In a message dated 8/12/2009 8:12:01 A.M. Pacific Daylight Time,
towertalk-request@contesting.com writes:
> I would be interested in 'opinions' on the need or utility for only one
thrust
bearing at the top of a tower vs. two thrust bearings one at the top and
the
other several feet below the first.
The alleged purpose of the middle thrust bearing is to hold the
mast vertically to aid in rotator replacement. You don't need a middle
bearing - all you have to do is capture the mast. You can do that with a
rotator
plate sans bearing or fabricate a mast holder made from a couple of pieces
of angle iron and U-bolts. You just install it when you need it.
A mid thrust bearing can potentially add more bind in the
rotator/mast system. The tolerances are relatively large and some misalignment
is
common.
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for hams
Cell: 206-890-4188
**************A Good Credit Score is 700 or Above. See yours in just 2 easy
steps!
(http://pr.atwola.com/promoclk/100126575x1222846709x1201493018/aol?redir=http://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=115&bcd
=JulystepsfooterNO115)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|