If I've read correctly and not all posts have shown up here. (I've read
parts of those as quoted text inside other posts so I don't have a complete
picture. Nothing that has digest in the subject makes it here) You have a
180 foot 45G tower on which you wish to raise one of the anchor points for
the bottom tier of guys a few feet.
If you are running the anchor points at 80% or 144 feet out from the base,
raising the anchor point a few feet or even 5 to 10 feet is going to be a
very small percent change in the angle. It should be nothing to worry about
unless you are either loading the system near it's limit in a high wind
area, or are a purist.
However it dosn't take many feet to get a tremendous force at the base of
the elevated guy anchor. Just multiply the horizontal force exerted by the
guy or guys on the post by the height of the anchor point above its base.
For the bottom set of guys most of the guy tension shows up as a horizontal
force while much less of the force exerted by the top guys will be exerted
in the horizontal plane. OTOH if the bottom tier of guys has a deep catenary
it's going to be closer to horizontal than the angle between the two points
would indicate which means the force on the anchor point will be higher than
calculated.
Yes, we should strive to get the same angles, but even engineering has
tollerances. The farther we stay from the ultimate load factors toward the
conservative side the more we can deviate within reason.
Just as in computer programming, changes from the design spec can have
undesirable and unpredictable side effects so it pays to stay as close as
possible.
73
Roger (K8RI)
> Hello,
>
> I have a situation where I can't guy at the normal 120 degree angles
> which are directly in line with each of the 3 legs on a Rohn 25G.
>
> Has anyone come up with a solution, like maybe some sort of ring that
> would allow attaching guys at different 120 degree points??
>
> Thanks for your opinions,
>
> Joe - KB9R
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