[TowerTalk] FW: Guy article in CQ

N1MM tfwagner at snet.net
Thu Jan 14 12:14:27 PST 2010

WC1M said:
I agree that the tension must be the same in all three directions, but not
only in magnitude. It must also be the same for the horizontal and vertical
vector components of the force along each guy wire.

The horizontal force components of a stationary tower guy point where the three guys intersect is always zero.  If they were not, the tower would be moving. F=ma.

Why must the vertical components be equal?  If a tower is guyed as designed with three symmetric guys, the vertical components will be unequal as soon as the wind starts to blow.  The windward leg(s) will be in tension, and the leeward leg(s) in compression.  

Bear in mind that Rohn 25 can be erected to 200' and Rohn 45 to 300' according to manufacturers specs.  If your tower is a third of that, there is a LOT of excess capacity in the strength of the legs. (Calculate the downward force of the guys that are not being used.) 

Tom - N1MM 

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