RE: RF Ground Connections - Wire Type

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

My recent measurements of conductor AC resistance confirm that stranded
wire is a POOR choice.  While one should strive for a high surface area,
this only applies to solid conductors.  RF currents want to travel only on
the outermost surface - they will not travel on strands inside the bundle.
When a strand goes from the surface of the bundle to inside the bundle, the
current will try to hop to an outer strand, through whatever surface oxides
might be in its path.  I did not compare finely stranded conductors with
coarsely stranded conductors, but I would speculate that a coarsely
stranded conductor might have a lower AC resistance, as it's a closer
approximation to a solid conductor.

Steel cable, solid or otherwise, would be a very poor conductor due to the
inherently higher resistance of steel compared to copper.

Since heavy gauge solid wire is inflexible and not practical for a cable, I
would recommend a copper ribbon for the best possible conductor.  Home
Depot sells copper roof flashing by the foot, you would have to cut it into
strips and solder them together.

Now to the practical aspects.  An RF ground, good or bad, will have
virtually no effect on the coil's performance.  Several list members have
accidentally forgotten to connect their secondary base to a ground of any
sort, and there was NO impact on performance!  The real reason for using a
ground has more to do with preventing RF interference and HV RF nasties
from entering your house wiring.

Gary Lau
MA, USA
.  

 -----Original Message-----
From: 	Tesla list [mailto:tesla-at-pupman-dot-com] 
Sent:	Tuesday, July 16, 2002 10:09 AM
To:	tesla-at-pupman-dot-com
Subject:	RF Ground Connections - Wire Type

Original poster: "Mccauley, Daniel H by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>



	Do you think steel braided cable (kind used in ground discharge
sticks, winches, etc...) would be a good connection.  Theres a lot of
surface area there, its cheap, but not sure on the material.

	Thanks
	Dan





> Use a proper copper ground rod available at almost any electric supply
> shop
> or hardware store.
> 
> Do not use a galvanized pipe.  Use copper.  You want the best possible
> ground you can get.  Also for lead wire use 2 to 4 gauge fine stranded
> welding cable.
> 
> Dr. Resonance
> 
> 
> 
> 
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Sunday, July 14, 2002 8:06 PM
> Subject: Simple RF Ground
> 
> 
> > Original poster: "Daniel McCauley by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>
> >
> > I currently live in a townhouse so I don't have a large (well actually i
> > don't have any except for a small patio area with a small garden).
> >
> > What is the simplest type of RF ground construction i can live with my
> coil
> > (15kv, 60mA)
> >
> > Can i get away with just a pipe hammered into the soil and then running
> the
> > RF ground cable to my living room where i'll have a chicken wire carpet
> > under my coil???
> >
> > Thanks
> >
> > Dan
> >
> >
> >
> >
> >
> >
> 
> 
>