EMBARRESED - READ THE FIRST PARAGRAPH OR THE RESPOSE AND THOUGHT YOU WERE
TALKING ABOUT RADIALS. VERY RED-FACED.
73, JIM
----- Original Message -----
From: "Jim Miller" <JimMiller@STL-OnLine.Net>
To: <towertalk@contesting.com>
Sent: Friday, May 11, 2007 7:15 PM
Subject: Re: [TowerTalk] Grounding, redux
> 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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> >
>
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