Barry:
Before you loosen the rotator u-bolts, consider adding a clamp above
the top bearing. I wouldn't rely on the two set secrews in the TB-3 to
support the vertical load of the mast and antennas while you're fiddling
with the rotator. You can also add the angle and two u-bolts as Don
suggests to keep the antennas and mast from rotating.
On my tower I have mast clamps that I made out of two face-to-face
muffler clamps. Insted of the u-bolt that came with each, I used two long
carriage bolts (all-thread will work also) to hold them together around the
mast. One set of clamps I have setting on top of the top bearing; I don't
rely on the bearing's set-screws for weight support. I have a second set on
the mast about an inch above the middle shelf. When I have to remove the
rotator, I'll lower this second clamp onto the shelf and tighten it. This
way I'll have two fairly heavy clamps that support the vertical load of the
mast and antennas while the bottom support (rotator) is missing.
You'll probably have to cut or grind a bit off the facing ends of the
clamps' saddles so they can fit around the mast without hitting each other.
Also, consider getting clamps one size smaller than the OD of your mast.
For my two inch mast I bought inch and seven-eighths clamps.
GL es be safe de
Gene Smar AD3F
----- Original Message -----
From: "Don Havlicek" <n8de@thepoint.net>
To: <w2up@mindspring.com>; "towertalk" <towertalk@contesting.com>
Sent: Monday, December 01, 2003 5:01 PM
Subject: Re: [TowerTalk] Rotor replacement
> Barry,
> Take a piece of angle iron with two u-bolts on it, one for the mast, and
> one for a tower leg. Attach it above the rotor. Then you won't have to
> worry about that 4.3 degrees at all.
> Don
> N8DE
>
> Barry wrote:
> > Hi all,
> > My Tailtwister has been acting up a bit (not bad for 13 years in
> > service) and I want to replace it with a spare I have. It is mounted
> > down about 8 ft from the top flat plate (with a TB-3 bearing) in a
> > Rohn 45. The mast is about 20 ft long with a TH7 up 6 inches and a
> > 40-2CD at the top, about 9 ft above the TH7.
> >
> > I want to make this as simple as possible, so have thought of the
> > following procedure:
> > If I simply remove the rotor from the plate, without doing anything
> > with the antennas or mast, the mast will lean until it hits a horiz.
> > strut on the a wall, which is a max. of 7.25 inches from center.
> > With 8 ft of mast below the TB-3, this amounts to a 4.3 degree
> > deflection (if my math is correct).
> >
> > Questions:
> > 1. Is there enough play in the TB-3 where this 4.3 degree out-of-
> > vertical is not a problem with respect to the bearing?
> > 2. Assuming the lean is OK, is there enough clearance between the
> > mast and diagonal struts to slip the rotor out (and the new one in)
> > between them without removing anything else, such as the rotor plate?
> >
> > Any other thoughts or ideas to make this as simple as possible for a
> > one-man job, without jacking up the mast, etc?
> >
> > Tnx,
> > Barry W2UP--
> > Barry Kutner, W2UP Internet: w2up@mindspring.com
> > Newtown, PA Frankford Radio Club
> >
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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