The prevailing attitude to night fighting left commanders on the ground to carry out research on their own; the first occurred in Berlin, by Luftkreiskommando II from May to November 1936.

The Nazi propaganda machine dismissed RAF bombers as "tired old cows", but the limited range of the precise Würzburg radar, and the inability to distinguish friend from foe, left the Luftwaffe at a disadvantage.

The Henaja belt, which provided three radars per searchlight battery, covered the area from the Danish border to Maubeuge, could detect bombers entering and exiting the zone with great accuracy, but RAF bomber pilots learned to dive upon departing the belt, accelerate past the search light batteries at low-altitudes and escape the most hazardous part of the defence zone.

The system remained the same, but the accurate, long-range Freya was introduced to maintain overall surveillance and often could bring the radar-less night fighters into visual range of the bomber.

The lack of airborne radar at this stage in the war meant finding and destroying Allied bombers at night was a difficult prospect, thus it was decided to use the Fernnachtjagd in operations over Britain.

[17] Major Kuhlmann, head of the wireless telegraphy interception service played a significant part in assisting the Luftwaffe night fighter force as did Wolfgang Martini's Luftnachrichtentruppe (Air Signal Corps).

Intercepting British signal communications by monitoring the radio traffic of enemy ground stations and aircraft the Germans could determine where and at what airfields RAF night activity was occurring.

The Gruppe was assigned longer-range and modified Do 17Z and Ju 88C aircraft for intruder operations as they could carry heavy armament and bombs, unlike the shorter-range Bf 110.

[27] Sommer proved intruders a threat to RAF training centres when he accounted for an Airspeed Oxford trainer on 29 April 1941, confirmed through British sources.

Other NJG 2 pilots and their supporting crews, Leopold Fellerer, Heinz Strüning (23), Heinrich Prinz zu Sayn-Wittgenstein (38), Rudolf Schoenert (23) began claiming bombers with growing frequency in 1942.

Even in August 1943, two years after its debut, eighty percent of the sets produced and delivered to operational centres at Werl and Gütersloh were defective and technicians were overloaded with repair work.

[50] Prior to the use of IFF devices, a night fighter had to return to orbiting a radio beacon after each attack to allow its detection by German radar controllers.

[55] The Battle of the Mediterranean and North African Campaign began in June 1940 with the Italian Empire's entry into the war on the side of the Axis powers.

[68] Stab and II./NJG 2 transferred to the Mediterranean and in December 1942 were carrying out convoy escort patrols, anti-submarine warfare operations along with the night fighter missions.

The Allied air forces now had a strangle hold on the aerial routes which supplied and evacuated material and personnel (Operation Flax) from Africa.

The night fighter Staffeln located in Tunisia remained until 11 May, in effect the last hours, when radar and technical specialists were flown out via Fieseler Fi 156 Storch light aircraft.

During June and July the night fighters managed to shoot down only three enemy bombers near the Strait of Messina, the area covered by the sole operational ground radar site.

[78] The German night fighter wings had improved also; their airborne radars accounted to an estimated 36 percent of British bombers shot down in the coming battle.

[102] In 1943 the development of the Serrate radar detector and their installation on de Havilland Mosquito and Bristol Beaufighters changed the air war significantly.

RAF pilots flew to known German night fighter airfields and patrolled them in an effort to destroy Luftwaffe interceptors as they got airborne or landed.

[103] As one German historian noted, the advent of the frequent Mosquito intruder operations from October 1943 meant "no airfield in Central Germany was safe.

"[104] In November 1943 Arthur Harris began the "Battle of Berlin" in the belief the destruction of the German capital would end the war without Operation Overlord, the planned amphibious invasion of France.

[109] The Monica radar gave only warning of a fighter within 1,000 metres (3,300 feet) in a 45 degree cone, while Flensburg could detect the bomber from 100 kilometres (62 miles) away.

[112][113] On 10 October the main body of I./NJG 2 transferred from Parchim to Greifswald, but its period of tenure here was extremely brief; a mere eleven days later, yet another order from above moved the Gruppe to Kassel-Rothwesten.

Harris direct route took the stream across several night fighter assembly points and the resulting battles left 95 RAF bombers destroyed.

Staffel, was tracking Short Stirling bombers laying mines when the compass malfunctioned the inexperienced crew latched onto a radio beacon they believed to be in the Netherlands.

"[109] The Allied bombing of oil caused chronic shortages in fuel leaving only the most experienced crews flying while the novices were inactive for weeks on end.

[141] The Allied breakout from Normandy in August 1944 destroyed a significant portion of German early warning systems supporting the Kammhuber Line.

Bomber Command's attack on Dresden, supported by the United States Army Air Force (USAAF) and Operation Clarion went virtually unopposed.

To avoid enemy radar raiders were told to fly at minimum altitude and then climb to 4,500 metres (14,800 feet) as they reached the coast, generally believed to be the average operating height of British bombers.