[TowerTalk] guying question
JoeCoolDXer at msn.com
Mon Jul 28 16:42:43 EDT 2008
Some tower twist is good, you don't necessarily want it totally rigid. During big wind gusts, it reduces shock loads on the rotator gear train, and tendency for boom-to-mast clamp to slip on the mast.
----- Original Message -----
From: Roger (K8RI)<mailto:K8RI-on-TowerTalk at tm.net>
Cc: Tower Talk<mailto:towertalk at contesting.com>
Sent: Saturday, July 26, 2008 2:23 PM
Subject: Re: [TowerTalk] guying question
john at kk9a.com<mailto:john at kk9a.com> wrote:
> Star guying substantially reduces the twist on a tower. Torque arms are
> much less effective.
I agree on both points.
> According to K7LXC : When Rohn implemented one of the
> early EIA/TIA-222 tower standards, they found that the torque arms added
> nothing to the torque resistance of the tower but they do help stabilize
> the tower as it's being climbed.
With this I disagree to a point. Much depends on how the torque arms
are installed, but at best they are no where near as good as star
guying. On my tower I found that following the instructions added
little if any resistance to turning, but mounting the torque arms
*rigidly* made a noticeable difference in the tendency for the top of
the tower to rotate in high winds. However, it's not nearly as
effective as star guying which I'd much prefer. There's an interesting
PP presentation at www.yccc.org/Articles/KE1IH_Dayton.ppt<http://www.yccc.org/Articles/KE1IH_Dayton.ppt> showing
forces on the tower with regular and star guying as well as the force
when using elevated guy anchors.
If possible I'm going to change the top level on mine from torque arms
to star guying. I have a lot of steel and aluminum up there.
Roger (K8RI - ARRL Life Member)
N833R (World's oldest Debonair)
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