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Re: [TowerTalk] Question on R-TA-45 Torque Bracket

To: <k7lxc@aol.com>, <towertalk@contesting.com>, <k9mk@flash.net>
Subject: Re: [TowerTalk] Question on R-TA-45 Torque Bracket
From: "Bob Shohet, KQ2M" <kq2m@kq2m.com>
Date: Fri, 14 Jun 2019 13:54:20 -0400
List-post: <mailto:towertalk@contesting.com>
The use of star guys reduces the wind induced torque on the tower by reducing 
the amount of twisting in the winds.  This reduces the twisting and stress 
experienced by the legs of the tower.  There are differences between whether 
the wind is coming from the direction of the guy vs opposite it or between the 
guy wires so it would not be accurate to assume that that a wind of “x” mph 
exerts a twisting force of “y” when the twisting force can vary significantly 
because the wind is coming from 45 degrees and the guy wires are at 45 degrees 
165 degrees and 285 degrees vs. if they were at 100 degrees. 220 degrees and 
340 degrees.  Although we don’t normally think about this, the wind direction 
relative to where the guys are can, in an extremely dangerous storm, make the 
difference between failure or not.

My 130’ of Rohn 45 tower is star guyed at the 80’ and 120’ levels and I can 
tell you that from watching it in two tornados and two hurricanes, the guy 
wires, at the same tension as before the star guys were installed, definitely 
move less now than they did before.  I do know (as explained to me by a P.E. 
who is a ham) that by using star guys, the tower can handle a larger wind load 
in a given speed wind than if it just had one set of guys and that is because 
the amount of tower movement in the wind is reduced and that in turn results in 
less torque on the tower legs, hence less mechanical stress and reduced chance 
of structural failure.

The wind loading on the tower is actually increased because the weight of the 
star guys creates additional compressive forces on the tower, especially with 
ice, but this is more than made up for by the decrease in torque on the tower 
and particularly the tower base, which can be reduced further by using a pier 
bin and a swivel base rather than the common practice of burying the first 
tower section in concrete.  

Star guys have another practical aspect to them.  Since there are TWO guys per 
tower leg, it is possible to raise a heavy antenna to the top vertically by 
loosening and unhooking one of the two guys, pulling up the antenna to the 
second guy, reattaching and tensioning the first guy, then loosening and 
detaching the second guy, pulling the antenna through, and then reattaching and 
tensioning the second guy.  N2NT and I have done this with excellent results.  
This is especially useful if there is not enough room or if the angle is too 
steep to use a tram line.   It also allows the tower worker to climb the tower 
and guide the antenna up instead of it dangling on a tram line and possibly 
getting caught on something.

Star guys are cheap and effective insurance to help protect a tower and tower 
installation and much better than using torque brackets alone.

A P.E. can do calculations for a tower installation with and without star guys 
so that you can get an accurate picture of just how much it may help you.  Well 
worth the money to do if you want peace of mind.


73

Bob  KQ2M


From: k7lxc--- via TowerTalk 
Sent: Friday, June 14, 2019 1:24 PM
To: towertalk@contesting.com ; k9mk@flash.net 
Subject: Re: [TowerTalk] Question on R-TA-45 Torque Bracket

>    I had one of these on the top guy set of my 110' R45 tower.   And I had 
> torque arms on the lower two guy sets.
>    My question is aside from twisting, does this change any of the wind 
> loading numbers?
>    My suspicion is the double guy sets per face can only help but I have 
> never seen it quantified.
    Since the capacity of a tower is determined by the leg strength, I'd say 
that the use of a star guy bracket doesn't really do anything to change it. I'm 
not an engineer so I don't have any calcs to provide.
Cheers,Steve     K7LXCTOWER TECH
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