That triangular movable plate with the ears is the rotor mounting plate. On my
have a Yaesu G-1000DXA mounted on it supporting a F12 C4XL. No problems in
years. I think that the plate is heavy duty enough to take most rotors.
Stu -- WH6H
Mike Wapner wrote:
> I am in-process of installing an LM470 that didn't come with a rotor
> mounting plate. The tower has a heavy duty 2" thrust bearing mounted on the
> very top plate. Also, welded to the underside of this top plate is a 2"
> I.D. sleeve with two set screws. The underside sleeve appears to be stock
> Tri-Ex. There is also a movable triangular galvanized steel plate (1/8"
> stock) that fits inside the top section. This plate also has a 2" I.D.
> sleeve with set screws that can be placed almost anywhere within the top
> section. It has small "ears" that catch the diagonal cross members to
> prevent it from slipping down the inside of the tower section, but it is not
> "attached" to the tower.
> I suspect that this movable plate could be used for a rotor mounting plate,
> assuming it was appropriately machined to mate to the rotor, but I am
> uncomfortable with 1) the thickness of this plate being inadequate and 2)
> the fact that it would be held in place vertically only by the weight of the
> rotor and the mast pushing down on it.
> My total vertical load (antennas & mast) will be approximately 275#, but
> this will be taken by the thrust bearing. The torsional load is
> approximately 22 sq. ft. The rotor weight is yet unknown, but will be 45#
> Does anyone have a sketch of an "adequate" (at least 1/4" or 3/16" steel)
> rotor mounting plate and that also shows how to rigidly affix it inside the
> top tower section of a LM470? I know that Tri-Ex originally offered one, so
> I suspect it is documented somewhere. I can easily fabricate one if I have
> the drawing(s). Thanks
> Mike, K6QD
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List Sponsor: Are you thinking about installing a tower this summer? Call us
for information on our fabulous Trylon Titan self-supporting towers - up to
96-feet for less than $2000! at 888-833-3104 <A
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Administrative requests: towertalk-REQUEST@contesting.com