[TowerTalk] Special grounding and/or cable routing?

[Jim Brown]

On 12/11/2019 5:49 AM, Paul Beckmann wrote:
> I'm writing the reflector members today to get their thoughts on my plans
> for coax and cable routing, grounding, and lightning suppression. Should
> suppression be installed at the base of the tower before it makes the 15'
> underground run? Should the tower ground and garage ground be directly
> interconnected? 

Absolutely yes -- one of the most fundamental rules of grounding and 
bonding is that ALL grounds must be bonded together. The only time you 
would NOT bond tower ground to other grounds is if it was more than 
60-100 ft from the building housing the shack. I would place arrestors 
on a panel near ground level where it enters the garage so that bonding 
from that panel (the arrestors) has the shortest practical path to the 
earth.

> If so, should the ground be placed inside or outside the
> coax and rotator cable conduit? 

In general, it's good practice to route all cables together. This would 
be a great application for steel conduit (EMT) if it's practical to 
install it. Bond it to ground at both ends, and it shields the wiring 
AND acts as a very robust bonding conductor. It is NOT, however, 
permitted to run power and low voltage wiring in the same conduit, and 
equipment grounding conductors associated with power (the Green Wire) 
MUST be run in the same conduit with power conductors.

> Is it necessary to ring the house with
> ground rods as well since the garage has it's own service entrance of sorts?

Probably not, but I would make sure that the driven rod(s) there are 
well placed (exposed to rainfall) and properly bonded to the service 
entrance.
> 
> I'm hunting for references (books/articles) as well as personal analysis.

Three references. First, N0AX's ARRL book on the topic, to which I 
contributed. Second, K7LXC's "Up the Tower," for which I wrote the 
chapter on the topic. Third, slides for a talk I've done at Visalia, 
Pacificon, and to several ham clubs.
http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC