Interesting. With it attached to the coax
I haven't tried rotating it with a
separate DC source to check.
Another thing I noticed is when I attached
the antenna to a separate radio connected
by a battery & nothing else, the problem
continues. If I listen with a remote
antenna 370' away on 6M I hear nothing.
If PWM is the culprit, any idea of what I
might try to filter Pulse width modulation
and not affect the function of the
controller or antenna?
73,
Gary
KA1J
> It's not the rotor - it's a side effect of the PWM coming from the GH
> controller and transmitted by the rotor wires.
>
> 73/jeff/ac0c
> alpha-charlie-zero-charlie
> www.ac0c.com
>
> On 11-Oct-18 6:55 AM, john@kk9a.com wrote:
> > Inside all of my TIC Ring rotators are filters connected to the
> > wiper motors. Perhaps a filter can be added at the Alpha SPID RAK
> > motor to reduce the hash.
> >
> > John KK9A
> >
> >
> > From: "Gary Smith" <Gary@ka1j.com>
> > Date: Thu, 11 Oct 2018 01:39:41 -0400
> >
> >
> > I have motor noise when I rotate the new
> > SPID RAK & I've held off asking here till
> > I completed properly grounding the house,
> > coax & rotor lines. Unfortunately it
> > hasn't helped the issue I'm having with
> > the rotor and maybe someone has a
> > suggestion of something I can try.
> >
> > The antenna is a 6M7JHV, it is on a tripod
> > mounted in the center of the house. There
> > is a #4 Gauge wire attached to the tripod
> > which goes to an 8' ground rod. This
> > ground rod is connected with #4 solid
> > copper to the breaker box and the ground
> > rod with the Polyphasers which goes to the
> > shack, the ground to the shack attaches to
> > this last ground rod. There are 3
> > additional ground rods attached to the #4
> > wire.
> >
> > When I turn the antenna it obliterates the
> > waterfall and raises the meter 7 S units.
> > As soon as the motor stops all is well.
> > The controller is a GH RT-21D. The
> > tailtwister it replaced never left any
> > indication it was turning other than the
> > meter.
> >
> > It was suggested it is because it is a DC
> > motor in the SPID and the noise is likely
> > coming from the brushes. Also that the #4
> > to ground is not a RF ground and if it
> > were attached to a tower instead of a
> > tripod I likely wouldn't have this issue.
> > The possibility was raised of the brushes
> > having an issue or perhaps the two caps
> > attached to the control lines to ground
> > may be a problem.
> >
> > Here is a photo of the SVGA output from
> > the K3.
> > http://doctorgary.net/spid.jpg
> >
> > I started at 180 deg and rotated clockwise
> > to 179 deg. The dark red is at 240-290
> > degrees, the two strips of blue where
> > there is no interference happens around
> > 340 and 80 degrees respectively.
> >
> > I've never read of anyone having this
> > problem before, guess I'm the lucky guy.
> >
> > Any suggestions I might try?
> >
> > Thanks & 73,
> >
> > Gary
> > KA1J
> >
> > _______________________________________________
> >
> >
> >
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> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
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