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Re: H/D Ratios



Subject:  Re: H/D Ratios
  Date:   Fri, 23 May 1997 16:00:14 -0700 (PDT)
  From:   "Edward V. Phillips" <ed-at-alumni.caltech.edu>
    To:   tesla-at-pupman-dot-com
Re: "Quarter wave coils"
        Have never understood what people mean by this , or what
it's importance is.  If you had a coil with no top loading (at
least until the discharge "breaks out") you would have an approximately
sinusoidal current/voltage distribution in the coil similar to
that in a resonant quarter-wave transmission line.  However, with
the amound of top loading which seems to give best results (lots)
the current must be nearly constant along the coil and what you have
is just a great big, lower (than the unloaded coil) surge impedance,
with which it is easier to get high coupling because of the kQ
factor (lower surge impedance resulting in higher Q for the same
discharge power).  At least, that's my opinion. 
        Also baffled by reference to the VSWR of a coil.
For what it's worth,
Ed