A broadcast engineer friend of mine (who is also a ham) always recommends
this time of ground whenever he initiates a new tower installation.
73
Harvey, KM4JA
----- Original Message -----
From: J. Kincade <w5kp@swbell.net>
To: EUGENE SMAR <SPELUNK.SUENO@prodigy.net>; Milcarsky
<jamvet@bellsouth.net>; TowerTalk <towertalk@contesting.com>
Sent: Friday, July 20, 2001 10:15 PM
Subject: Re: [TowerTalk] Adding copper in the ground
>
> With the new 45G (concrete arrives at 0730 tomorrow) I'm trying something
I
> haven't seen mentioned, hope it works ok. I placed a 6' long strip of 8"
> wide heavy gauge solid copper roofing material in the base hole, covered
> with a few inches of gravel. The strip runs across the bottom of the hole
> under the gravel, then up and out one side of the hole with about 6" to
> spare outside the hole. It's spiked to the side of the hole with a half
> dozen 8" spiral bridge nails (just to hold it solid while the concrete's
> poured). I plan to tie this copper sheet into the other ground setup for
the
> tower legs, which will be several (at least 6) copper clad ground rods in
a
> circle about a 6' radius around the base of the tower, all tied in with #4
> copper to all three legs. Don't know if the copper sheet under the tower
> base will help dissipate strikes, but I figured it wouldn't hurt and I had
> it on hand. My theory is anything that adds copper contact to the ground,
> especially down deeper where things stay fairly damp, can only help. Has
> anybody that's tried this got any comments? The tower will sit on a Rohn
> pier pin in the center of a concrete pad that will measure about 3' square
> by 3-1/2 feet deep. Concrete will be a fairly stiff mix of 3000 psi
28-day.
> No rebar in the base pad (compression load only), but lots of rebar in the
> guy anchor pads. The fun part will be trying to properly finish the base
top
> around the pier pin area with an ever-so-slight slope in all directions
away
> from the pier pin, so that water doesn't collect and stand under the tower
> base plate. Needless to say, a concrete finisher I ain't. :-)
> Jerry W5KP
>
>
> ----- Original Message -----
> From: EUGENE SMAR <SPELUNK.SUENO@prodigy.net>
> To: Milcarsky <jamvet@bellsouth.net>; TowerTalk <towertalk@contesting.com>
> Sent: Friday, July 20, 2001 8:46 PM
> Subject: Re: [TowerTalk] Routing cables - tower to shack
>
>
> >
> > Ed:
> >
> > I'm planning on putting the arrestors at the base of my tower,
bolted
> > to the insides of a metallic Hoffman box or similar. From the box the
> coax
> > and control cable runs will be in 3 inch sch 40 buried conduit to the
> > house/shack. The alternative is to put the arrestors in a box just
> outside
> > the house at the end of the conduit run and ground at that point, as
most
> > commercial installations have it.
> >
> > My thinking is that the ground field for a lightning strike
> originates
> > at the tower, where all the underground radials connect to the tower
legs.
> > Here the inductance of multiple parallel ground legs will be less than
at
> > the entrance to the house/shack, fifty feet from the tower, where I will
> > have only one radial to which to connect the arrestors' grounds. (I'm
not
> > planning on encircling my house with buried copper ground wires.) I'd
> > rather have the arrestors far away from the house and let them do their
> work
> > in a low-inductance part of the ground field, rather than close to the
> > house.
> >
> > I agree with Steve, though - keep the single-point ground outside
of
> > your house. Its connection into earth will be shorter and the lightning
> > energy is less likely to get into your house wiring. And don't put a
> bend
> > in your ground wire from the coax runs. Keep it as straight as possible
> > such that the lightning energy continues to move in a downward direction
> to
> > a metallic ground connection.
> >
> > GL es 73 de
> > Gene Smar AD3F
> > -----Original Message-----
> > From: Milcarsky <jamvet@bellsouth.net>
> > To: TowerTalk <towertalk@contesting.com>
To: <towertalk@contesting.com>
> > Date: Friday, July 20, 2001 7:03 PM
> > Subject: Re: [TowerTalk] Routing cables - tower to shack
> >
> >
> > >
> > >Steve,
> > >
> > >It's clear that grounding the coax at the tower base, before it bends
> > toward
> > >the shack is the right thing to do. However, I have only heard that
the
> > >coax shield should be grounded at this point. Why not also place an
> > >arrestor for the center conductor at this point as well? It would seem
> > that
> > >this would afford a certain amount of extra protection. What are your
> > >thoughts?
> > >
> > >Ed KG4ARN
> > >
> > >----- Original Message -----
> > >From: <K7LXC@aol.com>
> > >To: <kq2m@mags.net>; <towertalk@contesting.com>
> > >Sent: Friday, July 20, 2001 6:14 PM
> > >Subject: Re: [TowerTalk] Routing cables - tower to shack
> > >> Commercial specs call for grounding cables that come down the
tower
> > >> *before* they turn towards the building. The cables should be
grounded
> > >> directly to the tower at that point to offer the lowest resistance
path
> > to
> > >> ground. The bend in the cables introduces inductance at that point so
> you
> > >> want to be grounded before that so the lightning energy will go there
> to
> > >> ground.
> > >
> > >
> > >
> > >
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> > >
> > >-----
> > >FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> > >Submissions: towertalk@contesting.com
> > >Administrative requests: towertalk-REQUEST@contesting.com
> > >Problems: owner-towertalk@contesting.com
> > >
> >
> >
> > List Sponsor: Are you thinking about installing a tower this summer?
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> us
> > for information on our fabulous Trylon Titan self-supporting towers - up
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> > 96-feet for less than $2000! at 888-833-3104 <A
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> >
> > -----
> > FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> > Submissions: towertalk@contesting.com
> > Administrative requests: towertalk-REQUEST@contesting.com
> > Problems: owner-towertalk@contesting.com
> >
> >
>
>
> List Sponsor: Are you thinking about installing a tower this summer? Call
us
> for information on our fabulous Trylon Titan self-supporting towers - up
to
> 96-feet for less than $2000! at 888-833-3104 <A
HREF="http://www.ChampionRadio.com";>
> www.ChampionRadio.com</A>
>
> -----
> FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> Submissions: towertalk@contesting.com
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: owner-towertalk@contesting.com
List Sponsor: Are you thinking about installing a tower this summer? Call us
for information on our fabulous Trylon Titan self-supporting towers - up to
96-feet for less than $2000! at 888-833-3104 <A
HREF="http://www.ChampionRadio.com";>
www.ChampionRadio.com</A>
-----
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
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