RE: Ground box

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

Original poster: "Ray Robidoux by way of Terry Fritz <twftesla-at-uswest-dot-net>" <robidoux-at-basystems-dot-com>

Hi All,

I am very confused as to why this list has such a dislike
for braid. I have seen many comments like this against the
use of braid in TC work. My experience with braid is
that for the same amount of copper (and 90+% optical
coverage) the braid is an order of magnitude better than
solid wire at conducting RF energy. The reason for this
is exactly why we use refer tubing in the primary of a
TC. It is the skin effect, the fact that the center of
a conductor is useless in conducting RF currents. Therefore
you want to increase surface area in the conductor to
decrease current density. When using braid the most
important feature to examine is the so called
"optical coverage". This is the amount of light blocked by
the strands of braided wire (strand density). Braid comes
in all sorts of optical coverage(OC), from 10-% to 90+%. One
can imagine that 20% OC braid is useless, and in fact is
typically used in conjunction with aluminum foil to make it's
shielding and conducting properties better. I would not use
any braid with less than say 90% OC. If you look at the pics
that Terry has shown, which is going to be the better conductor,
I find it hard to believe its the center wire which has maybe
1/10th the amount surface area than the braid. I would like
to hear others thoughts on this matter.

Ray

> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Thursday, April 05, 2001 8:05 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Ground box
> 
> 
> Original poster: "Malcolm Watts by way of Terry Fritz 
> <twftesla-at-uswest-dot-net>" <m.j.watts-at-massey.ac.nz>
> 
> Hi Terry,
>            If the outer is braided, it will be probably the worst 
> ground conductor you can get.
> 
> Cheers,
> Malcolm
> 
> On 5 Apr 01, at 15:59, Tesla list wrote:
> 
> > Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
> > 
> > Hi All,
> > 
> > I have been using the following ground system:
> > 
> > http://hot-streamer-dot-com/TeslaCoils/Misc/GroundBox/Diagram.jpg
> > 
> > It is basically a length (40 feet) of RG-8U coaxial cable.  One side
> > has both the inner conductor and shield connected together to a cold
> > water pipe.
> > 
> > http://hot-streamer-dot-com/TeslaCoils/Misc/GroundBox/PipeConnection.jpg
> > 
> > The other end has the shield connected to a metal box and the inner
> > conductor connected to a terminal.
> > 
> > http://hot-streamer-dot-com/TeslaCoils/Misc/GroundBox/InsideBox.jpg
> > 
> > http://hot-streamer-dot-com/TeslaCoils/Misc/GroundBox/TerminalBox.jpg
> > 
> > The idea is that safety and general grounds can be connected to the
> > box/cable shield while the noisy secondary ground connection can
> > connect to the terminal.  Thus, the base ground lead currents will be
> > somewhat shielded buy the outer conductor.  The other general
> > grounding is through the shield.  I measure 0.2 ohms between the
> > ground box and the AC line ground at my control box.
> > 
> > I know this subject came up last month and I was wondering if this is
> > seems like a good idea or not.
> > 
> > Comment/thoughts/suggestions...
> > 
> > Cheers,
> > 
> >  Terry
> > 
> > 
> > 
> 
> 
> 
>