It makes sense to me, as I've seen the gear slip during startup.
This could apply to both start and stop - As the ring rotates, due to
slight variations in the ring gear diameter, there are spots where the
connection of the motor gear to the ring is tighter (and looser) than
others. If the ring is stopped at one of the looser points, the inertia
of starting causes the gears to slip. When starting at a slower speed,
the gears are less likely to slip.
> That is quite a claim. Either the potentiometer or the drive gear is
> slipping, If it is the drive gear you may not have a tight enough fit with
> the motor. The main gear is not round and setting it can be tricky. I just
> don't see how a controller can solve this problem, even with soft starts and
> stops, heavy winds will also cause slipping.
> John KK9A / P40A
> To: TowerTalk Post <firstname.lastname@example.org>
> Subject: [TowerTalk] Green Heron Controller Performs Miracles
> From: Jim Idelson <email@example.com>
> Date: Sun, 24 Feb 2008 15:01:32 -0500
> List-post: <firstname.lastname@example.org">mailto:email@example.com>
> Yes. It is true. The Green Heron Controller does perform miracles.
> For several years, I've been turning my big Optibeam OB4-40 4-element 40m
> with a TIC Ring Rotor. The rotor uses a single drive motor. With this setup,
> I've continually experienced the same problems of 'slipping' and losing
> calibration reported by many others. While some have been able to tame the
> rotor by getting it tweaked 'just rght', I have never been able to achieve a
> stable installation. We have never made it through a major DX contest here
> without my having to climb the tower and reposition the antenna and
> the TIC Ring and controller.
> About two months ago, I spoke to Carl at TIC General about this problem
> [again]. Although he insisted that a single drive motor should be enough, I
> insisted that I wanted to try the solution that others have found
> effective - a
> second drive motor. He didn't have any motors in stock, though, so I would
> to wait. Well I waited and never heard from TIC. But, in the weeks leading
> to the ARRL DX CW COntest, I was talking to Jeff W2FU about his plans for
> contest. I mentioned the 40m rotor problem and he suggested that his
> could very likely be a solution to the problem. He insisted that I try one
> my RT-20's on that rotor and see if things got better. I put a Green Heron
> and took the TIC controller out of the station setup.
> The results have been nothing short of a miracle. The Green Heron controller
> uses PWM, ramps the motor up to speed slowly, and ramps it down to a gentle
> stop as it reaches its destination heading. These advanced rotor control
> features have completely resolved the rotation issues I've experienced with
> 40m installation. The rotor operated perfectly throughout the CW weekend. I
> convinced that I don't need to buy that second drive motor for the TIC Ring.
> Jim Idelson K1IR
> email k1ir at designet.com
> web http://www.k1ir.com
> TowerTalk mailing list
Barry Kutner, W2UP Newtown, PA
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