Tesla

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

>>He didn't have a "local power supply" in the patent diagrams he
>>published.
 
> Some of the best receiver circuits are found in the COLORADO

> SPRINGS NOTES.

	I suggest these are the best receivers 100 years ago.
	In the interveningperiod, technology has learned much.

> In fact Tesla considered or investigated at least 125 different variations
> of receiver design while in C/S.  He included a battery along with a
> variable resistance in those circuits which used coherers, so that a small
> DC bias voltage could be placed across the device--an antenna and ground was
> also connected.

	I find it curious that a broadcast power system needs a battery.

  In operation the bias voltage would be adjusted to a point
> just below the coherer's breakdown voltage.   When so strained a small
> increase in voltage resulting from an incoming signal would result in
> coherence and the increased current flow would operate a small relay, which
> also required a battery.  In some of his receivers he would also mix the
> output of a local oscillator to create an audible tone in a telephone
> earpiece.  It can be argued this anticipates certain aspects of the
> heterodyne receiver.  He designed a small isocronous electromechanical
> oscillator that was used this purpose.
> 
> The circuit diagram of one of Tesla's regenerative-type receivers can be
> viewed at www.tfcbooks-dot-com/images/articles/tws5.1.gif.
> 
> 
>>>>August 3 he shows a number of receiver arrangements in which RF
>>>>
> current is
> 
>>>>fed back from the secondary side of a resonant transformer to a
>>>>
> coherer
> 
>>>>located on the transformer's primary side, making the coherer more
>>>>sensitive to incoming signals.
>>>>
>>That doesn't make sense.  The best any circuit can do is deliver ALL of
>>the received power to the load (the "sensitive device", in this case),
>>and without a local power supply and active component such as a tube or
>>transistor, "regeneration" doesn't make any difference.

> I have a little difficulty explaining it myself, but the fact remains that
> regenerative receiver circuits are real.  Regeneration is a means of
> increasing antenna current by counteracting the resistance of the entire
> antenna circuit.

	Thgis represents new physics.
	It is unknown in electronics.

> By the introduction of what might be called negative
> resistance through the addition of a feedback loop, antenna-field
> interaction is increased and energy is absorbed from a greater area of the
> incoming wave front.

	This effect has escaped the notice of all developers since.
	(Hint:
	The standard regen receiver works on a different
	principal....)

> The basic regenerative circuit is not often used in
> present day receiver front ends for a number of reasons, the most
> significant of these being an inherent form of instability.  Maximum
> sensitivity is achieved at a point just before the detector breaks into
> oscillation and this could be initiated by something as simple as wind
> shifting the antenna.  As the appearance of oscillating regenerative front
> ends on the broadcast bands became a more and more regular occurrence a
> decision was made to phase the regenerative detector out of general service.
	This is a standard regen receiver, and has nothing to

	do with the antenna.
	(hint:
	Isolate the regen section with a gain of 1 amplifier.
	The regen portion works fine.  Thus: it is not
	affecting the antenna....)


>>Actually coherers and magnetic detectors aren't very sensitive at all.
>>The typical coherer requires a signal of the order of FOUR VOLTS to
>>operate, with the power depending on the non-conducting impedance.



> What do you suppose would happen if you applied, say, 3.999,900 volts across
> your cohererer and then transmitted a little RF power from a few wavelengths
> away?
	I'd be interested in how to to deliver repeatable,

	quiet, 0.00001% accurate anything?


>>>        Much has been learned about RF propagation since
>>>        Tesla's day...

> Tesla would probably say, 'not enough.'  In 1919 he wrote:

>     "For more than eighteen years I have been reading treatises, reports of
> scientific transactions, and articles on Hertz-wave telegraphy, to keep
> myself informed, but they have always imprest me like works of fiction. . .
> . The Hertz wave theory of wireless transmission may be kept up for a while,
> but I do not hesitate to say that in a short time it will be recognized as
> one of the most remarkable and inexplicable aberrations of the scientific
> mind which has ever been recorded in history."
	Hint:

	If Hertz theories did not work, the internet would
	Stop.  (Yes.  I'm an engineer._
	The internet works.  One may draw certain conclusions
	from this.

	best
	dwp

...the net of a million lies...
	Vernor Vinge
There are Many Web Sites which Say Many Things.
	-me