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Message-ID: <35FE2EB5.5F514FAC@teleport.com>
To: <towertalk@contesting.com>
Date: Tue, 15 Sep 1998 02:09:09 -0700
From: Stan Griffiths <w7ni@teleport.com>
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To: k4oj@ij.net
Subject: Re: [TowerTalk] Mast alignment was:refurbish a Thrust bearing?
References: <01520801566189@ij.net>
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Hi Jim,
What ARE you talking about? The bolt in the top of a Rohn pointy top is not a
centering adjustment or a means of allowing use of a less than 2 icnh OD mast.
It is only for clamping the mast and antenna securely in place when the rotator
is removed for service. The rest of the time it is backed way off and
completely removed, in the case of my towers. When you use a pointy top
(25AG3), it is made to accept a 2 inch OD mast with a nice clearance fit so it
rotates freely but is not sloppy. If you, for some reason, want to use a
smaller mast, there are cast aluminum bushings made to insert in the top to
make it smaller and still center the mast in the tower.
I think you have the wrong idea about what the bolts in the top of the 25AG3
top section are used for, Jim.
Stan w7ni@teleport.com
Jim White, K4OJ wrote:
> N4ZR wrote:
>
> For that matter, the local big tower guru talked me out of using any sort
> of bearing at all for my tribander, suggesting instead that I use a Rohn
> pointy-top. As he says, a bearing that isn't there can't seize. They even
> come with a location for a set-bolt, so that when you need to remove the
> rotor you can just pry the mast up, set the bolt, and pull the rotor at
> leisure.
>
> So, when that ONE BOLT coming in from ONE SIDE is tightened down to the
> point where it is just prior to touching your mast it is NOT off
> center????? I think not, sir.....
>
> Your buddy was right with his logic about order for tightening...but the
> bolt in the pointy top is contra-indicated by the same logic since it is
> "one sided" adjustment. Imagine if you were using two different sized
> masts at different times in that same tower....you have centered the mast
> in the rotor...and the rotor in the tower....
>
> Now, you have two different settings for the solo bolt....
>
> NOPE.......don't work.
>
> 73,
>
> Jim, K4OJ
> k4oj@ij.net
>
> Less than 2 months until Sweepstakes CW, make sure you work me so you will
> not miss the elusive South Floirda multiplier!
>
> Proud member of the Florida Contest Group - visit our website at:
> http://www.4w.com/deemer/fcg.htm
>
> The Florida Contest Group sponsors the Florida QSO Party, check out the FQP
> website@:
> http://home1.gte.net/wd4ahz/fcg/ssqp.htm
>
> --
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FAQ on WWW: http://www.contesting.com/towertalkfaq.html
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