staccato CW RF envelope effects

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <FutureT-at-aol-dot-com>

All,

I arranged a mechanical staccato synchronous switch driven by 
a sync motor, to fire my tube coil for just a portion (half) of the
8mS positive 60Hz sine wave (RF envelope).  So the coil is "on" for
about 4mS, or 1/4 cycle.  By varying the motor phase,  I can select
either the initial portion, the middle portion, or the ending portion 
of the sine wave. The sync switch disconnects the tube cathode
from ground to disable the coil during "off" times.  The sync 
switch also reduces the firing rate to 30 pps, instead of the normal
60 pps of a typical tube coil.

Using the rising half of the wave (from 0 to sine peak), I get dim,
long straight sparks (raspy sound).  Using the middle portion, I get
bright, long straightish sparks.  Using the final portion of the sine, 
I get dim, short, very branched sparks.  So this pretty much agrees
with some things that Bert H and Richie said about the effect of the 
RF envelope shape.  It seems the peak power must be there for 
some time to make the sparks bright.  Declining waveforms cause 
bad branching and short sparks.  One of the best arrangements was
when the middle portion was used, but with the rising portion
favored somewhat.  

John Freau