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Re: [TowerTalk] Thoughts on a Grounding System for my new tower

To: "Joe Subich, W4TV" <>, <>
Subject: Re: [TowerTalk] Thoughts on a Grounding System for my new tower
From: "Jim W7RY" <>
Reply-to: Jim W7RY <>
Date: Sun, 2 Sep 2012 17:20:08 -0700
List-post: <">>
Don’t run the ground wire in conduit. Run it in the ground... Works better that way ;) Keep the ground wire at least 24 inches from other conductors. Ground radials with rods are a great way to go. Keep the rods spaced at lest 1.5 to 2.0X length of the rod. Installing rods on the ground conductor as it runs between the house and tower base is also a good idea. Use exothermic welding for all of the ground connections used outdoors.

Run the cables up underneath of the mobile home. I put a piece of pipe through the floor. That way you can keep the extra length under the house.

Agreed. Use PVC.

When you provide for drain holes in the conduit, make sure they can't snag cables wile being pulled in.

Sounds like a great project!
Jim W7RY

-----Original Message----- From: Joe Subich, W4TV
Sent: Sunday, September 02, 2012 3:22 PM
Subject: Re: [TowerTalk] Thoughts on a Grounding System for my new tower

Your thoughts appreciated.  This is my plan as of right now.

1) I would run the coax and the ground/power via the same route
even though they would be in separate conduits.

2) I would not bury steel conduit ... it will most likely rust
   in short order.  Use PVC conduit even for power and pull an
   extra ground conductor if necessary.  Better yet, get an
   armored cable designed for direct burial and avoid conduit


   ... Joe, W4TV

On 9/2/2012 5:54 PM, Larry Loen wrote:
OK, I got the base poured this week (haven't been out to look at it)
so now it is time to get serious about getting the tower going (tower
will be delivered in about six weeks maybe).

Next big step is to get the electrical and coax out to it.

Your thoughts appreciated.  This is my plan as of right now.

See flikr picture here:

The center of the red cross is where the tower will be.  For
convoluted reasons, my shed is between my operating position and the

Right now, I can only get my hands only on 8 foot copper grounding
rods, so I'm planning accordingly.

1.  At the tower, I will have two grounding rods (about 20 feet total
in each direction) radiating out from the tower.  I plan on having the
AC nearby (AC buried 24 inches as per code) below where the ground
wire back to the house is going to go (shallower, same hole).   Should
I make these separate holes (ground wire and the AC)?  If so, it's a
bit of a problem, because they will have to be reasonably close
anyway.  I'm not sure where the drain field runs, exactly, so I don't
want to be digging "east" of the purple lines if I can avoid it.  I'm
also having the third such "radiation" just keep right on going back
to the shack.

2. I plan on having no ground poles between the shack and the house,
just steel conduit (grounded by definition) going back to the house's
electrical box, the electrical service is roughly on the left (west)
end of the house inside.  Since it is a mobile home, I should be able
to route the cable up into the box without a lot of fuss, I hope.  The
main comes up that way.  This bit, I am hiring out anyway; the
connection to the home circuit.

3. I will have a "box" of ground wire around the house (clearing the
mobile-home-of-a-house by five or ten feet, perhaps, see purple
rounded square).  There will be the common area where the coax is
grounded to a box and that to the grounding system right outside the
operating position (on the east or right hand side of the house).

4,  I will bury the coax in 4 inch PVC as deeply as I can manage.  I
will have at least a couple of "T" joints to enable drainage pipes to
reach the surface to keep the coax mostly dry.  There will be no
connectors for the coax anywhere in the pipe, including the junction.
The "junction" area will be something suitable that I am still looking
for (some sort of large-ish plastic barrel that will enable me to
service the cable runs had have them readily go "around" the angled
corner it will create).  The big headache is the wash (see green
line).  It is as much as 2 feet deep.

5.  A colleague who just did this has some nice, thick copper wire at
the base of the tower.  With his help, I'll duplicated what he did for
that.  He had some custom "jigs" so that the wire would attach very
nicely to the tower.

6.  The AC and the shack entry will not be a single point of entry;
they will be about 30 feet apart.  No real way to improve on that;
just the reality of the home's layout.

7.  The grounding line will be #6 copper and I plan on doing the
welding thing (though I am struggling to figure out how to do that).

Since mine is a crank up, I'm not sure how to run a "real" lightning
rod.  There will be coax arms, but they will have coax in them
(obviously).  Where would I run lightning rod wire, or do I just skip
it for this?  The mast will be a good eight feed above the top of the
tower (structural support for the KT36).

Any thoughts would be appreciated.

Larry Wo0Z

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