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[TowerTalk] Radical alternative for pinning beams

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Subject: [TowerTalk] Radical alternative for pinning beams
From: (Chuck Dietz)
Date: Mon, 07 Jul 1997 22:18:11 -0500
Anthony R. Gold wrote:
> A while ago there was a supposedly humorous thread on element fatigue
> and the need to periodically change beam elements.  I've noticed that
> the reflector on my Sommmer XP-807 has indeed developed fatigue, but
> it's mechanical and not electrical and the ends of both sides are now
> drooping. I guess that the flapping in the wind over the 14 months
> it's been up caused the force from the half-elements' weights to
> exceed the tubing's elastic limits and they are now presumably in the
> course of progressive decline :-(  I'm going to try shoving some
> bamboo up inside the tubes to strengthen them.

No, the bamboo won't help.  The extra weight will cause vibration at a
lower frequency which may be more extreme over time.  The better
soloution to delay "element fatigue" is to tie bows made out of
waterproof plastic ribbon at a point 85% of the distance from the boom
to the element tip.  While this may sound a little strange, it really
works!  It has been shown, on a test range, to delay element fatigue in
the 20 meter beam by more than 2 years.

Of course, in a 40 meter or lower beam this technique has not been
proven to work.  The only known technique at these lower frequencies is
the plastic owl method.

Chuck, KE5FI

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