The first equipment on which we were to be trained was known as the Type 7. This was a search radar developed during the early war years intended to be used for Ground Controlled Interception purposes. The great problem with CH radar was that it looked fixedly in one direction only. Once the enemy had flown over it they could not be seen again, a defect which no lesser a person than the Prime Minister himself had noted during an early demonstration. The answer to this was to design a system that could sweep back and forth or be rotated to and halt on any bearing. The early result was a man powered machine and as common aerial technology had not been invented separate transmitter and receiver aerials were needed with a pedalling man in each cabin attempting to keep the bearings of both in synchronisation. The Type 7 with it's huge flat bedstead of an aerial overcame all these difficulties and could provide the height of a target too. For those interested in the technicalities I have prepared a fairly extensive illustrated description of this machine.
To our dismay there was no actual complete Type 7 provided for our amusement at Locking merely the transmitter cabinet. However this we could 'run-up' because the RF energy was cunningly absorbed by a 'dummy load' although from this there were no received echoes to be displayed. The most remarkable item within the cabinet was the highly polished rhodium plated six inch diameter 'Lecher' tubes which constituted the tuned circuit for the cross coupled high powered oscillator triodes. This was engineering of which I could never have dreamed. The much more complex part was the control unit used to 'run up' the transmitter. This arranged the sequential switching in of various power supplies, each stage dependent on the correct establishment of the previous one, and the process after about five minutes culminated in the application of the 11.5 kV EHT to the valves. There was plenty of scope for things to go wrong in that box and the aids to fault finding were few as I remember it, so several days were spent memorising the sequence and how it was achieved.
The modulator was a lethal place of high voltages and very high pulse currents with white porcelain insulators in plenty and it smelt of ozone. We shuddered at the thought of inadvertently getting too closely acquainted with this hell's kitchen.
Towards the end of the Type 7 training we spent an hour or so considering the the mobile version, the Type 15. A much smaller aerial was fixed to a steel cabin which rotated on the back of a large lorry. There were only 16 dipoles arranged in four rows of four, two rows to each of two arrays. Thus it could provide heights by beam splitting, but it had no capacity switch in the usual place, and presently I am unable to recall how the splitting was achieved. Otherwise the differences were small as the familiar Type 7 transmitter cabinet was squeezed into one end of the cabin. Although there was a Type 15 at Locking there was no working demonstration, nor were we allowed to see inside its cabin.
Somewhere around this time our instructor casually asked us how our 'Chuff Factors' were getting on. Nobody knew what he was talking about so he explained. If one divided the days of service completed by the number remaining one arrived at one's Chuff Number. We all duly did this and I was one of those most dischuffed with the result as I was in for three years and most of the others in for merely two. Half way through one's service the chuff number became less than one, and on the very last day of service, with a divisor of nought, an individual was deemed to be infinitely chuffed.
Throughout our technical training a couple of periods each week were spent in the workshops developing our practical skills. The ends of all those little pieces of tufnol earlier filed so exactly into small rectangles were now drilled and fitted with stubs of wire. After that we constructed a large tagboard out of paxolin by fitting two exactly spaced rows of pins. When we had been taught how to solder by our civilian instructor, an art in which I was already accomplished, we duly soldered our dummy small components to the tags. After that exercise we were required to solder wires to the terminals of a variety of types of connector. It was a great test of patience when as a test we had to do this with a Plessey Mark IV plug. These came in a variety of sizes but we had to connect up one with sixteen pins and was somewhat less than two inches in diameter. A complication here was that tight little rubber 'Hellerman' sleeves had to cover over each of the soldered joints and it was a fiddle to do this. First the sleeves had to be given a dot of Hellerman lubricant then a weird tool was needed to get the sleeves to go over the insulation of the wire before soldering it. This tool had three very slim metal prongs of a triangular section, which when closed together seemed like one thin pointed metal rod. The sleeve was slipped over that and when the handle was squeezed the three parts all moved away from each other thus expanding the sleeve. It seemed that for some reason a Hellerman tool was generally known as a 'Virgin Urger'.
At the end of three weeks we all duly passed the written paper and the associated severe oral grilling. All except one that is. This poor chap had been experiencing what he thought was pretty severe toothache for several days which he had been attempting to subdue with aspirins as he was firmly resolved not to 'go sick'. However one morning strange blotches appeared on the side of his face and neck. The next day some had developed into yellowish pustules and with the pain intensifying he had little alternative but to see the Medical Officer. At lunch time he was packing his kit ready to be taken to the RAF Hospital near Swindon for the treatment of his Shingles. We never saw him again. ( I found out for myself recently that this very painful condition needs to be recognised early as it is essential that a course of antibiotics is started before the pustules emerge. )
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