[TowerTalk] Horizontal tower movement at the top

[k7rdx]

I think he should go ahead with this mating of the tower&tree...Might just
be like "Jack&the beanstalk"...The towers great but the tree is free..Who
knows it may just grow expansion joints&he can report every QSO his antennas
are a few millimeters taller!Wow! 73 all,Jim K7RDX...
----- Original Message ----- 
From: <SavageBR at aol.com>
To: <w7ce at curtiss.net>; <towertalk at contesting.com>
Sent: Monday, May 07, 2007 2:12 PM
Subject: Re: [TowerTalk] Horizontal tower movement at the top


> >You have got to be kidding! April Fool's Day was over a month  ago!!
>
> Bruce
>
> From: "W7CE" <w7ce at curtiss.net>
> >To:  <towertalk at contesting.com>
> >Subject: [TowerTalk] Horizontal tower  movement at the top
> >Date: Sun, 6 May 2007 14:20:36  -0700
> >
> >Does anyone know how much horizontal movement is considered  acceptable
at
> >the top of 100' tall Rohn 25G, 45G and 65G towers?  I  don't see any
mention
> >of it in the Rohn catalog.  I know that the  tops move, I just don't know
> >how
> >much is considered  normal.
> >
> >I'm considering a rather unusual tower installation at my  QTH.  Because
of
> >large trees that occasionally lose branches during  wind storms and
property
> >line constraints, a guyed tower isn't  practical.  For years I've had my
3
> >element yagi on top of a 95'  Doug Fir tree and it has worked well there.
I
> >watched it during our  record setting wind storms last winter and the top
of
> >the tree was only  moving about 6-7" (less than the diameter of my Ham IV
> >rotator).   This is a big tree with a 42" diameter base and an 8"
diameter
> >stump at  the 95' level where the antenna is mounted.  The problem with
this
> >installation is getting up to the antenna to do maintenance, plus  I'm
> >planning on replacing it with a new SteppIR as soon as I figure out  how
I'm
> >going to mount it.  What I'm thinking about doing is  installing 100' of
> >tower as close to the tree as practical (less than 3')  and attaching it
to
> >the sides of the tree with angle iron at 20'  intervals.  With this
> >approach,
> >I don't think the tower  could ever come down unless the tree itself did
> >also, which is unlikely  based on our soil type and the excellent health
of
> >the tree.  I  would then mount the antenna on the top of the tower.  This
> >would  give me a much easier way to climb up to the top.  I can use 25G,
45G
> >or 65G for the installation, whichever would be best.  25G would  be the
> >easiest to install because of it's weight and I suspect that it is  the
best
> >choice.
> >
> >I'm looking for opinions on the viability  of this solution.  Will the
> >movement of the tree in the wind stress  the tower too much or will it
about
> >the same amount of movement that a  guyed tower would normally experience
in
> >a big wind?   Opinions?  Suggestions?  Am I thinking a little too far
> >outside
> >the box?
> >
> >73,
> >Clay   W7CE
>
>
>
>
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