After driving in six 8 foot rods and preparing to hook it all up with #2
solid a thought occurred to me:
Why do we drive ground rods into the earth at a verticle angle???
Apparently it is acceptable to drive rods in at a 45 degree angle to
miss a rocky shelf. Since lightning is a high frequency phenomenon that
dislikes making sharp turns, perhaps ground rods should terminate the
ground conductor at a gradual slope into the ground? Hmm? too late for
me since the hard work has been done. Any thoughts??
ROBERT WANDERER wrote:
>
> ----------
> From: Barry Kutner[SMTP:w2up@itw.com]
> Sent: Sunday, July 27, 1997 10:04 AM
> To: towertalk@contesting.com
> Subject: [TowerTalk] ground rods and connections
>
> Hi gang - I was re-reading some of the archives on ground rods, etc.
> on the reflector today, in preparation for some impvement in the
> tower ground. This brought up a few questions:
>
> 1. When you have mulitple ground rods in series (spaced at twice
> their depth) what is the best way to connect them, and with what
> material? For example, if you use #4 solid copper, do you run it as
> one long piece (meaning, not cutting it) and clamping it, and
> intersperse the ground rods, or do you cut it to length and clamp
> each piece with a separate clamp (meaning two clamps on each
> "middle" rod)?
> While probably an "ask 10 experts and get 11 answers" type query, I
> think either way would work although I'd suggest the first way to maintain
> continuity.
> 2. If using copper strap instead of round wire (this
> is better, isn't it?) MUCH how do you bury it? Same way as cable-in a trench.
> and how do you connect it
> to the rods? PolyPhaser 58R112S for a mechanical method.
> Can the strap be Cadwelded? Yes. Erico sells the molds for both 1.5 & 3"
> widths
> BTW Cadweld(TM) is a trademark of Erico for their exothermic welding products.
> Exothermic is the correct generic name. However, like Xerox for
> photocopying and even PolyPhaser for lightning protection,
> people use Cadweld to mean exothermic welding.
> 3. Speaking of Cadweld, I'd like to hear from someone who has
> actually done this and find out the details. Easy as pie. Put the mold
> around the materials to be welded, pour in the "gunpowder" (comes in
> pre-measured single-shot bags), close the mold and put the primer
> "gunpowder" in the top of the mold. Then fire it with the igniter. BANG!
> Great stress reliever (almost as good as taking your .45 to target practice
> and
> pretending the target's somebody you dislike).
>
> 4. How long do 8 ft copper ground rods last in average soil?
> Anywhere from 5-15 years, maybe more and maybe less. Best thing to do, Barry,
> is measure the pH of your soil. Adequate results can be obtained from using
> the
> same measurement devices sold by pool and spa shops. PolyPhaser sells a
> measuring kit (SPT, about $50) designed specifically for this measurement. If
> the pH is neutral to alkaline, it is a copper-friendly environment. If
> however, it is
> acidic, you would be better off using galvanized/tinned/aluminum rather than
> copper. The soil found in the eastern part of the U.S. is generally acidic,
> whereas it is alkaline in the western part. Realize that the pH may vary by
> depth and that you may, for example, have an alkaline stratum sandwiched
> between
> acidic strata. Without starting the thread again, this can cause corrosion to
> occur
> on the ground or guy anchor rod itself (as can the part of the anchor rod in
> concrete
> versus the part which is in soil).
> My system has been in 7 years now. Should I just start over
> with more rods, assuming corrosion has done its thing, or try to find
> where I left off 7 years ago (may not be easy with it all buried)
> and continue the daisy chain?
> If you've not done PM in 7 years (something which ought to be done yearly),
> I would check the condition of what is already in place first. If it looks in
> good
> shape (make a ground resistance [Megger or equivalent] test), employ it as
> part of your upgraded system. Otherwise, pull it out and restart.
> 73,
> Bob Wanderer AA0CY
> Senior Applications Engineer
> PolyPhaser Corp.
> Tnx/Barry
>
> --
> Barry Kutner, W2UP Internet: w2up@itw.com
> Newtown, PA FRC alternate: barry@w2up.wells.com
>
> --
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--
Joe Leikhim KE4TZH
Jleikhim@nettally.com
"tv dinner by the pool,
i'm so glad i finished school" -F.Zappa 1967
"The Revolution will NOT be televised" -Gil Scott Heron
--
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