Re: Query on toriod -> ground capacitance

Subject:      Re: Query on toriod -> ground capacitance
       Date:  Fri, 13 Jun 1997 19:48:07 +1200
       From:  "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Organization: Wellington Polytechnic, NZ
         To:  tesla-at-pupman-dot-com

Hi Rod,

>   From:   Rodney Graham Davies <Rodney.Davies-at-anu.edu.au>
>     To:   tesla-at-pupman-dot-com
> Hi all,
> A friend of mine wanted to know this -
> "Why does the capacitance to ground of a toroid increase when you bring
> it 
> up higher ? This is an odd occurrence and is probably not linear."
> My own theory is that raising the toroid is practically the same as 
> increasing the spacing between to capacitor plates. Here, the plates are 
> the ground plain and the toroid...I could be wrong...

         For what it's worth, the best answer I can give you is that 
by raising the toroid you are progressively removing from it the 
influence of the resonator below it. You are also increasing the 
*total* size of the whole structure. I cannot spell it out any 
clearer than that.

IMHO (and with a load of experiment behind it),