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

To: Tower Talk List <towertalk@contesting.com>
Subject: Re: [TowerTalk] Thoughts on a Grounding System for my new tower
From: Larry Loen <lwloen@gmail.com>
Date: Sun, 2 Sep 2012 23:00:23 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Rather than quote myself, I'll simply put in the revised plan.  Thanks to
all of you for your thoughts.

See flikr picture here:
http://www.flickr.com/photos/lwlpix/7916824198/in/photostream/lightbox/

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

*Right now, I can only get my hands only on 8 foot copper grounding rods,
so I'm planning accordingly.  I will space them about 10 - 11 feet apart
(as per "Up the Tower).*

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).  Trying to bury the
bare wire above the AC is apparently a little too clever.  It will instead
be about 24 inches to the side as well as shallower than the AC.*

2. I plan on having no ground poles between the shack and the house*,just
properly buried "armored" cable (if it meets code; if not, PVC).*  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). * I have thought hard about
having the cables come into the house through the floor, but having the box
outside (as per "Up the Tower") and a desire for shorter cable runs
suggests coming in through the outer wall.  I have done this with success
elsewhere and it is easy enough to cover up if I ever sell the property.  I
plan on doing at least some switching right at the common ground outside of
the house; so it will be less than one coax into the house for every coax
running on the property.  Still, I've thought about this both ways for some
time now.  I may still come up through the house.  One problem:  The AC
main appears to be running along the skirting; it might be simpler to have
it go directly through the wall and perpendicularly, too.*

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.  *I may buy
pre-drilled drain pipe to minimize the issue of cable drag.  Same basic
dimensions as what I am planning on now.*

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). * However,
colleagues nearby have done so, so I expect I can learn this one.*

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 further thoughts would be appreciated.


Larry Wo0Z
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