Oral History of Defence Electronics

MOONSHINE: This was a device that expanded and modulated the received pulse so that an enemy radar would believe that a large number of aircraft were commencing an attack. In response the Germans would launch its fighters, the reality was that only a few aircraft were sent carrying this device and lured the enemy fighters up into the air. When the enemy fighters landed to refuel the real raid would commence knowing that the fighters were not ready to attack. The Germans fell for this trick on many occasions! A similar device was used towards the end of the war called Window, later Chaff, which used aluminum strips which resonated at the frequency of the enemy radar. This gave the effect of a ship or aircraft on the radar screen. Back BAGFULL: This device was a swept frequency receiver which marked the frequency or frequencies that the Germans large Würzburg anti aircraft radars were using so that on future missions the correct jamming frequency could be used. The variable oscillator swept through all the frequencies until it detected the pulse from a radar. When this was found the frequency was recorded and the appropriate jamming signal was set up for future missions. Back CARPET 2: This was the next stage of the Bagfull system. When a plane came into contact with a Würzburg radar the system would automatically mark the frequency and then set the correct jamming frequency up. This system was extremely useful in that it did not need any personnel to operate it. The marking of the frequency had to be very quick so that the jamming signal was on the correct frequency, this was done using a GPO unit selector which was used to drop a latch within a split second of finding the correct frequency. The selecting of this frequency automatically started the correct jamming signal. Back Back to contents page.| Back| Forwards