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Original poster: "Dave" <dgoodfellow@xxxxxxxxxxxxxx>
How do you expand a ball? I find that toroids do better at
controlling corona at the top turns of the secondary, where balls
need to be placed as low as possible, at the top of the secondary. A
coil would look great with an insulator between the secondary and the
ball, but the corona becomes unmanagable.
By the way, since Waterscapes stopped selling gazing balls at the
nice price, I have found the best overall price and service from Amazon.com
Best price for an 8" is from artywoods on ebay. Don't look up 8"
though, search stainless gazing, and you will see his 7.65" gazing
ball for about $18.00
Cheers, Dave Goodfellow
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
Sent: Friday, March 02, 2007 12:52 AM
Subject: Re: Toroids
Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
The balls have the same advantages over toroids even with a classic
coil. The toroid can be raised and lowered, but not expanded. The
balls have "that" extra dimensional option. That in itself makes it
a superior topload (me thinks).
I will begin collecting these sphere's for toploads for my classic
coils. You've already figured out a nice mounting technique, so once
again, you did all the work and all we have to do is follow in your footsteps!
Thanks for always being "cutting edge". I know there was someone
else who had also did the same (he's cutting edge too!). It's not a
knew idea as most coilers have contemplated various topload
configurations (sphere configurations are always part of that
thought process). The difference is "you did it"! And it "is cool"!
I can even imagine a sphere topload like this on a super huge coil.
What a nice way to cut cost and enhance topload adjustment.
Tesla list wrote:
Original poster: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
PIRANHA-II can make "very good" use of an adjustable top load! The
primary is pretty well "fixed" hiding in its "bunker" and not meant
to be "tuned in" ever again at that point (just like Cheney >:O))...
The primary coil was chopped down step by step until the right
point was found:
The balls just slide in and out on the brass tubing from the hobby shop:
This varies the coil's secondary capacitance from 28 to 34 pF.
Combined with the 73.63mH secondary, I can tune from 100.6 to 110.8
kHz. So if you can get the coil's tuning pretty close in the first
place, no need for primary tap adjustments. I do hold the rods in
place with a bit of tape since the balls will slide right off if
Adjustment is useful in say going from an enclosed room to outside...
Instead of moving the primary tap around for the best arcs, you
just slide the terminal ball in and out for the best arcs...
The ball terminal works pretty good:
They really are much like a conventional torroid:
I really don't think I will ever plane on using anything "else"
now... In order to save lab space, I think I will just "crush and
discard" my old big dryer duct toroids since this new terminal is
pretty universally useful for all my coils now. I guess I consider
dryer duct and aluminum "real" toroids "obsolete" and far too expensive now...
I do note that at lower indoor power levels, I have to use a
breakout point or it just sits there and glows...
The dragons and all exposed metal ,like the handles, are fully RF
grounded... Sort of a "hidden" strike ring...
At 06:09 PM 2/28/2007, you wrote:
Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>
Hi Terry, et al,
There's no rain on the parade. The PIRANHA II is a work of art as well as a
Perhaps a better route would be to use dyer duck to bring the coil up, and
as time allows build the adjustable ball top load. Do you feel it needs to
be adjustable at this point? I am looking at using 6" OD Lexan or
Polystyrene. Is there any value to wind to 24" and add a little more
inductance to the primary?