Who developed the first VHF-band radar system?
27693223#127
Germany has a long heritage of using electromagnetic waves for detecting objects. In 1888, Heinrich Hertz, who first demonstrated the existence of these waves, also noted that they, like light, were reflected by metal surfaces. In 1904, Christian Hülsmeyer obtained German and foreign patents for an apparatus, the "Telemobilskop", using a "spark gap transmitter" that could detect ships and prevent collisions; this is often cited as the first radar, but, without directly providing range, it does not qualify for this classification. With the advent of the radio tube and electronics, other detection-only systems were developed, but all used continuous waves and could not measure distance.
In 1933, physicist Rudolf Kühnhold, Scientific Director at the "Kriegsmarine" (German Navy) "Nachrichtenmittel-Versuchsanstalt" (NVA—Experimental Institute of Communication Systems) in Kiel, initiated experiments in the microwave region to measure the distance to a target. For the transmitter, he obtained assistance from two radio amateur operators, Paul-Günther Erbslöh and Hans-Karl Freiherr von Willisen. In January 1934, they formed at Berlin-Oberschöneweide the company "Gesellschaft für Elektroakustische und Mechanische Apparate" (GEMA) for this work.
Radar in World War II
403883#28
VHF radar systems have wavelengths comparable to aircraft feature sizes and should exhibit scattering in the resonance region rather than the optical region, allowing most stealth aircraft to be detected. This has prompted Nizhny Novgorod Research Institute of Radio Engineering (NNIIRT) to develop VHF AESAs such as the NEBO SVU, which is capable of performing target acquisition for Surface-to-air missile batteries. Despite the advantages offered by VHF radar, their longer wavelengths result in poor resolution compared to comparably sized X band radar array. As a result, these systems must be very large before they can have the resolution for an engagement radar. An example of a ground-based VHF radar with counter-stealth capability is the P-18 radar.
Stealth aircraft
49613184#1
The Nizhny Novgorod Research Institute of Radio Engineering (Russian acronym: NNIIRT) has since 1948 developed a number of radars. These were mainly radars in the VHF-band, and many of which featured developments in technology that represented "first offs" in the Soviet Union. Innovations include the first Soviet air surveillance radar with a circular scan: the P-8 Volga (NATO: KNIFE REST A) in 1950, the first 3D radar: the 5N69 Salute (NATO: BIG BACK) in 1975, and in 1982 the first VHF-band 3D-radar: the 55Zh6 Nebo (NATO: TALL RACK). Other innovations were radars with frequency hopping; the P-10 Volga A (NATO: KNIFE REST B) in 1953, radars with transmitter signal coherency and special features like moving target indicator (MTI); the P-12 Yenisei (NATO: SPOON REST) in 1955 as well as the P-70 Lena-M with chirp signal modulation in 1968 or the widely used P-18 Terek (NATO: SPOON REST D) in 1970.
Russian air surveillance radars
3511733#0
The CXAM radar system was the first production radar system deployed on United States Navy ships, operating in the mid-high VHF frequency band of 200 MHz. It followed several earlier prototype systems, such as the NRL radar installed in April 1937 on the destroyer ; its successor, the XAF, installed in December 1938 on the battleship ; and the first RCA-designed system, the CXZ, installed in December 1938 or January 1939 on the battleship . Based on testing in January 1939, where the XAF was more reliable, the US Navy ordered RCA to build six XAF-based units for deployment and then shortly thereafter ordered 14 more.
CXAM radar
6888913#1
CHL traces its origins to early experiments with Airborne Interception radar systems in 1936. These were developed as a short-range radar that would be used to close the gap between Chain Home's (CH) approximate accuracy and the visual range of a night fighter pilot at about . Developed by a second team at Bawdsey Manor led by "Taffy" Bowen, the new radar had to operate at much smaller wavelengths in order to limit the antenna sizes to something that could be practically fit on an aeroplane. After considerable experimentation, the team settled on a set working at 1.5 meter wavelength, about 193 MHz in the VHF band.
Chain Home Low
48975617#13
In August 1940, the Army issued a specification for a new GL radar that combined a VHF set like the Mk. II with a microwave-frequency tracking system with high accuracy. It required:P. E. Pollard of the Air Defence Research and Development Establishment in Christchurch, Dorset had been one of the first people to consider radar as early as 1930, and had been working with the "Army Cell" at the Air Ministry Experimental Station for some time before joining other Army researchers at Christchurch, Dorset. They selected British Thomson-Houston (BTH), who built the earlier 5 m GL sets, to build a prototype. Pollard moved to BTH's plants in Rugby, Warwickshire to work on the new system.
GL Mk. III radar
25634966#8
The Germans had not yet developed a magnetron suitable for use in such systems, so their equipment operated in the VHF region. At the NTRI, they followed the Germans and built a prototype VHF set operating at 4.2 m (71 MHz) and producing about 5 kW. This was completed on a crash basis, and in early September 1941, the set detected a bomber at a range of 97 km (61 mi). The system, Japan’s first full radar, was designated Mark 1 Model 1 and quickly went into production.
Yoji Ito
977144#0
The Lichtenstein radar was among the earliest airborne radars available to the Luftwaffe in World War II and the first one used exclusively for air interception. Developed by Telefunken, it was available in at least four major revisions, called FuG 202 Lichtenstein B/C, FuG 212 Lichtenstein C-1, FuG 220 Lichtenstein SN-2 and the very rarely used FuG 228 Lichtenstein SN-3. (FuG is short for "Funk-Gerät", radio set). The Lichtenstein series remained the only widely deployed airborne interception radar used by the Germans on their night fighters during the war — the competing FuG 216 through 218 "Neptun" mid-VHF band radar systems were meant as a potentially more versatile stopgap system through 1944, until the microwave-based FuG 240 "Berlin" could be mass-produced; the "Berlin" system was still being tested when the war ended.
Early FuG 202 Lichtenstein B/C units were not deployed until 1942. They operated at a maximum RF output power of 1.5 kW, on the 61 cm wavelength (490 MHz, or low UHF band), requiring complex "Matratze" (mattress) antennas, consisting of thirty-two dipole elements, mounted in four groups of eight, each at the forward end of one of four forward-projecting masts.
Lichtenstein radar
43239543#21
Meanwhile, Hibberd had successfully built a new push–pull amplifier using two of the same tubes but working in the 1.25-meter band, an upper-VHF band (around 220 MHz); below 1.25 m the sensitivity dropped off sharply. Gerald Touch, originally from the Clarendon Laboratory, converted the EMI receiver to this wavelength by using the existing set as the intermediate frequency (IF) stage of a superheterodyne circuit. The original 45 MHz frequency would remain the IF setting for many following radar systems. On its first test on 17 August, Anson "K6260" with Touch and Keith Wood aboard immediately detected shipping in the English Channel at a range of . The team later increased the wavelength slightly to 1.5 m to improve sensitivity of the receiver, and this 200 MHz setting would be common to many radar systems of this era.
AI Mk. IV radar
43971988#2
Beginning in 1975, NNIIRT developed the first VHF 3D radar capable of measuring height, range, and azimuth to a target. This effort produced the 55Zh6 'Nebo' VHF surveillance radar, which passed acceptance trials in 1982.
Nizhny Novgorod Research Institute of Radio Engineering
43971988#6
Innovations include the first Soviet air surveillance radar with a circular scan; the P-8 Volga (NATO: KNIFE REST A) in 1950, the first 3D-radar; the 5N69 Salute (NATO: BIG BACK) in 1975, and in 1982 the first VHF-band 3D-radar; the 55Zh6 Nebo (NATO: TALL RACK).
Nizhny Novgorod Research Institute of Radio Engineering