up to 20 km. The type radars SC, SC-1, SC-2 and SC-3 were installed on various ships of small displacement: from torpedo boats to light cruisers.
.At the request of the Navy, in May 1941, under the direction of Ernest Pollard, the Radar SG of Massachusetts Institute of Technology created the SG 10 cm (3.3 GHz) radar. The radar had a power of 50 kW, was installed on cruisers and destroyers and allowed to detect low-flying aircraft at a distance of up to 30 km, and large ships - 41 km. The radar began to enter service since 1943 and was released in 955 copies.
Radar, Type SG
SG on Destroyer.
SG PPI Scope showing land and target ships.
Airborne radar
The first American airborne radar was the result of Tizard mission, during which the English radar “ASV Mk II” was transferred to the US for adaptation to American production. The first airborne radar “ASVC” or “ASE” was created for the US Navy, which was installed on the flying boats , torpedo-carriers and bombers.
SCR-521 in B-17.
In total, about 7,000 copies of this type of radar were produced, which operated at a frequency of 515 MHz (58.3 cm) and at a power of 8 kW it detected a submarine at a periscope depth at a distance of 12 km. Some of the radars were delivered to the UK by lend-lease as “ASV Mk II”.
In the US Air Force, this radar was put into production under the index SCR-521 and released in an amount of more than 26,000 copies.
To equip fighter aircraft in the United States, a compact radar was developed that operated on a 10 cm long wave and at 3.3 kW capacity, capable of detecting a bomber at a distance of 9 km and a fighter at 5 km. The “SCR-520” was tested at the end of March 1941, and almost immediately began to arrive at the arsenal of the heavy night fighters
Image of night fighter.
SCR-520-C scope shows target is 15 degrees to right and 5 degrees higher than fighter.
In addition to the basic modification, the SCR-517 radar was also manufactured, intended for installation on patrol flying boats. Since 1944, the radar IFF identification connections this model was issued under the designation SCR-720. In the UK, similar radars were produced under the “AI Mk X” index. Part of the SCR-720 radar was installed on the ships to provide control of the dead zone directly above the ship (“funnels”).
In Rad Lab were established a Cadillac project of creating early warning radar system. The result of the project implementation was the AN / APS-20 radar operating in the range of 20 cm (1.5 GHz) at a power of 1000 kW and located in the fairing under the fuselage of the deck torpedo carrier. The radar was able to detect a large aircraft at a distance of 160 km and was equipped with a television broadcast system. Which
Grumman TBF “Avenger” with the radar AN/APS-20
allowed to transfer the image of the indicator of a circular view to allied ships. The AN / APS-20 was adopted in August 1944 and became the prototype of the post-war radar detection system and the AWACS control concept. In 1941, Luis Alvarez invented a phased array antenna, which significantly improved the radar characteristics and reduced antenna sizes. The first radar with a phased array was the AN / APQ-7 “Eagle”, which operated in the 3 cm range (X-band).
Radar for other purposes
Another result of the interaction during Tizard was the contactless fuse VT (Variable Time fuze). The idea of creating a contactless fuse belonged to Alan Butement, who dealt with problems of coastal defense systems in the UK in 1939. The National Committee for Defense Research (NDRC) gave this work the highest secrecy.
Soon the first prototype of a fuse using a Doppler mini-radar was created. The detonator contained a generator, which after the shot continuously emitted radio waves at frequencies of 180-220 MHz. While the projectile was in the air, the radiation of the generator did not affect the receiver installed in the projectile, but as soon as some of the radio waves were reflected from the external obstacle, frequency beats appear, depending on the distance to the target. As soon as these beats reached their maximum, an electric fuse exploded. Thus, depending on the settings, it was possible to control the distance of the detonation, which significantly increased the efficiency of high-explosive and anti-aircraft guns. Weapons with a VT fuse began to be supplied in 1942, and since 1944 they have become the main product of the US electronic radio industry.
Proximity fuze MK53 fuze removed from shell.
Bibliography
- Bibliography and links
- Наземные американские и английские радиолокационные станции. — Москва: Военное издательство министерства вооружённых сил союза ССР, 1947.
- http://wiki.wargaming.net/ru/Navy:Радары_США
German Radars development history
Summary
Germany is a pioneer of using electromagnetic waves to detect objects. In 1888, Henry Hertz, who first proved the existence of electromagnetic waves, discovered that these waves, like light, can be reflected from metal surfaces. The radio engineering device for detecting ships was created in Germany by Christian Hulsmeyer in 1904. Often referred to as the first radar system, this did not directly measure the range (distance) to the target, and thus did not meet the criteria to be given this name.
Over the following three decades in Germany, a number of radio-based detection systems were developed but none were true radars. This situation changed before World War II. Developments in three leading industries are described
GEMA
In the early 1930s, physicist Rudolf Kühnhold, Scientific Director at the Kriegsmarine (German navy) Nachrichtenmittel-Versuchsanstalt (NVA—Experimental Institute of Communication Systems) in Kiel, was attempting to improve the acoustical methods of underwater detection of ships. He concluded that the desired accuracy in measuring distance to targets could be attained only by using pulsed electromagnetic waves.
During 1933, Kühnhold first attempted to test this concept with a transmitting and receiving set that operated in the microwave region at 13.5 cm (2.22 GHz). The transmitter used a Barkhausen-Kurz tube (the first microwave generator) that produced only 0.1 watt. Unsuccessful with this, he asked for assistance from Paul-Günther Erbslöh and Hans-Karl Freiherr von Willisen, amateur radio operators who were developing a VHF system for communications. They enthusiastically agreed, and in January 1934, formed a company, Gesellschaft für Elektroakustische und Mechanische Apparate (GEMA), for the effort. From the start, the firm was always called simply GEMA.
Work on a Funkmessgerät für Untersuchung (radio measuring device for research) began in earnest at GEMA. Hans Hollmann and Theodor Schultes, both affiliated with the prestigious Heinrich Hertz Institute in Berlin, were added as consultants. The first apparatus used a split-anode magnetron purchased from Philips in the Netherlands. This provided about 70 W at 50 cm (600 MHz), but suffered from frequency instability. Hollmann built a regenerative receiver and Schultes developed Yagi antennas for transmitting and receiving. In June 1934, large vessels passing through the Kiel Harbor were detected by Doppler-beat interference at a distance of about 2 km (1.2 mi). In October, strong reflections were observed from an aircraft that happened to fly through the beam; this opened consideration of targets other than ships.
Kühnhold then shifted the GEMA work to a pulse-modulated system. A new 50 cm (600 MHz) Philips magnetron with better frequency stability was used. It was modulated with 2- μs pulses at a PRF of 2000 Hz. The transmitting antenna was an array of 10 pairs of dipoles with a reflecting mesh. The wide-band regenerative receiver used Acorn tubes from RCA, and the receiving antenna had three pairs of dipoles and incorporated lobe switching. A blocking device (a duplexer), shut the receiver input when the transmitter pulsed. A Braun tube (a CRT) was used for displaying the range.
The equipment was first tested at a NVA site at the Lübecker Bay near Pelzerhaken. During May 1935, it detected returns from woods across the bay at a range of 15 km (9.3 mi). It had limited success, however, in detecting a research ship, Welle, only a short distance away. The receiver was then rebuilt, becoming a super-regenerative set with two intermediate-frequency stages. With this improved receiver, the system readily tracked vessels at up to 8 km (5.0 mi) range.
In September 1935, a demonstration was given to the Commander-in-Chief of the Kriegsmarine. The system performance was excellent; the range was read off the Braun tube with a tolerance of 50 meters (less than 1 percent variance), and the lobe switching allowed a directional accuracy of 0.1 degree. Historically, this marked the first naval vessel equipped with radar. Although this apparatus was not put into production, GEMA was funded to develop similar systems operating around 50 cm (500 MHz). These became the Seetakt for the Kriegsmarine and the Freya for the Luftwaffe (German Air Force).
Low-level aerial reconnaissance photograph of the Freya radar installations at Auderville, France
Würzburg-Riese and Freya
Kühnhold remained with the NVA, but also consulted with GEMA. He is considered by many in Germany as the Father of Radar. During 1933–6, Hollmann wrote the first comprehensive treatise on microwaves, Physik und Technik der ultrakurzen Wellen (Physics and Technique of Ultrashort Waves), Springer 1938
Telefunken
In 1933, when Kühnhold at the NVA was first experimenting with microwaves, he had sought information from Telefunken on microwave tubes. (Telefunken was the largest supplier of radio products in Germany) There, Wilhelm Tolmé Runge had told him that no vacuum tubes were available for these frequencies. In fact, Runge was already experimenting with high-frequency transmitters and had Telefunken’s tube department working on cm-wavelength devices.
In the summer of 1935, Runge, now Director of Telefunken’s Radio Research Laboratory, initiated an internally funded project in radio-based detection. Using Barkhausen-Kurz tubes, a 50 cm (600 MHz) receiver and 0.5-W transmitter were built. With the antennas placed flat on the ground some distance apart, Runge arranged for an aircraft to fly overhead and found that the receiver gave a strong Doppler-beat interference signal.
Runge, now with Hans Hollmann as a consultant, continued in developing a 1.8 m (170 MHz) system using pulse-modulation. Wilhelm Stepp developed a transmit-receive device (a duplexer) for allowing a common antenna. Stepp also code-named the system Darmstadt after his home town, starting the practice in Telefunken of giving the systems names of cities. The system, with only a few watts transmitter power, was first tested in February 1936, detecting an aircraft at about 5 km (3.1 mi) distance. This led the Luftwaffe to fund the development of a 50 cm (600 MHz) gun-laying system, the Würzburg.
Würzburg D in use. The quirl conical scanning antenna is prominent.
Lorenz
Since before the First World War, Standard Elektrik Lorenz had been the main supplier of communication equipment for the German military and was the main rival of Telefunken. In late 1935, when Lorenz found that Runge at Telefunken was doing research in radio-based detection equipment, they started a similar activity under Gottfried Müller. A pulse-modulated set called Einheit für Abfragung (DFA – Device for Detection) was built. It used a type DS-310 tube (similar to the Acorn) operating at 70 cm (430 MHz) and about 1 kW power, it had identical transmitting and receiving antennas made with rows of half-wavelength dipoles backed by a reflecting screen.
In early 1936, initial experiments gave reflections from large buildings at up to about 7 km (4.3 mi). The power was doubled by using two tubes, and in mid-1936, the equipment was set up on cliffs near Kiel, and good detections of ships at 7 km (4.3 mi) and aircraft at 4 km (2.5 mi) were attained.
The success of this experimental set was reported to the Kriegsmarine, but they showed no interest; they were already fully engaged with GEMA for similar equipment. Also, because of extensive agreements between Lorenz and many foreign countries, the naval authorities had reservations concerning the company handling classified work. The DFA was then demonstrated to the Heer (German Army), and they contracted with Lorenz for developing Kurfürst (Elector), a system for supporting Flugzeugabwehrkanone (Flak, anti-aircraft guns).
Bibliography
UK Radar development history
|Robert Watson Watt, an employee of the Meteorological Service, for a long time worked on the development of a radio instrument that captures the parameters of atmospheric electrical discharges. The need to identify the direction of the source of short-time signals led him in 1927 to create a system of directed rotating antennas, the signal from which was fed to the oscilloscope. In fact, this device was the prototype of the radio direction finder. In 1934, the UK created the Committee for Scientific Survey of Air Defense (CSSAD), of which Watson-Watt was one of the employees.
The course of further research was largely predetermined by the article of one of the tabloid newspapers about the huge radio emitters "death rays" allegedly developed in Germany. Members of the committee reacted to this news with a certain amount of skepticism, but nevertheless decided to contact one of the experts in the field of radio engineering, Arnold Wilkins, to receive substantiated comments on the mysterious rays.
In January 1935, theoretical calculations were carried out which led to the conclusion that the statements about the “rays of death” were fantastic, but the calculations themselves showed that in the case of the reflection of radio waves from various objects that are at a considerable distance, the reflected signal will have a sufficient level for its reception and display on the oscilloscope screen. Within a few weeks Wilkins prepared a report in which he outlined the general idea of receiving reflected radio waves.
He also gave detailed calculations of the required transmitter power, the signal reflection characteristics of the aircraft and the sensitivity parameters of the receiver. Wilkins suggested using a directional receiver based on the idea of detecting lightning by Watson-Watt. The delay time of the reflected signal made it possible to measure the distance to the aircraft that reflected the signal. On February 12, 1935, Watson-Watt sent this information to the Ministry of Aviation in a secret report entitled “Detection of aircraft by radio communication methods”.
The Ministry of Aviation was skeptical of the idea of Wilkins, since the reflection of radio signals at that time was not confirmed by practical experiments. To prove his idea, Wilkins conducted a scientific experiment. On February 26, 1935, the Handley Page Heyford bomber flew between the receiving station in Northamptonshire and the BBC broadcasting station in Daventry. The signal reflected by the aircraft was received by Wilkins' receiver.
The proof of reflection of the signal was the occurrence of a Doppler frequency shift , which occurs when the radio waves are reflected from moving objects. Thus, the experiment allowed not only to determine that the aircraft is at a distance of 13 km from the receiver, but also to calculate its speed. This convincing test, known as the Deventry experiment, was presented to the Ministry of Aviation and it decided to build a full-fledged demonstration system.
The construction was carried out at the military range Orford Ness in Suffole on the coast of the North Sea. In mid-May 1935, six transmitting and four receiving towers were built. In June, general testing began. On June 17, the Supermarine Scapa flying boat was discovered at a distance of 27 km. Thus, this day can be considered the day of origin of the British radar. Watson-Watt, Wilkins and transmitter designer Edward Bowen proposed to name their radar installation - from RAdio Detection And Ranging (RADAR) - radio detection and range detection.
In December 1935, the British Minister of Finance allocated 60,000 pounds sterling to build a system of five stations called Chain Home (CH), covering approaches to the Thames estuary.
Chain home coverage
At the end of 1935, Bowen suggested using a bistatic radar, the transmitters of which would be installed on the ground, and the receivers would be placed on airplanes. Thus, the beginning of the development of radars for the interception of air targets (AI) was started, and later, when the possibility of detecting ships - ASVs was discovered by chance.
In 1940, John Randall and Harry Booth finalized the electron tube - a magnetron, which allowed using a 10-cm range of waves in radars. This compact device made it possible to make a real breakthrough in radar, as it was able to generate radio pulses in the range of 10 cm, which required compact radar antennas freely placed on airplanes, and the waves themselves made it possible to detect submarines moving at periscope depth.
Bibliography
Soviet Union Radars development history
Summary
A number of outstanding scientists and engineers in the USSR conducted successful development of radar systems including their own development of magnetron and clyster. The first experiments on the use of radar in the Soviet Union date back to the early 1930s, and the first Soviet radar was adopted in 1939. During the years of the Soviet-Finnish war, mobile radars were provided with a complete coverage of the airspace on the periphery of Leningrad. After the opening of the Eastern Front of World War II, the radar stations played an important role in the air defense of Moscow, Leningrad and the oil fields of the Caucasus. In the USSR, mass production of land, aircraft and ship radar stations was established. .
First steps, implement of the first radio detection system
In 1895, Alexander Stepanovich Popov, a physics instructor at the Imperial Russian Navy school in Kronstadt, developed an apparatus using a coherer tube for detecting distant lightning strikes. The next year, he added a spark-gap transmitter and demonstrated the first radio communication set in Russia. During 1897, while testing this in communicating between two ships in the Baltic Sea, he took note of an interference beat caused by the passage of a third vessel. In his report, Popov wrote that this phenomenon might be used for detecting objects.
In December 1933, Yu. K. Korovin, an engineer of CRL (Central Radio Laboratory, Leningrad) who previously done a lot of experiments on radio communications proposed to GAU (Main Artillery Directorate of the Ministry of Defense, which was considered the “brains” of the Red Army) and then developed necessecary equipment and started the experiments of the radio detection of aircraft at Galernaya harbor of The Gulf of Finland near Leningrad.
His installation consisted of a continuous radiation transmitter operating at a wavelength of 50 cm with a power of 0.2 W, a superregenerative receiver, and parabolic antenna with a diameter of 2 m. In the report of the CRL (Central Radio Laboratory) “The direction of aircraft on decimal waves,” sent February 14, 1934 to GAU, Yu. K. Korovin formulated the first results of his work: With an antenna of power of 0.2 W and a wavelength of 50 cm was detected the aircraft at the distance of 600-700 m.
From the early 1929, the Scientific and Technical Committee of the Red Army had already worked on the problem of detecting enemy aircraft and did unsuccessful attempts to create a receiver of thermal radiation or acoustical rumor from the ignition system of aircraft engines. Thus, Korovin’s results revealed the possibility of practical use of the effect of reradiation of radio waves for practical purposes, including detection of reflecting objects and determination of the direction to them.
CRL report (original)
In October 1934 Air defense department of Red Army concluded agreement on the development of the first series of experimental radio detection stations for aircraft under the conventional names “Vega” and “Cone” for the complex of air defense named “Electrovisor.” Development was carried out under the leadership of young anti-aircraft commander and engineer of Leningrad Electro-Physics Institute (LEFI) P. K. Oshcepkov. They build a station “Vega” which was intended for long-range detection and operated on waves 3.5-4 m long and the station “Cone” allowed to determine the azimuth and range in the near zone to 15 km.
In February, 1934 GAU concluded a second contract with CRL, about a set of studies, calculations and experiments and more complex station creating, which could be able to determine three target coordinates (azimuth, elevation angle and altitude).
In 1934 a huge testing polygon with special landing field was built near Leningrad.
In the same year, in the LEFI, a group led by engineer M.D. Gurevich conducted experiments on pulsed radar. In the experiments of Gurevich, reflected signals from local objects were recorded, but it was not possible to detect the plane; then the work was suspended. In 1935, as a result of hard work of CRL, Oshcepkov and professor M.G. Grekhov at the Gorky Physico-Technical Institute (GFTI) made an installation, with a magnetron transmitter, developed under the code name “Enot” (which means Racoon), and detected aircraft at a distance of 11 km, but it was unstable due to the presence of noise on reception of reflected signals. At LFTI in the summer of 1935, an experimental radio detection installation for aircraft with two parabolic antennas with a diameter of 2 m was constructed, which could rotate in the horizontal and vertical planes.
In 1936 engineer Shembel from LFTI produced a mobile two-antenna aircraft radio detector Burya (Буря, a “Storm”), which had a detection range of 10-11 km. It was the first soviet microwave radio-detection system. Further work to improve the radio detector was continued at NII-9 (NII-9, Scientific Research Institute #9 ), which was formed due to the merger of LEFI with the Radio Experimental Laboratory.
The first soviet radio-detection system Burya
Great_Purge and blockade of Leningrad
The arrest of a number of leaders of NII-9 significantly slowed down the further development of radar technology. More precisely, in June 1937, all developments in Leningrad on radio-location were suddenly stopped. The infamous Great Purge of dictator Joseph Stalin swept over the military high commands and its supporting scientific community. The Soviet Air Defense Forces (PVO) chief was executed. Oshchepkov, charged with “high crime”, was sentenced for 10 years at a Gulag penal labor camp. NII-9 as an organization was saved, but Shenbel was dismissed and Bonch-Bruyevich was named the new director.
In 1939 M. Bonch-Bruevich formulated the idea of V-shaped beam, which could allow to a radiolocation station determine three coordinates (distance-azimuth-altitude). The draft project was ready in early 1941, but the war and the blockade of Leningrad prevented further developments in NII-9.
Experimental radiolocation station Zenit
Experimental radiolocation station Rubin
The development of radio aircraft detectors was also carried out in the Kharkov Ukrainian Institute of Physics and Technology (UFTI), where the Zenit installation was created, which operated on waves 64 cm long and at a power of 10-12 kW with detection range up to 30 km. In 1940, an aircraft-detector “Rubin” was created in UFTI, which had improved accuracy in determining the coordinates. Serial production of “Rubin” was also not started because of the outbreak of war. Further efforts, however, were disrupted by the invasion of the USSR by Germany in June 1941. In a short while, the development activities at Kharkov were ordered to be evacuated to the Far East.
Ground-based radars
Transmitter of radar RUS-1
In 1936, work on the creation of radar was concentrated in the Scientific Research and Test Institute of Communications of the Red Army (NIIS CA). The main development of the institute with collaboration of LFTI was a linear type radio detection system for the protection of state borders - the “Reven” (RUS-1) system. The system consisted of one transmitting machine and a pair of receiving stations, which were to be located at a distance of 30-40 km from the transmitter.
In September 1939, the “Reven” system was adopted for the air defense under the name of RUS-1. The first application of RUS-1 occurred during the Soviet-Finnish war, when the stations were installed in order to organize the air defense of Leningrad.
In 1936, at LFTI, worked on the installation of "Redut". Unlike RUS-1, the new installation was able not only to detect an aircraft, but also to determine its azimuth, speed and range.
In 1939 the Redut was tested in Sevastopol, it could detect ships at a distance of up to 25 km, but work on the shore was complicated by a high level of interference due to re-reflections. July 26, 1940 “Redout” was adopted for service under the name RUS-2, it was the first soviet radar. Like most Soviet pre-war radars, RUS-2 was produced in a mobile version and consisted of 3 wagons installed on an automobile chassis: an electric generator and a receiver mounted on vehicle carriage and a transmitter on the third vehicle. The receiving and transmitting cabins were equipped with a synchronized rotation drive. In the period 1940-1945, more than 600 RUS-2 stations of various modifications were produced.
RUS-2, transmitting system
Memories of radar operator about protection of the Baltic Fleet in 1941 watch
(Watch this video with English subs!)
In addition to the car installation, the version of RUS-2s Pegmatit was also available, which was placed on two trailers. Because of the shortage of cars in 1940, was developed a single-antenna version of RUS-2 “Redut-41”, in which the transmitter and receiver were placed on a common vehicle.
In 1943, RUS-2M installations began to be equipped with the IFF identification system. After upgrading, the radar stations received designations P-1, P-2 and P-2M, respectively.
“River” and “Dawn” Launched in 1939 and not completed because of the beginning of the war, the development of LFTI radar detection (“River”) and tracking(“Dawn”). In addition to these stations, it was planned to develop in 1942 a station “Redut-D” with a detection range of up to 300 km.
Stationary ground-based radars
Near Leningrad, in Toskovo , from the beginning of the war, the experimental radar “Gneiss-3” was operated with a power of 10-20 kW at a wavelength of 1.5 m. It operated in a pulsed mode, and its rotating antenna was placed on a special tower. The search for targets was carried out manually, by sound indication. Later, several analogous stations were built in the air defense regions of Moscow and Gorky.
Experimetal station of ground-based radiolocattion station, Toskovo
In Mozhaisk (military city near the Moscow), an experimental station “Porfir” was installed, based on the forced transmitter of the RUS-2 radar and a new receiver, which had a detecting range of 225 km.
Artillery aiming radar
Soviet engineers working on SON-2 radar station
In 1942, the anti-aircraft artillery radar SON-2 with a detection range of 40 km and a tracking range of 20 km with a power of 250 kW, which operated in the 4-meter range, began to receive armament. SON-2 was inherently adapted from the RII-20 of the English radar for the management of artillery fire GL Mk II, supplied by Lend-Lease. At the end of 1942, the advanced stations SON-2a and SON-2ot were manufactured.
SON-2 transmitter
In 1943, was tested the radar “Tourmaline” with a detection range of 35 km, but this development was discontinued. The development of the radio-projector “ Yahont ” (Яхонт, means Ruby ) was also stopped, as the industry of the USSR could not produce such a wide range of radars. After the termination of works on the project “Tourmaline”, a new station was developed for anti-aircraft artillery, which received the designation “Neptune”.
Tourmaline
Neptune
This radar operated at a wavelength of 1.5 m and at a power of 150 kW provided a detection range of 25 km. In 1944, this installation was adopted for the army and the equipping of meteorological stations, where it was used until the early 1970s.
Shipborne Radar
In 1936, at the request of the Navy, NII-9 developed the offshore detection station Strela
Feeder system consists of 16 antennas, radar Guis-1B
(Стрела, which means Arrow), created on the basis of the artillery radio detector “Burya”. The “Arrow” detected ships at a distance of up to 5 km. There was also the ship version of the RUS-2 station developed by the Radio Industry Research Institute under the name “Redut-K” and in 1941 it was installed on the cruiser and it warned in advance the air defense command about the impending raid.
The first truly shipborne radar instead was created in 1944 under the name “Guyce”.It was tested at the Northern Fleet and according to the test results, the upgraded radar “Guice-1M” was released, which was planned to be installed on small ships to detect submarines. The first ship, equipped in 1945 with a new radar, was the destroyer of “Strict” project 7-U. In 1944, a modification of the “Gyuys-1B” was developed, which differed in the decommissioned indicator and was tested on the destroyer.
Battleship Ognevoy with Guice-1B radar system
At the very end of the war, the Mars-1 radar was developed, which was tested on the Molotov cruiser and adopted for service under the Redan-1 . At the same time there were developments of a similar station “Mars-2”, intended for installation on destroyers, which were tested on the ship “Ognevoy.” (Огневой, which means “Of fire”) After successful tests, the radar received the serial designation “Redan-2”.
Aviation radars
The Petlyakov Pe-2 was a Soviet light bomber used during World War II. It was regarded[by whom?] as one of the best ground attack aircraft of the war and it was also successful in the roles of heavy fighter, reconnaissance and night fighter.
Scheme of visibility of the radar Gneys-2
Pe2gneys-2.jpg} Pe-2 the radar Gneys-2
In early 1941, the research institute of the radio industry commissioned by the Air Force began the development of an airborne radar in the centimeter range “Gneiss-1”.
The station was planned for deployment at Pe-2 and was supposed to provide a detection range of at least 5 km. Because of the evacuation, there were problems with the generator lamps and it was decided to develop a meter-range radar that received the Gneiss-2 index. The first experimental sample of the new station was installed on the Pe-2 in 1942 for flight tests. The radar operated on waves of length 1.5 m with a transmitter power of 10 kW. In the summer of 1942, the Gneiss-2 radar was installed on 15 Pe-2 and Pe-3 aircraft, which were transferred to military units. The combat application of the radar took place during the fighting near Moscow, Leningrad and Stalingrad. By 1944, more than 200 Gneiss-2 stations had been produced.
Airborn radar system Gneiss-2
The Gneiss-5 radar had a high-power transmitter and a detection range of 7 km. It was adopted in early 1945. For the arming of the Air Force of the Navy, modifications were made to the Gneiss-2M and Gneiss-5M, which could detect both airplanes and surface ships and were installed on IL-4
Radar system Gneiss-5C
aircraft. The range of detection of the ships by the station “Gneiss-5M” was 36 km, and the tracking of the target could be conducted at a distance of 20 km. “Gneiss-5M” was adopted on April 19, 1945.
Bibliography
- Bibliography and links
- http://wiki.wargaming.net/ru/Navy:Радары_СССР
Japan Radars development history
Summary
In the years leading up to World War II, the development of radar in Japan passed through the available technical capacity. The first locator in Japan was created just a few days before entering the war, in November 1941. The Japanese industry was ready to produce high-quality components, but the development of radar devices was casual and unsystematic. Some of the Japanese radar was copied from German, British and American developments.
Technology background
Hidetsugu Yagi with Yagi antenna
In the mid-1930s, some of the technical specialists in the Imperial Navy became interested in the possibility of using radio to detect aircraft. For consultation, they turned to Professor Yagi who was the Director of the Radio Research Laboratory at Osaka Imperial University. Yagi suggested that this might be done by examining the Doppler frequency-shift in a reflected signal.
Funding was provided to the Osaka Laboratory for experimental investigation of this technique. Kinjiro Okabe, the inventor of the split-anode magnetron and who had followed Yagi to Osaka, led the effort. Theoretical analyses indicated that the reflections would be greater if the wavelength was approximately the same as the size of aircraft structures. Thus, a VHF transmitter and receiver with Yagi antennas separated some distance were used for the experiment.
In 1936, Okabe successfully detected a passing aircraft by the Doppler-interference method; this was the first recorded demonstration in Japan of aircraft detection by radio. With this success, Okabe’s research interest switched from magnetrons to VHF equipment for target detection. This, however, did not lead to any significant funding. The top levels of the Imperial Navy believed that any advantage of using radio for this purpose were greatly outweighed by enemy intercept and disclosure of the sender’s presence.
Historically, warships in formation used lights and horns to avoid collision at night or when in fog. Newer techniques of VHF radio communications and direction-finding might also be used, but all of these methods were highly vulnerable to enemy interception. At the NTRI, Yoji Ito proposed that the UHF signal from a magnetron might be used to generate a very narrow beam that would have a greatly reduced chance of enemy detection. Development of microwave system for collision avoidance started in 1939, when funding was provided by the Imperial Navy to JRC for preliminary experiments. In a cooperative effort involving Yoji Ito of the NTRI and Shigeru Nakajima of JRC, an apparatus using a 3-cm (10-GHz) magnetron with frequency modulation was designed and built. The equipment was used in an attempt to detect reflections from tall structures a few kilometers away. This experiment gave poor results, attributed to the very low power from the magnetron.
The initial magnetron was replaced by one operating at 16 cm (1.9 GHz) and with considerably higher power. The results were then much better, and in October 1940, the equipment obtained clear echoes from a ship in Tokyo Bay at a distance of about 10 km (6.2 mi). There was still no commitment by top Japanese naval officials for using this technology aboard warships. Nothing more was done at this time, but late in 1941, the system was adopted for limited use.
In late 1940, Japan arranged for two technical missions to visit Germany and exchange information about their developments in military technology. Commander Yoji Ito represented the Navy’s interest in radio applications, and Lieutenant Colonel Kinji Satake did the same for the Army. During a visit of several months, they exchanged significant general information, as well as limited secret materials in some technologies, but little directly concerning radio-detection techniques. Neither side even mentioned magnetrons, but the Germans did apparently disclose their use of pulsed techniques.
After receiving the reports from the technical exchange in Germany, as well as intelligence reports concerning the success of Britain with firing using RDF, the Naval General Staff reversed itself and tentatively accepted pulse-transmission technology. On August 2, 1941, even before Yoji Ito returned to Japan, funds were allocated for the initial development of pulse-modulated radars. Commander Chuji Hashimoto of the NTRI was responsible for initiating this activity.
A prototype set operating at 4.2 m (71 MHz) and producing about 5 kW was completed on a crash basis. With the NTRI in the lead, the firm NEC and the Research Laboratory of Japan Broadcasting Corporation (NHK) made major contributions to the effort. Kenjiro Takayanagi, Chief Engineer of NHK’s experimental television station and called “the father of Japanese television”, was especially helpful in rapidly developing the pulse-forming and timing circuits, as well as the receiver display. In early September 1941, the prototype set was first tested; it detected a single bomber at 97 km (60 mi) and a flight of aircraft at 145 km (90 mi).
The system, Japan’s first full Radio Range Finder (RRF – radar), was designated as Mark 1 Model 1. Contracts were given to three firms for serial production; NEC built the transmitters and pulse modulators, Japan Victor the receivers and associated displays, and Fuji Electrical the antennas and their servo drives. The system operated at 3.0 m (100 MHz) with a peak-power of 40 kW. Dipole arrays with matte+-type reflectors were used in separate antennas for transmitting and receiving.
After the outbreak of the war with the United States in December 1941, the Germans sent a submarine to deliver the Würzburg radar to Japan. When the radar was transported the boat was destroyed, the same fate befell the second boat. As a result, the Japanese managed to get only part of the documentation, which was delivered by diplomatic mail. In February 1942, parts of the British GL Mk II radar and the SLC searchlight radar were found in occupied Singapore. Along with the equipment, a lot of handwritten notes were captured, which gave detailed information about the theory and operation of radars. During the Philippine operation in May 1942 on the island of Correchid in the hands of the Japanese were immediately two radar, abandoned by the Americans: SCR-268 in working order and heavily damaged SCR-270. As a result of the unusual interaction of the army and the navy for Japan in a short period, reverse-engineering of captured equipment was carried out and as a result, Japanese aviation, the army and navy received about 7500 radars of 30 types during the war years.
It is noteworthy that Japan was a leader in the development of powerful magnetrons, but their use was not planned for communication and radar, but for the transmission of energy. In 1943, in order to investigate the possibility of using microwave energy as a lethal wave weapon, a secret center for the “Ku-Go” project (“death ray”) was opened in the city of Simada. In 1943, an installation with an output power of 100 kW was created, and work was also carried out on the installation with a continuous radiation power of 1000 kW. In fact, all equipment and laboratory documents were destroyed before it was captured by the Americans.
Ground-based radars of the imperial army
On the left, the radar “Ta-Chi 1”, on the right - “Ta-Chi 2”
The Tama Research Institute of Technology (TTRI) was established by the army leadership to develop radar equipment. TTRI was staffed with qualified personnel, but most of their development was still performed on the side, in the research laboratories of Toshiba Shibaura Denik (Toshiba) and Nippon Electric Company (NEC).
In TTRI, a special system for designating radar equipment was created. The radars had the “Ta-Chi” prefix for ground systems, “Ta-Che” for ship systems and “Ta-Ki” for onboard aviation systems. ( “Ta” means Tama, “Chi” means earth, “Che” means water and “Ki” means air.)
In June 1942, NEC and Toshiba developed designs based on the captured american SCR-268, operating at a frequency of 200 MHz (1.5 m) and having a very complex set of three rotating antennas. The project, developed by NEC as the Ta-Chi 1 air target detection system, was essentially a copy of the SCR-268. But even a simple copying of this system was too difficult for the Japanese technology of that time, and the “Ta-Chi 1” was soon abandoned. In Toshiba, a similar project was named “Ta-Chi 2”, but in this case, the Japanese tried to simplify the American radar.
Tests showed that this development was also unsuitable for production due to insufficient reliability and the project was also closed. The British GL Mk 2 was much less complicated than the American SCR-268 and was easy to reverse engineer, in addition, the Japanese had the necessary components. As a result, NEC managed to create a copy of the English radar, “Ta-Chi 3”.
Ta-Chi 3 transmission antenna
Ttransmission antenna of British radar GL Mk 2
The radar operated on a wave length of 3.75 m (80 MHz) and at a power of 50 kW it detected airplanes at a range of up to 40 km. The company Sumitomo was built 150 copies of the radar, which came into service in early 1944. The radar was installed on the territory of the Japanese islands and the island of Formosa.
Despite the failure, Toshiba engineers continued to work on copies of SCR-268 and they were able to test and launch the “Ta-Chi 4” model. This radar operated at a frequency of 200 MHz (1.5 m) and at a power of 2 KW detected planes at a distance of 20 km. From the middle of 1944 70 copies of “Ta-Chi 4” were released, but by that time a more productive “Ta-Chi 3” was already available. Later, an attempt was made to modernize the “Ta-Chi 4”, which was developed under the index “Ta-Chi 31”.
Ta-chi-4
After investigating the American SCR-270 radar, Toshiba began work on a pulse-modulated radar. As a result, the “Ta-Chi 6” early warning station was developed. Its transmitter operated in the wavelength range 3-4 m (100-75 MHz) at a peak power of 50 kW.
Ta-Chi 6
Several receivers were located at a distance of 100 m from the transmitter, each of them had a manual drive of two-tiered antennas to determine the azimuth and target altitude. In this case, one station receiver could work in the tracking mode, and the rest in search mode. The data was displayed on the screen. About 350 “Ta-Chi 6” stations were built, which were in service since the beginning of 1943. In addition to the stationary version, the radar was produced by the “Ta-Chi-7” variant mounted on the car trailer, during the period 1943-1945, 60 radars of this modification were produced
Wurzburg radar reproduced by the Japanese Army from German drawings,Ta-Chi 24
“Ta-Chi 13” and “Ta-Chi 28” were designed as devices for targeting interceptors.
Other ground-based radars developed for the imperial army, the Ta-Chi 20 and the Ta-Chi 35, had altimeters in their composition, but were created at the very end of the war and were not produced serially. In the series did not go and two other models - “Ta-Chi 28” on the basis of the airborne radar and “Ta-Chi 24”, slightly modified copy of the German radar Würzburg. “Ta-Chi 18” was developed as an early warning radar based on SCR-270 and was intended for use outside the Japanese islands.
It operated on fixed waves of 3.19, 3.06, 2.94, or 2.83 m in length and had a detection range of up to 200 km. Serially, the model was not produced, as it was tested at the very end of the war. “Ta-Chi 31” was a variant of the radar “Ta-Chi 4”, protected from active jamming.
Ground radars of the Imperial Navy
Since August 1941, the Naval Technical Research Institute (NTRI) has been developing radar for the Imperial Navy. With the assistance of NEC (Nippon Electric Company) and the research laboratory of the Japanese Broadcasting Corporation NHK, a prototype radar was developed, with the main engineer in the development being NHK Chief Engineer Kenjiro Takayanagi. The radar was named “Mark 1 Model 1” [3]. The system operated at a frequency of 100 MHz (3 meters) with a peak power of 40 kW. In November 1941, the first sample of “Type 11” was installed as a ground-based early warning radar on the Pacific coast.
In total, about 30 sets were built, which were used until the end of the war. The detection range was about 130 km for a single aircraft, 250 km for a group of aircraft and 16 km for a surface ship. “Type 12” in many respects was similar to “Type 11”, but was placed on a mobile platform. Three versions were developed that operated in the 2.0 m (150 MHz) or 1.5 m (200 MHz) wave band with a peak power of 5 kW. The detection range was 50 km for a single aircraft and 100 km for a group. Since 1942, about 50 sets of all versions of these systems have been produced.
Shipborne Radar
=Imperial Army ships radar=
First, the land army began to equip its ships in Japan. This paradox is not surprising at all, given the complex relationship between the army, aviation and navy in Imperial Japan. The early warning radar “Ta-Se 1”, also known as “Mk.235” or “ultrashort wave signal device type B” was designed for use on Japanese own ships that are not part of the Imperial fleet.
The radar was to be installed on transport ships and submarines. “Mk.235” worked on waves of length 2.60-2.86 m and at a power of 50 kW had a detection range of up to 220 km. The radar was unsuccessful, in all, about 30 copies were produced in 1942-1943 for installation on transport vehicles. “Ta-Se 2” was designed as a radar for detecting submarines and worked on a wave length of 15.7 cm (1909 MHz). The transmitter power of 1 kW ensured the detection range of the submarine at a periscope depth of 2-6 km, and the surfaced boat was detected at a range of 10 km. This was one of the first attempts to create a microwave radar, but it turned out to be ineffective in combat conditions. Only two transport ships were equipped with this radar, the remaining 75 radars were dismantled.
Type 21 radar
“Type 21” was a modernized Type 12 radar, but operated at a single frequency of 200 MHz and was designed for installation on the ships of the Imperial Navy. At a power of 5 kW, the radar had a detection range of 100 km for a group of aircraft, 70 km for a single aircraft and 20 km for a large ship. The first radars were installed in April 1942 on the battleships Ise and Hyūga. A total of about 40 radars were launched, which were installed on the cruisers Aoba, Myōkō, Nachi, Haguro, Ashigara, Takao, Atago, Chōkai, Maya, Tone, Chikuma, Noshiro, Yahagi and Sakawa, as well as destroyers such as Tachibana and the aircraft carrier Zuikaku.
“Type 13” became the most widespread radar of the Japanese imperial fleet and was released in the quantity of about 1000 copies. It worked on a wave length of 2.0 m (150 MHz) with a peak power of 10 kW. Its detection range was about the same as that of the “Type 12”. Radar entered the arsenal of the surface ships in late 1942, and from 1944 it was adapted for use on submarines. In contrast to the “Type 13”, the “Type 14” early warning radars were manufactured in May 1945 in only two copies and were intended for operation on heavy ships.
Type 13
These radars operated at a frequency of 50 MHz and had a total weight of 30 tons. “Type 22” was developed on the instructions of NTRI by Japan Radio Company (JRC), the manufacturer of magnetrons. The radar operated at a frequency of 3 GHz (10 cm) and had a
Type 22 and Type 13
maximum power of 2 kW. The first prototype radar was installed on the battleship Hyūga in March 1942. The radar detected a single aircraft at a distance of 17 km, and the ship - 24 km. The serial production of the radar began in 1942, in all, about 300 pieces of radar were produced, which was mainly installed on submarines and battleships.
“Type 23” appeared as a result of an attempt to copy the German radar Würzburg and worked on a wave of 10 cm (3 GHz). Like Würzburg, the radar had a parabolic antenna and could detect large vessels at a distance of up to 35 km. Works on the radar “Type 23” were discontinued in March 1945. “Type 32” was also a 10-cm radar and equipped with horn antennas of square section. The detection range of large ships was about 30 km. The radar was produced serially since 1944, 60 copies were produced. Modification with antennas of circular cross-section received the designation “Type 33”, but it was not serially produced. Radars «Type 41», «Type 42» and «Type 43» were intended for equipping anti-aircraft batteries. More than 230 radars of this type were produced.
Aviation radars
The radar for aviation included in the Imperial fleet was conducted in Oppama Naval Air Technical Depot (ONATD) - Department of Naval Aviation of Oppama. Originally, the radar, which received the designation “Type 6 Mark 4 Mod 3 (Type 64)”, was intended for reconnaissance flying boats Kawanishi H8K2 “Emily”. It operated at a wavelength of 2 m (150 MHz) and at a power of 3 KW had a detection range of up to 130 km. The main drawback of the “Type 64” created in August 1942 was its heavy weight (more than 110 kg). Gradually, the weight was reduced and the radar produced in the amount of 2000 copies was later installed on the medium bombers Mitsubishi G4M1 Model 11 “Betty” and torpedo bombers Nakajima B5N1 “Kate”.
Type 64
ONATD also led the development of lighter radars. In October 1944, a Type N-6 weighing 60 kg was developed, but only 20 were produced. “Type N-6” worked on a wave 1.2 m long (250 MHz), had a power of 2 kW and was intended for single-engine fighter aircraft, modernized for the crew of 3 people: pilot, shooter, and radar operator. “Type FM-3” in its characteristics corresponded to the radar “Type N-6”, but was intended for installation on the anti-submarine aircraft Kyūshū Q1W “Tokai”. The radar was released in the number of 100 copies between January 1945 and the end of the war.
Together with NTRI and Yohji Ito, ONATD has developed an aeronautical microwave radar “Type FD-2” and its modification “Type FD-3”. The radar with a 2 KW magnetron transmitter operated at a wavelength of 25 cm (1.2 GHz) and weighed about 70 kg. The working range of the detection range was from 0.6 to 3 km. “Type FD-2” and “Type FD-3” were installed on night fighters Nakajima J1N1-S “Gekko”, but as night aviation in Japan was not in demand, only 100 of this type of radar were manufactured.
FD-2
The “Taki-1” radar was developed for the needs of the Imperial Army's own aviation. Originally it was intended for use on heavy bombers. Several modifications of this radar have been released, beginning in September 1943. Modifications 1-3 worked on the will of a length of 1.5 m, modification 4 - on 2 m. With an output power of 10 kW, the detection range of the submarine was 15 km, the large ship 60 km, and the formation of the ships - 100 km. 900 copies of model 1 and 300 copies of models 3 and 4 were produced.
The “Taki-13” radar, which operated on a wave length of 80 cm with an output power of 100 W, was intended for installation on torpedo bombers as a radio altimeter. His further development was the radar “Ta-Ki 15”. “Ta-Ki 11” was developed as a means of electronic counteraction to enemy radars.
Japan radar coverage in 1945
Bibliography
- Bibliography and links
- http://wiki.wargaming.net/ru/Navy:Радары_Японии
Netherlands
Early radio-based detection in the Netherlands was along two independent lines: one a microwave system at the firm Philips and the other a VHF system at a laboratory of the Armed Forces.[52]
The Philips Company in Eindhoven, Netherlands, operated Natuurkundig Laboratorium (NatLab) for fundamental research related to its products. NatLab researcher Klaas Posthumus developed a magnetron split into four elements.[53] In developing a communication system using this magnetron, C.H.J.A. Staal was testing the transmission by using parabolic transmitting and receiving antennas set side-by-side, both aimed at a large plate some distance away. To overcome frequency instability of the magnetron, pulse modulation was used. It was found that the plate reflected a strong signal.
Recognizing the potential importance of this as a detection device, NatLab arranged a demonstration for the Koninklijke Marine (Royal Netherlands Navy). This was conducted in 1937 across the entrance to the main naval port at Marsdiep. Reflections from sea waves obscured the return from the target ship, but the Navy was sufficiently impressed to initiate sponsorship of the research. In 1939, an improved set was demonstrated at Wijk aan Zee, detecting a vessel at a distance of 3.2 km (2.0 mi).
A prototype system was built by Philips, and plans were started by the firm Nederlandse Seintoestellen Fabriek (a Philips subsidiary) for building a chain of warning stations to protect the primary ports. Some field testing of the prototype was conducted, but the project was discontinued when Germany invaded the Netherlands on May 10, 1940.
Bibliography
France
In 1927, French physicists Camille Gutton and Emile Pierret experimented with magnetrons and other devices generating wavelengths going down to 16 cm. Camille's son, Henri Gutton, was with the Compagnie générale de la télégraphie sans fil (CSF) where he and Robert Warneck improved his father's magnetrons.
In 1934, following systematic studies on the magnetron, the research branch of the CSF, headed by Maurice Ponte, submitted a patent application for a device designed to detect obstacles using continuous radiation of ultra-short wavelengths produced by a magnetron.[57] These were still CW systems and depended on Doppler interference for detection. However, as most modern radars, antennas were collocated. The device was measuring distance and azimuth but not directly as in the later “radar” on a screen (1939). Still, this was the first patent of an operational radio-detection apparatus using centimetric wavelengths.
The system was tested in late 1934 aboard the cargo ship Oregon, with two transmitters working at 80 cm and 16 cm wavelengths. Coastlines and boats were detected from a range of 10–12 nautical miles. The shortest wavelength was chosen for the final design, which equipped the liner SS Normandie as early as mid-1935 for operational use.
In late 1937, Maurice Elie at SFR developed a means of pulse-modulating transmitter tubes. This led to a new 16-cm system with a peak power near 500 W and a pulse width of 6 μs. French and U.S. patents were filed in December 1939. The system was planned to be sea-tested aboard the Normandie, but this was cancelled at the outbreak of war.
At the same time, Pierre David at the Laboratoire National de Radioélectricité (National Laboratory of Radioelectricity, LNR) experimented with reflected radio signals at about a meter wavelength. Starting in 1931, he observed that aircraft caused interference to the signals. The LNR then initiated research on a detection technique called barrage électromagnétique (electromagnetic curtain). While this could indicate the general location of penetration, precise determination of direction and speed was not possible.
In 1936, the Défense Aérienne du Territoire (Defence of Air Territory), ran tests on David’s electromagnetic curtain. In the tests, the system detected most of the entering aircraft, but too many were missed. As the war grew closer, the need for an aircraft detection was critical. David realized the advantages of a pulsed system, and in October 1938 he designed a 50 MHz, pulse-modulated system with a peak-pulse power of 12 kW. This was built by the firm SADIR.
France declared war on Germany on September 1, 1939, and there was a great need for an early-warning detection system. The SADIR system was taken to near Toulon, and detected and measured the range of invading aircraft as far as 55 km (34 mi). The SFR pulsed system was set up near Paris where it detected aircraft at ranges up to 130 km (81 mi). However, the German advance was overwhelming and emergency measures had to be taken; it was too late for France to develop radars alone and it was decided that her breakthroughs would be shared with her allies.