on 1/27/03 10:57 AM, Tom Anderson at ww5l@gte.net wrote:
> If you're disconnecting the coax outside, don't forget about the equipment
> grounds. Several years ago a friend of mine in Arlington TX had all of his
> coax disconnected when lightning hit the top of his 60 ft. tower. The surge
> came down the tower and into the ground underneath his house and came back up
> his equipment ground located on the opposite side of the house from the tower.
> It fried everything he had common point "grounded" in the shack, including his
> Icom 751A.
I thought about this some more. I bet he did not have his shack ground and
tower grounds connected.
I wouldn't say the lightning "traveled through the ground and up into his
shack again." Rather, when the lightning struck, it raised the potential of
the ground at his tower. Since the ground acts as a large capacitor it can
only dissipate so much of that charge instantaneously and the rest decays
over time (I think I said that right!). From what you told me, he had his
shack well grounded with multiple rods. So while his tower is raised high
in potential, his shack stays at ground on the other side of his house.
That's a large potential difference and * POOF! * his equipment went.
Just another example of why connecting grounds is important so that
everything rises and falls together. Sure glad everyone on the reflector
convinced me of that after putting my tower up! :-)
73,
Jon
NA9D
-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)
Citizen of the People's Democratic Republik of Illinois
Life Member: ARRL, NRA
Member: AMSAT, DXCC
http://www.qsl.net/na9d <- Updated on 1/22/03!!!
"A life lived in fear is a life half lived."
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