On 12/27/2011 8:12 AM, Barry N1EU wrote:
> >>> I'd also appreciate comments on why this happened in the first place
> >>> and how to prevent a repeat. The rotor was assembled to factory
> >>> instructions with lock washers. Instead of using anti-seize on those
> >>> four bolts, perhaps what is really needed is loctite?
I put up a G-800 in the last year with a lower mast clamp.
If I remember right, I had to swap out the bottom bolts that came with the
G-800
with longer bolts, when the mast clamp was used.
I had the green bolts sitting around from some other time, so I'm not sure if
normally the longer bolts come with the mast clamp or what.
what length bolts did you have..be interesting to measure the thickness of the
mast clamp and the depth of the holes, and figure out if you had the max length
bolt length possible
the way the Al broke off has me wondering. I thought the holes were deeper than
that.
unless that happened after loosening. Then it's just a loosening problem.
Yaesu has some formulas for using rotators with mast clamps. They severely
derate the tolerable load on the rotator.
Come to think of it, it's hard to believe that a 3 element Steppir meets the
Yaesu limits with a mast clamp
they say [Antenna Wind Load Area] * [Height of antenna mast] = 0.45
(wind load is in m**3 and height of mast is in m.
what's a 3 element Steppir? 6.1 sq ft is 0.56 sq meters
they also recommend 60% of the max for margin.
So maybe it's just overloading a pole mount.
-kevin
ad6z
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