Steve-
May the force be with you... (or should I say, it appears the force is
with you TOO MUCH!).
(Sigh... when man makes plans, G-d laughs.)
Sorry for all your troubles.
I have no idea what I'll be facing here in the western foothills of NC.
I'll find out, though; I'm sure.
PS - If you move to Oregon, then all your connections and equipment
might corrode/rust!
Dick, K0CAT
======================
Steve London wrote on 7/26/2016 9:37 AM:
K9YC wrote:
The problem with this (and any) analysis of a lightning event is that
it is FAR more >complicated than anything we can compute, simply
because the voltages and currents induced >in any system (stuff wired
together) will be different in each conductor depending on >WHERE the
strike is, the physical geometry of the conductors that make up that
system, how >energy from the strike gets to the earth, etc.
I can attest to that ! In 13 years of living on a dry, New Mexico
hilltop, I have learned a lot about mitigating lightning damage.
Frankly, the cost and effort of doing lightning protection "perfectly
right" is prohibitive. The approach I have settled on is simple
disconnection to keep the bulk of the lightning energy out of the
house. All RF and control cables to/from the towers (I have 3 towers,
with 5 rotator controls and a number of remote antenna switches)
terminate on a bulkhead panel about 30 feet from the house. During
lightning season (May-October), everything is disconnected at the
panel, except when I am on-the-air. All AC power to the ham shack is
disconnected, except when I am on-the-air (unplugged - I don't trust
the small air gap in switches and relays). Yes, this makes it
inconvenient to be on-the-air during the summer. Even with these
measures, I have learned the hard way about interconnectedness (K9YC's
"stuff wired together"). A nearby or direct hit to a tower will
destroy USB ports on computers and radios, if they are interconnected
with a USB cable. I have tried commercial USB optoisolators, but have
found they generate too much RF noise. The latest incident was earlier
this week. I had a direct hit. The only "stuff wired together" was an
Astron power supply, connected to a 2 meter radio. Just before the
storm, these were working fine. I unplugged the antenna from the 2
meter radio, and the AC power from the power supply. There was still a
3' long power cable connecting the power supply and 2 meter radio.
After the storm, the power supply blew fuses. The root cause was a
fried LM723 in the power supply, causing the voltage to go high, and
the crowbar protection to be activated.
Sometimes I think moving to relatively lightning-free coastal Oregon
would be a good idea !
73,
Steve, N2IC
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