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Re: [TowerTalk] KLM 5el 20m monobander - High SWR

To: towertalk@contesting.com
Subject: Re: [TowerTalk] KLM 5el 20m monobander - High SWR
From: Bill Tippett <btippett@alum.mit.edu>
Date: Wed, 15 Oct 2003 07:31:43 -0400
List-post: <mailto:towertalk@contesting.com>
VA7NT wrote:
A friend of mine has a pair of KLM 5el 20meter monobanders which
are resonant around 14,300 with an SWR over 2 to 1 in the CW portion
of the band.

        Something is seriously wrong with that antenna!  I pulled out
my nearly 20 year old SWR plot of the one I had in Colorado, and
SWR was 1.08 at 14.0 with 1.18 at 14.35 (1:1 resonance at 14.240).

        Since both antennas are identical, I would suspect some
sort of assembly problem (dimensions).  About the only thing
that can go wrong is the phasing straps shorting or a bad balun,
and it is unlikely that both antennas would share the same problem
at the same time.  The older KLM's used flat phasing straps that
were prone to shorting but this normally shows up as intermittently
high SWR under power.  Also you might want to make sure there is
not a measurement problem by checking the SWR of the lower one
on the tower using a portable SWR bridge.

73, Bill W4ZV

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