[Lf] Re: re Rugby GBR

[Andre' Kesteloot]

Thanks, Alan, for the details of Rigby, which I am passing on to the rest of the
LF communityn here.
Do you know for a fact that Rugby is stiill transmitting on 16 KHz?
Both WB5MMB and K0BRA have heard it very clearly here recently
73
Andre' N4ICK
*********************
Alan Melia wrote:

> Hi Andre', Rugby GBR on 16kHz, has probably changed a bit since I last went
> round the site. If you ever travel up our main North-South motorway M1, its
> aerials can be seen on the left hand side just before the junctions with the
> M6 to Birmingham. The aerial is slung from 9 lattice lattice masts, 750 feet
> high. The main part was intended to be a 'figure of 8' top-load capacitor,
> but the final mast was never erected, and the top-load looks more like a
> greek 'alpha'. It is made from multiple wires separated by large spreaders,
> several feet in diameter. The vertical section, hung from the join, makes a
> 600 foot vertical radiator. Yes it looses nearly 150 feet in the sag below
> the supporting masts.
>
> I last saw the transmitter in the early 60s and it has been updated to solid
> state since those days. It was operated by the Post Office for the
> government, mainly the Ministry of Defence. It consisted then of three banks
> of brighly glowing valves (= tubes), each bank capable of generating 500kW
> output. I don't remember how many valves in each bank, but it was probably
> about 10. Possibly using a readily available broadcast transmitting 'tube'
> Thus a total capability of 1.5MW, but even in those days of the cold-war, we
> were told that it loafed along on one bank, a mere half megawatt, and was
> capable of talking to nuclear subs anywhere in the world. The second bank
> was on hot stand-by and the third bank in maintenance. I was intrigued by a
> large meter on the ends of the banks and wandered across to see what anode
> current it showed. I was flabbergasted to see a meter calibrated in 'lbs of
> steam'  It was the cooling system!! The valves were water jacketed and there
> was a sizable fish pond outside as part of the cooling sytem. Rumour
> suggested the waste heat heated the offices and labs on the rest of the
> complex, but I can't vouch for that.
>
> An upper gallery to the transmitting hall was suffused by a pale blue
> flickering glow. When we were taken up there it turned out to be a four foot
> high ignitron, mercury arc rectifier in the power cage, connected directly
> across the 11kV three phase AC feed. On the adjacent panel was a small meter
> calibrated in megawatts showing that the station was consuming from the
> National Grid enough to supply a small town (or two!) This also went up and
> down considerably as the key was pressed ( I have a recollection of a peak
> reading of 11MW!!). The twinkling light we had seen was the ignitron
> flashing out the callsign as the TX was keyed.
>
> The variometer used for tuning was made on an oak frame with joints and
> dowels for fixings (No screws we were told or the whole thing would catch
> fire.) The wire was litz, and I seem to remember it was quite a bundle,
> probably about one and a half inches diameter. We were told it was 800odd
> strands, I think (isn't litz laid up in powers of 3?). I remember someone
> commenting about the poor apprentice who probably had the job of cleaning
> and tinning each strand. The aerial was fed out of the tuning loft through
> an insulator similar to the one shown on your photographs. I seem to
> remember it was about 15 inches in diameter and about 6 feet long and let
> into a thick glass window which must have been about 6 feet in daimeter. We
> were told that this was no overkill, as it had been blown out of the wall on
> a least one occasion when the transmitter had been keyed into a damaged
> aerial (What price a high SWR there!!)
>
> I imagine it's all a little less 'stone age' now, but not that much.
>
> Cheers de Alan G3NYK
> Alan.Melia at btinternet.com