[Towertalk] Ground wire impedance

N2TK n2tk@arrl.net
Tue, 30 Jul 2002 13:02:10 -0400


With all the recent comments on grounding - solid vs. stranded wire, thought
I might pose my setup to get some feedback.

I have a 100' tower with 9 - 8' ground rods They are copper plated steel.
They have been in the ground 8 years. The rods are spaced 3-4' apart with 3
in a row spread out from each tower leg. I used stranded bare #6 wire. I
think there are 7 strands to the wire. I cadwelded the wire to the ground
rods. The wire and tops of the ground rods are a few inches below the
surface. The wire is attached to the tower legs via brass ground clamps.

All the coax, hardline, and control cables come together from the tower into
the basement. Immediately they connect to an aluminum plate mounted on the
wall. All coax and control cables go through an ICE device for lightning.
>From the center of the panel, I have a stranded copper #6 wire going through
the wall and cadwelded to 3 ground rods in-line and spaced 3-4' apart.
Besides the ICE lightning protection devices, on the panel I have mounted a
low pass filter (HF),  two 2mtr filters, and a coax switch.

I have my Acom 2000a tied into the panel for grounding - it is mounted right
next to the aluminum panel. The 100amp sub-main next to the aluminum panel
is also tied to the panel. I have installed an ICE ac protector on the
200amp main box on the other side of the cellar - 45' away. All circuits for
the ham shack come off of this sub-main.

I have 4 coax runs (2 for 2- 2mtr rigs, 1 for receive antennas and one for
HF, plus control cables going straight upstairs with a total run of about
12' to the equipment.

>From the recent comments on Towertalk, it sounds like I should replace the
stranded #6 with solid #4 copper wire. Will this make a significant
difference in safety?

Presently I am installing 4 Polyphaser Cable Grounding Kits on the hard line
and coax at the base of the tower.

Any other changes you would recommend?
What about adding lightning devices at the base of the tower for control and
rotor cables?

In the 8 years the tower has been up here in upper New York state, the only
lightning damage I have had has come through the phone line and has only
affected modems. Phone lines and all utilities are underground in this
development.

I have never disconnected or unplugged anything. Maybe I should leave well
enough alone?

Tnx for any feedback.
Tony
N2TK