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
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