An RAF officer with a captured FuG 240 "Berlin" radar. The primary antenna is visible just to the left of the disk-shaped reflector, on the end of the mast.A "pair" of the "subsets" for a Lichtenstein B/C or C-1 "mattress" UHF radar antenna system.
The FuG 240 "Berlin" was an airborne interception radar system operating at the "lowest end" of the SHF radio band (at about 3.3 GHz/9.1 cm wavelength), which the German Luftwaffe introduced at the very end of World War II. It was the first German radar to be based on the cavity magnetron, which eliminated the need for the large multiple dipole-based antenna arrays seen on earlier radars, thereby greatly increasing the performance of the night fighters. Introduced by Telefunken in April 1945, only about 25 units saw service.
The German Luftwaffe first introduced an airborne interception radar in 1942, the FuG 202 "Lichtenstein B/C" and its direct follow-on version, the FuG 212 Lichtenstein C-1. Both units operated at 490MHz, in the low UHF band with a wavelength of 0.61 meter. Radar antennas are sized roughly to the operational wavelength, or a fraction thereof, so the FuG 202 and 212 initially required large, 32-dipole Matratze (mattress) antenna arrays that projected in front of the aircraft and caused considerable drag - this was later reduced to a one-quarter subset of the same antenna design, centrally mounted on the aircraft's nose.
By 1943 a series of efforts and lucky intercepts had allowed the Royal Air Force to introduce jammers, which interfered with the AI radar's operation. The RAF also introduced the Serrate radar detector, which allowed British night fighters to home in on the Lichtenstein radars. Over the summer and fall of 1943, the RAF downed an impressive number of German night fighters.
The Luftwaffe responded by introducing the FuG 220 Lichtenstein SN-2 in late 1943. To avoid RAF jamming, the SN-2 operated in the low-VHF range, at 90MHz, or 3.33 meter wavelength. The SN-2's lower frequency range required enormous eight-dipole Hirschgeweih (stag's antlers) antennas, which created so much drag that aircraft were slowed by some 50 km/hour.
The Lichtenstein SN-2 was eventually supplanted by the Neptun radar. Based on the same basic technology as the Lichtenstein, the Neptun operated on six mid-VHF frequencies between 158-187MHz. with shorter dipole antennas, still in the "antler" mounting format. This unit was only a stop-gap solution.
Rotterdam Device
The Royal Air Force's first Airborne Intercept radars operated in the 1.5 meter band and featured antennas similar to their later German counterparts. However, the introduction of the cavity magnetron in 1940 changed things dramatically. The magnetron efficiently generated microwaves from a device the size of a coffee tin, lowering operational wavelengths from the several-meter range to less than 10 centimeters. This reduced the antenna size to a few centimeters. Instead of simply using a smaller Yagi antenna, the system was paired with a new parabolic dish which allowed for conical scanning. The result was a small, lightweight, powerful, long range and easy to read radar.
The magnetron was initially limited to aircraft operating over the UK or sea, so that if the aircraft was lost the magnetron would not fall into German hands. However, as the war progressed several new uses for the magnetron were developed, notably ground-mapping systems like the H2S radar. These allowed the operator to obtain a crude cathode ray tube image of the ground below in any weather. This was of great use to RAF Bomber Command's efforts, and an intense debate broke out over whether to allow its use over continental Europe. In the end the decision was taken to allow H2S units in strategic operations, starting with the Pathfinder Force.
The inevitable occurred on 2 February 1943, when a Short Stirling Pathfinder was downed near Rotterdam. German forces examining the wreckage found an apparatus which they called the "Rotterdam Gerät" (Rotterdam Device). They quickly determined it to be a centimeter wavelength generator, although its exact purpose was unclear. This was revealed when a second example was captured, and the crew of the aircraft revealed it to be a mapping system. Wolfgang Martini immediately set up a team to understand the new system and devise countermeasures. This work led to the FuG 350 Naxos device, a radio receiver using a DF loop for an aircraft installation, covered with a teardrop-shaped fairing and tuned to the H2S frequencies, that was used to track the Pathfinders in flight. However, this was introduced just as the RAF was introducing the H2S Mk. III and the US their H2X radar, which operated at 3cm (10GHz) and thus was not seen by Naxos.
Berlin
The captured magnetron was sent to Berlin and a group assembled from the German electronics industry met at the Telefunken offices to discuss it. Only days later those offices were attacked and the magnetron was destroyed. However, a second example was recovered from an aircraft taking part in that raid.
Telefunken used it as a basis for a German version of the device and an AI radar based on it. The system which Telefunken developed was similar to its British counterpart, differing largely in the display system. Given the limited number of changes, it is unclear why it took so long to get into production, over two years. Production units were not ready until the spring of 1945, and were not installed in German aircraft until April, just before the war ended.
Ju 88G-6 with FuG-240 behind the plywood radome nose
The Berlin N-2 model was installed primarily in Junkers Ju 88G-6 night-fighters, behind a plywood radome. This so greatly reduced drag compared to the late-model Lichtensteins and Neptun that the fighters regained their pre-radar speeds. The power output of the N-2 radar was 15 kW, and was effective against bomber-sized targets at distances of up to 9 kilometers, or down to 0.5 kilometer, which eliminated the need for a second short-range radar system. The N-3 version used an updated display system that featured a C-scope output, which simplified the intercept.
The N-4 was a further development of the N-3; it rotated the antenna in the horizontal plane under an FuG 350 Naxos-antenna style teardrop housing atop the aircraft fuselage. The result was a 360-degree image of the sky around the aircraft that was presented on a plan position indicator (PPI). This version was later renamed the FuG 244 "Bremen", but was not approved for production.
A year after the end of the war, this American copy appeared as the AN/APS-3.
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and EHF bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz. In all cases, microwaves include the entire SHF band at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations.
A night fighter is a fighter aircraft adapted for use at night or in other times of bad visibility. Night fighters began to be used in World War I and included types that were specifically modified to operate at night.
The Junkers Ju 88 is a German World War II Luftwaffe twin-engined multirole combat aircraft. Junkers Aircraft and Motor Works (JFM) designed the plane in the mid-1930s as a so-called Schnellbomber that would be too fast for fighters of its era to intercept. It suffered from technical problems during its development and early operational periods but became one of the most versatile combat aircraft of the war. Like a number of other Luftwaffe bombers, it served as a bomber, dive bomber, night fighter, torpedo bomber, reconnaissance aircraft, heavy fighter and at the end of the war, as a flying bomb.
H2S was the first airborne, ground scanning radar system. It was developed for the Royal Air Force's Bomber Command during World War II to identify targets on the ground for night and all-weather bombing. This allowed attacks outside the range of the various radio navigation aids like Gee or Oboe, which were limited to about 350 kilometres (220 mi). It was also widely used as a general navigation system, allowing landmarks to be identified at long range.
The Naxos radar warning receiver was a World War II German countermeasure to S band microwave radar produced by a cavity magnetron. Introduced in September 1943, it replaced Metox, which was incapable of detecting centimetric radar. Two versions were widely used, the FuG 350 Naxos Z that allowed night fighters to home in on H2S radars carried by RAF Bomber Command aircraft, and the FuMB 7 Naxos U for U-boats, offering early warning of the approach of RAF Coastal Command patrol aircraft equipped with ASV Mark III radar. A later model, Naxos ZR, provided warning of the approach of RAF night fighters equipped with AI Mk. VIII radar.
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.. 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 stop-gap 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.
The low-UHF band Würzburg radar was the primary ground-based gun laying radar for the Wehrmacht's Luftwaffe and Heer during World War II. Initial development took place before the war and the apparatus entered service in 1940. Eventually, over 4,000 Würzburgs of various models were produced. It took its name from the city of Würzburg.
The history of radar started with experiments by Heinrich Hertz in the late 19th century that showed that radio waves were reflected by metallic objects. This possibility was suggested in James Clerk Maxwell's seminal work on electromagnetism. However, it was not until the early 20th century that systems able to use these principles were becoming widely available, and it was German inventor Christian Hülsmeyer who first used them to build a simple ship detection device intended to help avoid collisions in fog. True radar, such as the British Chain Home early warning system provided directional information to objects over short ranges, were developed over the next two decades.
Serrate was a World War II Allied radar detection and homing device used by night fighters to track Luftwaffe night fighters equipped with the earlier UHF-band BC and C-1 versions of the Lichtenstein radar. It allowed RAF night fighters to attack their German counterparts, disrupting their attempts to attack the RAF's bomber force.
Jagdschloss, officially the FuG 404, was the designation of a German early warning and battle control radar developed just prior to the start of World War II. Although it was built in limited numbers, Jadgschloss is historically important as the first radar system to feature a plan position indicator display, or "PPI". In Germany this type of display was referred to as "Panorama". It is named for Jagdschloss, a hunting lodge.
During World War II, the German Luftwaffe relied on an increasingly diverse array of electronic communications, IFF and RDF equipment as avionics in its aircraft and also on the ground. Most of this equipment received the generic prefix FuG for Funkgerät, meaning "radio equipment". Most of the aircraft-mounted Radar equipment also used the FuG prefix. This article is a list and a description of the radio, IFF and RDF equipment.
Radar in World War II greatly influenced many important aspects of the conflict. This revolutionary new technology of radio-based detection and tracking was used by both the Allies and Axis powers in World War II, which had evolved independently in a number of nations during the mid 1930s. At the outbreak of war in September 1939, both Great Britain and Germany had functioning radar systems. In Great Britain, it was called RDF, Range and Direction Finding, while in Germany the name Funkmeß (radio-measuring) was used, with apparatuses called Funkmessgerät . By the time of the Battle of Britain in mid-1940, the Royal Air Force (RAF) had fully integrated RDF as part of the national air defence.
The FuG 200 Hohentwiel was a low-UHF band frequency maritime patrol radar system of the Luftwaffe in World War II. It was developed by C. Lorenz AG of Berlin starting in 1938 under the code name "Hohentwiel", an extinct volcano in the region of Baden-Württemberg in southern Germany. The device had originally been entered into a design contest held by the Luftwaffe for the new FuMG 40L. When competitor Telefunken won that contract with its "Würzburg radar" in 1939, the device was shelved.
Neptun (Neptune) was the code name of a series of low-to-mid-VHF band airborne intercept radar devices developed by Germany in World War II and used as active targeting devices in several types of aircraft. They were usually combined with a "backwards warning device", indicated by the addition of the letters "V/R" Vorwärts/Rückwärts, meaning Forward/Backward). Working in the metre range, Neptun was meant as a stop-gap until scheduled SHF-band devices became available.
Radar, Airborne Interception, Mark IV, produced by USA as SCR-540, was the world's first operational air-to-air radar system. Early Mk. III units appeared in July 1940 on converted Bristol Blenheim light bombers, while the definitive Mk. IV reached widespread availability on the Bristol Beaufighter heavy fighter by early 1941. On the Beaufighter, the Mk. IV arguably played a role in ending the Blitz, the Luftwaffe's night bombing campaign of late 1940 and early 1941.
FuG 224 Berlin A was a German airborne radar of World War II. It used rotating antennae and a PPI display to allow its use for ground mapping.
German Luftwaffe and Navy Kriegsmarine Radar Equipment during World War II, relied on an increasingly diverse array of communications, IFF and RDF equipment for its function. Most of this equipment received the generic prefix FuG, meaning "radio equipment". During the war, Germany renumbered their radars. From using the year of introduction as their number they moved to a different numbering scheme.
Radar, Air-to-Surface Vessel, Mark III, or ASV Mk. III for short, was a surface search radar system used by RAF Coastal Command during World War II. It was a slightly modified version of the H2S radar used by RAF Bomber Command, with minor changes to the antenna to make it more useful for the anti-submarine role. It was Coastal Command's primary radar from the spring of 1943 until the end of the war. Several improved versions were introduced, notably the ASV Mark VI, which replaced most Mk. IIIs from 1944 and ASV Mark VII radar, which saw only limited use until the post-war era.
The SCR-720 was a World War II Airborne Interception radar designed by the Radiation Laboratory (RadLab) at MIT in the United States. It was used by US Army Air Force night fighters as well as the Royal Air Force (RAF) in a slightly modified version known as Radar, Airborne Interception, Mark X, or AI Mk. X for short.
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