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Re: [TowerTalk] [Bulk] Re: Cadwelding to Rohn 45G and 55G

To: Larry Loen <lwloen@gmail.com>
Subject: Re: [TowerTalk] [Bulk] Re: Cadwelding to Rohn 45G and 55G
From: Grant Saviers <grants2@pacbell.net>
Date: Fri, 12 Feb 2016 13:14:34 -0800
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Ground (pipe/rod) clamps come in an bronze or brass alloy. For clamping on galvanized steel, I think they are brass (Zn + Cu) but either may be ok?

I ran a 2 radials from each leg, that offers redundancy, lower inductance, more capacitive ground coupling, and shortest paths. I would not recommend a ground ring if you want to measure your ground rod resistances. Any loops prevent that assuming the leads from it to the rods are buried cadwelds. I've also a convert to using bare #2 stranded 3 rods per radial connection spaced 15' or more apart. One at 5' from tower then 20 and 35' out. 9 rods or more if more radials. Best if buried below the frost line as frozen water is a particulary poor conductor.. The #2 also has enough surface area to act as a horizontal grounding element. I started with #6 for the first set of rods, then used some #2 and after some measurements became convinced #2 was worth it.

Grant KZ1W

On 2/12/2016 11:58 AM, Larry Loen wrote:
That may be a nice alternative, but what advantage does it offer over
simply connecting a regular ground clamp?

It seems like a very nice idea, but I need to understand what I gain versus
just clamping and having done with it.  If I did the "classic" thing and
cadwelded to the tower legs, I would not be depending on bolts.

On the other hand, I'm already (arguably) depending on six sets of bolts
"above" me to connect the top sections to the bottom tower section anyhow.
You could argue:  What's one more set of bolts?

Anyone know what I would be trading-off here?


WO7R

On Fri, Feb 12, 2016 at 12:44 PM, <TexasRF@aol.com> wrote:

Larry, can you connect some tinned copper lugs to the lower set of three
(or six) leg bolts using the existing bolts? For added security, you could
add six locking nuts. The ground wires would then connect to the lugs of
course.

73,
Gerald K5GW



In a message dated 2/12/2016 1:39:10 P.M. Central Standard Time,
lwloen@gmail.com writes:

I am in the process of putting in two new towers on my property (yes, I am
blessed).

I'm a little nervous about Cadwelding to the legs.  I suppose you'll all
tell me it has been done dozens of times, but I have visions of blowing a
hole through one of the legs near the bottom of my tower.

The alternative, I suppose, is to get a set of quality ground clamps, clamp
it maybe three times (I assume this would help the impedance a bit) and the
inspect it over time.

I also plan to have an extensive "ground ring" around the tower.  On my
current crankup, I cadwelded to all three "legs" except it was easy to
Cadweld to a nice thick base and not to the tower, proper.  Effectively
required, in fact.  So, I Cadwelded to stuff that wasn't a big deal,
structurally.  Here it would be.

1.  Do I Cadweld anyway?  How to be sure the tower leg isn't weakened?

2.  Do I do it to a single leg or all three?  I could "feed" my ground ring
from a single leg, I suppose.

This is all in excess of what Rohn shows, which is a single, clamped line
from the tower, but I've always taken it for granted the smart thing to do
is have a more extensive network.  I plan on three rods, connected as a
ring, and then copper "lines" out from each of them to another rod, a total
of six in all.  That's all easy and been done (by me) before.  Question is,
what's the best way to connect to the tower itself?  I have the "buried
tower section" type of base.  We will be pouring concrete late next week.
So, I have about a month to plan and execute my ground system.


Larry WO7R
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