[TowerTalk] Thrust bearings?

[Jim Berry]

I had a tower up once with a beam on it.  At the moment I don't.  I really
enjoy reading about other folks tower and antennas.  I am in a situation
where I use simple wire antennas now. I did learn a few things, or at least
I think I did.  If I am all wrong in my assumption, I am sure you good folks
will tell me so.

The first thing I learned was that the bearing at the top of the tower was
nothing more then a line shaft bearing.  The rotor contains the thrust
bearing.

Go to a place like a marine equipment supplier and you can see the
difference between a line shaft bearing and a thrust bearing.

Take a rotor apart and it is a motor assembly setting on a thrust bearing.

A line shaft bearing then can be anything.  I looked at several and saw
nothing but trouble with one of those things hanging out in the weather.  I
used a piece of split plastic PVC pipe around the mast so the the mast would
not rattle around inside the top tower section.

The antenna was a Cushcraft A4, the tower was 60 feet of Rohn 25G and I
forget the brand of roter now.  Sure I was no "big gun" but did work 275
countries on CW before I took the tower down because of a move.

Oh yes, the mast was probably 8 feet of pipe.  If 2 feet stuck above the top
section of the tower, then the rotor plate must have been 6 feet down inside
the tower.

I never had a bit of trouble with this install, but it was only in the air
for 5 years at the very most.

73 Jim K7SLI





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