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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 --