Vic:
Certainly I agree; likewise substations and skyscrapers take hits fairly
often.
Let me qualify my comments by two clarifications:
1) You can design to survive an "average" direct hit. While the cost to do
so can be met by commercial broadcasters, power companies, and commercial
real estate operators, it is utterly out of reach of practically all hams.
2) Even in a commercial setup, you cannot design to be completely lightning
proof. You can design to withstand a certain stroke current, perhaps a
current that is higher than that found in 99.9999% of strokes in your
region. If so you still have a one in a million chance of being wiped out,
pretty good (if perhaps prohibitively expensive) odds, but not dead-certain
protection.
73,
Steve
AA4AK
At 03:15 PM 9/1/2005 -0700, Vic K2VCO wrote:
Stephen W. Kercel wrote:
BTW, you cannot really design to survive a direct hit. If your antenna is
actually struck by lightning, the antenna itself will most likely be
destroyed, along with the coax and the rig. Also the building will suffer
structural damage.
I don't think that's quite true. BC stations survive direct hits every
day. I would agree, however, that it would cost more than most hams are
willing to spend.
You would need an antenna some distance from the building, with an
appropriate lightning ground system (multiple radials, each with several
ground rods on it) at the base of the tower. Then you would need
lightning suppressors at the top and bottom of the tower for all coax and
control lines. At the entrance to the building, you would need a single
entrance panel, through which all power, antenna, telephone, etc. lines
feeding the building would pass and on which were mounted the appropriate
suppressors for all the above. At this point there would be another
ground system, bonded of course to the antenna ground system.
If you had a separate building for a shack, this probably wouldn't be too
hard; but for a building that also serves as a home it might be difficult!
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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