[BC] what happened I wonder

[Clive Warner]

I was looking for photos of my Gambia install that show the feed points and
found two, and just as I thought, there is no lightning protection at all.
The combiner/rejector cabinets sit close to the mast, on 1 metre high
concrete caissons, and earthed via four-inch by one-eighth copper strap to
the mast base plate.The descenders (three) are about four metres wide by the
look of it, and connect directly via pigtails to the bowl insulator studs.
The cabinets were twelve gauge alloy and specially made for the tropical
environment. During the monsoon the site suffered plenty of lightning, it
was the only high point for miles (and the only buildings pretty much).
Location was a swamp by the side of the river. Umbrellas were stayed with
some special kind of line like Kevlar or whatever, that Marconi Antennas
developed. High tensile strength but high voltage too. As I recall there
were seven umbrella elements, hmm, what length? Maybe about one-twelfth
lamda.
This setup was standard practice for all MCSL low power (up to 20KW) AM
sites and I put in many more, in Nigeria and Zaire and Congo and Niger and
so on. None of them had any form of LPD, they were all pretty much as in the
Gambian site except that Gambia was two transmitters paralleled on one
frequency, and another two transmitters paralleled on another frequency,
both frequencies combined into the folded-umbrella, and with a reflector
behind it. The reflector was hard to tune because both frequencies were a
fair way apart and of course with change of frequency every darn item in the
equations go all over the shop.
I have another picture somewhere, can't find it at the moment, of a whopping
big strike on an antenna I was lucky to catch on film in Nigeria. These
installations were designed and built with plenty of experience as to the
monsoon conditions, and used to sail through the storms; the transmitters
quite often didn't even trip if a strike ocurred. However we did have some
problems with damage to the umbrella elements. Not surprising.

But while I was going through all this stuff, I wondered what happened to
the guys from Marconi's antenna department? It no longer exists. Perhaps it
couldn't survive after the broadcast division failed in the UK? Maybe
someone here knows. . .
Clive