[TowerTalk] 2nd thrust bearing inside tower - you opinions??

mryan001 mryan001 at tampabay.rr.com
Wed Feb 21 12:17:54 EST 2007

John, The issue may be more related to the length of mast you have to work
with here. The Rohn 45AG4 ( flat top section ) as I recall has the location
close to the top where the accessory plate/shelf can be installed and most
would place the rotator there. If you were to use a second bearing, I doubt
you would find a suitable place other than at that point to place a second
one. Therefore, the rotator would have to be placed at the bottom of the
45AG4, or actually in the top of the NEXT section down in order for you to
be able to get the rotator in or out. The 45AG4 as I recall is about 8ft
long.  If you have a long enough mast to enable you to separate those
antennas you plan to have above the tower with the rotor in the lower
location, this may or may not be a problem. You will have to decide that. I
did this very thing for 9 years with no sweat when I was in Manassas, Va in
the '90s.  Clint makes a comment about today's rotors being 'rated' to hold
the vertical forces of almost anything....well, the brakes on my car are
rated or given a "lifetime guarantee". To me that's marketing talk. I would
no more assume that my rotor would handle the weight of my antennas I used
there than brakes lasting the life of my car. That's the reason we use the
bearing in the first place. I was using chrome molly steel mast 24ft long, a
3 modified element HyGain 40 and a modified HyGain 204BA, one of 3 on the
tower, 2 more side mounted. Looking at what you are using or going to use on
your tower I would absolutely use a thrust bearing and two if you can
accommodate it, again for no other reason than to make rotator changes
easier. I used T2X rotators cause I could not afford more expensive ones
that may or may not have done a better job. But once in a while I had to
yank it out ( if I can say that here ) to work on it over the years.
 That's my 2 cents...  - Mike, K4CVL

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com]On Behalf Of Clint Talmadge
Sent: Wednesday, February 21, 2007 9:57 AM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] 2nd thrust bearing inside tower - you

Getting two thrust bearings and a rotor aligned to rotate and not bind at
some point takes great skill or great luck. If you are putting the second
thrust bearing in so it can be run loose and only tightened when you need to
pull the rotor for maintenance that would be O.K. . Most rotors today are
rated to hold the vertical force of almost anything you can mount above

Clint - W5CPT

  ----- Original Message -----
  From: K5XA John
  To: towertalk at contesting.com
  Sent: Wednesday, February 21, 2007 8:37 AM
  Subject: [TowerTalk] 2nd thrust bearing inside tower - you opinions??


  Need a little advice.

  Planning about 130 feet of Rohn 45 - 20 to 22 feet of mast - Force 12
  240N over a Force 12 C31-XR at the top - side mounting another C31-XR.

  Considering a 2nd thrust bearing inside the tower.

  Any suggestions/ideas/experiences you might share?


  73 ............... K5XA

  John Guida
  k5xa at godfather-ridge.com


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