JC:
You'll have your hands full trying to get two bearing blocks AND a
rotator AND the attaching shelves all lined up on the tower. Leave out the
second (middle) bearing assembly and make your life a whole lot easier.
When you have to remove the rotator, jack up the mast a bit with a
come-along and losen the top muffler clamp pair (resting on top of the
bearing*) and slide it down the mast a bit so it now sits atop the bearing
again. Then attach a second muffler clamp pair to the mast so it rests on
top of the center plate. Some folks would recommend attaching a couple of
angles pieces to this second set of clamps so the angles butt up against a
tower leg. This way the mast won't rotate in a heavy wind while the
rotator is out of position for repairs.
*Don't rely on the bearing's set screw to support any of the dead
weight of the mast/antenna/coax. This screw just keeps the mast attached to
the collar so the two rotate simultaneously. I use a pair of back-to-back
(or maybe they're face-to-face?) muffler clamps that sit on top of the to
bearing to support some of the mast and antenna weight. You can use a
similar assembly to help support the weight of the mast/antennas against the
middle plate while the rotator is missing. I'd also use this second clamp
assembly, as well as the top clamp set and the rotator itself, to support my
weight if I ever get crazy enough to climb the mast to replace an antenna,
etc. (Each Trylon plate is rated to support 300# so all three should be
able to support 900# with proper application of muffler clamps.)
73 de
Gene Smar AD3F
----- Original Message -----
From: "JC Smith" <jc-smith@comcast.net>
To: "'JC Smith'" <jc-smith@comcast.net>; <towertalk@contesting.com>
Sent: Tuesday, June 07, 2005 10:35 PM
Subject: Re: [TowerTalk] installing monster masts in towers (and ? two
thrustbearings?)
> Wow, a great bunch of response (both on and off the list) and quick too.
> Thanks guys! Forgive me for not thanking you all personally, there were
> just too many.
>
> There were some very ingenious ones too; the round-ball hoop and the
counter
> weight were very interesting.
>
> As I suspected, forget about the helicopter. Also as I suspected, the
best
> idea is to build the tower around the mast. Nope, it's not built yet, but
> as a couple of you suggested, it's not completely impossible to partially
> disassemble the tower and slip the mast inside, even after it's built.
>
> Actually, the best idea I picked up wasn't really an answer to my question
> but just another helpful suggestion. Installing a shackle under the top
> plate and a winch at the bottom to pull on block and tackle, and a shackle
> or hook on the mast, really does make servicing the antennas and/or rotor
> much easier. One could even install a small powered winch part way up the
> tower, and use a remote control cable to run the mast up and down as
needed.
> Hopefully I won't need to do it often enough that cranking by hand will
> become tedious. Another thought would be to install just a block
> (pulley-wheel thingy) at the bottom of the tower to transition from
vertical
> cable to horizontal cable and use the four-wheeler to pull on the cable.
>
> Now, one other question. How important is that second thrust bearing some
> of you mentioned? I definitely plan on two rotor plates (with holes in
the
> center of course) but with an Orion 2800 rotor down near the bottom of the
> top tower section and a thrust bearing at the top do I really need another
> bearing on that middle plate (assuming the hole diameter is close to the
> mast diameter)? I hope to install two antennas on the mast. Approx. 7
sq.
> ft. about 12' above the tower and approx. 10 sq. ft. about a foot above
the
> tower. Possibly some sort of UHF/VHF vertical at the top. I could
possibly
> reduce those dimensions a bit and use a 20 ft. vs. a 24 ft. mast. Save
some
> weight and a few bucks.
>
> Thanks again for all the help. We plan to start digging the foundation as
> soon as the TX-472MDP (which appears to be sold) is moved off the concrete
> pad so the backhoe can get into the back yard.
>
> 73 - JC, k0hps@amsat.org
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com]On Behalf Of JC Smith
> Sent: Tuesday, June 07, 2005 12:02 PM
> To: towertalk@contesting.com
> Subject: [TowerTalk] installing monster masts in towers
>
> OK, so lets say I've got my new, super HD, 70', freestanding, Trylon or AN
> Wireless tower up in place. Now I've got to get that 24' Chrom-Moly mast
> up there and through the thrust bearing somehow. How the heck do you do
> that (no cranes allowed, it looks like I'm going to have to stick build
the
> tower)? The antennas I can tram up on temporary guy wires, but even if I
> could do that with the mast I've still got to stand it up to get it
through
> the center of the tower. Big gin pole? Seems like you'd need a gin pole
to
> raise a gin pole big enough to handle one of those monster masts.
> Helocopter? Maybe... gee, might as well have them pick up the tower as
> well, but how much does that cost? Anyone have experience with that and
can
> give me a ballpark number? It's gotta be big bucks, and doing it over a
> residential neighborhood? Maybe not even possible. So, how the heck do
you
> do that? Build the tower around the mast and pull it straight up the
> middle? Any other suggestions?
> Thanks & 73 - JC, k0hps@amsat.org
>
>
>
> _______________________________________________
>
> 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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