Re: H/D Ratios

To: tesla-at-poodle.pupman-dot-com
Subject: Re: H/D Ratios
From: Tesla List <tesla-at-stic-dot-net>
Date: Mon, 26 May 1997 23:35:11 -0500
Approved: tesla-at-stic-dot-net
Subject:  Re: H/D Ratios
  Date:   Mon, 26 May 1997 13:47:07 -0400 (EDT)
  From:   richard hull <rhull-at-richmond.infi-dot-net>
    To:   Tesla List <tesla-at-pupman-dot-com>


At 12:55 AM 5/23/97 -0500, you wrote:
>Subject:       Re: H/D Ratios
>       Date:   Thu, 22 May 1997 08:46:30 +1200
>       From:   "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
>Organization:  Wellington Polytechnic, NZ
>         To:   tesla-at-pupman-dot-com
>
>
>Dear List,
>           Please indulge me once again :)
>
>> I have seen several references to a physical 1/4 wavelength of wire
>> being used to wind a secondary. What is the 1/4 wave length based on?
>> Is it free space or based on some velocity factor? Is there some magic
>> to be had by striving for this.
>> 
>> Based on no facts at all my next secondary will have a H/D ratio of PI.
>> It just seems right.
>
>Love it :)
>     The quarter wavelength thing: In the distributed resonator, no 
>matter what the length of wire, the profile is 1/4 wavelength at 
>resonance. Well, that is _strictly_ true for no top load (or nearly 
>so because like a standard antenna, there is an end capacitance 
>effect that requires the physical length of the straight wire to be 
>somewhat shorter than the free-space length). As soon as one adds a 
>topload, the antenna/coil will resonate at a lower frequency because 
>of the additional capacitance. That makes the structure shorter than
>90 degrees electrically at its resonant frequency. The lower the L/C 
>ratio, the more the electrical length trends towards zero degrees.
>     Explanation of physical length: for a straightened out wire, the 
>wire length is 1/4 wavelength physically as well as electrically. For
>the TC resonator, the physical and electrical lengths are entirely 
>different (we are not talking about wirelength anymore). The 
>electrical 1/4 wavelength of the resonator is that associated with 
>its resonant frequency which is dictated by its distributed L and C. 
>The _physical_ 1/4 wavelength is the _height/length_ of the coil 
>(former). 
>snip

All,

Man, I thought we hashed over this months ago!  They don't call a wire
helix
a slow wave resonantor in the biz for nothing!!!!  It is physically
impossible, based on the vacuum speed of light to build a 1/4 wave
helical
resonator which resonates at the classic frequency given by the simple
formula.  

All, repeat all, helixes resonate at a quarter wave frequency related to
their L and C and thus the reduced velocity of light in the wire helix
due
to the reactances! (this is in theory) Thus, they all obey the simple
equation, but the speed of light is never the same in any differeing
helical
system!  

I think we need to absolutely irradicate the idea of the quarter
wavelength
of physical wire from our head.  All wire....of any length....has a
quarter
wavelength of resonance based of a highly variable speed of light due to
various geometries.

Richard Hull, TCBOR