EMI: A student perspective 1952-4
by David Birt
My “false start” at the Poly. was not entirely wasted time, for I did learn how to use a lathe, and how to file flat. In those days (1951), all the machinery in the basement workshop was powered via clutches and by belt drive from two shafts which ran the length of the workshop. In turn, these shafts were powered by 50 hp electric motors. Health & Safety – what’s that?
The EMI College of Electronics occupied a large Victorian house in Pembridge Square, Notting Hill Gate. You may wonder why EMI should have established their own college (-a kind of Wood Norton?). It should be appreciated however that electronics was very much the poor relation in those days. As regards degree courses at the better-known establishments, the nearest you could get was “Electrical Engineering- light current”, and the syllabus contained very little indeed about electronics. I conjecture that it was this educational vacuum which motivated EMI to set up the college. The “bread” of the 3-year EMI course was full-time study at the college, and the “jam” was a year as an apprentice at the factory in Hayes, with day release for studies. It was at this time that my mode of transport changed for ever from train to motorcycle.
The Dawley works (at the end of Blythe Road, Hayes)
I found the time at the EMI factory in Hayes very interesting, and it was there that I first heard of Alan Blumlein. There was still quite a lot of his H2S airborne radar equipment around, and numerous pieces of test equipment which he had designed – like the “in-situ” bridge. Mind you, it did come as something of a shock to discover that in one of the factories of this esteemed ‘electronics world leader’ , Cyclemotors were being made, and in another, brake drums for Landrovers. The well-known elliptical loudspeaker cones were made on an adapted Victorian hat-press, adjacent to gramophone needle manufacture where the rough steel shanks were placed in sacks along with some grinding paste and then stuffed into a potato peeler until they were judged to be “done”. 78 rpm records were pressed just across the road. (The vinyl LP had not yet arrived.)
Out in the car park of the Dawley works was a wooden shed, and it was there that the famous BTR2 tape recorders had their final tests and tweaking. They were auditioned via one of the EMI “flagship” loudspeakers – the one which incorporated the curved-strip electrostatic tweeter. A very impressive sound!
The British “class system” was quite evident. There was a separate ‘management’ car park at the Dawley factory. There was a separate ‘management’ canteen, with waitress service. There were even separate ‘management’ loos accessed by Yale lock! Management started work at 9am, whereas the ‘plebs’ had to clock-in by 7.30am and generally work on Saturday mornings as well. This did have a useful spin-off in that one could sneak a private chromium plating job into the appropriate vat, unnoticed!
This class structure was not unique to EMI at that time, and indeed it is my contention that it was one of the causes of the poor industrial relations which plagued British industry for so many years. Traces of it remain to this day do they not? Annual leave was 2 weeks.
I started work assigned to the Calibration Room, and designed and built a test jig which confirmed the attenuation of an aircraft power-line filter at 1.5 MHz and 60 MHz on a pass/ fail basis. I don’t quite know how this job came to be assigned to “calibration”, for most of the work in the section was to do with Avo meters, signal generators etc. I got so stuck-in to the test jig that I was retained in the Calibration Room, and did not move on to other sections to the same extent as my colleagues. Incidentally our section head, Mr Brockway, used to arrive in a bull-nosed Morris. Motorcycles with sidecars, were a common form of family transport. Oh, and so much was made from Bakelite, including the HMV “Cavendish” D-shaped fan heater (which still serves me well). What ever happened to Bakelite?
I did spend a short time in Goods Inward, which had quite a large test lab. In those days, components were tested on arrival. For example, each capstan motor for the BTR2 tape recorder had its torque curve plotted in goods-in test. The motor was made in Croydon, and indeed virtually all components were made in England. It riled me to learn that EMI paid 2d (in old money) for an FW4/500 rectifier valve for which I had just paid £1-7s-6d in a shop!
Next to the Calibration Room was a generator room filled with numerous alternators providing power at e.g. 400Hz for various aircraft and marine equipment throughout the factory, for this was one of the places where the wartime H2S radar sets had been built.
There was also a superb coil-winding shop where the level of quality control and testing was of a very high order, even by today’s standards. A huge range of transformers and coils were manufactured there.
All in all, I would say the course was good, and quite comprehensive. Transistors had not yet arrived, and calculations were pretty tedious and time-consuming in those days of log. tables and slide rules. Making measurements with the equipment available was in general time-consuming and often not very accurate.
This was particularly true of the measurement of frequency, which required a 6ft bay of equipment if you needed accuracy to parts in 106. The Marconi Instruments spectrum analyser of the day (later to be seen decorating the set in the second series of Dr Who) was huge, weighed ‘a ton’, and drifted so much that it could take a whole morning for it to settle down so you could view a spectrum plot on its long-persistence CRT.
There were also laboratories back at the college in Pembridge Square where we students did various didactic experiments such as plotting response curves of coupled circuits. I remember plotting the anode characteristics of triode and pentode valves (with and without feedback) a point at a time. One of the lecturers at the college had constructed a rather good system for displaying the polar radiation characteristics of aerials. This used an ex-radar 3 GHz (10 cm) coaxial- line oscillator (with a “doorknob” triode) as the signal source which drove a rotating Yagi array mounted above a copper ground plane.
Peripheral activities ( aka. “homework”)
“Smith’s” in Edgware Road was easily visited at lunchtime to acquire bits for my FM tuner project. (No yellow lines in those days!) A nice bit of hard-drawn brass for the chassis, copper sheet for the screens, stacked-mica capacitors for decoupling. I acquired a PCC84 double-triode valve, newly developed for the impending Band lll TV service: just right for a low-noise front end. The IF stage used the ubiquitous EF50, and for the oscillator, an ex-RAF IFF equipment EC52 seemed like a good idea as it was only 1 shilling – since nobody seemed to quite know what you could do with it! I soon learned that Selotape was entirely unsatisfactory for use as inter-winding insulation in ratio-detector transformers due to its hygroscopic characteristics. However, in Smith’s you could buy also for a shilling, (the same price as a valve) 4 inch squares of this rare material polythene sheet! Problem solved. It seems hardly credible today that polythene was once so rare and expensive. I also find it hardly believable that just a bit later in 1954 when I took a second “fringe area” tuner design with me to the Army camp in Scotland (in order to use the Army’s signal generators to line-up the IF amplifers) one could tune over the whole of Band ll, and hear only noise!! So, tuner 1 was up and running before Wrotham was properly on-air. It remains in daily service 52 years later, and who knows, it might even outlive the FM service. A bolt-on stereo decoder had been added before regular stereo transmissions were inaugurated.