[TowerTalk] Another Grounding Question

[Tom Rauch]

> This came up in discussion with one of the locals. The
> question came up about connecting the tower
> coax/control line entrance panel to the AC/telco
> groung system. I said that these could be connected
> together with a low impedance connection within the
> building if this was the only way to "reasonably" do
> it .

Stew,

I have about 35 feet of 4 inch flashing in my house's
crawlspace. It runs from my radio entrance to my house
breaker box and eventually to the entrance ground in a
straight line. I did this because my breaker box is in the
middle of the house while the service entrance with light
meter is on the opposite wall.

I have no qualms at all running that ground under the house
even though it lays under a plastic vapor barrier for part
of the distance and is also attached to wooden floor joists.

I look at it this way...I'd rather have a solid low
resistance path that keeps energy out of the small wiring in
walls and all the electronics in the house than have
something 150 feet or more long that goes around the outside
and doesn't do anything.

I do have a ground ring around the house, but I'm sure
nearly all strike energy goes right through that flashing.
How do I know? Because during one big hit on my 300 ft tower
last winter or spring (during an ice storm) enough current
passed through feedlines to the house that telco lines to
the pole failed (melted inside). I didn't even lose a modem
or a telephone, so obviously most of the energy passed
through that flashing. That was one of those super hits. It
even melted the shield off some 7/8th inch heliax!

My equipment damage was mostly coax connectors and coax and
one antenna switch box on the tower.

If it makes your friend feel any better, I installed or
rewired dozens of BC stations in the 70's. I always ran
flashing right through the buildings in a bee line from
service entrance to antenna feeds. Never had a problem.