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[CQ-Contest] Re: [Towertalk] More on Lightning protection

To: cq-contest@contesting.com, towertalk@contesting.com
Subject: [CQ-Contest] Re: [Towertalk] More on Lightning protection
From: Bill Tippett <btippett@alum.mit.edu>
Date: Thu, 16 May 2002 14:34:41 +0100
List-post: <mailto:towertalk@contesting.com>
Someone wrote:

> I recall an anecdote from W0UN describing how severe lightning
> storms would come across the Colorado prairie toward his field of
> towers, striking frequently as they came, but would stop as they
> approachedhis towers, and resume once past them.

        I lived about 30 miles due East of John on the Eastern edge
of the Rocky Mtn foothills.  From 1980 until 1993, I had two towers
which were the tallest structures for miles around (25G with a KT-34XA
at 105' and another 45G with a KLM-340 and KLM 520 at 155'), all with 
grounded parasitic elements.  To my knowledge, I was never struck by
lightning.  However it was not uncommon to hear static discharge clicks
in my receiver even on a partly cloudy day if a charged (i.e. dark)
cloud drifted overhead.  I usually took this as a sign to disconnect my
antenna...unless I was in a contest of course!  :-)

        I could even audibly hear the static discharges across the coax 
connector inside when it was disconnected, and this was RG-17 which has 
an RMS voltage rating of 11 kV!  Here in NC, I often can hear audible
clicks coming from my top KLM 610 at 105' (parasitics are not grounded).  
I've had numerous strikes from two different NC locations on my bare 150' 
160 vertical at my first location and on my 180' at my present location.  
I've always attributed the lack of strikes on towers with antennas to the
antennas bleeding the charge before it had a chance to build up.  One of 
these days I plan to put my KLM 340 and 520 back on the 180' tower and it 
will be interesting to see if the strikes stop then.  

                                               73,  Bill  W4ZV

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