Re: Propagation velocity in long helical coils.

To: tesla-at-pupman-dot-com
Subject: Re: Propagation velocity in long helical coils.
From: "Malcolm Watts" <malcolm.watts-at-wnp.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 29 May 2000 15:55:09 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi Gavin,
               I think your results confirm my suspicions that the formula 
is giving C values that are a bit too low. I am going to backtrack a bit 
on an earlier statement and say that in the light of this, I think my 
reading of 52pF or so on my 10" resonator was probably pretty 
close. It would now be nice to see a theoretical justification for the 
formula. 

Regards,
Malcolm

On 29 May 00, at 12:27, Tesla List wrote:

> Original Poster: "Gavin Dingley" <gavin.dingley-at-astra.ukf-dot-net> 
> 
> Hi all,
> I wrote another little program to check the true self C, or Ccox formula,
> and so
> tested it against the info given in this post from Terry. My values are in
> brackets
> next to the originals given.
> 
> Regards,
> 
> Gavin, U.K.
> 
> Tesla List wrote:
> 
> > Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
> >
> > Hi Bob,
> >
> >         I suspended my two coils from the ceiling with heavy nylon cord
> and strung
> > a wire down to the LCR meter with the other lead of the meter grounded.  As
> > I approached the coils, they seemed very stable and they were not
> > excessively affected by surrounding objects in my case.  The distances from
> > other things was about 3 feet minimum.
> >
> > For the small coil:
> > L=22.1mH (measured)
> > D= 4.26 inches
> > L= 26.125 inches
> > Fo measured= 351.5 kHz
> > Fo Medhurst= 337.1 kHz    (341.19kHz)
> > Fo Jones= 356.1 kHz    (362.63kHz)
> >
> > For the large coil:
> > L=75.4mH (measured)
> > D= 10.26 inches
> > L= 30.0 inches
> > Fo measured= 146.5 kHz
> > Fo Medhurst= 146.3 kHz    (148.77kHz)
> > Fo Jones= 151.11 kHz    (161.58kHz)
> >
> > So it looks like your formula works extremely well!!
> >
> > Cheers,
> >
> >         Terry
> >
> >
> >
> 
> 
>