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Re: RF Ground, House Ground, Ground....



Original poster: "Allanh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <allanh-at-starband-dot-net>

I think you may have misunderstood my question. In the
Radio Eng. handbook, I've been an engineer for almost 40 years and a coiler
for 30, ground conductivity values are listed for all areas of the U.S. In
my area, N. Ga., the values given are 700 to 100 ohms, that value obtained
between two ground rods 3 feet apart, driven into the ground 3 feet. I used
this technique to determine the ground conductivity in my yard. It measures
1000 ohms.
The lowest reported ground conductivity in the U.S. is in
Fla. at 250 ohms. I can also measure about the same value between my coil
ground and the power ground. The resistance of the house wiring is
negligble( .01 ohm). I hope this clears up the question. I realize this is
very different from impedence, but only resistance values are used in the
standards tables.

allan

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, June 24, 2002 7:59 PM
Subject: Re: RF Ground, House Ground, Ground....


>
> Original poster: "Daniel Hess by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<dhess1-at-us.ibm-dot-com>
>
>
> Allanh;
>
> Yes. Basically I measure the RF ground rod to house ground via the nearest
> grounded outlet in my shop. This also includes the 40 feet of 4 gauge
cable
> which delivers the RF ground to my secondary base. Have to keep in mind
> that the outlet's ground is going to have a little resistance of it's own
> as it makes its way back to the breaker box where the house's ground
should
> be bonded, so have to take this in to consideration. I'm certain that this
> is not the ideal reference point but the gist of this thread is that your
> RF ground should not have a lot of resistance and if it does, need to find
> out why else it probably won't serve effectively.
>
> Daniel
>
> "Tesla list" <tesla-at-pupman-dot-com> on 06/23/2002 02:02:00 PM
>
> To:    tesla-at-pupman-dot-com
> cc:
> Subject:    Re: RF Ground, House Ground, Ground....
>
>
>
> Original poster: "Allanh by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <allanh-at-starband-dot-net>
>
> I've never seen data to indicate that ground conductivity in the U.S.
> approaches 1.5 ohm. I'm wondering if you are measuring between the ground
> rod alone( no wires connected to it) and the power company ground. If you
> have any wires, other than the meter, connected to the ground rod, you
have
> a false reading.
>
> allan
>
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Wednesday, June 05, 2002 10:28 AM
> Subject: Re: RF Ground, House Ground, Ground....
>
>
> >
> > Original poster: "Daniel Hess by way of Terry Fritz
<twftesla-at-qwest-dot-net>"
> <dhess1-at-us.ibm-dot-com>
> >
> >
> > Matt;
> >
> > Sounds like your ground may be sufficient. You can test it by measuring
> the
> > resistance between the RF ground and the house ground. Ideally, I
believe
> > you want to read no more than 1 ohm. Mine tests out a 1.5 ohms but seems
> to
> > be performing adequately. I'm also running a 4 Ga. cable from the base
of
> > my secondary to the RF ground; even if the resistance between house and
> RF
> > ground is low, too small a gauge cable may not handle the current and
> it's
> > performance may suffer. If the resistance is too high you may have to
add
> > additional ground rods. I use six x 10 feet x 1/2" copper water pipe.
> >
> > Regards,
> >
> > Daniel
> >
> > "Tesla list" <tesla-at-pupman-dot-com> on 06/05/2002 09:12:53 AM
> >
> > To:    tesla-at-pupman-dot-com
> > cc:
> > Subject:    RF Ground, House Ground, Ground....
> >
> >
> >
> > Original poster: "Matt Woody Meyer by way of Terry Fritz
> > <twftesla-at-qwest-dot-net>" <meyerml-at-stolaf.edu>
> >
> > Just for clarification sake, I'm curious if there's any major difference
> > between
> > the RF ground that you're all using and mine.
> >
> > My ground is simply a long copper tube driven a good 6-8" in very moist
> > soil.  My
> > protection filter and my secondary are grounded to seperate tubes, and
> then
> > a
> > discharge rod (long wooden stick with a nail in the end of it wired to
> > ground) is
> > grounded to a third (Discharge rod used for discharging coil after
> > operation and
> > also for measurement purposes (never manually held near coil while in
> > operation)).
> >
> > Is this an appropriate RF ground, or should I be doing something else?
> >
> > Thanks,
> > ><>Matt
> >
> > ><>  ><>  ><>  ><>  ><>  ><>  ><>  ><>  ><>  ><>  ><>  ><>  ><>  ><>
> > Matt "Woody" Meyer                  St. Olaf College Physics Major
> >
>