Dimming the lights in Building 46!
Tony Curtis http://www.iwishihad.com.au
I am, I suppose, 0.25 of a Marconi Veteran. While working for British Relay Wireless I applied to Marconi for a job, circa 1965. My Mini broke down on the way from London to Chelmsford and I phoned Mr Cranston. Upon arrival he interviewed me in a dark room in Building 46, one with a long table. The job required a degree and I had only HNC, so I wasnâ€™t expecting the result. Mr Cranston advised that Marconi preferred proven abilities and my prior design work in vestigial sideband TV transmission showed ability.
I started shortly afterwards, travelling daily from Southwark, London, to Chelmsford. I had been allocated to the High Power Transmitter Group in Building 46, as a Junior Engineer. I had a desk in an office and commenced work on a 100 kW LW Tx under the guidance of one Curtis Brown. The bloke in charge was Dave, and within the office were Gordon and Peter (none of whose surnames I can now recall), and another whose name totally eludes me.
My first tasks were the output coupler, tuning discriminators and the penultimate stage; Curt soon left me alone as it appeared my capability was acceptable. As the Tx. â€˜grewâ€™ I was delegated to design the control circuit. The output stage used an Eimac 4CX35000C pair with a magnificent Curt-designed Cu square section Pi coil made from large diameter pipe. I had never seen such an inductor as this before. It was to be the first device using feedback to linearise performance.
The saleable prototype was finished and fired up only to squeg when feedback was applied, dim the lights in 46 and emanate sparks everywhere, before â€˜dyingâ€™, just before an ASWE evaluation! My weekend fixed things and the evaluation went off well with no feedback being applied.
Tom spent some time proving the feedback network had a phase-shift of 180 degrees at 160 kHz, ergo the instability. I suggested â€œtune out the Cin of the pen(ultimate) stage with an Lâ€. Curt laughed, yet he adopted my suggestion and Marconi got a patent out of it. We got one shilling and wrote it up in â€˜Point to Point!â€™
During that time I married and we moved to a Marconi flat in Noakes Avenue thanks to Wally Eden, the Marconi Housing Manager. Susan, my wife, got a job in the silver-service canteen at New Street and hobnobbed with people I had only heard of! It appeared some members had the penchant for â€˜guidingâ€™ her placement of the vittles by the laying of a hand on her rear?
Dave, the Group Leader was destined to take over the leadership but took a job in Surrey working for an RF heating firm. Either Bill Barbone or Raymond Rowe was mooted to get the job; that at least was what I heard from my level.
I was moved to Writtle, under Brian Skingley, to work on radio relay stuff it appeared, but when some bloke in a suit and tie wandered round and asked where the baseband combiner was, things changed.
I never worried. I had to design an FM discriminator for Goonhilly, Matt Snodgrass did the VCO, John Osborne the IF amp, Minnow Irani wandered about wasting peopleâ€™s time, John Rodgers was doing other stuff, Dudley left for Plessey and Mike Haygreen left for Beckman.
It then appeared that Raymond Rowe was to take over the â€˜Tropoâ€™ Group, (us) and we moved to the building opposite the cemetery. It was there I finished the baseband combiner and used the Baddow-generated film wire, much to the worry of Brian Skingley. But it worked! Thence on to the pre-detection combiner that, alas, I never finished as I left to join Cambridge Consultants.
From there we went to Africa for a short time, returned to UK and became a Marconi Principal Engineer at the Vineyards for a short time, then emigrated to Australia to design target range training equipment. Currently I teach ADF trainees the fundamentals of RF stuff in Wodonga, Australia.
I take great personal satisfaction in being lucky to have been associated with the engineers I worked with at the Marconi Company, Chelmsford.