[BC] lightning

[DANA PUOPOLO]

Actually, Grounded towers don't do much better. It seems that when the charge
travels down the tower to ground, it induces voltage in the outrigger wires. 

-D



------ Original Message ------
Received: 
From: <clive at citiria.com>
To: broadcast at radiolists.net
Subject: [BC] lightning

Seems like another recommendation to use grounded antennas like the shunt
fed.
NO lightning problems at all since the structure is solidly attached to the
earthing radials.
Oh by the way, I would have thought those dissipators would cause massive
corona
problems on any high power setup. I once had the top of a quarter-wave Rohn
discharge into low cloud and that was without a dissipator. Admittedly it was
1.5
MWatts.

I nearly did a Ben Franklin on myself once. It was a Marconi 20KW FM and the
weirdest place ever, on top of a mountain in the south of France, there was a
zoo
there too and I would walk past the animal enclosures going in and out. Lions
and
tigers roaring.
The transmitter was put into an abandoned ruined monastery with the antenna
on
the roof.

So I was doing my inspection prior to the first on-air test. Clouds covered
the
mountain top so we were as if in heavy fog. The feeder was disconnected so I
picked it up by the EIA flange connector and was about to bolt it to the
output
socket when I received a big jolt that made me shout. I dropped the flange
and
said to the cowboys who'd installed the gear (NOT Marconi people, the
self-taught
locals) "You have earthed the antenna mast haven't you?"
They looked confused so I repeated this in French. The reply: "Earth? Ground?
But
this is an FM antenna, not AM!"
Needless to say there wasn't a ground in sight. At that moment a brief glow
lit
the cloud outside and I saw a big bright spark between the flange and the
floor.
I told them to call me as soon as they'd installed a proper earthing system
and
left pretty damn quickly. It all worked out OK in the end, I wonder if there
is
still a transmitter there.
Clive



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