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Re: Low Impedance Negative Resistance Tesla Coils

Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx>

----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx> To: <tesla@xxxxxxxxxx> Sent: Friday, January 28, 2005 8:00 PM Subject: Re: Low Impedance Negative Resistance Tesla Coils

> Original poster: stork <stork@xxxxxxxxxxxxxxxxxxx> > > No, "couteracting" the resistance in the entire antenna. It's an antenna > (TC secondary) effect. It's a negative resistance feed back to the entire > secondary. Not, just a feed back to the switch in a CW coil.

Not all power oscillators use the device in "switch mode", some do exactly
what you say.

I would venture to guess that ALL regenerative schemes use an amplifier to
generate a signal that exactly counteracts the losses in some external
device (the secondary coil in your example).

While you may have taken care of the ohmic losses in the antenna (or coil),
you still have losses in the amplifier, and have to supply more energy to
the system than you get.

> One of the factors that limits antenna current is the ohmic resistance of
> the tuned detector tank circuit and the antenna wire itself.  Regeneration
> is a means of increasing antenna current by counteracting the resistance
> the entire antenna circuit.

Agree.. This is true of ALL negative resistance oscillators.  A regenerative
receiver/antenna/whathave you is just adjusted so that's on the verge of
oscillation, but not quite.

  By the introduction of what might be called
> negative resistance through the addition of a feedback loop,

Feedback loop implies amplifier.  Amplifiers are not 100% efficient, so
energy is being dissipated somewhere (if only the amplifier)

> antenna-field
> interaction is increased and energy is absorbed from a greater area of the
> incoming wave front.

In this, I think you are conflating such things as "antenna physical
aperture" and "antenna effective aperture".  There are phenomena such as
superdirectivity which result in antenna directivities larger than expected
from the physical size, but they also have losses, so while the directivity
is high, the gain is not.

> > >I'm sure you mean that the DC resistance is "compensated" not eliminated. > >To a certain extent, this is what a CW coil is.. since an oscillator is just > >something with a bit more feedback than would be needed to compensate > >forthe losses in the system. > stork > >