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Re: [TowerTalk] Horizontal tower movement at the top

To: "Gerald Boutin" <>,<>
Subject: Re: [TowerTalk] Horizontal tower movement at the top
From: "W7CE" <>
Date: Tue, 8 May 2007 07:37:00 -0700
List-post: <>
Thanks for the pointers to the engineering data.  That gives me exactly what 
I need.  It also reminded me of an analysis that K7NV has on his website at:

I need to read it again in detail, but the baseline model in the study is 
very close to my situation.  A quick glance indicats that movement of 6" or 
so in a 90MPH wind might not be all that unusual.  It also reminded me that 
putting the tower on a pier pin will reduce the stress on the base.  I'll 
read the study more carefully and also do the calculations based on EHS 

I originally planned to use the 25G only as a ladder, but if I can also 
mount the antenna to it, it will simplify the antenna installation.  I don't 
think it should make much difference structurally since the tree and the 
tower will move together.

Thanks again.

Clay  W7CE

> If you stick a 25G on a pier pin, you can pretty much ignore what typical
> tower movement might be. The tree is going to be holding up the tower.
> I sort of liked the suggestion to put up a ladder instead. So, what would 
> be
> a good ladder? How about 100 feet of 25G?
> If you still want an answer to your initial question, it is relatively 
> easy
> to approximate when you know how much guy wire stretches and use the data
> from the Rohn catalog and the law of cosines equation.
> Law of Cosines Equation
> (
> Guy Wire Stretch
> 6.77 inches of stretch per 100 feet of 3/16" EHS when under a 3000 pound
> load
> --
> Gerald Boutin, VE1DT


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