Kammhuber joined the Luftwaffe in 1933 and then held a variety
of staff and command positions, including chief of staff of
Luftflotte 2 (Second Air Fleet). During the 1940 Battle for
France, he commanded 51st Kampfgeschwader (51st Bomber Wing) and
was shot done and taken prisoner. Following his release after
the defeat of France, Kammhuber was ordered to organize the
primitive German night defenses. He developed them into a highly
efficient system that came to be known as the "Kammhuber Line,"
an interlocking system of radar, aircraft, and ground
controllers stretching from the North Sea to southern France.
With advances in radar technology, the line was effective, but
it was a defense in width rather than depth. RAF Bomber Command
eventually exploited this weakness by blinding the German radars
with strips of foil called "window" (known as "chaff" by the
Americans). Following several devastating British raids,
Kammhuber was relieved as general of night fighters in autumn
1943 and posted to Norway. Following