Re: Tesla Coil RF Transmitter

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gary Peterson" <gary@xxxxxxxxxxxx>


> Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>
>
> Tesla list wrote:
>
> > Original poster: "Gary Peterson" <gary@xxxxxxxxxxxx>
> >
> > > Original poster: stork <stork@xxxxxxxxxxxxxxxxxxx>
> > >
> > > Does the current in the earth from the ground connection move as a 
> > > conduction current . . . ?
> >
> > Yes, true conduction current flows outward through the earth from a 
> > Tesla coil transmitter's ground terminal.  Assuming a uniform 
> > texture and composition of the surrounding terrain, this current 
> > diminishes in strength equally in all horizontal directions as the 
> > distance from the terminal increases.  This situation changes if an 
> > identically tuned Tesla receiving transformer is brought into 
> > operation at another location.  In this case there is an increase 
> > in the current that flows from the transmitter's ground terminal 
> > and a conduction current passes through Earth in direction of the 
> > receiver's ground terminal.
>
> This looks quite excessive. There is no way where the transmitter can
> be aware of the existence of the receiver, if it is out of its local
> field. The receiver receives signal significant time after it was
> transmitted, and can't inform the transmitter to redirect its ground
> current on its direction. The power transmitted by radio stations
> does not depend on the number of receivers receiving the station...
> The energy that is not recovered by the receivers, taken only from
> the electromagnetic waves at their immediate vicinity (their local
> field area), is lost.
>
> Antonio Carlos M. de Queiroz

    The earth is 4,000 miles radius.  Around this conducting earth 
is an atmosphere.  The earth is a conductor; the atmosphere above is 
a conductor, only there is a little stratum between the conducting 
atmosphere and the conducting earth which is insulating.  Now, on the 
basis of my experiments in my laboratory on Houston Street, the 
insulating layer of air, which separates the conducting layer of air 
from the conducting surface of the earth, is shown to scale as you 
see it here [see http://www.teslaradio.com/images/079.gif]. Those 
[radii lines] are 60deg of the circumference of the earth, and you 
may notice that faint white line, a little bit of a crack, that 
extends between those two conductors.  Now, you realize right away 
that if you set up differences of potential at one point, say, you 
will create in the media corresponding fluctuations of potential. 
But, since the distance from the earth's surface to the conducting 
atmosphere is minute, as compared with the distance of the receiver 
at 4,000 miles, say, you can readily see that the energy . . . will 
be immediately transformed into conduction currents, and these 
currents will travel like currents over a wire with a return.  The 
energy will be recovered in the circuit, not by a beam that passes 
along this curve and is reflected and absorbed . . . but it will 
travel by conduction and will be recovered in this way.  Had I drawn 
this white line to scale on the basis of my Colorado experiments, it 
would be so thin that you would have to use a magnifying glass to see it.

Counsel

    Will you pardon me for interrupting again.  You spoke some time 
ago about getting all of the energy from your transmitting into your 
receiving station by this method of yours.  I do not understand how 
you can get all of it.

Tesla

    Oh, that is hardly true; I am speaking as a matter of 
principle.  You never can get all the energy, because there is no 
such thing as perfect apparatus.

Counsel

    I did not mean it in that sense.  I understand that there is, of 
course, always some loss, but my conception was that when you created 
the disturbance in the electrical condition of the earth at your 
transmitting station, that that extended out in all radial directions.

Tesla

    Yes, it did.

Counsel

    And therefore how, at any given station, can you get more than a 
very small fraction of that energy?

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 instruments.  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 [created] 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.

Counsel

    Why is that, on your theory?

Tesla

    I will explain it by an analogue.

    Suppose that the earth were an elastic bag filled with 
water.  My transmitter is equivalent to a pump.  I put it on a point 
of the globe, and work my little piston so as to create a disturbance 
of that water.  If the piston moves slowly, so that the time is long 
enough for the disturbance to spread over the globe, then what will 
be the result of my working this pump? The result will be that the 
bag will expand and contract rhythmically with the motions of the 
piston, you see.  So that, at any point of that bag, there will be a 
rhythmical movement due to the pulsations of the pump.

   That is only, however, when the period is long.  If I were to 
work this pump very rapidly, then I would create impulses, and the 
ripples would spread in circles over the surface of the globe.  The 
globe will no longer expand and contract in its entirety, but it will 
be subject to these outgoing, rippling waves.

    Remember, now, that the water is incompressible, that the bag is 
perfectly elastic, that there are no hysteretic losses in the bag due 
to these expansions and contractions; and remember also, that there 
is a vacuum, in infinite space, so that the energy cannot be lost in 
waves of sound.  Then, if I put at a distant point another little 
pump, and tune it to the rhythmical pulses of the pump at the central 
plant, I will excite strong vibrations and will recover power from 
them, sufficient to operate a receiver.  But, if I have no pump there 
to receive these oscillations, if there is nowhere a place where this 
elastic energy is transferred into frictional energy (we always use 
in our devices frictional energy --
everything is lost through friction), then there is no loss, and if I 
have a plant of 1,000 horsepower and I operate it to full capacity, 
that plant does not take power, it runs idle, exactly as the plant at 
Niagara.  If I do not put any motors or any lamps on the circuit, the 
plant runs idle.  There is a 5,000 horsepower turbine going, but no 
power is supplied to the turbine except such power as is necessary to 
overcome the frictional losses.

    Now the vast difference between the scheme of radio engineers 
and my scheme is this.  If you generate electromagnetic waves with a 
plant of 1,000 horsepower, you are using 1,000 horsepower right along 
-- whether there is any receiving being done or not.  You have to 
supply this 1,000 horsepower, exactly as you have to supply coal to 
keep your stove going, or else no heat goes out.  That is the vast 
difference.  In my case, I conserve the energy; in the other case, 
the energy is all lost.

Counsel

    Mr. Tesla, does that not presuppose that the fluid must be incompressible?

Tesla

    I should say so, and electricity, whatever it is, certainly it 
is incompressible because all our experiments show that.

Counsel

    Now, if you were giving that a name, what principle would you 
say was involved by which the radiation loss, where there is no 
receiver, becomes a gain or a conservation where there is a receiver?

Tesla

    There is no radiation in this case.  You see, the apparatus 
which I devised was an apparatus enabling one to produce tremendous 
differences of potential and currents in an antenna circuit.  These 
requirements must be fulfilled, whether you transmit by currents of 
conduction, or whether you transmit by electromagnetic waves.  You 
want high potential currents, you want a great amount of vibratory 
energy; but you can graduate this vibratory energy.  By proper design 
and choice of wave lengths, you can arrange it so that you get, for 
instance, 5 percent in these electromagnetic waves and 95 percent in 
the current that goes through the earth.  That is what I am 
doing.  Or, you can get, as these radio men, 95 percent in the energy 
of electromagnetic waves and only 5 percent in the energy of the 
current.  Then you are wondering why you do not get good results.  I 
know why I do not get good results in that way.  The apparatus is 
suitable for one or the other method.  I am not producing radiation 
in my system; I am suppressing electromagnetic waves.  But, on the 
other hand, my apparatus can be used effectively with electromagnetic 
waves.  The apparatus has nothing to do with this new method except 
that it is the only means to practice it.  So that in my system, you 
should free yourself of the idea that there is radiation, that energy 
is radiated.  It is not radiated; it is conserved. . . .

Nikola Tesla, 1916