[TowerTalk] Yaesu Rotors

[Pete Smith]

At 11:36 AM 6/11/00 EDT, K7LXC@aol.com wrote:
>    Well, yeah but let's get practical. This is not an engineering/lab 
>exercise. Us amateurs just want an idea of load compatibility for towers, 
>antennas, masts, rotators, etc. I don't think it's unrealistic and it IS an 
>approximation. It doesn't take wind-induced mast/antenna torque into the 
>equation either but it's REASONABLE.

>    Personally I think the K-Factor/Effective Moment is a GOOD benchmark. It 
>is admittedly an ESTIMATE by the manufacturer but is much better than the
old 
>'square footage' capacity that was used for years. 

Of course.  But at least admit for the record that it IS a worst case -- in
other words, all practical real-world arrays will have less effective
moment at the rotator than the one on which the K-factor is calculated --
and the difference may be as much as 50 percent.
>
>
>     I would be delighted if you calculated and published the real sum
moment 
>for antennas and rotators that you elucidated above. What say?
>

I would suggest this is a calculation that the antenna manufacturers are
much better suited to do than I am, since I lack the data on
lengths/diameters/wall thickness of the tubing in popular antennas.  While
they're at it, they should also state the wind area of their arrays in
terms that are consistent with those used by the tower manufacturers (or
perhaps vice versa).  As things now stand, many people are probably being
badly misled by most antenna manufacturers to load more on their towers
than the towers are rated to take.

73, Pete Smith N4ZR
n4zr@contesting.com 



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