In a message dated 97-03-01 19:56:22 EST, AA6WG@directnet.com writes:
<< I am interested in their insulated base section for Rohn 25. I am also
looking for a well built spark gap that I can install across the insulator
bleed off static electricity. >>
Like your proposed installation, a spark gap is typically used by AM
broadcast stations since the tower is insulated (and connected to the
transmitter) and live with RF; the spark gap being a 'brute force' method of
getting a lightning strike to harmlessly jump to ground avoiding costly
damage. You need to contact a commercial tower manufacturer or supplier to
get specific info; I've never seen anything available in the ham market.
I'll do some checking and see what I can come up with.
A typical amateur tower/antenna installation is already grounded through
the antenna, cables and tower hardware so while the challenge is the same
(minimize lightning damage), the tools are different. Of course in
conjunction with your spark gap, you'll need a workable ground system.
Since whole books are written on this topic, I'm not going to try to
summarize it here in 25 words or less. If you do want to learn more, I have
a reprint available on 'grounding for amateurs'. An SASE to TOWER TECH, Box
572, Woodinville, WA, 98072, will get you a free copy.
BTW, by the time enough static electricity is built up to jump across
your spark gap, your sensitive electronic equipment has already been toasted.
Although the tower is insulated, your feedline is still directly connected
to it - ouch.
73, Steve K7LXC
TOWER TECH -- professional tower supplies and services for amateurs
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