Take a look at http://www.cebik.com/gp/ir.html . Insulation makes "no"
difference = contact to earth makes "no" difference. Insulation will likely
make the wire last longer. The size of the wire is generally irreverent
except for physical strength if you think you need it for some reason. The
deeper it is "buried" the more earth the signal has to penetrate to get to
the wire to return to the antenna. MY summary = lay insulated wire "on top
of the ground" (use sod staples or old single piece wooden clothespins to
hold it down for a couple of weeks, available at the hobby section of Ben
Franklin or a hobby store).
--MY-- Opinion, Flame away,
73, Jim
----- Original Message -----
From: "K4SAV" <RadioIR@charter.net>
To: <towertalk@contesting.com>
Sent: Friday, May 11, 2007 5:38 PM
Subject: Re: [TowerTalk] Grounding, redux
> W2IRT asked:
>
> Questions:
> 1) How far below ground should I run these wires? I'm just using
> hand-tools to trench, not a ditch-witch, so the plan was about 3 or 4
> inches.
>
> You can get a little help from conduction of the bare wire to the
> surrounding ground. The top layer of soil (at least around here) tends
> to dry out a lot, and when that happens the conductivity drops, so a
> little deeper would be better. It's difficult to determine exactly what
> the difference would be, but if you already have enough ground rods it
> may not be worth the effort.
> -----------------------------
>
> 2) Polyphasers. This is a big question mark. Most things I've read
> say to mount 'em all on a single-point panel inside the house,
> strapped with a 2" or 3" copper bus to a ground rod outside the
> house, which in turn is connected to the ground rod system. I 've
> seen lots of pics online of polyphasers outside, in a NEMA box on
> a tower leg, others saying I should have them physically connected
> to the tower and the top and bottom, AND inside the house on the SPGP
> panel, etc.
>
> Outside is usually better because as someone already said, you don't
> want the lightning transients coming inside. However your system should
> be designed such that the major portion of the lightning current goes
> into the ground before it gets to the transient suppressors, so some
> amount of variation can be done if you are careful. For example, my box
> is inside my garage wall at the floor. Immediately adjacent to that
> box, outside, is a ground rod maybe 2 feet away, and the ground rod for
> the AC power entrance is 6 feet from that.
>
> The suggestion for transient suppressors at the tower and just outside
> the house was for long runs (which you don't have). The coax shields
> should be connected to the tower at the top and bottom, and of course
> they will be connected to ground at the suppressor box at the house.
> ------------------------
>
> 3) TVSS (transient voltage surge suppressors): Yes? No? Maybe??
>
> For me, yes. There are guys that don't use them and rely on good
> grounding to remove the transients, and some are successful at this, but
> for me it's a small price to pay for extra protection. Note that
> without suppressors long antennas (80 & 160) will still require some way
> to get rid of the static charge.
> ---------------------
>
> Guys, am I over-thinking this or over-engineering this project for a
> 70; crankup?? I've got 3 trees higher than that on the property, as
> do most of my neighbours, 250kV transmission lines at the end of the
> street and a 20 year history of never taking a direct hit at this
> house (100' tower by the previous owner with one ground rod and 4 GA
> round green wire). the only lightning hit that did anything came in
> on the power line as a surge that cooked my motherboard on the radio
> PC, despite an APC UPS.
>
> If your time is as cheap as mine, it pays to over-engineer it. Remember
> that a hit on your antenna is not all you have to worry about. A hit on
> those power lines may sent transients into your house, and you don't
> want your radio stuff to be sitting at zero volts when thousands of
> volts enters common mode on the power lines. Also think about all the
> other lines entering your house (phone line, TV cable, whatever. Is your
> water line copper or PVC?). You want all these to be tied into the same
> ground system so that everything goes up and down together.
>
> Jerry, K4SAV
>
> Peter Dougherty wrote:
>
> >Hi all,
> >
> >Getting ready to put my ground system in shortly but will be shopping
> >for Polyphasers, etc at Hamvention next week.
> >
> >Here's what I have. One 70' crank-up tower about 5 feet from the back
> >wall of my house. I've driven in a bunch of ground rods ~16 apart
> >(most are down all 8', some only 5 feet due to rocky soil, however)
> >going around my house on 3 sides. The fourth side is a paved
> >driveway, so that's not happening any time soon. It will eventually
> >connect to the service panel once I can get an electrician to come by
> >and hook it up, per NJ code.
> >
> >I also have a bunch of Cadweld one-shots for AWG-4, but I haven't
> >purchased the wire yet. I'm guessing AWG #4 solid is the right choice
> >for this application? Given copper prices, 2-gauge is too expensive.
> >
> >Questions:
> >1) How far below ground should I run these wires? I'm just using
> >hand-tools to trench, not a ditch-witch, so the plan was about 3 or 4
inches.
> >
> >2) Polyphasers. This is a big question mark. Most things I've read
> >say to mount 'em all on a single-point panel inside the house,
> >strapped with a 2" or 3" copper bus to a ground rod outside the
> >house, which in turn is connected to the ground rod system. I 've
> >seen lots of pics online of polyphasers outside, in a NEMA box on
> >a tower leg, others saying I should have them physically connected
> >to the tower and the top and bottom, AND inside the house on the SPGP
> >panel, etc.
> >
> >3) TVSS (transient voltage surge suppressors): Yes? No? Maybe??
> >
> >Guys, am I over-thinking this or over-engineering this project for a
> >70; crankup?? I've got 3 trees higher than that on the property, as
> >do most of my neighbours, 250kV transmission lines at the end of the
> >street and a 20 year history of never taking a direct hit at this
> >house (100' tower by the previous owner with one ground rod and 4 GA
> >round green wire). the only lightning hit that did anything came in
> >on the power line as a surge that cooked my motherboard on the radio
> >PC, despite an APC UPS.
> >
> >I'll be at the lightning panel in Dayton next week (probably asking a
> >lot of questions afterwards, too), but can always use more guidance.
> >
> >
> >
> >Cheers,
> >
> >Peter,
> >W2IRT
> >
> >_______________________________________________
> >
> >
> >
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> >TowerTalk@contesting.com
> >http://lists.contesting.com/mailman/listinfo/towertalk
> >
> >
> >
>
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