And the answer is... pick one... tension it to spec and ignore the others.
And the reason is... you can not independently control the tension in each
guy wire, no matter what you do the forces will all be in equilibrium when
the tower is vertical (and not moving or being pushed by the wind). And if
the angles with respect to the tower are not the same the tensions will have
to be different. Since the difference in angles is so small you will
probably never measure the difference anyway, so ignore it.
David Robbins K1TTT
email: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
ARCluster node: 145.69MHz or telnet://dxc.k1ttt.net
> Original Message
> From: Scott Dickson, W5WZ [mailto:W5WZ@arrl.net]
> Sent: Sunday, August 10, 2008 23:42
> To: towertalk@contesting.com
> Subject: [TowerTalk] Tower Guying when the 3 guy points and the tower
> baseare not at the same elevation
>
> I have a question regarding computing guy tensions for an installation
> where
> the 3 guy points and the tower base are not at the same elevation.
>
>
>
> My guy posts are large Ibeams that protrude 3.5 feet above ground level.
> The referenced elevations are to the actual points on the Ibeam where the
> guy wires will attach. I used my bubble level (transit) to establish
> elevations.
>
>
>
> Tower Base = 0 inches
>
> W guy point = +68 inches relative to tower base, at a distance from tower
> base of 88 feet
>
> SE guy point = +19 inches relative to tower base, at a distance from tower
> base of 97 feet
>
> NE guy point =  48 inches relative to tower base, at a distance from
> tower
> base of 113 feet
>
>
>
> Using a tower guy point at + 100 feet (arbitrarily chosen for
> calculations),
> I calculate the following angles, which are close but vary from guy post
> to
> guy post
>
> W = 47 degree angle with ground
>
> SE = 45 degree angle with ground
>
> NE = 43 degree angle with ground
>
>
>
> I suppose I know just enough to be dangerous here. From physics classes
> long ago, I believe that since the guy wire angles are different, it
> stands
> to reason the tension in the wires needs to be different, because of the
> vertical and horizontal components of the guy wire. However, I do not
> remember those calculations. Before I go dig the formulas up, assuming my
> angle calculations are correct, my question is simply:
>
>
>
> Is there enough variance to matter?
>
>
>
> Is there a "ready reference" anywhere for these calculations?
>
>
>
> Scott, W5WZ
>
> _______________________________________________
>
>
>
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