In a message dated 5/15/2011 1:45:26 AM Greenwich Standard Time,
k8ri-on-towertalk@tm.net writes:
An antenna and feed line left floating (ungrounded) can develop a very
high, and dangerous potential even without lightening. The typical
strike a mile away can induce as much as a 1000 volts per meter into
that antenna and feed line. If it's floating, there is no way for it to
bleed off safely. Grounded the precipitation static can not build up
and the induced charge is rapidly bled off.
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You bet it can. A good friend of mine used to just disconnect the coax
and lay it on the floor when he wasn't on the air. Uh, this wasn't a good
idea in the thunderstorm capitol of the US. He came home one summer
afternoon to find his radio room rather dusty with chards of concrete embedded
in
the ceiling and walls.
It seems there was a lightning hit which traveled down the coax into the
radio room and blasted a hole in the concrete floor on it's trip to ground.
He no longer uses that disconnect method.
Bill K4XS/KH7XS
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