Re: SSTC As a transmitter.

["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>

Tesla list wrote:

> Original poster: "Gary Peterson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <glpeterson-at-tfcbooks-dot-com>
 
>>Maxwell's equations were well established by Tesla's time, and we
>>can be sure that he did not want the transmitter to radiate any
>>more than necessary beyond the targeted receiver, . . .

> Even the slightest amount radiation from the vertical conductor of a
> Tesla-type transmitter is undesirable as the wave energy is dissipated into
> space and becomes, for the most part, unrecoverable.

>>. . . but to avoid
>>radiation altogether is to avoid broadcasting power.  What perhaps
>>Tesla failed to appreciate is that to send an electric influence
>>from one place to another requires radiation.  EM radiation is the
>>essential mechanism here, not just an undesirable side-effect.

> Tesla
> 
>      "Pardon me, you are mistaken."
> 
> Counsel
> 
>      "That is what I want you to explain.  I must be mistaken,
> because my conception does not fit in with your statements."
> 
> Tesla
> 
>      "All right, I will explain that.
> 
>      "In my first efforts, of course I simply contemplated to
> disturb effectively the earth, sufficiently to operate instru-
> ments.  Well, you know you must first learn how to walk before
> you can fly.  As I perfected my apparatus, I saw clearly that
> I can recover, of that energy which goes in all directions, a
> large amount, for the simple reason that in the system I have
> devised, once that current got into the earth it had no chance
> of escaping, because my frequency was low; hence, the electro-
> magnetic radiation was low.  The potential, the electric
> potential, is like temperature.  We might as well call
> potential electric temperature.  The earth is a vast body.
> The potential differences in the earth are small, radiation is
> very small.  Therefore, if I pass my current into the earth,
> the energy of the current is stored there as electromagnetic
> momentum of the vibrations and is not consumed until I put a
> receiver at a distance, when it will begin to draw the energy
> and it will go to that point and nowhere else. . . ."
	Perhaps.

	No one else has observed this since.
	It is not predicted by the other theories.


>>The TC transmitter is an electrode at height h connected to earth
>>through some sort of a charge pump, eg a secondary coil.  If the
>>pump displaces a charge q between the earth and topload, then it
>>exerts a dipole moment q*h on the EM field.  News about that
>>dipole's existence and its subsequent changes of value with time,
>>propagate outward from the dipole as variations in the EM field,
>>ie EM waves.  It is the history of EM wave output from the dipole
>>radiator which establishes the instantaneous E-field gradient at
>>any potential receiving point.

> That explains what takes place on and around the vertical conductor, but
> that's only half of the story.  Let's take a look at an entire Tesla-type
> system modeling it as a modified bipolar Tesla coil.  Start with a few
> primary turns.  Next add a vertical coil, a vertical conductor and a topload
> for one half of the oscillator.  Next envision an open vertical shaft
> directly below it with one or more ground rods in the form of iron pipes
> driven either horizontally or further downward from the shaft's bottom, and
> then connect a vertical conductor from the bottom of the coil down to the
> iron-pipe ground connection.  You end up with a bipolar Tesla Coil with a
> small capacitance at one end and a very large capacitance at the other.
> BTW, unlike a symetrical bipolar TC which has a voltage node at the very
> center of the secondary, the node will shift in the direction of the larger
> conducting body.  Tesla explained it this way:

>     "Consider now the effect of such a conductor of vast dimensions on a
> circuit exciting it. The upper diagram of Fig. 6 illustrates a familiar
> oscillating system comprising a straight rod of self-inductance 2L with
> small terminal capacities cc and a node in the center. . . ."

> http://www.tfcbooks-dot-com/writings/images/wireless-06.gif

> ". . . In the lower diagram of the figure a large capacity C is attached to
> the rod at one end with the result of shifting the node to the right, thru a
> distance corresponding to self-inductance X. As both parts of the system on
> either side of the node vibrate at the same rate, we have evidently, (L+X)c
> = (L-X)C from which X = L(C-c/C+c). When the capacity C becomes commensurate
> to that of the earth, X approximates L, in other words, the node is close to
> the ground connection.  The exact determination of its position is very
> important in the calculation of certain terrestrial electrical and geodetic
> data and I have devised special means with this purpose in view. . . ."

> Some of Tesla's early experiments involved the transmission of electrical
> energy through a single wire, taking advantage of the displacement current
> phenomenon which you referred to earlier.  Here is what Tesla wrote as this
> relates to his system:

>     "Granted, then, that an economic system of power transmission thru a
> single wire is practicable, the question arises how to collect the energy in
> the receivers. With this object attention is called to Fig. 5, . . .

>  http://www.tfcbooks-dot-com/writings/images/wireless-05.jpg

> ". . . in which a conductor is shown excited by an oscillator joined to it
> at one end. Evidently, as the periodic impulses pass thru the wire,
> differences of potential will be created along the same as well as at right
> angles to it in the surrounding medium and either of these may be usefully
> applied."

> The point is that with a Tesla system you can couple your receiver directly
> to the energy source and ignore the EM radiation component.  Sky wave or
> surface wave eminating from the elevated vertical conductor, who cares? as
> long as every single one of your circuits is precisely in tune with the
> others.  As for coil losses these can be minimized in a number of ways that
> we can discuss later on.  I believe it will be found that ground-conduction
> losses are associated primarily with the quality of the local ground
> connections at the transmitter and receiver sites.

>>[regeneration] implies a power source local to the receiver, enabling some
>>sort of positive feedback to assist with signal recovery.

> Yes, possibly involving a local oscillator as well.


	Assuming power is being transmitted, the requirement for
	local power seems curious....


>>Without an antenna, a TC has a limited dipole moment and would not
>>be expected to broadcast far. . . .

> I agree, the isotropic cap will have to be big and high to acheive the best
> results.
	How big?

	How high?
	Smaller than the earth?


>>The important factor now is the size of the signal
>>at the receiver compared with the background noise at the
>>receiver.

> I believe the S/N ratio will be found to be quite favorable compared to
> short-wave systems.

	Hint:
	Use is made of all the freqs involved for other purposes
	on daily basis, by a variety of users.  No stray
	effects (extra good propagation) is observed.


>>We are not discussing two alternative mechanisms here,
>>when we talk about radio comms with EM waves, versus TC comms with
>>ground/displacement currents, . . .

> That's right.

>     "It is just like this:  I have invented a knife.  The
> knife can cut with the sharp edge.  I tell the man who applies
> my invention, you must cut with the sharp edge.  I know per-
> fectly well you can cut butter with the blunt edge, but my
> knife is not intended for this.  You must not make the antenna
> give off 90 percent in electromagnetic and 10 percent in cur-
> rent waves, because the electromagnetic waves are lost by the
> time you are a few arcs around the planet, while the current
> travels to the uttermost distance of the globe and can be
> recovered. . . ."

	cf above.  No one has seen any sharp edges.


>>. . . By comparison with what we
>>use nowadays, Tesla's wireless proposals seem primitive and naive.

> We'll see.

	The experiment is done on a daily basis, by a variety
	of users of high power RF.  No stray effects have
	been observed.

-- 
	best
	dwp

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