RE: realistic expectations from mini coil ??

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

Original poster: "Tom Luttrell PWRCOM" <tom-at-pwrcom-dot-com.au> 

The new toroid sounds like it will make an appreciable difference. All 
those little sparks are robbing energy from your main arc.

Also if you are using the building safety earth, which is not a terribly 
reliable RF earth, you may improve things by connecting an earth mat 
(counterpoise) to the base of your secondary.

Make it at least as big in radius as your coil is high. I use heavy duty 
plastic coated aluminium (aluminum to you yanks) screen door mesh. It 
connects in the centre via an M8  bolt where I have scraped some of the 
plastic insulation back. Plastic coating is not required at all, any 
conductive material even street signs will work, though maybe with some 
eddy current losses. Also mesh rolls up nice and small when not needed or 
for transport.

This counterpoise will help complete the capacitively coupled circuit 
(through the air) from your top load streamers back to ground.

Tom L.

 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Friday, 5 March 2004 12:00
 > To: tesla-at-pupman-dot-com
 > Subject: Re: realistic expectations from mini coil ??
 >
 >
 > Original poster: "Jon Lagler" <rockcrawl-at-enter-dot-net>
 >
 > I have the primary tapped for maximum arc length to ground,
 > half a turn in
 > either direction reduces output. Spark gap is as wide as it
 > can go and still
 > operate reliably. The toroid is just a loop of 1.25"
 > convoluted split wire
 > loom wraped with a kitchen foil. it's not perfectly round,
 > the foil is as
 > smooth as I can get it by rubbing it out with my fingers, but
 > I wouldn't say
 > it's smooth. I am getting lots of small 1-2 inch arcs all the
 > way around as
 > well as the main 5" arc to ground. I've actually had the best
 > results by
 > placing an empty soda can on top of the toroid and retuning,
 > which tells me
 > I need a larger toroid. I also found that the ground arcs are
 > brighter and
 > longer going to a metal chair placed on the carpeted floor
 > next to the coil
 > than they are to a grounded rod connected to the bottom of
 > the secondary. I
 > don't understand why, it must have something to do with the
 > metal chair
 > altering the ground plane, but this is on a carpeted wood
 > floor, the chair
 > has no connection to ground. The only grounding I have for
 > the system is the
 > third prong on the power cord. The bottom of the secondady is
 > wired to the
 > case of the NST which is connected to the ground on the power
 > cord. I have
 > been running it off the GFI outlet in my kitchen.
 >
 > Jon