[TowerTalk] Stacking Antennas and Windloads

[K7LXC at aol.com]

In a message dated 4/6/2007 3:24:30 P.M. Pacific Daylight Time,  
towertalk-request at contesting.com writes:

>  Also be sure to include the wind area of your  feedlines--they add up
quickly!  For example, for RG-8/LMR-400  (diameter 0.405"), 87 ft along the
tower leg gives you another 87 ft x  0.405 in x 1 ft/12 in = 2.94 ft^2.  Two
of these lengths gives you  5.87 ft^2, etc.  (These numbers don't include the
factor for round  members, but Rohn specs include this factor in their "round
member"  ratings.)


    Well, yes and no. Commercial towers typically  have each feedline going 
down the middle of the face down a cable ladder so it  and all of its brethren 
are totally exposed to the wind. OTOH hams don't use  that technique and run 
the cables down a leg or two. So instead of having to  add up all of the 
exposed cables, ham cables make the leg(s) slightly larger -  and much less of a 
factor than the commercial towers and Rohn spec. 
 
Cheers,
Steve     K7LXC
TOWER TECH








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