Electron Flow, Imaginary Numbers and a Self-lighting Fluorescent Tube

During the last three weeks of the course we were taken daily to a secure area where we learned about Typex machines

When I returned from leave I found that Sparky Wale and I were now part of course GSp22. Most ground wireless fitters courses were GWF plus a number. They were designed for airmen who’d already served at least one tour of duty as a wireless mechanic. GSp stood for Ground Special courses which were specifically aimed at those airmen who were considered likely to cope with the syllabus by dint of their civilian technical experience or qualifications. Sparky Wale and I were the odd ones out because we were regular airmen but all our fellow students were National Servicemen who had only just completed their recruit training course.

One day, early in the course, Sparky and I were told to report to the Squadron Training Office where a squadron leader formally presented each of us with a Certificate of Merit, signed by the Station Commander, for outstanding performance on our mechanics course. We were jolly proud. The squadron leader then paid us two shillings each out of his own pocket to deliver some coal to his married quarters. Coal for domestic use was in very short supply at the time but it was not for us to question why we were moving coal from an RAF coal dump to a private house!

The Officer Commanding Training Wing, Wing Commander Kidd, told us that in June Sparky and I would be allowed to sit the promotion board for Senior Aircraftman. In the event that didn’t happen but we did get promoted to Leading Aircraftman, with a pay rise, instead.

The fitters course was much more demanding than the mechanics course had been and I was forced to pay more attention to evening study. I found the mathematics taxing because I had only GCE O Level Mathematics, Sparky Wale didn’t even have that, while most of the rest had A Levels. In particular alternating current theory was treated mathematically with frequent references to ‘the square root of minus one’ and ‘imaginary numbers’. It was fascinating but took some getting used to. No longer could AC be dismissed as mere ‘wiggly amps’!

There was a little bit of electrical history at the start of our fitters’ course. All the way through the mechanics’ course we’d been taught that electricity flowed from positive to negative. The negative, ground, terminal of batteries or other power supplies was always zero volts, the same as the earth. In thermionic valves, we had been taught that current flowed from the anode, positive terminal, to the cathode, the negative, terminal. Electrons were not properly understood. Now we were told all that was wrong. We were introduced to the new concept of ‘electron flow’ whereby negatively-charged electrons were emitted from the cathode and were attracted to the positively-charged anode. What we had been taught earlier was now to be known as ‘conventional current’; in future all teaching would be based on ‘electron flow’. The subject is too complicated to go into in more detail here but it all seems so obvious now.

Our introduction to aerial (antenna) theory was even more interesting. When GSp22 arrived at a classroom in a part of one of the hangars that we’d never visited before, a gaggle of Aircraft Apprentices was just leaving. The instructor, a middle-aged civilian, was apparently tidying his bench.

“Sit down and make yourselves comfortable,” he said, barely looking up at us. “I’m just tidying up after my Apprentices’ class.”

I found myself sitting on the end of the front row. The instructor stopped in front of me.

“What’s your name?”

“Cunnane, sir.”

“No need to call me sir – I’m a civilian – Mr Jackson will do.” He handed me a long fluorescent tube that he’d just picked up off his bench. “Hold on to this for a minute will you Cunnane.”

I carefully grasped the end of the tube and it immediately crackled into life and shone brightly. I, and the rest of the class, gasped out loud – in fact I almost dropped the tube onto the floor.

“You’re a bright chap, Cunnane,” he chuckled. “Sorry, poor joke but it never fails! That little demonstration is your introduction to aerial propagation theory.

He explained that I was sitting in the beam of a small dish aerial in the corner of the room that was transmitting low level radio frequencies just powerful enough to strike the fluorescent tube into life. So started one of the most interesting and baffling parts of the course.

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