[TowerTalk] new tower

[K7LXC at aol.com]

In a message dated 7/14/2007 8:46:00 A.M. Pacific Daylight Time,  
towertalk-request at contesting.com writes:

>  The tower will still move but it is not twisting as in  winding up to a 
point 
of possible fracture. The commercial site over on  the next hill had 140' of 
45G with the base buried in concrete and a bunch  of sticks on it. After 
about 15 years the bottom section fractured. The  tower didnt collapse but 
they replaced it with 55G on the same pad but  drilled it for a pin.
 
    There is practically no movement of a  tower at the base. Any torquing of 
the tower due to wind forces is pretty much  absorbed by the upper part of 
the tower - it doesn't really twist the whole  structure uniformly. A typical 
ham tower with a big 40M antenna will  definitely move at the top but not at the 
bottom.
 
    I'm surmising that the aforementioned failure was  due to lack of leg 
moisture drainage resulting in a freezing split leg and  subsequent failure. 
 
    Of course big loads and big wind torque forces  are pretty much 
eliminated with six-way guying using a star bracket. 
 
Cheers,
Steve     K7LXC
TOWER TECH 



 



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