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Old April 1st 04, 02:13 AM
Joseph Fenn
 
Posts: n/a
Default Lightning Protection

Well what I do is remove the HF coax line when thungder and lightning
is approaching. In the shack I have a mounting box with a normal
coax connector where I attach the ant feed to the xmtr.
I made a little device useing a new Coax plug which has a 2k resistor
connected to its center connector. This 5 watt resistor is then
connected to a 1/4 watt neon bulb which is in turn connected to the
gnd side of the connector. As a storm approaches, I glance at
it once every 5 mins or so and if If see the neon bulb flashes
due to static buildup on the feed line from the antenna, I keep my
eye on it. If it startes flashing about every 15 seconds or even
every 5 seconds, I get the hell out of the shack. This system
was used on many varieties of commercial radio systems as well as
in Military rcvr front ends where even small amounts of static
buildup could ruin the front end of a sensitive receiver.
Particularly on VHF freqs this often occurred. No amount of
grounding of your Ant is going to totally prevent damage from
a direct lightning strike on your metal mast or tower.
Lightning can strike either a tower and or feedline and then arc
accross to the structure such as your house or ham shack. That
type of strike can even split a concrete house wall right down
the middle. We had a person here a couple of months ago that
got struck by lightning but not directly. The bolt hit a power
line then arced from it down to the person it struck. That
person survived. In fact he was hospitalized just to check
him out and no permanent physical damage occurred to the
guy!
Kokomo Joe


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