[TowerTalk] Alpa SPID RAK motor noise - Resolved

[Patrick Greenlee]

Copper braid, especially if not tinned, corrodes in many exterior 
environments and can suffer a loss of performance over time. Copper 
strap of similar dimension is superior to braid in environmental survival.

Patrick        NJ5G


On 10/17/2018 8:36 PM, Gary Smith wrote:
> Folks,
>
> Many replied off & online to help me out,
> some went above and beyond in offering
> their time and experience and thank you
> for that, helping others is much of the
> joy in our common bond.
>
> To recap the issue: The RFI I have been
> having is on 6M when the SPID rotated my
> 6M7JHV on the tripod on my ranch house.
> The tripod is DC grounded by #4 solid
> copper wire to the a grounding rod which
> is bonded to the breaker panel and antenna
> input/station ground. The noise was only
> experienced when rotating, it was
> determined NOT to be PWM in origin and a
> 360 rotation seen on my P3 SVGA display
> looked like this and sounded as bad as you
> would suspect.
>
> http://doctorgary.net/spid.jpg
>
> I have the problem now resolved to maybe
> 95% and I wanted to share this resolution
> with you. Jeff at Green Heron has been
> most helpful in being willing to work with
> me as I bought the SPID RAK, GH controller
> combo from him. Among the suggestions he
> gave me was ferrite clamp on chokes on the
> rotor control line and running a copper
> braid between the mast ground and the
> tripod.
>
> I had an abundance of clamp-on ferrites
> bought at the suggestion of Jim, K9YC a
> few years back and placed around 10 on the
> rotor cable starting at the SPID. I added
> 4-5 more to the coax attached to the boom,
> just before the coax loop. The loop is
> held in place by a clamp-on dacron roped
> to the boom clamp. - I also took the braid
> from 7' of 50 ohm coax, doubled it by
> folding it in half, using Penatrox at each
> connection, radiator clamped the fold/bend
> to the mast, ran the two braids to the
> grounding wire of the SPID. I screwed the
> ground screw through the penatroxed braids
> and then attached the two loose ends, now
> penatroxed, to the tripod.
>
> I don't know which of the three things
> made the difference, I already had a few
> clamp-ons added to the coax at the antenna
> between the hardline and the loop but I
> did add 2-3 more. But I did add those to
> the rotor line and I did run that double
> braid between the mast, the SPID ground
> wire and the tripod. This is the result:
>
> http://doctorgary.net/spid-rfi-fixed.jpg
>
> This photo was taken after the exact same
> 360 degree rotation & same frequency I
> showed in the earlier photo showing the
> tremendous RFI.
>
> So to those who have this issue, you might
> want to do as Jeff suggested and what I
> followed through with, obviously, it is a
> solution that works beautifully.
>
> Hope this helps someone.
>
> 73,
>
> Gary
> KA1J
>
>
>> 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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>
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