16.10.1940 Josef Kammhuber was promoted to Generaloberst with the charge of “General of the Night Fighters” and established his HQ in Utrecht, the Netherlands.

He has planned and successfully implemented two roles for his units:
1. Defensive line in limited part of German border (”Kammhuber line”).
2. Long range raids against homebases of British bombers.

For the first part of the plan he build line of searchlights, a little bit later, in spring of 1942 after Hitlers has ordered to pass all the searchlights to the AA forces this line has left only with “Himmelbelt” zones, Kammhuber installed in the summer 1941.
“Himmelbelt” station consisted of:
- “Freya” radar with 100 miles effective range for the early warning
- One “Wurzburg” radar for the bomber detection
- One “Wurzburg” radar for the fighter guidance
- “Seeburg” demoscreen was showing red and green point - courses of the two planes
One “Himmelbelt” station was able to track only one bomber and to guide only one fighter. For the lonely British bombers it worked great, but it was absolutely ineffective
against thousands of bombers to come in may 1942.

In terms of the second part of the plan he had three groups of nightfighters.
NJG1, commander captain Wolfgang Falk had two groupes:
I/NJG1 with commander captain Radush (was formed up from two squadrons of I/ZG1)
III/NJG1 with commander major Blumensaadt (was formed up from IV/JG2 and the only group to re-equip from Me-109 to Me-110)
NJG2, commander captain Heize had the only group of long-range night fighters:
I/NJG2, commander captain Hulshof (was formed up from three squadrons of Ju-88 and Do-17)
Later, 1st November 1941 II/NJG2 was created

These groups of nightfighters were performing very successfull night raids to the British bombers homebases, while intercepting bombers on their way home, especially during landing procedures - when bombers were very nicely seen in landing lights of the airfield and enemy AA wasn’t able to attack.

These raids were stopped in 13 october 1941 by the direct Fuhrer’s order. Afterwards night fighters were able to perform only in German skies.

Source: Cajus Bekker “The Luftwaffe War Diaries”