Ernst on a Wurzburg in Calais
1941 - Radar War
In 1941 Großmann was sent to radar operator's school in Berlin where he trained to Operate the Würzburg radar. He became part of the Kammhuber Line where he provided data on bomber streams to the night fighters defending Germany and the occupied territories in the west.
While the ground war in the West was dormant, the air war was escalating. In January 1941, the RAF Fighter Command, under Air Marshal Douglas, initiated the "Circus" operations. These were aggressive fighter sweeps escorting small numbers of bombers ("bait") to attack targets in Northern France and Belgium. The strategic objective was to force the Luftwaffe to scramble its fighters, engaging them in a war of attrition over French soil.
Großmann's unit, Flak Abteilung 402, equipped with heavy 88mm guns, was on the front line of this new phase. As 1941 progressed, the Luftwaffe began moving the bulk of its fighter units (Jagdgeschwader) to the East in preparation for Operation Barbarossa, the invasion of the Soviet Union. This strategic resource allocation stripped the West of its fighter cover, leaving the defense of the Channel coast increasingly reliant on ground-based air defense systems like my Großmann's Flak unit.
"Circus" defense in Knokke, Belgium in February 1941
88mm ammunition
Flak Abteilung 402, Knokke 1941
Brandenburg Gate, Berlin, June 22 1941 during a weekend while at radar school
In the summer of ‘41, Großmann’s war changed. He was transferred to a radar school in Flak Artillerie Schule III near Berlin in Heiligensee to master the Würzburg radar, a piece of high-tech equipment used to track Allied bombers. This transfer likely saved his life, sparing him the meat-grinder of the Eastern Front where many of his former comrades perished as the flak crews were drawn down and transferred to the infantry. Among his family serving in Russia was his brother Heiner who was in the infantry and his future brother-in-law Gunther, a paratrooper who would lose his foot outside Moscow.
Ernst toiled in a Berlin classroom for 6 weeks studying radar. Developed by Telefunken, the Würzburg was a technological marvel of 1941. Unlike the Freya radar, which provided long-range early warning (range and bearing) but lacked precision, the Würzburg was a tracking radar designed for gun-laying. He returned to the Western Front in late August 1941, stationed in Antwerp, Calais, and Knokke, with Flak Abteilung 402 where he became part of the Kammhuber Line providing radar guidance to night fighters. He also started training others in the operation of radar.
Unter den Linden, Berlin, June 22, 1941
taken during radar operator school
Changing position to Lillo, Belgium
Gare du Nord, Brussels
The Kammhuber Line was a sophisticated defensive belt of radar stations, searchlights, and night fighters stretching from Denmark to France. It operated on the principle of "Himmelbett" (four-poster bed) zones. In each zone, a Freya radar would detect incoming bomber streams and direct a night fighter to the general vicinity. Then, two Würzburg radars would take over: one would track the bomber, and the other would track the night fighter. A ground controller would compare the two blips on a plotting table and radio vectoring instructions to the fighter pilot to achieve an intercept.
Großmann’s unit, operating a Würzburg, was a critical node in this network. His diary entries from late 1941 are filled with technical jargon. The radars were temperamental, utilizing vacuum tube technology that required constant maintenance and stabilization, hence the oft used term “technicians” in his diary for when they went down and needed repair.
Großmann
