[TowerTalk] [Bulk] Re: RF Ground is a Myth

Wed Jan 21 09:40:13 EST 2015

Empiricism is probably my greatest strength and perhaps weakness in my survey of concrete 
possibilities. I like things that work rather than what is calculated to work.

I will probably not use or need a UFER Ground. I am not doing new construction so that 
possibility is out unless I want toi jack hammer through to some rebar. "Ain't a-gonna do 
that."

I will just be interested to see what comes up with a multimeter / ohm meter
measurement using probes or something else to come into contact with some concrete.

I am guessing most radio amateurs still prefer copper clad steel ground rods rather than 
some kind of concrete pillar that you can't buy or install conveniently. 

Wikipedia says that UFER ground is for dry areas. If the soil requires it. These are just things 
I am reading. 

Also - one theme is recurrent:

"If Ufer grounding alone was enough, the manufacturers of ground rods would go out of 
business. But a Ufer ground alone it is not adequate. Few buildings, even those under 
construction today are built to take advantage of the Ufer ground. It is common to see the 
use of "Ufer grounding" in military installations, computer rooms, and other structures with 
very specific grounding specifications. It is not common in most industrial plants, office 
buildings and homes. More common today is grounding to national and local electrical codes. 
This will involve one or more driven ground rods connected (bonded) to the neutral wire of 
the electrical service entrance. The purpose of this bond is what is known as life safety 
ground. It is used for many other things but the code required life safety ground is why it is 
there to begin with."

On 21 Jan 2015 at 0:08, David Gilbert wrote:

> You're going to need to duplicate the surface area of a typical Ufer 
> conductor, and you're going to need to somehow bond it intimately to the 
> bulk concrete.  I'll be interested to see what your test setup is, 
> because I can't think of a legitimate method other than pouring some new 
> concrete on top of the old with the conductor embedded in it.  Possibly 
> you're more clever than I.
> 
> And you should probably be prepared to compare it to alternate schemes 
> (ground rods, etc) to establish an appropriate baseline.
> 
> Dave   AB7E
> 
> 
> 
> On 1/20/2015 5:22 PM, Brian Carling wrote:
> > I suspect it's not as conductive as some may have us think...
> >
> > Best regards - Brian Carling
> > AF4K Crystals Co.
> > 117 Sterling Pine St.
> > Sanford, FL 32773
> >
> > Tel: +USA 321-262-5471
> >
> >
> >
> >
> >> On Jan 20, 2015, at 1:22 PM, David Robbins <k1ttt at verizon.net> wrote:
> >>
> >> just remember when you do it to not use the point of an ohm meter probe.... it is not easy to measure bulk material resistivity like in soil or concrete or other types of materials.
> >> you need to have some relatively large surface area to contact the material, which is hard to do with already poured concrete.
> >>
> >>
> >> Jan 20, 2015 12:59:36 PM, bcarling at cfl.rr.com wrote:
> >>
> >> So far I am not convinced about using concrete. I'm going to do some resistance testing on the concrete in my yard.
> >>
> >> Best regards - Brian Carling
> >> AF4K Crystals Co.
> >> 117 Sterling Pine St.
> >> Sanford, FL 32773
> >>
> >> Tel: +USA 321-262-5471
> >>
> >>
> >>
> >>
> >>> On Jan 20, 2015, at 10:13 AM, Grant Saviers wrote:
> >>>
> >>> If your house slab was installed correctly with a vapor barrier and/or foam insulation, then it is insulated electrically from earth.
> >>> Tower bases make good Ufers as do perimeter foundations, so my towers and shop both had the rebar set as Ufers when constructed.
> >>> I also noticed that a new service transformer I had installed is set on a concrete vault that has a ground stub cast into the side. The power company used it, no ground rods. I'd estimate its surface area in contact with earth as more than 16 sq ft. Compare that to less than 2 sq feet for a 10' 3/4" ground rod.
> >>>
> >>> Grant KZ1W
> >>>
> >>>
> >>>> On 1/19/2015 6:52 PM, Mike Reublin NF4L wrote:
> >>>> The electrician I had (who does a LOT of grounding work here) come out to connect my tower ground to the service ground told me he would be glad to drive the extra rods extending out from the tower, but doing so would add no benefit at all. I have no idea if this is true or not. At some point, lacking personal knowledge, ya have to take someone's word for it. My tower megged out at 4 ohms.
> >>>>
> >>>> Mike NF4L
> >>>>
> >>>>> On Jan 19, 2015, at 8:29 PM, Brian Carling
> >> wrote:
> >>>>> The advice varies about this considerably. This week is the first time I've even heard of UF ER or conductive concrete!
> >>>>>
> >>>>> The professional experts that I know recommend putting a 20 to 30 foot ground rod into the ground at each corner of your house and connecting heavy gauge copper conductors up to lightning rodsup on the roof.
> >>>>>
> >>>>> It seems like if the only thing you need is a large area of this allegedly conductive concrete stuck in the ground, why not ground everything to the concrete slab your house sits on!!
> >>>>>
> >>>>> Best regards - Brian Carling
> >>>>> AF4K Crystals Co.
> >>>>> 117 Sterling Pine St.
> >>>>> Sanford, FL 32773
> >>>>>
> >>>>> Tel: +USA 321-262-5471
> >>> _______________________________________________
> >>>
> >>>
> >>>
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