[TowerTalk] Best mast location?

[john at kk9a.com]

A good rotator should be able to handle the side load.  The rotator has a 
bearing and adding a third bearing in between the top bearing and rotator 
just makes line up more difficult.  Even with very large antennas I have 
never seen the need for it.

John KK9A



To: <towertalk at contesting.com>
Subject: [TowerTalk] Best mast location?
From: "Jim Thomson"
Date: Fri, 14 May 2010 04:42:04 -0700


<snip>

##  which is why you should always use TWO thrust bearings.  Then you
won't have a sideways load on the rotor at all !  Per Leeson [ dunno if he
got this part right]  you take the bending moment where the mast enter's the
top bearing... and divide that number by the distance between the top 
bearing
and what ever is below it... like a 2nd bearing.. or  the rotor.   If the
distance between
top bearing and next item below it is only 2'... VS  4'...... you can kiss 
the
top 2'
of the tower goodbye in a big wind storm.

Later.......... Jim  VE7RF