Guy tension ??

[Chuck Brudtkuhl]

Mail*Link(r) SMTP               RE>>Guy tension ??

Stan's comments:

>I have heard this advice several times but I am not sure how important it is
>either.  When you say "tension all guys the same amount", you must be saying
>tension the set at 30 feet the same as the set at 60 feet and the same as
>the set at 90 feet.  The tension in all three guys at any one level will
>pretty much equal each other since the tower will flex to make it so.  So
>why is it important to have all the sets equal to each other?  In fact, on
>further reflection, that advice conflicts with the advice to tension guys to
>"10% of their breaking strength" since the Rohn book often shows guys of
>different breaking strength used at different levels on the same tower.

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No Stan, I WAS in fact referring to guys on the same level being equal.  I
agree that one would think that all tensions would be "automatically" equal
out, but doesn't seem to work that way in real life..for me anyway.  (In
another life, I've spent hours and hours adjusting guy tensions on a 150'
trailer mounted crankup I used to be involved with.  It had 5 sets of 3 guys
and what a job!)  Anyway, I would utilize a transit to check plumbness of the
tower while adjusting the guys and still do likewise on the towers at the QTH.
 

I also at one time figured the inverse of your statement....i.e. if all guys
on a level are equal tension, that implies the tower must be plumb to that
point...not true either.  Bottom line in my experience is that one is looking
at two variables when adjusting.... 1) Tower relationship to plumb, and 2)
individual guy tension.  If I'm wrong on this, I'd like someone to point out
what I'm doing wrong and save me alot of WORK!!

And one more comment about the 10% rule ..... a 3/16" guy with 300lbs of
tension is not "slack", so why is 600lbs better?   Of course, may have
something to do with the fact that when the wind is such that your "windward"
guy has increased from 300 to 600lbs from the wind load on tower, the
"leeward" guys may have decreased from 300 to 200lbs (or some such)? 
Potential loss of "control" there?  It's the only answer I can think of....but
that again begs the question "why 10% vs 5% or 15%?".  Where's the mechanical
engineer in our midst?

73 Chuck
WA0ROI