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[TowerTalk] Non-sagging antenna elements

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Subject: [TowerTalk] Non-sagging antenna elements
From: "Tod - ID" <>
Date: Thu, 30 Dec 2010 09:25:19 -0700
List-post: <">>
 Roger, K8RI, commented on the tension required to install a sloper antenna
so that it had little or no 'sag' as it went from top to bottom. 

That caused me to contemplate the 'requirement' that all elements of slopers
and dipoles must be in a single plane -- essentially a straight line in a
single plane in three-space.

Since we have a number of skilled EZNEC model makers on this reflector,
perhaps one of them could do a small amount of modeling and help us
understand just how much of a penalty we pay when our antennas 'sag' from
end to end?

I certainly hope this is one of those things that can easily be demonstrated
to be very necessary.  I have read with interest and watched with even more
interest as folks have invested much time and treasure seeking to achieve
the magic single plane state. If we had an idea of the penalty paid for
failing to meet the ideal situation, it might allow us to make a
knowledgeable decision on just how much time, energy and money should be
devoted to achieving that state.

As someone who is quite lazy and lets my wire antennas sag in a relaxed way
by using only sufficient tension to keep the elements 'sort of in the same
plane",[by no means do they really occupy space in a single plane] I am
curious to know just how much of a catenary curve is tolerable  -- or at
have an idea of the rate of change of radiated energy from the antenna as a
function of the departure from a straight line in a single plane.

Tod, K0TO


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