My quarter wavelength vertical tower (driven element in my vertical
parasitic array - see last 3 editions of the ON4UN low band DXing book) has
a shorted quarter wavelength of coax connected to the feedpoint. That keeps
the vertical at ground potential for lightning, etc. This is one method
cellular operators use for lightning protection. Easy and very
straightforward.
73
Tim K3LR
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of
donroden@hiwaay.net
Sent: Monday, October 7, 2019 9:49 PM
To: topband@contesting.com
Subject: Re: Topband: spark gap construction ideas for 160m tower
If you gap a pair of spheres .... graphite, brass, or stainless
steel... typically the thickness of a credit card for a 1/4 wave
broadcast tower at 1KW carrier / 4KW peak; unless you shield the gap,
water WILL bridge the gap either side-by-side or stacked vertically.
Rain drops are typically pure distilled water, but if the water runs
down a galvanized tower, all bets are off. Make a rain shield out
of a plastic Coke or Pepsi bottle and replace a couple of times a
year as you inspect all of your connections.
Don ( still doing Broadcast AMs after all these years ) W4DNR
Quoting Jim Thomson <jim.thom@telus.net>:
>> ## Place a plastic cover above any outdoor spark gap. Any
> bugs will be fried.
>
> Jim VE7RF
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