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Re: [TowerTalk] Overhead cables from tower to shack

Subject: Re: [TowerTalk] Overhead cables from tower to shack
From: K8RI <>
Date: Sat, 22 Sep 2012 00:10:11 -0400
List-post: <">>
On 9/21/2012 8:58 AM, Hans Hammarquist wrote:
To save some (~250 feet) of wires and cables I am thinking of hanging a steel 
wire with attached cables (coax and control) between the (near) top of my tower 
directly to my radio shack located on the top floor of my house. Instead I can 
pull all the cables down the tower, through a ditch i the ground and up along 
the side the house up to my shack, with much better possibilities of good 
protection from light-strikes.

The tower is well grounded (as far as I know, 9 grounding rods, Ufer ground and 
whatever else)

The house has a Faraday grounding cage with a total of 6 grounding spots (plus whatever it gets through the utility connections).

The lightning protect has been tested (by direct lightning strikes) at least twice. Burn-marks to prove it.

I am planning to let the coax cables be grounded in the tower through a plate 
equipped with bulkhead connectors

and ground them at the house with a similar plate - bulkhead connectors. That plate will be directly connected to

the lightning protection next to my shack. There are 4, thick, copper wires that connects the lightning rods over my shack

to the grounding rods four stories down.

What I am afraid of is, in case of a lightning strike (direct hit or near-by), 
the big open loop created by my overhead wires

together with the tower, the lightning protection of the house and the ground will induce enough current to cause damages.

This loop will have an about 70 x 125 feet opening, enough to make it a good loop antenna (not the purpose though).

125' of cable with ice just a quarter inch thick is going to be heavy.
With an inch thick it's almost unbelievably heavy.

(No I don't have any AM stations around that will have their radiation pattern altered.)

Anyone with experience from this, or any objections? I would not like to find 
my installation looking

like a fried chicken after inclined weather.

As you are in ice country (VT) I'd recommend against using a messenger cable supporting overhead lines to the tower. It'd be convenient and save a fair amount of money, but you'd be playing the odds.

Faraday cage? Your house or at least operating room is a copper, bronze, or brass screen room?

In addition to the lightning problem, a little ice weighs a LOT and I believe New England has had some big problems with ice and wet snow just in the past few years. I've seen miles of power poles broken over out here in the open farm country just SW of where we live now.

About 6 years ago... or so... here we had about an inch of ice. The power line sagged right down onto the cable distribution coax and then a tree folded over onto the whole works and those trees had lost their leaves.


Roger (K8RI)

73 de,

Hans - N2JFS

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