On 3/11/2019 1:40 PM, Peter Dougherty wrote:
I've got my bonding about as good as I can get it for the moment, although
I'm probably going to do some improvements this year. The lightning
arrestors are built in to the RCS-12 antenna switchbox (RCS-12L with the gas
discharge tubes), and everything's bonded at the base of the tower.
The function of GDTs is to offer some protection of equipment in the
event of a strike. To do that, they must be close to the equipment, not
at the tower. Lightning can induce a lot of current on the coax between
the tower and the shack. I suggest that you add arrestors (including
that vertical you use for RX) where all of your coax enters the shack,
bond them to your rod(s), and to the shack bonding. That's probably the
missing bonding that I suspected! Also, what about bonding to the power
entry panel?
There's
a single feedline coming inside from that tower-mounted switchbox. Each
piece of radio gear and the computer inside is bonded by 1" braid going to a
copper bus. LAN and voice line comms are not, however the connection from
the pole is fiber, not copper so that's not likely a problem.
Agreed.
The copper bus
inside is bonded to a ground rod outside the shack, which in turn is bonded
to the tower ground system.
The deficiency is that the copper bus is not grounded to the same point as
the tower, since the tower is about 50 feet away from the shack.
This distance is borderline for bonding to the house.
I guess I
could run a 50 or 60' run of 2" strapping from the desk, through the floor,
across the crawlspace, and out the conduit to the tower, but I suspect that
might be more a hindrance than a help, quite honestly.
Agreed.
My shack is in what used to be a "mother-in-law" apartment of a detached
garage. I have a rod where power enters that building (fed from the
house), a half-perimeter #6 running around the building to the shack,
where there are five driven rods, all exposed to rainfall, and three
rods along that perimeter ground. The coax entry panels (added a second
one when the first filled up) on the wall of the shack are bonded down
to the rods and up to the ground bus for the equipment. They're also
bonded to steel conduit that runs back to the entry panel.
73, Jim K9YC
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