[TowerTalk] Sidemount yagis

[Kurt Andress]

> Barry Kutner wrote:
> >
> > Rich,
> > Not quite correct. The square foot rating is total, wherever antennas
> > are mounted. Kurt, K7NV, has the calculations on his Web site
> > proving this for guyed towers, though it intuitively doesn't seem
> > correct.
> >
> Hi Barry et al,
> 
> Most everyones intuititon about moving antenna loads down freestanding
> towers is ok. Guyed towers are different.
> 
 An important thing to note about the example cited here is that the
 guinea pig was a catalogue Rohn configuration meant to have the entire
 antenna load at the top. The guy cables on that tower are sized for a
 concentrated top load. Placing part of the rated antenna area at a
lower
 location resulted in the cable near the low antenna elongating more,
and
 the upper one less. This caused the loaded tower to get out of column,
 and close to the same limiting base stress was created. There is
another
 example that shows that increasing cable sizes fixed the problem and
 left some room to increase the loads and hence the antenna areas, to
 arrive at a total that is more than the original.
 
 Remember, this is just what happened with this tower and these changes.
 other initial configurations may behave differently.
 
 The one example just showed why the tower dudes said to use the same
 total area regardless of placement. They sure know that they don't know
 what the user is gonna do about changing guy sizes, so their statement
 is safe and correct.
 
 There is a limited range of optimum solutions for every configuration,
 so we've got to be careful about forming broadly generalized
 conclusions.
 
 --
> 73, Kurt, K7NV
> 
> YagiStress - The Ultimate Software for Yagi Mechanical Design
> Visit http://www.freeyellow.com/members3/yagistress/

-- 
73, Kurt,K7NV 

YagiStress - The Ultimate Software for Yagi Mechanical Design
Visit http://www.freeyellow.com/members3/yagistress/

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