Re: RF ground connection

["Albert Hassick" <uncadoc-at-juno-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Kurt,  We experimented with connecting and disconnecting my dedicated
rf ground while the coil was putting out 60" streamers while I videotaped
the effect on the spark length.  After studying the video, I could see no
discernable effect one way or the other.  The camera was set on a bench
10' away from the coil and the video was also not affected as far as the
ground being connected or not.  The picture was normal on playback in the
VCR.  I used an older 'expendable' Goldstar camcorder, one of the big
clunky old ones.  I did however note an increase in rf interference on
the 19" test tv that I leave on when I am running the coil,  there was a
noticeable increase of rfi when the dedicated Tesla ground was
disconnected.  The use of a good ground however may save your life.  Be
careful with higher output coils, there is a lot of energy there just
looking for something to strike and destroy!   Al.   

On Fri, 15 Sep 2000 08:09:19 -0600 "Tesla list" <tesla-at-pupman-dot-com>
writes:
> Original poster: "Kurt Schraner" <k.schraner-at-datacomm.ch> 
> 
> Hi all,
> 
> it is common practice to ask for a heavy connection of the
> secondary base to the RF-ground. But how big is the need? - If we
> have a secondary, it is probably wire AWG 26...22...or, if it's a
> big coil: AWG 17. This seems to be big enough for the RF-current
> of probably some 5...30A RMS (not pulse!) of RF. But suddenly,
> after leave of the lower end of the secondary, the recommendation
> goes to use copper-strap or -tube or very heavy cable. I
> understand, fixing the earth potential is somehow like a vice,
> fixing a spring for resonant oscillation (wrong analogy?). But
> how big is the influence on coil performance (=sparklength)? - On
> the way from the lowest secondary turn to ground, we encounter
> several impedances: lowest turn to ground line - ground line (
> Length=?) - line to ground. What are the relative impedances?
> Some coils are even operated with counterpoise, without 'real'
> ground connection (capacitive grounding). How small, a ground
> connecting line can be, without sacrifying performance? Excuse my
> ignorance, not having checked the archives! Is there any
> quantified experience? Any help appreciated!
> 
> Kurt
> 
> 
>