FuG 200 Hohentwiel
 FW 200 with radar antenna of FuG 200 | |
| Country of origin | German, German Air Force |
|---|---|
| Introduced | 1938 |
| Type | Airborne search |
| Frequency | 525–575 MHz MHz/57.1-52.1 cm |
| PRF | 50 Hz |
| Pulsewidth | 2 μs |
| Range | • 10 km (6.2 mi) Submarines • 70 km (43 mi) Surface Ships • 150 km (93 mi) Land |
| Azimuth | left 30°, middle, right 30° |
| Power | 24V 30A, Synchronous inverter |
 FuMO 61 Hohentwiel U | |
| Country of origin | German, Kriegsmarine |
|---|---|
| Introduced | 1943 |
| Type | U-boat surface search |
| Frequency | 556 MHz/53.9 cm |
| Range | • 10 km (6.2 mi) Surface Ships * 25 km (16 mi) Aircraft |
The FuG 200 "Hohentwiel" was a radar device of the German air force in World War II. It was developed by C. Lorenz AG of Berlin starting in 1938. The device had originally been entered into a design contest held by the Luftwaffe for the new FuMg 40L (ground based fire-control radar). When competitor Telefunken won that contract with its „Würzburg radar“ in 1939, the device was shelved.
In 1941, Lorenz started to re-design it for another design contest by the Reichsluftfahrtministerium for an airborn naval search radar. As no special antenna had been specified, initially the simplest possible layout with three antennas was chosen - one for transmitting and two others for receiving, one of these on the left, the other on the right. For rough guidance, the radio operator had to manually switch the receiving antenna. Later, the device received a motor-driven antenna switch. The received signal strength was displayed on a cathode ray tube so the observer or pilot could roughly gauge the target's heading as 'left', 'right' or 'head on'. The maximum range was 150 km for convoys on the Atlantic. The device was first deployed on Junkers Ju 88, Focke-Wulf Fw 200 and other torpedo bombers. In order to avoid capture after a crash, it was fitted with several small explosive charges which could be triggered by the pilot.
Further details are found in the air force manual (PDF, German language).
Marine Version
In 1943 Lorentz was instructed to adapt Hohentwiel for naval use, and soon the Hohentwiel appeared on U-boats, small surface ships, and coastal installations.
There are two U-boat versions of the FuG 200 Hohentwiel used during World War 2; FuMO 61 Hohentwiel U and the FuMO 65 Hohentwiel U1. The U-boat versions were easier to maintain and more reliable compare to the other versions. However, the U-boat versions had several disadvantage, the smaller dimension of the antenna and the height of the antenna installation. The antenna was restricted to a smaller dimension as it had to fit within a small area on the port side of the conning tower. In addition, the reduce height of the installation of the antenna, affected the range of the radar. The range of both U-boat versions was between 8 and 10 kilometres (5.0 and 6.2 mi) for naval targets and between 15 and 25 kilometres (9.3 and 15.5 mi) at an altitude of 200 metres (660 ft).[1] Resolution was about 3 degrees, and at short range its range accuracy was 100 metres (330 ft). Both U-boat versions work at a frequency 556 MHz and had four rows of six dipoles. While the U-boat was submerged the antenna was retracted into a well on the conning tower. Both U-boat versions of the antennas were 1,400 millimetres (4 ft 7 in) wide by 1,000 millimetres (3 ft 3 in) in height, the total overall dimensions of the antenna frame was 1,540 millimetres (5 ft 1 in) wide and 1,022 millimetres (3 ft 4.2 in).
There are two types of radar transmitter for the FuMO-61 Hohentwiel U and FuMO-65 Hohentwiel U1, the Type F431 C1 and the Type F432 D2. The Type F431 C1 was used on the Type VII and the Type F432 D2 on the Type XXI.
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Radar Transmitter Type F431 C1 -
Radar Transmitter Type F432 D2
FuMO 61 Hohentwiel U
The FuMO 61 Hohentwiel U was the marine version of the FuG 200 Hohentwiel used by the Kriegsmarine on Type VII, Type IX and Type XXI U-boats. Beginning March 1944, it began to be installed on Type VII and Type IX.
FuMO 63 Hohentwiel K
The FuMO 63 Hohentwiel K became available at the beginning of 1944. It was the fitted with to the foremast and mainmast of surface naval ships (Destroyers, Torpedo boats and Light Cruisers).
FuMO 65 Hohentwiel U1
The FuMO 65 Hohentwiel U1 was the marine version of the FuG 200 Hohentwiel used by the Kriegsmarine only on Type XXI U-boats. The FuMO 65 Hohentwiel U1 had an updated radar display over the older FuMO 61 Hohentwiel U, it had a Plan position indicator display, known to the Germans as Drauf.
Image gallery
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Air force manual with full technical specification -
US intelligence assessment of captured devices -
Submarine version FuMO 61 "Hohentwiel" antenna and FuMO Ant.3 "Bali" on board a Type XXI U-Boat -
Same boat seen from further aft
See also
Sources
External links
Literature
- G. Müller: Funkmessgeräte-Entwicklung bei C. Lorenz AG, 1935–1945. Internal archive volume of the SEL company, 2. expanded edition, December 1981
- RLM Werkschrift 4108, Bordfunkmessgerät FuG 200. Geheime Kommandosache, August 1943
- RLM Vorschrift Nr. 75/790, Prüffibel für Bordfunkmessgerät FuG 200. October 1944
- RLM Luftfahrtsröhren Ringbuch, Daten und Richtlinien über die Verwendung von Luftfahrtsröhren. January 1945
- K. Steimel: Bericht über den Zustand der Röhrentechnik in Deutschland zum Abschluss des Krieges. August 1945
- U.S. Air Materiel Command Dayton OH, Summary Report No. F-SU-1109-ND, The High Frequency War – A survey of German Electronic War. 10th May 1946
- CIOS Final Report 1746, German development of modulator valves for radar applications
- CIOS report XXX-36, Physikalisch-Technische Reichsanstalt. June 1945
- CIOS Report XXVII-46, Design of Radar Test Equipment at Siemens-Halske Munich
- BIOS Report 1228, HF Instruments & Measuring Techniques
- Achievement in Radio, Radio Science, Technology, Standards and Measurements at the National Bureau of Standards. US Department of Commerce, October 1986
- Gerhard Megla: Dezimeterwellentechnik. Fachbuchverlag Leipzig, 1952 (Chapter on measuring devices and measuring methods in the decimeter range of wavelengths)
- Radio Measurements, Proceedings of the IEEE, Volume 55, June 1967. Hewlett Packard, Microwave *Measurement Handbook, Chapter RF Peak Power Measurement, Procedures and Equipments
- Boonton Electronics Company, Application Note AN-50, Measuring the Peak Power
- U.S. Naval Research Laboratory, ASB Radar Alignment Procedure. November 1942