By the end of 1940, it had become apparent that the increased Radar work allotted to us would far exceed the capacity of the factory. The Coach yard was roofed over for a machine shop and sadly, one Peach House of some 1500 sq. feet was converted into a capstan shop. To increase assembly and test capacity we decided to build a 10,000 sq., ft. assembly shop on the lawn, rather grandiose terrace and steps led down from the 1st floor of the original house which had to be demolished.
This terrace figured in an amusing episode just after Dunkirk; the Regional Controller of the LAP in Bristol, a retired Governor of Burmah, had come out to offer us his help. He stood on the terrace, surveyed the steps and garden and said: "You know - all that is missing here is a pair of Peacocks!
With this new extension, and numbers going up at the rate of 200 employees a year, we had to install a sewage plant and filter beds which we managed to camouflage inside a group of trees. I still left an attractive garden area where, during the lunch break in Spring and Summer, the employees enjoyed the pleasures of Country House life.
On the roof of the new building we built a canteen of equal area which we used for recreation evenings and weekends, and which at peak times supplied over 1000 lunches a day. We also started a bus service to and from villages up to 10 miles away both to utilise the labour and take advantage of additional billetting.
In February 1942 an event occurred which really cast us down. The famous German Battleships Scharnhorst and Gneisenau, which had been damaged by our raids on the French Atlantic ports were expected to try to make their way up the Channel to their home base in Germany. Watch was kept by shore Radar stations, and Coastal Command using the American Aircraft known as "BOSTONS".
One foggy day the two ships slipped up the Channel and in spite of all the Coast Stations (which had been jammed by the Germans) and the frequent sweeps by a squadron of ASV equipped Bostons the ships got through. This was at the time regarded, quite rightly, as a great victory for the Germans and a nasty defeat for the Allies. For us particularly, knowing the reliance placed on our ASV sets, it was a terrible blow.
We could get no information from the Fleet Air Arm, as the matter had been raised in secret session in the House of Commons, and a commission had been set up to investigate the fiasco, Their report was not available till after the war, when we learned that it was not our ASV sets which had failed to function, but a blown fuse which had not been detected in one aircraft's electrical circuit at the crucial time when the "Boston" was passing over the fog-hidden ships.
Great progress was being made in the job of making Radar sets more reliable under difficult search conditions and to increase the accuracy with which they could pin-point targets, The big sets used by the Army and Navy for gun laying were of course a different kettle of fish, being vastly more elaborate and accurate than the airborne equipment could be.
The Germans of course also had Radar, but whereas theirs had been developed mainly for defense purposes, we had very early on developed Gun Laying Radars which were already installed in many ships by the outbreak of the war; the sinking of the Italian ships at the Battle of Matapan was by Radar controlled fire.
The first proof that the Germans were using Radar in their warships was when Naval divers went down to examine the Graf Spee which was sunk off Montevideo early in the war by the Royal Navy, and brought up some polythene insulated cable; polythene had only recently been developed and was used almost exclusively for the cables carrying the very high frequency signals to the aerial, no other material providing the necessary degree of insulation at these frequencies.
The next advance in Radar technique arose from the invention at Birmingham University of a revolutionary new transmitter valve known as the magnetron. Whereas most Radars had previously worked at a wave length of 1 ½ metres, if my memory serves me correctly, the Magnetron was capable of getting down to a frequency equal to 10 cm - thus rapidly approaching the light portion of the electro magnetic spectrum.
The shorter the wave length the smaller the error in pin-pointing the target and brighter and more legible the trace on the screen of the display unit. Of course, at this frequency, the Radar Beam can only, like light, travel in a straight line, so that the target has to be almost in a straight line. While the uses of new device were being developed at TRE, intermediate marks of AI and ASV were introduced and produced by us in collaboration with EMI and other laboratories and factories, ranging to AI Mark V, which all had some success in night fighter detection of Bombers, and other applications.
A later by-product of one of these sets was a very compact display unit which showed on its 6" screen the return signal from the target. The navy had by then got its own sets widely installed in a whole range of ships, and found that one of these display units known as indicator 271, being only about 8" x 8" x 20", could usefully be installed in many restricted parts of naval vessels and some cargo ships to enable various personnel to see what was coming in on the Radar Screen, and the Admiralty ordered some hundreds of these, which we turned out literally like sausages.
