Re: Ground box

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-uswest-dot-net>" <m.j.watts-at-massey.ac.nz>

Greetings Terry,

On 5 Apr 01, at 18:13, Tesla list wrote:

> Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
> 
> Hi Malcolm,
> 
> I am using the outer braid of the heavy coax (it is braided) for
> things like motor case ground, NST ground, safety gap ground.  I would
> be using the center conductor (heavy stranded wire) for the "RF"
> ground for the secondary base.  Thus, the low frequency stuff like AC
> faults and such would go through the outside braid while the RF
> currents go through the center conductor.  I was thinking the radiated
> RFI from the long secondary base ground would be somewhat shielded buy
> the outer braid.  It was just one of those thoughts that "looked" good
> so no guarantee that it is any good...  Perhaps, the RF strike rails
> and safety gaps should go to the center conductor too?
> 
> Cheers,
> 
>  Terry

Something inside me says there could be problems with this approach. 
I think it would be an idea to do some Z measurements on both 
conductors to ground before proceeding. Someone has already blown up 
mains equipment by mixing grounds. The capacitance between the braid 
and inner is significant at high frequencies. If you wouldn't mind 
taking the time, I'd be very keen to see what measurements say about 
this. I'll put it on my "to be done" list as well but it could be 
quite a while before I manage to get it to the Out basket. Far too 
many distractions for serious coiling investigation at the moment 
unfortunately.

Best Regards,
malcolm