RE: rf ground?

["Brian Helms" <bhelms-at-dialpoint-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Technically, your wire to your ground should be as short as possible due to
the fact that the wire will have some inductance and capacitance and affect
the overall ground.  A good earth ground is hard to come by in the first
place and if you have multiple ground rods(8ft preferably) then that will
definitely help an already bad situation ground wise.  A capacitive plate
can also serve as an rf ground even thought it is not commonly used in Tesla
coil systems.  Also a wire hooked to the ground for your secondary a 1/4
wavelegnth of the frequency that you are using would be great for a ground.
The problem is that a wire for a coil with a resonant frequency of 500khz
would be 464 ft long.  300khz--773 ft   150khz--1546 ft
formula = 232/freq. =legnth in feet  1/4 wavelegnth
Very long to say the least. A capacitive plate above the ground but not
touching it would have to be very large to work well.  It really is a losing
battle if you are looking for a perfect ground.  AM radio stations spend
lots of time and money trying to achieve a decent ground system by burying
wire and wire mesh in the ground.  So there are some of the basics but if
you are like me, if your coil is working and you are happy with it then use
what you have.  On a lot of my coils I just use the AC ground.  Of course
they do not perform as well as they could but I still have lots of fun with
them and that is the primary function of Tesla coils for 98% of all people
who build them.

Brian Helms
KD4RLD

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, July 18, 2000 10:08 AM
To: tesla-at-pupman-dot-com
Subject: rf ground?


Original poster: "John Morawa" <morawaj-at-interaccess-dot-com>


Hey everyone,

I sent this msg out last Friday but never received any answers so I'm trying
one more time.



Hey folks,

I havent done any coiling in 10+ years.  Back then the largest system i had
was powered by a 15/60 NST.  At the time i just ran a long piece (15') of
#18 stranded wire from the base of the secondary with the other end clamped
to any electrical conduit I could find.  It seemed to work fine.  I have
been reading some posts in the archives about the secondary being a
different ground.  An rf ground.  My question is this, was what i did a
BADDDD thing?  Also, had i driven multiple pipes into the ground and
interconnected them and used them as my secondary ground would i expect to
get any improvement in discharge length?


Thanks again,
John M.