RAFairman's Blog

An RAF Airman's Blog

Waveguide Theory…

Do you remember being at school? You might actually still be at school as you read this, but the older readers may have to think back a bit…I am sure you were taught stuff that you have never used. Like, oh I don’t know, how to solve quadratic equations, or what the various bits of the eye are called. 

 I thought that this would have ended when I left school and certainly wouldn’t have continued when I joined the RAF…but oh no.

As you may know, I did the vast majority of my training back in 1987-1989. This was at RAF Cosford, to make me into an Electronics Technician Air Radar.  This was 18 months – well nearer 20 months actually – of basically classrooms. It was just like being at school…it seemed to last forever and the stuff we were taught all seemed very real – until we left and then we realised that we’d never actually need to use Flemings Right Hand Rule (whatever that is – I forget now) when changing boxes on aircraft. It was almost as though the training back then was training for a different age – one that had past and didn’t really match up to the world we were going into.

This sounds a bit disparaging.  It’s not meant to.  For instance, we sat in classrooms trying to learn how Waveguides work (something that to this day I only have a basic grasp of!) – for it not to really matter when I got to working on the aircraft.

Basically a Waveguide is a pipe that a radio wave travels down. You might even have one in your microwave. There is some jiggery-pokery involved and the signal goes into a tube (which to add to the confusion is rectangular) and pops out the other end often. How it actually gets from one end to the other is a bit of a mystery, but can be explained by some complex maths, a bit of physics and a good portion of imagination.

The upshot is that it will only actually work if the pipe is in perfect shape and the connections to the pipes are snug and well made. If there is any damage to the pipe, the signal will be either reduced in strength or else lost completely. When I started fixing the radar that had a waveguide fitted to it, all I needed to do was check that it was connected up correctly and that it wasn’t damaged in any way and it was sorted.  Did I even use the complex maths? No. Did I need to understand about angles of propagation?  Did I need to be able to work out the frequency of the Radar from the cross-section of the waveguide itself – or vice-versa?


There were lots of things like this, but it’s the one that sticks in my mind.

But the good thing is that it’s not happening now.  My last job was as an instructor at Cosford.  Which was cool as it was sort of like coming home.  But I was glad to see there were lots of changes between the training I had and that going on today.

You see, it’s got more specific. Instead of 18 months of training, the new aircraft engineering entrants into the RAF get specific training that is appropriate to what they will be doing when they leave training.  They will be working first line – doing aircraft servicing and essential maintenance, and assisting more experienced personnel in fixing the aircraft. So instead of me spending three days on learning how to marshal a jet around and six weeks on how a transistor works – now it’s pretty much the opposite.

Which is good. Because when I arrived to work on the aircraft I was totally unprepared for it, despite 18 months of training. I was in a bit of a daze really as the stuff I’d been taught was, well, far too deep for what I needed. I was all of a sudden faced with having to refuel a Tornado and marshal it out of a Hardened Aircraft Shelter and replace a transmitter that weighed a third of a tonne, when I had been taught about Flemings Left Hand Rule and waveguide propagation and how to solder a resistor onto a circuit board.  I had a steep learning curve.

Now the lads and lasses coming out of training are able to hit the ground running a lot faster. They still have the learning curve, but they are a lot more familiar with what they will be doing when they get out of training and into the real world.  I had never even touched a nitrogen trolley for how to inflate aircraft tyres…these newly qualified airmen and women are very familiar and understand what they need to do. Yes they need some training for the type of aircraft, but the general principles – they have them from their training.

And to be honest I envy them.  My mind was full of stuff I would never use.  I had been told this stuff was very important, but in the end it wasn’t. It didn’t make me a better technician for knowing how to spot the difference between a PNP and an NPN transistor. My training was a long time sitting in a classroom.  Modern training is more practical.  They do have some classroom time, but a lot more of it is practical, hands on stuff that means they are more used to working on, in and around aircraft to what I was. 

The lucky buggers…


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