Instruct: Given a question, retrieve documents that can help answer the question.
Query: Who developed the first VHF-band radar system?
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.
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.
The HF radar CODAR SeaSonde and Helzel WERA are well established as a powerful tool for sea current measurements up to a range of 300 km. It operates in the HF and low VHF frequencies band corresponding to a radar wavelength in the range of 10 to 300m. The Doppler shift of the first order Bragg lines of the radar echo is used to derive sea current estimates in very much the same way as for the dual frequency microwave radar. Two radar installations are normally required, looking at the same patch of the sea surface from different angles. The latest generation of shore-based ocean radar can reach more than 200 km for ocean current mapping and more than 100 km for wave measurements Helzel WERA. For all ocean radars, the accuracy in range is excellent. With shorter ranges, the range resolution gets finer. The angular resolution and accuracy depends on the used antenna array configuration and applied algorithms (direction finding or beam forming). The WERA system provides the option to use both techniques; the compact version with direction finding or the array type antenna system with beam forming methods.
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.
Communications equipment includes a Kongsberg dynamic position system and joy stick control, X-band and S-band radars for tracking ship traffic and the falling SRBs, global positioning system, handheld VHF radios and GPS units, digital video and recording systems, voice and data satellite communication capability, VHF automatic direction finding, high-frequency single-side band radios, electronic chart plotters, night vision and Sea Area-3 Global Maritime Distress Safety System consoles. To satisfy NASA's need for more observational data during shuttle launches, a Weibel Scientific Continuous Pulse Doppler X-band radar was mounted on MV "Liberty Star" to provide velocity and motion information about the shuttle and any debris during launch.
Overall from mid-1944 until the end of the war a total of 210 aircraft were built. In February 1945, production was switched to the C variant. It was hoped that by November 1945 production would reach 500 per month.
In addition, it was intended to modify upwards of 30 Ar 234B-2 airframes for the night-fighting role, from a proposal dated 12 September 1944 between Arado director Walter Blume and Goering's top aviation technologist, Siegfried Knemeyer. Designated Ar 234B-2/N and code named "Nachtigall" (Nightingale), these aircraft were fitted with FuG 218 "Neptun" VHF-band radar, with the appropriately reduced-dipole length version of the standard "Hirschgeweih" eight-dipole element, VHF-band transceiving AI radar antenna system, and carried a pair of forward-firing MG 151/20 autocannon within a "Magirusbombe" conformal gun pod on the ventral fuselage hardpoint. A second crew member, who operated the radar systems, was accommodated in a very cramped compartment in the rear fuselage. Two of these jury-rigged night fighters served with "Kommando Bonow", an experimental test unit attached to Luftflotte Reich. Operations commenced with the pair of 234Bs in March 1945, but Bonow's team soon found the aircraft to be unsuited for night fighting and no kills were recorded during the unit's very brief life.
The Dnestr radar came from work on ballistic missile defence undertaken in the late 1950s and early 1960s. System A, the prototype for the A-35 anti-ballistic missile system, was set up in the Sary Shagan testing grounds, in the Kazakh SSR. Work on the system was led by design bureau KB-1 which proposed using VHF radar RTN () and the Dunay-2 UHF radar. Other alternatives were sought from Soviet industry and RTI proposed using VHF radar TsSO-P () and UHF radar TsSS-30 ().
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. 
Charles Orr Stanley CBE (15 April 1899 – 18 January 1989) was a businessman who played an important role in the early development of commercial radio and television in Great Britain, especially in his role as head of Pye Ltd. Pye produced receivers for use in Chain Home, the British coastal defence radar system, and helped with the supply of EF50 valves for later British radar operating at VHF.
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).
The previous programs, Mercury and Gemini, had separate radio systems for voice, telemetry, and tracking. Uplink voice and command, and downlink voice and telemetry data were sent via ultra high frequency (UHF) and very high frequency (VHF) systems. The tracking capability was a C band beacon interrogated by a ground-based radar. With the much greater distance of Apollo, passive ranging was not feasible, so a new active ranging system was required. Apollo also planned to use television transmissions, which were not supported by the existing systems. Finally, the use of three different frequencies complicated the spacecraft systems and ground support. The Unified S-band (USB) system was developed to address these concerns.
Linesman was a comprehensive upgrade of the UK air defence system; along with work on the signalling and communications issues, upgrades to the existing radars were also planned. The existing Type 80 radars used in the MRS network were powerful but relatively easy to jam. Upgrades were aimed primarily at offering improved jamming resistance in the event of a noisy ECM environment. To augment the existing Type 80 a new Type 84 radar had already been proposed. Linesman proposed that three new radars were developed, two primary long-range search radars; Marconi's Type 84 and the AEI Type 85 "Blue Yeoman", with additional height finding capability being provided by the Decca HF 200 height-finder. To improve system resilience to jamming the two primary radars operated on different frequency bands, the Type 84 in "L" band, the Type 85 in "S" band. As the system developed more systems were added to improve the ECM capability of the system.
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.
The design of the P-14 2D early warning radar started in 1955 by decree of the CPSU Central Committee. The P-14 being the first high power VHF radar to be developed by the Soviet Union, the radar was accepted into service in 1959 following the successful completion of the radars test program. The P-14 was developed under the direction of V.I. Ovsyannikov by the SKB Design Bureau, a division of State Plant No.197 named after V.I.Lenin, the predecessor of the current Nizhniy Novgorod Research Institute of Radio Engineering (NNIIRT). The development team was awarded the Lenin prize by the Soviet Union in 1960 for the development of the P-14 radar.
The system features two tethered aerostats, roughly in length, that float to an altitude of for up to 30 days at a time. Each aerostat utilizes a different radar system—one has a VHF-band surveillance radar and the other an X-band fire-control radar. JLENS is designed to provide 24/7, 360-degree coverage extending . The surveillance radar scans in all directions to pick up targets, then the targeting radar looks only in a certain segment to guide weapons to it. Its detection capability seeks to equal 4–5 fixed-wing aircraft, and is designed to operate at 15–20 percent of the cost of fixed-wing aircraft.
The German bombers were afforded some protection in the form of the new, mid-VHF band FuG 216 "Neptun" radar system, usable both as an airborne intercept system (as a replacement for the post-July 1944 compromised Lichtenstein SN-2 system) and as a tail-warning radar, which could detect approaching RAF night fighters from the rear. To confuse British radars further various medium bomber types were equipped with "Kettenhund" radar jammers, specifically carried in the Ju 88, which had some effect in jamming the upper-VHF band, 205 MHz frequency SCR-268 gun laying radar used by anti-aircraft artillery, but was ineffective in countering microwave-frequency radars like the 3 GHz frequency, SCR-584 radar. German bombers also used "Düppel" (chaff) techniques to confound British ground radar as they approached the British coast. The tin foil strips swamped the radar screens and masked the true height, direction and speed of approaching bombers.
The USB system did not completely replace all other radio transmitters on Apollo. Apollo still used VHF between astronauts and the Lunar Module (LM) and lunar rover during extra-vehicular activity; between the lander and the command module, and between the spacecraft and Earth stations in the orbital and recovery phases. As a backup the CM could measure range to the LM over the VHF voice link. The spacecraft radar systems operated on frequencies separate from those of the USB.
The first version of the Ju 88C was the C-1 with 20 aircraft converted from A-1 airframes. Some of them entered service in the "Zerstörerstaffel" of KG 30 which became part of II./NJG 1 in July 1940. The C-1 was followed by the C-2 of which 20 aircraft were converted from A-5 airframes with enlarged wingspan. The C-4 became the first production version with 60 produced and 60 converted from A-5 airframes. The C-6, of which 900 aircraft were produced, was based on the A-4 airframe with more powerful engines and stronger defensive armament (single- or dual-mount belt-fed 7.92 mm MG 81 or 13 mm MG 131 instead of drum-fed MG 15 machine guns).
The C-6 as night fighter was typically equipped with FuG 202 "Lichtenstein" BC low-UHF band airborne intercept radar, using the complex 32-dipole "Matratze" antennas. The first four C-6 night fighters were tested in early 1942 by NJG 2. The trials were successful and the aircraft was ordered into production. In October 1943, many C-6s were upgraded with new radar systems. The first new radar equipment was the FuG 212 Lichtenstein C-1. After the UHF-band Lichtenstein radars had been compromised to the Allies in the late spring of 1943, the next development in German AI radar was the VHF-band FuG 220 "Lichtenstein" SN-2, discarding the 32-dipole "Matratze" antennae for the much larger eight-dipole "Hirschgeweih" (stag's antlers) aerials, required for the longer wavelength SN-2 system.
TI went on to produce side-looking radar systems, the first terrain following radar and surveillance radar systems for both the military and FAA. TI demonstrated the first solid-state radar called (MERA). In 1976 TI developed a microwave landing system prototype. In 1984 TI developed the first inverse synthetic aperture radar (ISAR). The first single-chip gallium arsenide radar module was developed. In 1991 the (MIMIC) program was initiated– a joint effort with Raytheon.
The "Pegmantit 3" which is abbreviated to P-3 was one of the first 2D early warning and ground control radars to be developed by the former Soviet Union. The development of the radar was initiated in 1943 as a replacement for the previous RUS stations used during the second world war and by the end of 1947 the radar was completed and in operational service. The P-3 was the first radar to be developed by the SKB Design Bureau, a division of State Plant No.197 named after V. I. Lenin, the predecessor of the current Nizhniy Novgorod Research Institute of Radio Engineering (NNIIRT). The radar had to be able to detect an aircraft to a range of no less than 130 kilometers, cover 360 degrees in azimuth and 4-18 degrees in elevation. A response time of no more than 25 seconds was stipulated and the radar had to be accurate to within 650 meters in range and within 700 meters in altitude, as well as operate in the VHF band. SKB managed to meet these performance requirements with the P-3 radar and this was confirmed during testing in 1945 before entry into service with the PVO.
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.
The FuG 227 "Flensburg" was a German passive radar receiver developed by Siemens & Halske and introduced into service in Spring 1944. It used wing and tail-mounted dipole antennae and was sensitive to the mid-VHF band frequencies of 170–220 MHz, subharmonics of the Monica radar's 300 MHz transmissions. It allowed Luftwaffe nightfighters to home in on the Monica tail warning radar fitted to RAF bombers.
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.
While the benefits of operating in the microwave portion of the radio spectrum were known, transmitters for generating microwave signals of sufficient power were unavailable; thus, all early radar systems operated at lower frequencies (e.g., HF or VHF). In February 1940, Great Britain developed the resonant-cavity magnetron, capable of producing microwave power in the kilowatt range, opening the path to second-generation radar systems.[4]
The ACO electronics were the second generation of the British CH (Chain Home) type of radar, a "floodlit" system operating on the VHF band. The British electronics contained panels and features not used in other radars or deemed necessary in the Pacific.