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[TowerTalk] Long Masts -- Intermediate Bearing?

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Subject: [TowerTalk] Long Masts -- Intermediate Bearing?
From: (Dale L. Martin)
Date: Fri, 3 Apr 1998 14:44:28 -0600

>At 10:44 AM 4/3/98 EST, K7LXC wrote:
>> You can have some sort
>>of fixture to hold it but most people use an additional
accessory shelf with
>>an additional thrust bearing. That way the mast is always
captured. This'll
>>work on 45G and 55G but not 25G.
>>     A bushing would work as well to hold the mast but probably
involves more
>>fabrication than the AS/TB version.
>On advice from a local professional tower guy, I used a pointy
top section
>on my 25G. At least for the relatively light load I'm dealing
with, it
>works fine to hold the mast while the rotator is out.  I use a
>clamp above the pointy-top (actually two, for safety) to hold
the mast up.
>I suspect that a mast/antenna combination that is heavy enough
to bend the
>pointy top probably has no business being up there on 25G
>73,  Pete Smith N4ZR
>In wild, wonderful, fairly rare WEST Virginia
Pete (et al),

You can do what I did on my tower (bigtime A3S on top):

Got two U-bolts and a piece of holey angle iron from Home Depot
secured the angle iron to a tower leg and the mast.  That held
the mast in place during the time the rotor was out for
refurbishment (about a month -- shipping, rework, and weather
time).  Worked like a champ.

I used a similar setup with three holey angle iron pieces and
U-bolt sets on our club station's 80' 45G flattopped/thrust
bearing'ed tower with 4el 15m and 4el 20m beams.  The three angle
irons held the mast on centerline and no rotation was noted
during the two weeks the rotor was out.

dale, kg5u

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