Re: Resonant Frequency

Tesla List wrote:
> Original Poster: Wallace Edward Brand <webrand-at-brandlaw.dgsys-dot-com>
> Some believe that the medium Tesla was relying on for power transmission
> was the earth-ionosphere cavity.  The ionosphere is a boundary layer
> between conducting and nonconducting media with the less compressed air
> a good conductor(Tesla proved this to the patent office) and the more
> compressed air an insulator.  The earth is a good conductor so the
> earth's surface is a boundary between a conductor and an insulator.  The
> so-called Schumann resonant frequencies can be found in Jackson's
> "Classical Electrodynamics" second or third edition.  My recollection is
> that there are several ranging from about 16 to about 43.  Wallace
> Edward Brand

Extensive measurements of propagation characteristics and losses at
extra low frequencies through ultra-high have been done on surface and
sky wave transmission, and satellite communications. Thus far, there
appears to be no evidence for any of any high-Q resonances,
although there are many frequencies which show heavy absorbtion. 

Per Jackson ("Classical Electrodynamics", 2nd ed., John Wiley & Sons,
1975) the Q's of the Schumann earth-ionosphere cavity resonances for the
first few frequencies (about 8, 14, 20, and 26 Hz) is only between 4 and
10. These resonances manifest themselves as peaks in the noise power
spectrum at extremely low frequencies propagating around the earth -
with lighting serving as the initial source of radiated energy. It
appears that even 10-100 million volt lighting pulses are not sufficient
to trigger high-Q resonance "ringing" other than at the Schumann
resonance frequencies, and these are of low Q (quite lossy). There
simply does not appear to be any empirical evidence for any high-Q
electrical resonance involving the Earth, or Earth-ionosphere cavity.

-- Bert --