In a message dated 2/22/2007 10:03:15 A.M. US Mountain Standard Time,
towertalk-request@contesting.com writes:
> John you need a 2nd thrust bearing and the correct mast,be it 4130 chrome
molly or what ever.I run 45G with the 1st bearing on the top section.The
second bearing is midway down the top section. Then the rotor close to the
bottom of the top section.
Actually I don't recommend a middle bearing. It's just another chance to
introduce more bind in this imprecise system.
An intermediate something would be useful when you have a long mast and a
stack of some sort of yagis. That way the top-heavy mast is captured in case
you need to do a rotor swap. A rotator shelf with a hole in the middle would
suffice for the intermediate capturing device. An intermediate thrust bearing
is redundant and a waste of money since the top bearing typically holds the
vertical weight, leaving nothing for the middle one to do.
> The antenna is a Force 12 C3S/HH turned by a Yaesu G-1000DXA.Yaesu has
the specs on how much weight can set directly on the rotor.I believe they call
it the K factor.
Actually the K Factor is used to rate the rotator for antenna load; it's
weight times turning radius.
For a relatively small single yagi installation like the aforementioned
C3SS, a second TB might make you feel better but is even less necessary.
Cheers,
Steve K7LXC
TOWER TECH
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