A passive early warning radar receiver, capable of covering 360° on 9 and 3 cm
Working on a query put forward recently on German IR technology, I came across two pages which are describing the principle of this system. Two pictures are shown, which were taken from U249 (VII C) when it surrendered to the British at the Weymouth on 9.5.1945.
My brief explanation is, that 4 main quadrants exist of which in each sector the existing loop antennae were interconnected in parallel. Thus providing 4 (grouped) signals originating from the four 90° sectors. These were amplified similarly as was done in Naxos. Their four LF output channels were fed onto the four deflection plates of an oscilloscope. Painting a lissajous pattern on the CRT screen. These loops were having a 45° angle as to make them sensitive to both horizontal and vertically polarised radar signals. The upper small ring section is covering 3 cm and the lower one is used for 9 cm.
I don't know whether this was done twice, thus for 9 and 3 cm separately, or that both sector output channels were wired in parallel (the latter is the most likely one). As the system was mainly meant for early warning. It was most significant to know that a danger was approaching from a certain sector and not what type of radar apparatus was pointing towards them.
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