[TowerTalk] Rotator Cable Protection

[Michael Tope]

Hi John,

Yes, I understand about the lack of shields on most rotator cables. That 
is in part what prompted my question. It seems like the rotator cable is 
"the elephant in the room" when it comes to grounding and bonding. When 
you consider the cost of a rotator, especially some of the larger ones 
designed to turn large HF arrays, it seems like it would be something 
important to address.

By the way, what has your experience been with the reliability of having 
MOVs up on your tower(s)? I am asking in part because I am helping with 
an installation that sits on a high ridge where the rotator is 
controlled via 1700ft of heavy duty control cable (multiple 12 AWG 
conductors), which in this particular case, happens to be shielded. I am 
trying to decide whether bonding the shield at the base of the tower and 
up at the rotator will be sufficient, or whether adding some transient 
protection at the rotator and/or the tower base is warranted. Climbing 
the tower is a PITA, so I don't want to include transient suppressors 
that need frequent replacement (facility rules require that we hire a 
professional tower climber to service anything on the tower that can't 
be reached from the ground).

73, Mike W4EF.............

What has your experience been with MOV reliability?

On 10/15/2021 8:05 AM, john at kk9a.com wrote:
> Rotator cables typically have no shield to bond to the tower. I use MOVs
> near all of my rotators to protect the motors and potentiometers.
>
> John KK9A
>
>
> Michael Tope W4EF wrote:
>
> Jim, et al:
>
> What about control cables coming down the tower? I just skimmed through
> the first edition of Ward's grounding book. It recommends bonding the
> coax shields to the tower, but doesn't say anything about control
> cables. Typically there is a least one rotator control cable in the mix
> and oftentimes additional control cables for array switches and multiple
> Tic ring rotators on larger more sophisticated installations. That seems
> like an inconsistency, no?
>
> 73, Mike W4EF...........
>
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