Hohentwiel (Radar)
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).
Submarine version FuMO 61–65
"Hohentwiel U" was a FuG 200 adapted for naval use, especially on type VII- and type IX U-Boats.
- Range (antenna height 8m): 8–10 km against naval targets and 15–20 km against aerial targets flying at an altitude of 200 m[1]
- 4×6 dipole did not have a seaworthy mount and needed to be retracted before diving, see picture below.
Specifications
| Name |
FuG 200 "Hohentwiel" |
| Transmission frequency |
525–575 MHz (50 cm) oscillator |
| Pulse power |
30–50 kW |
| Pulse repetition frequency |
50 Hz |
| Pulse width |
2 μs |
| Swivel range |
left 30°, middle, right 30° |
| Beam width |
??° |
| Antenna |
2×4 element group of dipoles with reflector; rceiving antennas slanted 30° to the sides |
| Range |
- 70 km against war ships
- 150 km against land
- 10 km against submarines
|
| Weight |
22 kg |
| Electric power supply |
24V 30A, Synchronous inverter |
| Tubes |
2× DS323 – later 2× RD12TF, 1× LG7, 1× LD1, 4× LV1, 2× LG1, 2× LV1 |
Image gallery
See also
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German radars of World War II
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| Aerial radars |
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| Land-based radars |
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| Naval radars |
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Sources
- ^ cdvandt.org
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