VTTC/SSTC Spark Appearance Comparison

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Original poster: "Justin Hays by way of Terry Fritz <teslalist-at-qwest-dot-net>" <pyrotrons2000-at-yahoo-dot-com>

Hi All,

First let me say, that I think Steve Ward has done a fabulous job
with his VTTC and his website. The VTTC arcs look disproportionately
long in many of the pictures...way cool, good job Steve.

http://hot-streamer-dot-com/srward16/index.htm

On this page, notice the VTTC arcs that are *perfectly straight*. I
see a couple of teeny tiny branches at the ends of two of the longest
arcs, but for all practical purposes the arcs are 100% straight w/ no
branching. These are referred to as "sword-looking" I believe.

The only time I can get an SSTC arc to look like that is when I'm
running low power (less than 700W - 1kW or so) and not using a
topload. I think the other SSTC'ers can vouch for that too.

As soon as I add any top whatsoever, the arcs start branching like
crazy. I mean, if I put a coke can up there, it will cause the arcs
to branch a lot. I would much rather the arcs be perfectly
straight......and give a nice "hummmmmmmmm" sound versus a loud
irritating "WWAAAAAAAAAAAAHHHHH".

So my question is, why are VTTC arcs perfectly straight, and SSTC
arcs not? Don't they work the same way? They both (VTTC and SSTC)
switch CW power into the primary right? I know exactly how SSTC's
work, but I've never looked into VTTC's, so can someone please inform
me exactly...exactly...what the primary sees in a toob coil? If you
can describe, or link to a waveform, it'd be great.

There must be something majorly different in the waveforms going to
the primary. Has to be. We're talking two completely different arc
appearances...

My guess is, there is some form of pulsed power input with an SSTC
that is not present in a VTTC.

Oooooh.....this may have something to do with pulse by pulse RF
waveforms.....I think real live streamer effects may be showing up
here. Anyhow, I'm going to keep my mouth shut until I learn what a
VTTC puts into a primary ; )

Justin Hays
KC5PNP
Email: justin-at-hvguy-dot-com
Website: www.hvguy-dot-com