大象传媒

鈥淲颈苍诲辞飞鈥�

In the summer of 1942 new radar equipment, known as Type 14, was issued to certain RDF stations in the southeast. At Foreness Point this equipment was completely mobile, being accommodated in a three-ton prime-mover caravanette with a trailer to house the transmitter and rotating parabolic aerial array. This Type 14 radar operated on the same frequency band as the German radar and had been designed so that changes in operating frequencies could be made in minutes rather than the half-hour or so required for older types of equipment. The idea behind this design was to thwart the increasing tendency the Germans had of trying to jam our radar. With Type 14 we could quickly change our frequency to that which the Germans were using themselves making it impossible for them to jam our radar without affecting their own equipment. In 1942 and 1943 the new equipment was kept on the various stations in reserve. The technical staff only ran it up once each day for a short time (always with the aerial array pointing north-west away from Jerry to keep its presence secret), so as to check its serviceability. This new chain of Type 14 radar was rather encouragingly known as the 鈥淰ictory Chain鈥�.

Late in 1942 a radar watch of two operators plus two mechanics (a Canadian by the name of Callaghan and myself) were detached from RAF Foreness Point with the Type 14 radar to Mundesley in Norfolk. There we were to participate in trials in the charge of a Wing Commander Jackson. The trials consisted of plotting the course of an aircraft making repeated flights over the sea (well away from occupied Europe) to the northeast. To us at the time it seemed from the radar that the aircrew in the bomber was releasing a series of large balloons. The responses from these 鈥渂alloons鈥� appeared on the radar screen as a line of echoes remaining more or less stationary in the aircraft鈥檚 flight path. The radar watch, both operators and mechanics were unable to conceive how it was possible for the aircrew to inflate and release large balloons from a bomber flying at speed. Of course, unbeknown to us, the wing commander from TRE Malvern was testing the effects of "window". That is the dropping by aircraft of bundles of metallic strips cut to half wavelength for maximum effect or to a harmonic of it. The aim was to clutter the enemy radar, and so make it difficult for their operators to distinguish real aircraft responses from the spurious 鈥渨indow鈥� echoes. There is no doubt that our Type 14 radar working on the German frequency for those trials proved the effectiveness of "window".

Because of fears that once used by us against the Germans, they would soon know how to retaliate in kind, it was only used much later in the War, during a raid on Hamburg in July 1943. Strangely enough, the Germans had already discovered "window". But on the strict orders of Hermann Goering its use by the Luftwaffe was forbidden for the self-same reasons as stopped it being used by the RAF up to the time of the Hamburg raid. (See Churchill's Second World War Memoirs, Volume IV pages 257-259).

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