Re: Tesla Coil RF Transmitter

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Paul Nicholson <paul@xxxxxxxxxxxxxxxxxxx>

Gary Peterson wrote:

> 1.2 ... In the case of this type transmitter, the transfer of
> electrical energy is between the two ground terminals in the
> form of true conduction currents, and also between the elevated
> terminals.

This is a radio wave by another name.  'true conduction current'
doesn't offer an alternative to EM waves for transferring energy.

What you have here are two resonators sharing their near fields.
The transfer of energy between the two is by a small far field
(in-phase E and H) component of the EM field around the resonators.

The currents are artifacts of the field and don't provide an
alternative pathway for energy transfer.   This case is really
just a resonant transformer.   As the coils are moved further
apart, the coupling coefficient drops very rapidly.   You may
try to mitigate that by demanding higher and higher Q factors,
but it is the loaded Q that must rise, and of course this means
that you cannot apply much load to the receiving coil.  This
relates to the fact that the recieving coil can, at most, only
make available the power that it can 'capture' from the field,
by virtue of its physical size in relation to the free space
wavelength.

Dan (DUllfig@xxxxxxxxxxxxx) wrote:

> Tesla was transmitting energy by pumping a charge into the
> ground itself

This is the same misconception, held it seems by Tesla and
elaborated by many of his disciples.  The charge 'pumped' into
the ground by the coil remains in the vicinity of the transmitter.
It doesn't spread evenly over the earth's surface, as I think
Tesla had claimed it would.   Instead, the charge is trying to
return to the place (the topload and coil) where it was taken
from by the 'pump'.   So it hangs around the transmitter, causing
spectacular effects and warming up the ground nearby.

Unfortunately, this is one of the cases in which nature just
doesn't work the way Tesla hoped it would.

> why is it so hard for anyone to believe that Tesla was
> transmitting by conduction through the earth, and not propagation
> through the air?!

Because, really they are the same thing!!!   You show me a system
that is driving current through the earth, and I'll show you that
the fields which are driving that current are, in every respect,
an EM wave emitted by the transmitter.

--
Paul Nicholson
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