[TowerTalk] Yaesu Rotors

[wa4dou@juno.com]

Hi Pete,
  This is why my Rohn 25G, although rated at 8.2 sq.ft. at 110 mph, only
has a Yaesu 450A rotator, 4 ft. of 2" dia. aluminum mast, and a 4.4 sq.
ft. C3SS on it! 73 Roy WA4DOU
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On Mon, 12 Jun 2000 00:54:04 +0000 Pete Smith <n4zr@contesting.com>
writes:
> 
> 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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