[TowerTalk] Alpa SPID RAK motor noise

[Gary Smith]

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