[TowerTalk] 3 guys vs 4

[jim.thom jim.thom@telus.net]

Someone a while back was asking about using 4 x guy wires, spaced
90 degs apart..... vs  3 guys, spaced 120 degs apart.

With the 4 guys and 90 deg spacing, the stress on the guy wires (wind
directly between any 2 x guy wires) is reduced by 12% on each  of the 2 guy
wires.

On some old material I was reviewing,  the example for 3 x guys spaced 120
degs was.... IF the wind was directly INLINE with any one guy wire, the
tension on the guy wire was 600 lbs.....and the downforce on the tower was
700 lbs. (forget the wind velocity.  It was a simple 50' tall tower, with
only one set of guy wires).

With the wind blowing at the exact midpoint between any 2 guy wires, EACH
guy wire had 600 lbs of tension, and the total downforce on the tower now
becomes 1400 lbs.

In the case of the 4 x guy wire setup, spaced 90 degs, and wind at a
midpoint between any 2 x guys, both the tension on each guy wire, and the
total load on the
tower is reduced by 12%.

Jim  VE7RF