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Re: 3/4 wavelength secondaries



Robert, all,
             To clarify:

> From rwstephens-at-ptbo.igs-dot-netTue Jul 23 21:47:18 1996
> Date: Tue, 23 Jul 1996 15:23:28 -0500
> From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
> To: tesla-at-pupman-dot-com
> Subject: Re: 3/4 wavelength secondaries
> 
> Malcolm wrote,
> 
> >Hi all,
> >        This from Robert caught my eye....
> 
> >> There are no physical restrictions that I am aware of  that would
> >> ever prevent one from winding a secondary that was the entire 90
> >> electrical degrees (1/4 wavelength) in length and resonating it
> >> without any sort of topload to a given Tesla coil system.
> 
> >I'd be grateful to any body who produces data for a terminal-less 
> >coil that can do this.
> <snip>
> 
> >Malcolm
> 
> Malcolm,
> 
> If you can calculate the isotropic capacitance represented by a
> 1/4-20 bolt about 2 inches long that might be used as a coil top 
> terminal as I gave in one of my examples, and then determine how much this 
> isotropic capacitance will 'pull' the resonant frequency of a 100 KHz 
> Tesla secondary, then I'll gladly have no objection to your refering to it as
>  a
> Top Load!:)
> 
> Happy Coiling!, with or without the donut, rwstephens
>
     I think this thread might be blowin' in the wind a bit. 
My original finding was that you cannot make a helical resonator
resonate at a frequency such that its wire is 1/4 wavelength long at 
that frequency without adding some additional capacitance. I know that 
electrically a bare coil does the full 90 degrees at its natural 
frequency but that ignores the length of the wire used to make it.
To date I've not been given a single example of a coil which meets
the f and wirelength conditions without a terminal and can only 
assume that my finding stands. My personal opinion is that it really 
doesn't matter but others may have different views.

Malcolm