German Luftwaffe and Navy Radar Equipment (Funkgerat) Of World War II

During World War II, the German Luftwaffe and Navy relied on an increasingly diverse array of communications, IFF and RDF equipment. Most of this equipment received the generic prefix FuG for Funkgerät, meaning "radio equipment". During the war the Germans renumbered their radars. From using the year of introduction as their number they moved to a different numbering scheme.

Search Light and Fighter Control

No German ground radar was accurate enough for Flak fire direction. The operation method for Flak during the day was to use the radar to be used to set the optical fire control for the flak onto the target. Once acquired the flak was controlled by the optical equipment to complete the engagement. During the night the Radar would be used to indicate the target to the search light crews. The rest of the engagement would be carried out optically. During the dy fighters would be directed with sufficient precision that they would be able to see their targets and during The night they would use their onboard AI radar to find the target after initial direction from the ground based radars.

Early Units


FuMG 38 L Kurfurst. Two 2.4-meter parabolic reflectors (one transmit and receive) mounted on a converted Flak mounting. Wavelength 62 cm range approx 8-12 km.

FuMG 39 L Kurfalz. A more powerful development of the 38 L. (the L in the designation meant Lorenz). Dished were mounted on the operations van.

FuMG 40 L Kurmark Developed version of the 39 L range now up to 25-40 km.

Würzburg


FuMG 62 / FuMG 39 Würzburg: 3D fire-control radar. Used to direct the flack optical directors and searchlights. Wavelength 50 cm approx. In response to jamming various models of Würzburg radar were developed to operate on various frequencies called "Islands". Over 4000 units delivered in various models. Range approx 30 km 3-meter reflector.

Würzburg A First production version introduced in 1940. 50 cm operating wavelength. Operation range was approximately 30 km. Included a IFF system that worked with the FuG 25z airborne unit.

Würzburg B Integrated IR telescope to increase accuracy. Proved unsatisfactory and not placed into production.

Würzburg C Replaced the model A in production in 1941. Had lobe switching to improve accuracy. On this unit the integral IFF system was replaced by a system based on the FuG 25a airborne. To Support this system which worked at approx 125-160 Mhz two antenna were placed inside the main dish. A separate interrogation and receiving units were attached to show the IFF responses.

Würzburg D Replaced the model C in production in 1942. It now had a usable range of approximately 40 km. Conical scan was used for fine accuracy. The IFF antenna was now fitted in the center of the dish rather than on the sides. Better instruments were fitted and generally it was an the best of the small Würzburg.

FuMG 65 Würzburg Riese(Giant): The electronics of the D model Würzburg combined with a 7-meter dish to improve resolution and range. Range approx 70 km. Version E was a modified unit to fit on railroad flat cards to produce a mobile Flak radar system. Version G had the 2.4-meter antenna and electronics from a Freya installed. The antenna dipoles were inside the reflector. The reason for this was that the allies were flying very high recon flights which were at altitudes above the maximum height of the Freya. The standard Würzburg Riese's 50 cm beam was to narrow to fid them directly. So by combining the two systems the Freya could set the Würzburg Riese onto the target.[1]

Mannheim


FuMG 63 Mainz The Mainz, introduced in 1941, was a development from the Wurzburg with its 3-meter solid metal reflector mounted on top of the same type of control car as used by the ‘Kurmark’. Its range was 25-35 km with an accuracy of ±10-20 meters, azimuth 0.1 degrees, and elevation ±0.3-0.5 degrees. Only 51 units were produced before being superseded by the ‘Mannheim’.

FuMG 64 Mannheim The Mannheim was an advanced development from the ‘Mainz’. It also had a 3-meter reflector, which was now made from a lattice framework covered in a fine mesh. This was fixed to the front of a control cabin and the whole apparatus was rotated electrically. Its range was 25-35 km, with an accuracy of ±10-15 meters; azimuth and elevation accuracy of ±0.15 degrees. Though accurate enough to control Flak guns it was not deployed in large numbers. This was due to its cost (time and materials to manufacture was about 3 time that of a Würzburg D.

FuMG 75 Mannheim Riese Just as the Wurzburg’s performance was greatly improved when fitted with a 7-meter reflector, so was the Mannheim’s, and the result called a Mannheim Riese (Giant Mannheim). There was an optical device for the initial visual acquisition of the target. With its narrow beam it was relatively immune from ‘Window’. Its accuracy and automatic tracking enabled it to be used in anti-aircraft missile research to track and control the missiles in flight. Only a handful were manufactured.

FuMG 68 Ansbach There was a need for a mobile radar with the range and accuracy of the ‘Mannheim’. The result, in 1944, was the Ansbach. It had a collapsible reflector of diameter 4.5 meters, operating on a wavelength of 53.6 cm, and peak power of 8 kW, giving it a normal range 25-35 km (70 km in search mode) with an accuracy of 30-40 meters. Azimuth and elevation accuracy was around ±0.2°. The antenna and reflector were remote controlled from a Bayern control van up to 30 meters away. The control system was based on the remote control system of the Michael microwave communication system, this was based on the Ward-Leonard AC/DC control system. The Ansbach was to be installed in large Flak batteries with six or more guns, but only a few were produced by the end of the war, and these didn’t see operational service

Medium Range Search

Freya & similar units

FuMG 450 Freya / FuMG 41G: This was a 2D Early warning radar. (2D means unable to indicate height). It was used for fighter direction and target indication for the Würzburg. Operating wavelength of approx 2.4 meters (125 MHz). In response to jamming various models were developed to operate on various frequencies called "Islands". Over 1000 units delivered in various models

FuMG 401 / FMG 42 FREYA - LZ (Models A - D). An Air portable version, the model differences were due to an operating frequency range being in 4 descrete bands between 91 and 200 MHz.

Freya-Rotschwarz and Freya-Grünschwarz: These two systems were Freya modified to operate on the same frequency as the British radio navigation system GEE to avoid jamming. However, as by the time they were ready the Germans were jamming GEE it is not clear whether any were ever deployed.[2]

FuMG 451 A Freya Flamme: Freya which had been built to use the "Island D" band were modified to be able to trigger the British IFF equipment. Ranges of up to 450 km were obtained. Fell from use as British IFF procedures improved.[3]

FuMG 401 Freya Fahrstuhl: A 3D version of the Fraya. (3D means could measure height). Measurements made by moving the antenna up and down on a rack. Only a very rough estimation of height available. originally intended for early warning most of the systems produced went to help "jammed" Würzburg

Freya EGON: EGON stood for Erstling Gemse Offensive Navigation system. Where Erstling was the codename of the Fug25a transceiver in the aircraft and Gemse was the codename for the receiver. The system operated on a principle similar to the British OBOE navigation system. An IFF signal was sent from a Freya, that had had its receiver antenna removed, to the aircraft. The Fug25a in the aircraft responded and the received signal was displayed as an range offset on the Freya display. Using a second transmitter and triangulation the position of the aircraft was resolved. Though the system was tested to guide night fighters it was found to be to limited by the number of aircraft that it could control at one time (the same limitation was found with Oboe). The "Y system" was used instead for night fighter control. The EGON system was used to control pathfinders for bombing raids over both England and Russia, however by now the Luftwaffe bomber force was running out of planes, pilots and fuel so the results were minimal. Work was done using a third transmitter to improve system performance. Range with a normal Freya was up to 250km, work was underway to use a Wasserman system instead of a Freya to increase range too 350Km. (the Freya signal was to weak to trigger the Fug25a at ranges beyond 250km), but this was not completed.

Long Range Search

For area air defense (vs point defense) Frays's range was found to be insufficient. This led to attempts to use Fraya technology to achieve greater range. This resulted in the Wassermann and Mammut. All though the Mammut units achieved their aims they were large installations, with large arrays built on bunkers. This resulted in long building times and vulnerability to air attacks. The Wassermann was a better solution in that being smaller they were harder to locate and quicker to build, 3-4 weeks. However sources indicate that they never achieved the desired range of 400 km, the best was approx 300 km. This may be why there were so many variants deployed.

FuMG 401 Mammut: First deployed in 1942 this was a long range 2 D search radar. It consisted of 8 Freya class antenna arranged in a 4 x 2 configuration. It measured 25 meters wide and ten meters high and was mounted on four pylons fixed in concrete. Some installations had a second array mounted back-to-back. Each array could be electronically swung through about 100 degrees, so the dual sided array could look behind itself to continue to track bombers as they flew into Germany. Frequency was the same as Freya (125 MHz). Range was up to 300 km with a transmit power of 200 KW. Installations being very large took up to 4 months to build.

FuMG 402 Wassermann: This system was deployed in 1942. It was basically 6 Freya antenna mounted on a rotation cylinder. Frequencies were similar to Fraya (125 MHz) transmit power was 100 KW resulting in a usable range of approx 200 km. Three main versions were produced with sub variants in each class.

Wassermann L: The original light version. Some sources indicate that it had structural problems.

Wassermann S: The heavy version. first deployed late 1942 Some sources indicate it had more than 6 arrays.

Wassermann M: The last family were the medium class units. Again it is not clear exactly how many Freya arrays were attached to the mast. In 1944 this version received a modification that allowed it to electronically tilt its beams by 16 degrees which allowed it to perform height determination turning its into a 3 D search radar.

Elefant & See Elefant: These bi-static radars were an attempt to combine jamming resistance with long range. They operated in two bands 23-28 MHz or 32 - 38 MHz. Range was approximately 400 km but under certain RF conditions much greater ranges were obtained. Antenna were usually mounted on Wassermann towers (all units differed in detail from each other). 3 Elefants were in operation at the end of the war with one See Elefant. Sources are unclear what the difference between the two types were.

Panoramic Search

The first type of early-warning radar set giving panoramic display which come into operation in usually referred to as the Jagdschloss, although it’s official designation is Jagdschloss F, to distinguish it from later types, such as the Michael B and Z.

Jagdschloss F: The antenna was 24m wide and 3m high, consisting of sixteen pairs of double horizontal transmit and receive dipoles. Above this, an 8.5 metre wide antenna array of eight vertical dipoles was mounted for the IFF.The first 62 Jagdschloss were of the Voll Wismar type using wide band antenna covering the band 1.90-2.20 metres. Another 18, used the band 1.20-1.90 meters. Range was 100 km. An optional feature known as Landbriefträger (Postman) was a remote PPI display for use with Jagdschloss. This allowed the PPI display from the radar station to be sent simultaneously to command HQ by HF cable, or by a UHF radio link.

Jagdschloss Michael B: A ponderous aerial array of two rows of eighteen Würzburg mirrors measuring 56 metres long x 7 metres high was used in the Würzmann experimental early-warning radar, and formed the serial array for Jagdschloss Michael B with the array in a horizontal position. The wavelength employed, was that of a Voll Wismar 53.0-63.8 cm. Range approx 250km. None may have entered service, though one source mentions one entering service.

Forsthaus F: This system was a development of the Jagdschloss Michael B using the so-called Euklid 25-29 cm. waveband employed by the Navy. Once more a very long aerial array 48 metres long and about 8 metres high was used, employing a cylindrical paraboloid. A wave guide antenna (Hohlraumstrahler) was placed along the focal line with a second and a third wave guide parallel to it above and below respectively.Range was expected to be over 200 km. Probably none completed.

Forsthaus KF: Development of the Forsthaus F. Reduced in size so that the system would fit in a railway carriage. Antenna 24 meters long. Range 120km.

Dreh Freya: This set, which was also known as Freya Panorama, was first introduced in June 1944. It consisted of a Freya aerial of the Breitband type working in Bereich I (1.90-2.50), the frequency of which could be adjusted at will. The aerial was so built that it rotated through 360° and gave a remote panoramic presentation. About 20 equipments were in use in January 1945. The range claimed for it was only about 100 km.

Jagdhütte:This apparatus, which was produced by Siemens, gave a panoramic P.P.I. display of the German I.F.F. responses, using 24 metre or 36 metre rotating aerials. The wavelength employed was 2.40 metres and it was planned, with its aid, to trigger off the FuGe 25A. In this way friendly fighters were to be controlled from the ground at ranges up to about 300 km. It was fully realised that if the FuGe 25A frequency was ever jammed the Jagdhütte would be useless, but it was not considered likely that the Allies would attempt to jam it. Small numbers may have been completed at the wend of the war.

Jagdwagen: Jagdwagen was designed as a mobile Panoramic radar to control fighters at close ranges immediately behind the front. It was a project of the firm of Lorenz. The aerials were considerably smaller than the Jagdhütte, the array being only 8 metres long. The aerial array was to be mounted on the Kumbach stand as used in the Egerland Flak set. The frequency bend used was that of the A.S.V. set Hohentwiel namely 53-59 cm. Range 40-60Km. Prototypes only.

Jagdhaus (FuMG 404): Jagdhaus was designed and built by Lorenz in 1944 as an early warning radar. It was the most powerful radar built by the Germans, with a peak pulse power of 300kW, which Lorenz planned to increase to 750kW. The whole assembly was the size of a house, which is possibly how it got its name; ‘haus’ being the German for ‘house’. The rotating upper part of the construction housed the separate parabolic transmit and receive antennae and reflectors, with the IFF above them as usual. It weighed 48 tons and rotated at 10 rpm. It operated on wavelengths of 1.4 to 1.8 metres, and had a range of about 300km. It could measure altitude, azimuth and range. The control room was located below the antennae, from which its PPI image was also transmitted to command HQ at Charlottenberg by Landbrieftrager, similar to the Jagdschloss system. It is believed that only one Jagdhaus was constructed, which fell into Soviet hands when it was captured by their troops in 1945, during which time it was damaged. The Soviets compelled the Germans to repair it and instruct them in its operation.

Centimeter Radars

All though the Germans were carrying out research at centimeter wave lengths at the start of the war the work was abandoned as it was decided that the war would be over before the research & development could be completed. In February 1943 a RAF Sterling bomber was shot down over Rotterdam and a damaged H2S system was recovered. The Germans started a crash development program to use the information deduced from the captured system. All though a range of prototypes were produced, very few reached front line troops. Due to the device being recovered near Rotterdam the Germans used that name in several code names for the Centimeter (9cm) systems, such as "Rotterdam Device".

Rotterdam: To get the quickest start with development, german industry copied, as far as possible, the H2S system. Approximately 20 systems were manufactured for R&D work. They led to the Roderich jammer and the Berlin & Korfu receivers.

Jagdschloss Z: The 9 cm version of the Jagdschloss F panoramic radar system. Prototypes only.

Forsthaus Z: The 9cm version of the Forsthaus panoramic search radar. Prototypes only.

FuMG 77: Rotterheim. A combination of the 9cm receiver/transmitter of the Berlin system with the Antenna and other systems from a Mannheim. Its range was about 30km and it was found to be unaffected by allied jamming. Its name changed to Marbach V later in the war.

FuMG 76: Marbach. A combination of the Berlin transmitter/receiver with the Ansback 4.5 meter reflector and systems. Controlled by the "Michael" remote control system. Sources suggest that 3 systems were completed.

FuMG 74: Kulmbach. A 9cm panoramic search radar. 6 meter antenna and remote controlled like the FuMG76. When combined with that radar it was known as the Egerland system. Only 2 completed. range of approx 50Km.

Passive Search

FuG 221 Freya-Halbe : This was a Freya modified to locate British airborne jammers. Development completed but due to lack of parts never deployed.[4]

FuG 221 Rosendahl; This was a Freya modified to locate British bombers by tracking their Monica warning radar emissions. By the time development was completed the British had ceased using Monica, so never deployed[5]

Klein Heidelberg was the code-name give to a passive radar system devised in 1941. The system was a bi-static radar system. What was unusual was that the transmitters were British rather than German! The system worked by using the reflections from the Chain Home (British coastal radar system) rather than transmitters associated with the receivers. Klein Heidelberg worked by sensing Chain Home (CH) transmission pulses directly with a small auxiliary antenna, close to the main antenna, whose receiver was tuned to a particular CH station whose exact location, bearing and range was known. The CH signal was then used to synchronise the KH with the CH transmission pulses. The CH pulse started a circular trace on a cathode ray tube (CRT) divided into forty sections. The main antenna received the reflection of these pulses from the target and displayed them on the CRT. Range was between 300 - 600 km. The display was 2D. Resolution was not very good but it allowed the Germans to see bomber formations forming up over England and the general path of the bomber streams. Its big advantage was it was not possible for the British to jam without jamming their own radars. The system entered service in late 1943 and by late 1944 six system were commissioned on the Dutch coast. [6]

References

Notes

  1. ↑ The Radar War: Germany's Pioneering Achievement 1904-45
  2. ↑ http://www.cdvandt.org/ADIK390all.pdf
  3. ↑ http://www.cdvandt.org/ADIK390all.pdf
  4. ↑ http://www.cdvandt.org/ADIK390all.pdf
  5. ↑ http://www.cdvandt.org/ADIK390all.pdf
  6. ↑ The Development of German Radar in WW2: emanson,August 2014, http://www.worldnavalships.com

Bibliography

External links

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