Re: [IC-7000] Lightning Protection References
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I¡¯ve been following the thread on lightning with great interest having had
the shack struck by lightning twice.?
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As I result I have the following theory and I would like the ¡°experts¡± to
look it over.?
My tower sets just outside the shack and coax and cables enter directly
into the equipment via a short 20 ft. run.?
On one occasion all radios were connected as usual and the tower took a
direct strike.? The vertical 2 meter antenna on the top was blown all over
the neighborhood.?
Most of the electronic equipment in the house suffered some sort of
damage.? However, all of the damage can through the power lines.?
Anything with a choke or coil in the power supply was destroyed.? All of
the radios were connected to their antenna and non of them suffered any damage
to the antenna coils of associated circuitry.?
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So here is my theory:
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The tower provided a clear path to ground.? When the strike occurred
it dumped a HUGE pile of electrons to the tower.? As this large flow of
electrons ran to ground the tower acted as the primary of a large
transformer.? All of the house wiring in close proximity acted as the
secondary to the transformer.? A large voltage was induced into the house
wiring and thus through any equipment that was plugged in.? As this pile of
electrons dissipated the induced voltage reached levels that were high enough to
jump an open switch and smoke and choke.?
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I had a pocket knife sitting on top of one of my rigs and it was touching
one of the other rigs.? It became spot welded to both chassis.? Both
rigs were hooked to the antennas and neither one suffered any damage to their
antenna circuitry.?
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Now my question is:? How do you protect from this kind of
strike.?? The only thing I have done is add a number of extra ground
rods out and around of the tower and bond them al together and to the legs of
the tower.??? However, I offer this suggestion:? Tie a knot
in the equipment power cable.? Even better, tie two knots.? Any
inductance in the power line will stop the surge of current.? Make sure
that all equipment is grounded to a common point.
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Anyone have any comments on my theory and suggestions??
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Tom
WA0LRE
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