HISTORY



RADAR

Radar in WW II
compiled by Larry Belmont

Webmaster's Note: This document is a work in progress.
A Brief History of Radar Through 1941

SCR-268 A pioneer in radar, Colonel William Blair, director of the Signal Corps laboratories at Fort Monmouth, New Jersey, patented the first Army radar, which was demonstrated in May 1937. Even before the United States entered World War II, mass production of two radar sets, the SCR-268 (shown at left, with Afro-American GIs training in its use in the early 1940s) and the SCR-270, had begun. Along with the Signal Corps' tactical FM radio, also developed in the 1930s, radar was the most important communications development of World War II.

Radar Development through December 1941

  • 1886-1888 — Heinrich Hertz demonstrates generation, reception, and scattering of electromagnetic waves
  • 1903–1904 — Christian Hulmeyer develops and patents primitive form of collision avoidance radar for ships
  • 1922 — M.G. Marconi (in acceptance speech for an honor) announces an angle-only radar for ship collision avoidance
  • 1925 — First short-pulse echoes from the ionosphere are observed on a cathode ray tube (CRT) by G. Breit and M. Tuve of The Johns Hopkins University
  • 1934 — First photo of short-pulse echo from aircraft made by R.M. Page of U. S. Naval Research Laboratory
  • 1935 — First demonstration of short-pulse range measurements of aircraft targets, by British and Germans
  • 1937 — First operational radar built: the Chain Home in Britain, designed by Sir Robert Watson-Watt
  • 1938 — The U. S. Signal Corps SCR-268 becomes first operational antiaircraft fire control radar; 3100 sets eventually produced; range, over 100 miles; frequency, 200 MHz
  • 1938 — First operational shipboard radar, the XAF, installed aboard the battleship U.S.S. New York; able to detect ships at 12 miles and aircraft at 85 miles
  • December 1941 — By this date, 100 SCR-270/271 Signal Corps early warning radars have been produced. One of these radars, located on a point in northwest Oahu, detects Japanese planes approaching Pearl Harbor
A Brief History of British Radar During the Battle of Britain


CHAIN HOME (22 K) vspace=10

The painting (by Chris French and reproduced here by permission) shows three steel towers with their transmitter antennas slung between. On the lower left, the "girl on the tube" interprets the "blips" of enemy aircraft on the screen. The information was then sent via the telephone (lower right) to filter and operations rooms where the table-map could be updated by a "plotter" (top right). The markers represented hostile and friendly aircraft and were used to plan and monitor air battles. 234 Squadron’s Spitfires (top left) peel of to intercept enemy bombers. The succession of functions became commonly known as "Read", "Report", "Filter", "Identify", "Tell" and "Plot."

    Radar has been described as the weapon that won the war, and the atomic bomb the weapon that merely ended it. This is a pretty accurate statement, radar having played a crucial role in the outcome of the Second World War. It was one of the most important factors in the winning of the Battle of Britain and the Battle of the Atlantic and was of great importance to air support for ground operations in N.W. Europe, North Africa, S.E. Asia and the Pacific island-hopping campaigns.

    It is not generally appreciated how widely used radar was during the war. Britain, Germany, U.S.A., Canada, Australia, New Zealand, South Africa, U.S.S.R., Italy, France and Japan all developed and deployed their own radar equipment before and during the Second World War. Despite such widespread use, however, not all nations realised its potential as part of an integrated air defence system, such as that which played a crucial part on the victory of the Royal Air Force in the Battle of Britain. Failure to adopt such a system for aircraft warning radar could result in disaster, as shown when the radar warning of Japanese aircraft approaching Pearl Harbor on 7 December 1941 was not acted upon. Although radar performed many different roles (including ground stations for tracking shipping, ballistic missiles, mortar bombs, etc., as well as airborne equipment for the detection of aircraft or ships), it is the use of ground radar for the detection of aircraft that is best known and its finest moment came with the Battle of Britain. The following will give a brief description of the British ground radars in use during the battle and how they were of such importance.

    The mainstay of British early warning radar in 1940, and indeed through the war, was the Chain Home system. The photo below shows the only Chain Home radar transmitter tower remaining in its original form. In 1956, this tower, constructed in 1937 and standing 110 meters high, was moved from its original coastal site to Marconi Research Laboratories at Great Baddow where it stands today. CH TOWER (41 K) This operated on the relatively long wavelength of around 11 metres. This long wavelength, which required aerials around 5.5 metres long, meant that the aerials could not be rotated but were fixed in a single direction, known as the line of shoot, flooding with radio waves an arc of about 150 degrees centred on the line of shoot. By installing a line of such stations with overlapping coverage, it was intended to provide a radar 'fence' through which no aircraft could penetrate without being detected. Whereas a rotating radar might be facing the opposite direction at the crucial moment, continuous coverage from the Chain Home stations would, in theory, never fail in this respect.

    Chain Home had three separate stages of development: Advance, Intermediate and Final. Advance Chain Home (A.C.H.) stations consisted of equipment housed in huts or lorries and with aerials mounted on 90 foot masts. Intermediate (I.C.H.) used the same hutted accomodation but with two 240 foot wooden towers, one for the transmitting aerials and the other for the receivers. The Final C.H. stations consisted of protected brick buildings housing transmitters and receivers, with 350 foot steel towers for the transmitting arrays and 240 foot wooden towers (as used by I.C.H. stations) for the receiving aerials. At the time of the Battle of Britain, most stations were Intermediate C.H.s, with a few Advance C.H. stations being set up to provide emergency coverage in areas not already equipped with radar. The amount of warning given varied on a great many factors, such as the equipment in use at the station, the quality of the chosen site, the skill and experience of the staff, the availability of equipment spares, etc. Most important of all was the height of the aircraft, low-flying aircraft being particularly difficult to detect except at very short distances from the station. As a rough guide, the following are the performance figures for a C.H. station from July 1940:

Aircraft Height

Detection Range

1,000 feet 55 miles (exceptional!)
2,000 feet Good Performance
3,000 feet Poor Performance
10,000 feet 120 miles
15,000 feet 50 - 80 miles
30,000 feet 50 - 80 miles

    Despite the figures given above, Chain Home was generally poor on aircraft flying below 3,000 feet and thus aircraft at such heights were able to approach quite close to the British coast before being detected, greatly reducing the amount of warning time for fighter aircraft to take off and intercept. The scientific team working on radar development for the Air Ministry were, however, aware of this problem. A solution was discovered in the adaptation of an equipment being developed by an Army team attached to them. This set, known as C.D. for Coast Defence, was intended to track shipping to assist coastal batteries in their task. However, the Air Ministry team were able to adapt it for the detection of low-flying aircraft. In view of the urgent need for low-level coverage, the supplies of this set were given to the R.A.F. and became Chain Home Low. These stations were installed in several 'crash' programmes in late 1939 and early 1940. The speed with which this construction prgramme was carried out can be seen from the fact that from the first station going on the air in November 1939, 30 stations were operating by the beginning of the Battle of Britain.

    These Chain Home Low stations consisted of two separate aerial arrays, one of the transmitter and one for the receiver, mounted on 20 foot high wooden gantries, with the equipment housed in a hut undeneath each gantry. Since C.H.L. operated on a wavelength of 1.5 metres the aerials were short enough that the arrays could be rotated, which was done by hand. It was not until well after the Battle of Britain that power turned, single arrays (which combined transmitting and receiving) were introduced.

The performance of C.H.L. can be seen from the following data from 1940:

Aircraft Height

Detection Range

500 feet 25 - 30 miles
1,000 feet 40 miles
2,000 feet 50 miles
4,000 feet 55 - 60 miles
15,000 feet 107 miles

This demonstrates what is rarely appreciated, that C.H.L. could supplement the C.H. coverage at medium heights, as well as filling the low-level gaps.

    The importance of these radar systems during the Battle of Britain is hard to over-estimate. Without them the Royal Air Force would almost certainly have lost. The early warning provided by radar enabled the R.A.F. to intercept incoming raids which would otherwise have been undetected until within visual range. In this case, fighters would not have had sufficient time to reach the bombers before they had attacked their target and were on their way home. The only alternative would have been to mount standing patrols of aircraft in the path of likely attacks. However, the critically short supply of pilots, as well as aircraft, in 1940 would have made such tactics unfeasible.

    The important lesson from the Battle of Britain was that radar was only effective as part of an integrated air defence system. Whilst radar could detect approaching bombers, this information was in itself only of use if it reached those people who could act upon it. This was where Britain really had a lead in the technology, because the Fighter Command organisation had at its core the use of radar information. Radar plots were sent by telephone line to Fighter Command Headquarters. In the filter room there the information from separate stations was compared and sorted, removing any inconsistencies, with the intention of producing a true picture. This was then passed to the operations room where aircraft movements around Great Britain could be seen at a glance. Thus, Air Chief Marshal Sir Hugh Dowding, Air Officer Commanding-in-Chief of Fighter Command, had a complete picture of the battlefield, making it possible for him to direct his forces to maximum effectiveness. This was the real achievement of the C.H. and C.H.L. radar stations during the Battle of Britain.

The above text was prepared by Ian Brown who can be reached at ibrown@radararchive.freeserve.co.uk

TREWORTH     At the outbreak of war, the Air Ministry's radar research establishment at Bawdsey Manor on the East Coast was evacuated to Dundee. Early in 1940 the team moved to a purpose built site at Worth Matravers in Dorset (picture at left). Here, a greatly expanded staff of scientists and engineers from the universities and industry researched and developed a whole range of systems that helped win the war. The introduction of centimeter wavelength technology, made possible by the invention of the Cavity Magnetron by Randall and Boot, was followed by a number of significant centimeter radar developments at Worth Matravers.

The wartime developments originated while the Telecommunications Research Establishment (TRE) was based in Dorset and which played a vital part in the D-Day operation including:-

    GCI (Ground Controlled Interception) for guiding night fighters to within range of an enemy bomber for interception by Air Interception (AI).

    Gee An accurate radar navigation system to guide bombers to their targets

    Oboe A blind bombing system

    Rebecca To guide paratroops to a selected landing zone

    Babs A homing beacon for airfields

    Development work on other earlier systems, such as Air Interception (AI), and Air Surface Vessel, continued and more effective versions of these devices were brought into use.

    In late 1941, Sir Bernard Lovell set up a team to develop a centimetric navigation and bombing equipment. The intensive program of development, necessary to provide the RAF with a minimum range of 15 miles, was severely set back, just after TRE moved to Malvern in 1942. The Halifax bomber that was being used to test the equipment, crashed killing five of the small team, including Alan Blumlein from EMI, and wrecking the equipment. However, by the end of that year a device called H2S, that enabled effective bombing attacks to be made through 10/10ths cloud and in the dark, was installedand operating in the heavy bombers of Bomber Command. [More information is available from the Center for History of Defence Electronics (CHiDE)].
Pearl Harbor


SCR-270     The Army's Aircraft Warning Service (AWS) was in operative condition, for all practical purposes, on Sunday morning, December 7, 1941. It was comprised of an information center and five mobile stations (one of which is pictured at left, using an SCR-270-B unit). The radar systems in use that day were SCR-270-B radio sets. They were mobile units housed in two trucks. The unit's heart was the oscilloscope that gave a picture similar to a heart monitor in hospitals today. The operator would move the antenna through a given arc until the line across the bottom showed a small spike or pip. By adjusting the antenna and the controls, the pip was enhanced until the operator could tell the approximate distance to the target. Next, the operator looked out the window to a plate mounted on the antenna base, with an arrow on it that would give the direction of the contact. Unlike today's radar scopes, the antenna did not oscillate and there was no constant repainting of the picture on the scope. This system did not tell an incoming target's altitude, its size or number, nor did it differentiate friend from foe.

    In July 1941, these radio sets had begun arriving on Oahu. Signal Company personnel began assembling them at Schofield Barracks and then began learning how to operate them. Once assembled, personnel moved them to prepared sites throughout the island. The Signal Corps planned for six sets. On the morning of the attack, five were operational, with the sixth still at Schofield. The five operational sets were at Kaaawa, Opana, Kawailoa, Fort Shafter, and Koko Head. The sets began operating at 0400 on 7 December except at Opana, which came on the air at around 0415 due to a delay for early morning maintenance on the generator. The operators had been on duty since noon Saturday. They divided their tour between standing guard, maintenance, and operating the sets. The schedule called for each site to have a crew of three: one operator, one plotter, and one person to maintain the power generators. PEARL HARBOR WRECKAGE Because several units worked from commercial power and used the generators as standby power, some crews cut back to two people per shift on the weekend. Opana had two crew members that Sunday morning. During the first two hours, no radar contacts were made. At 0613, Koko Head and Fort Shafter began picking up sightings south of the island. Then at 0645, Kaaawa, Opana, and Kawailoa picked up a target approximately 135 miles north of Oahu heading south. All three stations called the Information Center with the targets, which were then plotted on the master plot board. Personnel at the center included five plotters (one for each radar site), a historical information plotter; PFC Joseph P. McDonald, the switchboard operator; and Lt Kermit Tyler, a pursuit pilot. The radar sites phoned the plots to the five plotters, and no one present found anything unusual with the information. McDonald had worked the switchboard for several months and knew the radar operators, while Tyler had been to the Information Center only once before. On 3 December he had worked from 1200 to 1600 with just the switchboard operator. On that occasion nothing happened, because the sites were not operating. Therefore, this was the first time he had actually seen personnel plot targets. When the reports began coming in, Tyler went to the historical plotter's position and talked with him about how he recorded the information. These first plots were probably the scout planes sent ahead of the main attacking force.

    At 0700, all the radar sites began shutting down. At the Information Center, the five plotters and the historical information plotter shut down and left the area, leaving McDonald and Tyler behind. At Opana, Privates George E. Elliott and Joseph L. Lockard were to work until noon, but the next shift came back early from a pass to town so they relieved them at 0800. This meant that when the truck arrived to take them to breakfast, they would be through for the day; however, the same call that informed them about the early release also let them know the truck would be late. Lockard was a trained radar operator and had been with the 270s since they arrived on the island, while Elliott had just transferred into the Signal Corps from the Hawaiian Air Force and only knew how to operate the plotting board. Because the breakfast truck was late and they were going to be off for the remainder of the day, the two decided to use the time to work on Elliott's training. A few minutes after seven, Elliott saw a large spike on the screen. Thinking he had done something wrong, he immediately began to check the settings. Lockard then took over the operation and also rechecked the controls. This was the biggest sighting he had ever seen since learning how to operate the system. Elliott then tried to call the Information Center, using the phones connected directly to the plotters. No one was there to take the call. He then called on the administration line and got McDonald. The switchboard operator knew both of the radar operators and tried to explain to them that there was nobody on duty in the Center after 0800. McDonald then spotted Lt Tyler and called him over to talk to Elliott. Meanwhile, Lockard got on the phone and tried to explain the large target that might be significant. McDonald interjected that if the targets were so large, maybe they should call back the plotters so they could practice handling a big aircraft movement. Tyler thought about this for a moment and then told Lockard and McDonald not to worry and closed the conversation. Since the breakfast truck had not arrived, Elliott and Lockard continued tracking the incoming target until about 20 miles from the coast of Oahu. At that point ground interference blocked the signal, and the target was lost. This was approximately 0745. Just then the breakfast truck pulled up and the two young radar operators shut their unit off and headed down the mountain to breakfast, devoid of the knowledge that they had discovered the first wave of the Japanese attack. Why had Lt Tyler told the operators not to worry, and why had he not followed McDonald's advice to call back the plotters? Tyler saw no reason to change the normal operations that morning. PEARL HARBOR HQ ON FIRE First, there was no alert or warning of an impending attack. Second, the U.S. Fleet's carriers were at sea and the sightings could well have been the carrier's aircraft returning to port. Third, a bomber pilot friend had explained just a few days before that one could always tell when aircraft were arriving from the US because the local radio stations would play Hawaiian music all night. The incoming aircraft would use the music to tune their directional finders and locate the islands. (This was exactly what the Japanese did.) On the way to the Center, Tyler heard the Hawaiian music, so he assumed a flight was coming in. Finally, although Lockard had said this was the biggest flight he had ever seen, he did not say how many aircraft he thought it might contain. Later, Lockard would claim he knew the flight had to number over 50 aircrah to make that large of a pip on the screen, but at the time he did not give that information to anyone. Had Tyler known the sighting was over 50 aircraft, he might have reacted differently; but with what little information he had, second lieutenants did not wake up commanding officers at seven o'clock Sunday mornings with wild speculations. Lockard and Elliott heard about the attack when they returned to their camp. After a quick breakfast, they returned to Opana and helped keep the site operating 24 hours a day for the next several months. The first Lt. Tyler heard about the attack was a telephone call from someone at Wheeler Field shortly aflter 0800. The plotters were immediately called back, and soon a full complement arrived. Tyler stayed in the Center except for short rest breaks for the next 36 hours. During the morning's activities, two plots began to form 30 to 50 miles southwest of Oahu. Not knowing what these were and thinking they could be the retiring Japanese circling before landing on their carriers, the senior controller passed this information to bomber command as the possible location for the Japanese attack force. No one remembered to check the early reports coming in before 0700 or the Opana sighting after 0700. It wasn't until several days later that people assembled this information and realized the radar stations had located the direction from which the attack was launched . In summary, the AWS was sufficiently operative to successfully pick up the approaching Japanese force 132 miles from Oahu. This was done by Privates Lockard and Elliott, respectively, a radar operator and plotter, and reported by these privates on their own initiative to the information center, where the Sergeant in charge of the switchboard received the information and relay it to Lieutenant Tyler, who was a pursuit officer of the Air Corps on temporary duty for training. The stations had been used from 0400 to 0700 hours each morning for the training personnel, and the personnel was reasonably trained by that time, with the exception of certain liaison officers who were still getting their training, like Lieutenant Tyler. If the radar system and information center had been fully manned, as it could have been and as it was immediately upon the disaster at Pearl Harbor and thereafter without further physical additions, it could have been successfully operated on December 7 and perhaps enabled the Air Corps to respond in time to avoid much of the disaster that befell the U.S. forces that day.
Airborne Radars


JU88

The Primary Allied "Airborne Radars

    This section is being written.

The Primary German "Airborne Radars

The following material is reprinted from Pauke, Pauke! The German WW II Night Fighters Resource Page (see German Radars especially.) (In the photo above, a Ju88 night fighter sports nose-mounted airborne radar.)

    SPANNER I-IV: IR light detectors developed by AEG. Spanner I used an IR searchlight, Spanner II used passive detection only. Only Spanner I was used mainly in Dornier heavy night fighters and some experimental Bf 110 (the first one was a Bf110 D-1/U1).
    FUG 202 “LICHTENSTEIN BC: Developed by Telefunken, the “Lichtenstein“ is first tested in august of 1941. It enters production during the Spring of 1942. It was ther first AI device largerly used employed by the Nachtjagd. Its aerials were mounted in four main masts in the nose of Me 110 or Ju 88 at a downward angle of 5° ca. An "X"-formed frame on the tip of each main mast supported the vertical dipole elements (see illustration below). The radar operated at 490 MHz, with a range of 200-218 m to 5000 m and a power of 1,5 kW. The vision angle was 70°. The FuG 202 was replaced both by the FuG 212 and later the FuG 220 due to enemy jamming problems.
    FUG 202 “LICHTENSTEIN BC/S: It was an experimental device whose main aim was to increase the operating angle from 70° to 120° by means of side antennae.
    FUG 211? “LICHTENSTEIN O: This was an upwards aiming device for night operations. It worked at 490 mHz using antennae similar -perhaps even the same- as the “Lichtenstein B/C." One single prototype was build in 1943.
    FUG 212 LICHTENSTEIN C-1: This Telefunken AI device entered production during the late Spring of 1943 as a simplified version of the FuG 202. The performance was approximately the same as FuG 202. Its aerials differed in having longer main masts and a newly sharp shaped mast tip.The FuG 212 operated at 91 MHz and had a range of 200 m to 6000 m. After August 1943 the frequency could be changed by means of a selector from 420 to 480 mHz. It fell into disuse when the RAF discovered efficient methods for jamming this and the FuG 202 devices. Production stopped in November 1943.
    FUG 212 “LICHTENSTEIN C22": Development of FuG 212 with improved short-range capabilities. It was discontinued and substituted by the SN2 project. FUG 214 “LICHTENSTEIN BC/R” Tail warning experimental device. Discontinued and substituted by the FuG 216. FUG 215 “PAUKE A” Telefunken aiming device. It worked with six frequencies from 410 to 490 mHz using two types of antennae. The first prototypes used a single mast dipole antennae, similar to “Weitwinkel” one. Later devices used a ø 70 cm dish installed in the fuselage under a plywood teardrop cover. Only 10 units were build.
    LICHTENSTEIN C-1 "WEITWINKEL": Substitute for the FuG 220 SN-2b to improve short-range interception. It featured a single mast antennae and a 120° vision angle as results of FuG 214 research, but its range was only 2000 m.
    FUG 216 “NEPTUN”: This research tail warning/AI device, developed by FFO, was used on Bf 109 G6's and Fw 190 A6's single engine night fighters of JG 300, 302, 10 and 11 for experimental purposes only and in very small series. There were two versions: the FuG 216 R1, used as tail warning, with 1 kW power working at 182 mHz, and the FuG 216 V, AI, with 1,2 kW at 125 mHz. It had a range of 500 to 3500 m at a search angle of 100°. antennae were fitted to the outer panels of upper and lower surfaces of the middle part of both wings.
    FUG 217 “NEPTUN”, R2, J2: This was a search AI developed by FFo in two versions: the R2 and J2. Tests were undertaken in Werneuchen over Me 109 G-6/R7 (PP+??). In 1./NJGr 10 a Fw 190 A-6/R11 and A-8/R11 and R12 were also fitted with the FuG 217 (black 8 is an example). The R2 was a tail warning device while the J2 was specifically developed as AI for single engine night fighters. The “Neptun” operated with two fixed frequencies, 158 and 187 mHz with a range of 400 to 4000 m at a 120° vision range. Its antennas consisted in groups of three or four vertical elements installed in rows over the top centerline of the fuselage in front and behind the canopy (4 front, 3 rear) and three rows in the upper surface of the middle part of both wings. These typical arrangements of three vertical antennas gave the FuG 217 the name of Neptun.
    FUG 218 “NEPTUN”, R3, J3, V/R, G/R: This set was developed during sumer of 1944 both by Siemens and FFO together, to substitute the SN-2 as the Allies discovered new countermeasures against the latter. It was a derivative of the FuG 217 from which it kept the name. Four versions were provided. These versions of the “Neptun” had a range of 120 to 5000 m and operated with six fixed frequencies ranging from 158 to 187 mHz. The FuG 218 was mounted in a "X" support similar to the earlier SN-2 antennae but smaller. The dipoles -of two different lengths- were mounted on this "X" support which was installed on a single main mast mounted on the centerline of the nose of Ju 88 or Me 110. The support was nicknamed Hirschgeweih ("Stag's Antlers"), the name also given to the big SN-2 antenna. The Neptun entered service during the last months of 1944 and also featured tail warning capabilities using a small curved mast with two horizontal elements, all installed on the tip of the vertical fin. A version with four sets of three inline vertical antennae was fitted to some Fw 190 A-6s for “Wilde Sau” operations. A further development increased the power of the G/R transmitter from 30 to 100 kW.
    FUG 219 “WEILHEIM”: This was a further development of the “Neptun” carried out by Siemens. It operated with 100 kW power at 172 – 188 mHz. Its range was supposed to be about 15,000 meters.
    FUG 220 “LICHTENSTEIN SN-2: This Telefunken AI device was parallely developed with the FuG 202 and 212 in 1943. This was one of the most sophisticated radars used by the Luftwaffe. It entered mass production in September 1943. The SN-2 could not be jammed by window but in its models "A" and "O" it had a minimum range of (547 yards) which was a problem for close interception. To solve this problem FuG 202 or 212 sets were carried together with the FuG 220; this produced a massive antennae nose with a strong speed drag. When later with the SN-2 "B" model was enhanced its close range capabilities the FuG 202/212 sets were definitively removed allowing the interceptor a 300 m to 4000 m range.(3,125 miles). Early FuG 220 operated with three fixed frequencies: 73/82/91 Mhz, later it operated with a variable range of frequencies from 37.5 to 118 mHz. The SN2 had a power of 2,5 kW and featured the large 120° vision angle. Its larger antler antennas were composed by four main curved masts in the nose of Me 110 or Ju 88, each mast supported two vertical dipoles. A refinement in the design of the SN-2 dipoles consisted in mounting flat section dipoles instead of tubular ones. It is not sure if this kind of aerial is related to the SN-2 or its derivative the SN-3. Late developments of the SN-2 led in 1944 to additional tail warning capabilities with two different tail antenna installations: the one was a mast below the tail rudder fixed on the Ju 88 G's to the fuel-jettison housing; the other, easier to install, consisted in direct installation of the dipoles on the vertical fin eliminating any mast. Also attempting to eliminate the speed drag of the SN-2 antennae was developed the Morgenstern arrangement. It was of a different installation consisting in a main center line mast with the dipoles directly attached in "X" configuration (Ju 88 G-6 C9+AC of II./NJG 5 for example). This allowed the optional installation of a plywood cone nose over the whole installation. Variations consisted in the FuG 220 C series, without wide-angle antennae, and FuG 220 D series, with slanted dipoles and no tail warning mast.
    FUG 221 “FREYA-HALBE”: Passive homing device by Siemens. This device was used for homing enemy a/c sending radio-disturbing signals against the German “Freya” radio beacons. It worked at 115 – 135 mHz with a range of 100 km. Small series production.
    FUG 221-A “ROSENDAAL-HALBE”: Passive homing device by Siemens. This device was designed to recognize and intercept the signals of the “Monica”, “ASV” antiship, “Rosendaal,” and “Magic Box” tail-warning transmitters. It had a 100-km range and worked with 190 – 230 mHz frequencies. The “Rosendaal-Halbe” never entered mass production.
    FUG 222 “PAUKE S”: Telefunken aiming device. It worked with frequencies from 3250-3330 mHz with a range of 300 – 10,000 m. Vision range of 100 degrees horizontally and 20 degrees vertically. The device was connected to an electrical ReVi device and monitor. Only 3 apparatus were build. FUG 226 NEULING IFF experimental device by Lorenz. Me 262A Wrk.Nr. 170056 was equipped with this ground-to-air and air-to-air IFF device together with the FuG 218 Neptun. FUG 227 “FLENSBURG” It was a passive homing device developed by Siemens. The Flensburg could detect from a distance of 65 Kms (45 miles) the emissions of the “Monica” tail-warning radars of the RAF bombers. Production of this set began in Spring of 1944. The Flensburg antennas were installed in both the wings: at the top and bottom panels of the starboard wing tip and in the leading edge of the port wing. When on 13.7.44 the Ju 88 G-1 of 7./NJG 2 felt under Allied hands its FuG 220 and 227 sets were rapidly examined and countermeasures developed against them. Three different Ausführung with many improvements were delivered for a total of 250 apparatus.
    FUG 228 “LICHTENSTEIN SN3”: This was a long-range 20 kW AI device developed by Telefunken. Its range was from 250 to 8000 m at 120° horizontal vision angle and 100° vertical vision angle; it was operating in frequencies from 115 to 148 mHz. Its antennae were very similar to thos of SN-2 except for the thicker dipoles. Only 10 devices were completed and nothing is known about their eventual use in battle. Research was also carried out to use “Morgenstern” antennae with 1/2 and 1/4 of wavelength.
    FUG 240/1-4 “BERLIN” N1A, N2-4: This was the last developed AI device. Only approximately 20 to 30 sets were built and used during the last month of war. The Berlin radar had no aerials since it featured an adjustable advanced dish antenna; this reduced drag problems because the dish could be covered with a light plywood nose cone. The “Berlin” used a wavelength of 9 cm 3250-3330 mHz and had a 500-5000 mts range and was mounted almost exclusively on Ju 88 G-6's (3c+NM of NJG 4 for example). It is said that it was based on captured examples of the British cavity magnetron. The most advanced version of the “Berlin”, the N3, used a single “panoramic” screen to show both height and range of the target; it also featured a rotating parabolic dish.The top of the research in the “Berlin N3” was developed into the FuG 244 “Bremen 0”. The N4 version consisted in a research apparatus for night flying control a/c; it was supposed to give a global panoramic view of enemy a/c over the whole hemisphere of the sky. The N4 was thus designed to be a rotating dish fitted in a teardrop in the shoulder of the control a/c instead of its nose. This was the very first “AWAC” project by Telefunken in 1944.
    FUG 244 “BREMEN” 0: This Telefunken device was based on the “Berlin” N3. It used 3250 to 3330 mHz frequencies with 20 kW of power. Its range was from 200 to 5000 m at 100 degrees of horizontal vision and 20° of vertical vision. Only one prototype was finished at the end of the war.
    FUG 245 “BREMEN”: This device was a parallel development of the FuG 244 which it had to replace. Performance was similar to the FuG 244. Only one prototype was built.
    FUG 247 “PAUKE SD” - “BREMERHAVEN” Aiming device project. It should have worked with 3-cm wavelengths. Vision range of 120 degrees horizontally for 10000 m range. The device featured a rotating dish in a 120 degree cone. The pilot could have an optical representation of the target on a monitor screen.
    FUG 280 “KIEL”: The Kiel was a passive IR vision detector developed by Zeiss. It operated using lead-sulphite photocells amplified in a vision screen. Its range was about 4000 m; the unit weighed only 42 kg. Only a few devices were built.
    FuG 350 “NAXOS Z”: The Naxos was a Telefunken passive homing device similar to the FuG 227 ("Flensburg"). It was developed during the Summer of 1943. Production began in the early months of 1944 and the device entered service together with the Flensburg and remained in use until the end of the war. Unlike the Flensburg, the Naxos detected the H2S ground mapping radar (as well as the H2X, AN APS 15) instead of the Monica tail warning radar. Models I, II, and III used frequencies 82 – 84 MHz; IV, V, VI, and VII, 91 – 116 MHz. Its range was as far as 50,000 m in its best Ausführung, 10,000 in its very first versions. In whole 25 series were developed being the “Z” series the most successful with 700 apparatus built alone from “Z” to “ZR” series! The “Naxos Z” were used in Ju 88 G's in combination with the covered Morgenstern antennae because its elements could be easily installed inside the wooden nose cone or inside teardrop-shaped covers. Tests with Naxos were also carried in single-engined Me109G's (NH+VZ, for example) housed under a plexiglass dome on the second panel just behind the radio antenna mast behind the canopy.
    FUG 351 “KORFU Z”: The “Korfu” was a passive homing device (“Z” stands for Zielanfluggerät) developed by Telefunken. It was a “Naxos” with very long range capabilities, about 300 km. Very few devices were built, but they did see action against the enemy.
    WÜRZBURG, FUMG 39/62: Short-range ground radar. Range 170 km, frequency 560 MHz, range precision 100 m, angle precision 0.2 degrees. FUGM 80 “FREYA” Long-range ground radar and beacon. Its range was of 120 km, and worked with a frequency of 125 Mhz. Its range precision was about 125 m with an angle precision 0.5 degrees. FUGM 402 “WASSERMANN” Long-range ground detection radar. Range 190 km, frequency between 120 and 158 MHz. Range precision 300 m, angle precision 0.25 degrees. FUMO 51 “MAMMUT” Long-range ground detection radar with a range up to 300 km. It operated with frequencies between 120 and 138 MHz. Range precision 300 m, angle precision 0.5 degrees.
SCR-584 After D-Day


    Drawing upon experience ranging from the Western Desert and Tunisia through the Sicilian and Italian campaigns, Allied tactical air control in Normandy and during the subsequent European campaign was generally excellent. Fundamental to this success was the wartime evolution of radar. The Allied air forces had radar available to them from the very first day of Normandy operations, and it was soon incorporated into tactical air control as well as for early warning and air defense purposes. Radar had first been used for tactical air support control during the Sicilian and Italian campaigns, and now, in Normandy and the subsequent breakout, it reached new levels of refinement. Each TAC had a radar control group built around a Tactical Control Center (also called a Fighter Control Center), a microwave early warning radar (dubbed a MEW), three Forward Director Posts, three or four SCR-584 Close Control Units (the SCR-584 being a particularly fine precision radar used for positioning data and antiaircraft gun laying; see picture above), and, finally four Direction Finding stations, dubbed Fixer stations. The MEW, considered the heart of the system, would be located within ten to thirty miles of the front.

    Originally developed for air defense purposes, this radar network now took on added importance for the control of tactical air strikes. For example, when an Air-Ground Coordination Party sent in a request for immediate air support, that request went directly to a Combined Operations Center functioning between the TAC and the Army. There, the Army S2 and G-3 and the TAC A-2 and A-3 evaluated the request. Assuming it was considered legitimate, the Army G-3 and Air A-3 would each approve it, and the Air A-3 would relay it to the Tactical Control Center with a recommended course of action. D-DAY RADARTypically, the TCC would relay the request to airborne fighter-bombers, and a geographically appropriate Forward Director Post would furnish precise radar guidance and navigation information from the MEW and SCR-584 radars to the strike flight, vectoring them to the target area. Once in the target area, of course, the strike flight leader would communicate with the Air-Ground Coordination Party that had sent in the request for final details. For its part, the Air-Ground Coordination Party would arrange for artillery to mark the target with colored smoke and also, if possible, to undertake suppressive artillery fire against known enemy antiaircraft defenses. Radar was also used for so-called blind bombing in conditions of reduced visibility. SCR-584 control eventually enabled blind bombing strikes with accuracies on the order of 400-yards from the predetermined aiming point, notably during the Battle of the Bulge in winter 1944-45.



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1942-1945

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