This first story relates to a Saturday shift in London Switching Centre in 1970.
Saturdays were always busy due to all the OBs for Grandstand and Match of The Day. Whereas most of today's OBs seemingly rely on satellite technology, back in those days OB vision feeds made extensive use of terrestrial microwave links. The majority were BBC links, a few were provided by the Post Office (pre-B.T.), and some were a hybrid, with the BBC providing the link from the OB site to the nearest P.O. link repeater station where the P.O. would intercept a BBC rented contribution link and connect the OB feed into it. This connection required an "injection set" - basically a modulator (because the P.O. links normally went through the repeater stations at I.F.) and a pilot tone generator to stop the automatic link fail switching at the receiving end from going berserk.
The OBs for the Saturday in question required two such "injections" - one in the Midlands for the coverage of the World Cycling Championship at Leicester and one at Sparsholt Firs to feed football from Swindon Town into the Bristol - London contribution circuit for Match of the Day.
The saga begins with a phone call from the P.O. Tower: "Why is one of your links guys standing at our door in Sparsholt Firs offering my man there the end of a length of co-ax?" "Because," says I, resisting the obvious rude reply, "your man needs to plug it into the injection set that he should have plumbed into the Bristol V8." "But he can't", says the voice from the Tower, "'cos the injection set's up north for the Cycling." "But the second set should be at Sparsholt", I insisted. "What second set?" came the reply.
This triggered a flurry of phone calls which eventually led to the voice from the Tower admitting, with a note of surprise in his voice, that "You're right, there is a second set, but it ain't at Sparsholt - it's still here." Urgent arrangements were made to transport said second set to Sparsholt but doubts were being expressed as to whether it would arrive in time. So it was 'lash-up' time.
Fortunately the BBC man at Sparsholt had been busying himself persuading his P.O. counterpart that an IF-IF bodge was worth a go. I was impressed. They de-rigged the BBC link from the roof of the links van and re-rigged it up on the P.O mast. An IF feed was taken from the BBC receiver and coupled into the P.O. link towards London (having first had the pilot tone detectors in London disabled). Eventually the voice from the Tower rang and said: "Well, we've got you a signal, but I'm not sure what you're gonna do with it. I don't think your modulators and our demodulators are very compatible."
I think that was the first time I'd seen a pulse-and-bar upside down! Or more to the point, a very bent pulse-and-bar upside down.
Stuffing it through half of a balanced-pair send amp sorted out the inversion and then, with the aid of a clamp and two Bode equalisers, I arrived at a decent looking signal. Further testing revealed an unbelievably good signal-to-noise ratio but slightly iffy results on diff gain and diff phase. "No problem" I thought to myself, "we'll just drop the sending level."
I rang our man at Sparsholt. "It's looking good", I said. "I've equalised it OK and the noise figure is excellent. But it's a bit adrift on diff gain and phase. Can you contact the link starter at Swindon and get them to reduce the deviation?"
"Pardon?" came the reply. I tried again: "The circuit's a bit iffy on diff gain and phase, but we've got loads in hand on signal-to-noise, so we can safely drop the level. Can you ask Swindon to turn down the deviation?"
"I'm sorry, I don't understand, said the man at Sparsholt.
"Look", I said impatiently, "we've got a linearity problem, but I'm sure we can fix it if Swindon reduce deviation.
I don't know what you mean by deviation" came the puzzled and puzzling response from Sparsholt.
"What sort of links engineer are you if you don't understand FM deviation? I yelled down the phone. This prompted the immortal reply: Don't you have a go at me, mate! I'm only the driver. The engineer's been down the pub all morning - he don't know nothing about this."
The second story also relates to Switching Centre, but is much shorter.
In March 1969 I was on the receiving end of what was probably the shortest ever phone conversation between Switching Centre and the P.O. Tower. It consisted of the guy in the Tower saying just two words, namely "It has."
A seemingly strange and meaningless comment, unless you know that the previous conversation, from a few seconds earlier, had ended with me saying: "Stop pissing about - I'm busy!"
and had started with him asking: "Do you know your transmitter mast at Emley Moor has fallen down?"