You can also add a plastic "paddle" to balance aerodynamic loads. Basically
you look at the cross sectional area wind load on each side of the mast
mounting point. The idea is the paddle adds enough cross section area to
make each side of the boom balanced. Of course I wonder what happens for
all the various wind directions with the changing cross section area.
Perry K4PWO
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
john@kk9a.com
Sent: Sunday, December 10, 2017 7:16 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] PST61 Rotor Reliability?
I am not following how moving one antenna ~6" sideways makes a significant
different in rotational torque.
John KK9A
To: xdavid@cis-broadband.com, towertalk@contesting.com
Subject: Re: [TowerTalk] PST61 Rotor Reliability?
From: k7lxc--- via TowerTalk <towertalk@contesting.com>
Reply-to: k7lxc@aol.com
Date: Sun, 10 Dec 2017 13:36:16 -0500
> The problem is that in the springtime when it gets really windy here,
the high ridge line to the west and south of me blocks those prevailing
winds and turns them into swirling wind gusts that AVERAGE anywhere from
50 mph to 80 mph about every three to five minutes ... with peaks sometimes
reaching 90 mph on a bad day. When those swirlers hit the tower head on, the
forces on each end of the boom don't balance ... they add.? The resultant
torque on the mast must be tremendous, and in any
case it eventually managed to strip the gears in the NE position.? If the
antennas are mounted on the same side of the mast - yes, the additive torque
is significant. My advice is to mount the antennas on opposite sides of the
mast.
That way, much of the torque is cancelled out. Dick Weber pointed this out
in a QEX article years ago. That should have positive effects on your
rotator as
well.Cheers,Steve K7LXCTOWER TECH
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