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[TowerTalk] Crank UP

To: <towertalk@contesting.com>
Subject: [TowerTalk] Crank UP
From: tmartin@chartermi.net (Tom Martin)
Date: Mon Apr 21 23:16:50 2003
It might be nicely made by the toolmaker, but it does not demonstrate
proper engineering. The legs that went into concrete, I assume were
steel, but they should have some cross bracing, I saw only straight
pieces, one bent?

I agree.  Also, there is no re-rod in the concrete base.  The straight
legs with no bracing and the lack of a cage in the concrete make for a
precarious situation without any guys.

Top section between the rotator and thrust bearing has no cross bracing,
which is a major no-no. No way you should have 40m beam on the top!!!
This thing would fold like a parallelogram right at the rotor plate.

Very true!  I have a two element 40 meter beam over a 20 meter
monobander on a 72 foot Heights self supporting tower with a 14"
reinforced top section and the top eight feet of the tower twisted a few
degrees in a 75 mph wind last fall.  I doubt if guys at the very top
would have stopped this torquing motion  Guys at 75% of the height of
this 96' tower will not stop the folding you suggest.  No way should a
two element 40 be atop this tower!

Go with the Step-R and guy the tower.  Add slopers, or a delta loop for
40 meters.

Tom W8JWN



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