Re: How with no RF ground?

To: tesla-at-pupman-dot-com
Subject: Re: How with no RF ground?
From: open_minded <bturner-at-apc-dot-net>
Date: Tue, 17 Sep 1996 23:18:44 -0700
Tesla List wrote:
> 
> > Subject: Re: How with no RF ground?
> 
> >From bert.hickman-at-aquila-dot-comTue Sep 17 22:13:46 1996
> Date: Tue, 17 Sep 1996 06:19:11 -0700
> From: Bert Hickman <bert.hickman-at-aquila-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: How with no RF ground?
> 
> Tesla List wrote:
> >
> > >From MALCOLM-at-directorate.wnp.ac.nzMon Sep 16 23:08:00 1996
> > Date: Tue, 17 Sep 1996 17:09:01 +1200
> > From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> > To: tesla-at-pupman-dot-com
> > Subject: Re: How with no RF ground?
> >
> > Hi Bob,
> >         You wrote....
> >
> > > My house is old and all plugs are just 2 prong with no
> > > 3rd plug for ground. When I remodeled my bathroom
> > > I hammered a ground rod out back and ran a ground
> > > cable into a newly placed 3 prong fixture in my
> > > bathroom. Recently in testing my TC before I
> > > dismantled it for final construction, I was getting
> > > 14" sparks from a 9kv-at-30ma transformer. I ran
> > > an extension cord/box from my bathroom and was
> > > using the 3rd prong of my extension box as my RF
> > > ground connection to my coil. Yesterday I took the
> > > plate off the wall in my bathroom to look at the
> > > wiring when I noticed that the ground cable had
> > > broke away from the wall socket long ago. So in
> > > my testing, I actually never had an RF ground
> > > at all! I do not understand how I could have
> > > gotten the output I did without this ground.
> >
> > I've done it too at low power. I think the ungrounded wiring is
> > acting like a counterpoise (capacitive coupling to earth). But
> > perhaps someone else could set me straight on this. I wouldn't
> > attempt this at higher power. Sooner or later the wiring will break
> > out. You could end up with a fire.
> >
> > Malcolm
> 
> Bob,
> 
> I second Malcolm's comments. The amount of RF current and voltage
> wanting to go to ground from the base of the coil is surprisingly high.
> I once had a bad connection at the base of my secondary. The resulting
> arc to the groundstrap looked like a heavy power arc (hot, blue-white,
> almost like a welding arc).
> 
> Safe (and grounded) coilin' to ya!
> 
> -- Bert --


Couldn't help but jump in on this one....

Well yeah!

Think about it. You have a 1/4-wave resonantor cranking out voltage at
the top end, at significant power levels. The bottom end is at a null
(low-impedance) point, so it's gonna be mostly current. Hence the reason
for a really stout ground. It maintains the low-impedance node.

- Brent