There is a lot of debate on towertalk as to whether adding guys to a
freestanding tower improves it's strength. I still believe that it does.
Adding guys to a crankup tower is a different scenario. Unless the
sections lock together somehow adding guys adds a lot of stress on the crank
up cable and motor. This tower is quite high with small sections so I would
be fearful of even mounting at Step_R antenna on it. I have seen stronger
looking aluminum top sections shear off in strong winds.
John
----- Original Message -----
From: "Tom Martin" <tmartin@chartermi.net>
To: <towertalk@contesting.com>
Sent: Tuesday, April 22, 2003 03:18
Subject: [TowerTalk] Crank UP
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
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
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