Re: performance/tuning question

[FutureT-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

In a message dated 7/25/00 6:31:45 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

> Original poster: Hollmike-at-aol-dot-com 
>  
>  John,
>     To a point, this will likely increase the output - if something else is 
>  not the limiting factor.  The output voltage is largely dependent of the 
>  Cp/Cs ratio(or conversely the Ls/Lp ratio which would be the same if the 
> coil 
>  is tuned to the fundamental frequency of the secondary system and not a 
>  harmonic).  There are of course other factors involved with spark 
>  propagation, but this is one way to possibly improve performance of a 
coil.  
> 
>  It is certainly worth experimenting with if you have the caps to do it.
>  Mike

Mike, John,

Increasing the cap size to 2 or 3 times the matched value will not
increase the spark length or brightness, but it will "protect" the NST
by keeping the voltage lower.  I have run my 42" spark TC in both
matched cap size, and LTR size, and it gives the exact same 
performance in either case.  This work was done mostly with a 120
bps sync gap, but if I remember correctly, I tried both configurations
with static gaps also.  The sync gap worked much better, however
Gary Lau has gotten excellent results using an air blast single
static gap in LTR systems.  When an LTR cap is used, it is probably
a good idea to use a large amount of inductance in both the primary
and secondary to keep the tank surge impedance high..... thereby
keeping gap losses low.  If I remember correctly, matched cap size
operation is the only one that can draw more than the NST's rated
power without using a 140V step up type variac, but I'd have to 
check my notes to be sure.

   http://hometown.aol-dot-com/futuret/page1.html

Cheers,
John Freau

>  
>  > Hello,
>  >  
>  >  I was wondering, if I was to build a TC with the tank cap double or 
> triple
>  >  the value derived from the formula used to match it with the impedance 
of
>  >  the power supply (say .01ufd or .015ufd instead of the matched value of
>  >  .005ufd) and decreased the primaries inductance appropriately so that 
the
>  >  primary and secondary would both resonate at the same frequency.  What
>  >  affect would that have on the system and output compared to starting 
with
>  >  the cap matched to the power supplies impedance.  Has anyone done this 
> and
>  >  would this have much affect on the streamer length and "look" (whiter 
but
>  >  less smooth, etc.)?   BTW this would be in a rotary gap setup if that 
> made 
>  a
>  >  difference.
>  >  
>  >  Thanks experienced ones,
>  >  John M.
>  >