Date: Tue, 3 May 2016 16:47:28 -0400
From: "john@kk9a.com" <john@kk9a.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Rotator Choice for Larger Yagi
I am not even sure that torque means much. All of the rotator issues that
I have had (broken gears, worn keyways, failed potentiometers, etc)
occured while the station was QRT.
I currently use a small and a medium prop pitch. The small has a 9576:1
gear ratio and the medium has a 7063:1 ratio. It is possible that the
small one has the same or more torque than the medium. Which one is less
likely to break, I would guess the medium. I think you would be happy
switching to prop pitch rotator and Green Heron controller.
John KK9A
## A buddy had the monsterstepIR, turned by an OR-2800....and it lasted
exactly 9 days ! 2 other folks with the exact same ant / rotor combo had
similar results.
## If I remember correctly, the small prop pitch had its final gear driven in
3 x places, every 120 degs, by small gears. The OR-2800 has its final gear
driven by only one small gear. By using 3 x small gears, the back lash is
distributed over 3 gears.....and not just one.
## Back in the late 70s, early 80s, a japanese rotor maker had a rotor out that
used from 1-4 external, bolted on motors, every 90 degs around the perimeter
of the motor. You could buy it initially with 1 motor, then add more, if you
required
more tq..and less back lash.
## I currently have 1 OR-2800 left..and its final small gear is chewed up /
trashed.
Back in the late 70s, early 80s, I sold my ham-4 to a buddy, who used it to
turn a
hb 6-el 10m yagi on a 36 ft boom. He always kept it pointed in one direction
99%
of the time. Eventually, due to constant wind buffeting, it literally ate 1-2
teeth, completely
gone.
## perhaps what needs to be done is to use a worm gear to drive the final gear,
that would
eliminate the back lash, + provide more surface area. That and /or use a
better grade of steel.
and /or thicker gear teeth. Or provide some form of isolation between mast
+ rotor.
Jim VE7RF
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