Re: Rotary Spark Gap Design

To: tesla-at-pupman-dot-com
Subject: Re: Rotary Spark Gap Design
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
Date: Fri, 17 May 1996 17:09:58 +1200

Skip,
      You wrote...

<snip>
> Would there be any application of lumped constant delay line theory to 
> our problem? 

I have a gut feeling that the characteristic impedance formula the 
Corums use is not valid (they do admit it doesn't work for all coils).
Up to now, I have done the simple SQRT(L/C) thing effectively 
averaging the distributed L and C. I am going to do some experiments
this weekend using resistive terminations to determine where the truth
lies on this. I have previously seen scoped evidence that SQRT(L/C) is
the one, but I think this needs to be proved one way or the other. The
formula the Corums use (Schelkunoff) gives values MUCH lower than the 
alternative.
    One thing I realized yesterday : we are dealing with structures 
that have a VERY low radiation resistance whereas helical antenna
are designed to have a high radiation resistance (effective radiation)
and this might well make the difference (what say you Ed Harris?).

Will post results next week.
Malcolm