Good Idea>
I am planning to install an XM-240 ten feet above a Force 12 C-31XR on a 20 foot
0.25" wall 1026 DOM mast. Sixteen feet of the mast will be above the top of the
tower.
Tod, K0TO
_____
From: N7KA@comcast.net [mailto:N7KA@comcast.net]
Sent: Tuesday, August 11, 2009 10:52 PM
To: Tod -ID
Subject: Re: [TowerTalk] One thrust bearing vs. two
A lot has to do with mast length above tower and antenna load. The lower thrust
bearing is mostly used to take the lateral thrust load presented by a long mast.
I use 2 since my 21 ft mast is 15ft out the top of tower and 6 feet inside top
section. Not a single problem in 22 years.
However if a short mast 2 thrust bearigs is not really needed. In fact I used
Rohen 25G tube top for years with NO thrust bearings, and that with several
yagis 20/15M, or 20/40M.
For best advice detail what you plan to do. General questions will get a mixed
bag of answers.
Arne N7KA
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