The defences – Air detection (III)May 30, 2017
The Freya systems of the German early warning radars were highly successful, but they need another set to help in targeting air objectives.
Anti-aircraft targeting radars, or FuMG (from Funkmeßgerät, or radar) were not in service when the war broke out. From 1939, GEMA and Telefunken starting to develop more accurate radars with a more concentrated beam to firing accuracy of the heavy anti-aircraft artillery’s guns.
This radar, called the Würzburg FuMG 39 operated on 50 cm wave length and had a range of 25 km with a range accuracy of 25 m. A rotating dipole antenna and a pulsed radar was used. The rangefinder was provided with a cathode-ray tube screen (CRT). The distance and ranging data would be provided to a command and control system at a Flak battery. Twenty of these units were delivered by 1940 to the Ruhr area. By the end of the war, over 4,000 units of this and upgraded models (Würzburg D) had been deployed in Europe, making it the standard radar system with the Luftwaffe. They were manned by a crew of six.
[These photographs show a Würzburg FuMG 39/62 model T, seen with its wooden traverse plate.
This radar unit was set up atop the control tower of the FlakTurm at Berlin Tiergarten, in Zoologischer Garten and was on duty to track and control the AA guns which protect the western sector of the city. Note brush paint to camouflage the radar’s dish and Siegessäule (‘Victory Column’) at background. The women next to the radar were American WACs (Women’s Army Corps), examining the site after the war in July 1945.]
[Another Würzburg radar placed at the Tiergarten, apparently used by the Germans as traffic control unit at the improvised Ost-West-Achse’s landing strip during the last days of the Berlin garrison. Note the Siegessäule column in the background.]
[Two images of a German Luftwaffe crew manning a Würzburg at a radar site; the man in the foreground is moving the system on its lateral axis. He is looking into the range and bearing indicator in front of him. Behind, other crewmember operate the elevation crank of the radar housing while watching the elevation monitoring. These monitors are covered with weather protectors.]
[The control tower as viewed from the main Flakturm located at Berlin Tiergarten, in Zoologischer Garten. A Würzburg FuMG 39T and a Würzburg-Riese (at left) can be seen atop of the roof. The Reich’s capital had three of these complex of towers to lead the AA guns, the one at the Zoo manned by the 123 Turmflakabteilung.]
In 1941, Telefunken followed up on their successful Würzburg system with a larger, more sophisticated set fittingly known as FuMG 65 Würzburg-Riese (“Giant”). Making use of the same conical-scanning system, the Riese was a much larger system with a 7.4 meter antenna and much more powerful transmitter that gave it a range of up to 70 degrees. Combined with the added accuracy afforded by the conical scanning system, the Würzburg-Riese provided the Luftwaffe with a long-range system capable of providing accurate enough information for gun-laying. with a range of about 60 km. This type began to enter service in 1941, and over the course of the war roughly 1,500 would be built.
[The massive FuSe65 Würzburg-Riese radar atop of the L-turm at Humboldthain in Berlin.]
[A disabled Würzburg-Riese system after being captured by US forces, installed next to a Normandy Arromanches-les-Bains beach in June 1944.]
Today, an original Würzburg-Riese radar unit can be seen at the Luftwaffenmuseum Berlin-Gatow.
Several types and improvements were developed by Germany during the war, increasing range and facing British radio countermeasures, being the Jagdschloß radar antenna-array the other great advanced unit. This system, called FuG 404, became operational in 1944 and it was very difficult to jam. Just 80 of them were built. With a detection range of 300-400 km, long range warning devices like this or the FuMG 41/42 Mammut radar unit (six or eight Freya switched together) detected enemy formations assembling over the North Sea prior move towards the Reich, alerting German defences for incoming air raids.
[A Jagdschloß type II at a German radar site located in the Danish coast.]
[The cathode-ray screen of a German Jagdschloss radar shows the RAF offensive on Berlin with approximately 400 bombers, on 30 January 1944. The circle constitute the 100 km range marker, the gap in top indicates ‘geographical north’.]
All German systems and radars were highly jammed by the British countermeasures chaff from the summer of 1943, named “Window” (known as ‘Duppel’ by the Germans), metal strips with aluminium foil. This obliged the Germans to improve their early warning system -the Kammhuber Line- and radar AI devices (airborne radar) with new frequencies and create new night fighting tactics.
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