Re: Tesla Coil RF Transmitter

["Tesla list" <tesla@xxxxxxxxxx>]

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


> Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>
>
> These may have been the ideas that Tesla had about radio transmission,
> but both have serious problems, to not say that they are wrong:

I believe it's too soon to say one way or the other whether Tesla's 
ideas on the wireless transmission of electrical energy are entirely valid.

> The idea of conducting current through the air is simply unworkable.

I disagree.  An insulating gas such as air can be made conductive 
through the process of atomic and molecular ionization, i.e., the 
creation of plasma.   Charges flow more or less freely in plasma 
depending on its strength or the degree of ionization.  By way of 
practical example, say that we have two precisely attuned Tesla coils 
each having independent ground connections and slightly elevated 
toploads.  Next, space them far enough apart so sparks cannot jump 
between the terminals.  The conditions now exist for the creation of 
capacitively coupled discharge plasma between their respective 
elevated terminals through which an electrical current will flow. 
Current will also flow between the two ground terminals.  BTW, this 
is the type-two transmitter configuration.

> Tesla's idea of using a very elevated terminal is of completely
> inviable construction, . . .

I assume you're refering to U.S. Patents No. 645,576 and 649,621 
where he makes reference to, "maintaining terminals at elevations of 
fifteen miles or more above the level of the sea."   Read these 
patents again and you'll see that he follows this up by saying, 
"Through my discoveries before mentioned and the production of 
adequate means, the necessity of maintaining terminals at such 
inaccessible altitudes is obviated . . ."  Tesla also said, "when I 
filed the applications of September 2, 1897, for the transmission of 
energy in which this method was disclosed, it was already clear to me 
that I did not need to have terminals at such high elevation . . . I 
had already calculated and found that I did not need great heights to 
apply this method. My patent says that I break down the atmosphere 
"at or near" the terminal. . . . my experiments in Colorado showed 
that at a height of 1 mile it is plenty enough rarefied to break down 
under the stress and conduct the current to the distant points. . . . 
If my conducting atmosphere is 2 or 3 miles above the plant, I 
consider this very near the terminal as compared to the distance of 
my receiving terminal, which may be across the Pacific. . . . I have 
constructed and patented a form of apparatus which, with a moderate 
elevation of a few hundred feet, can break the air stratum down.  You 
will then see something like an aurora borealis across the sky, and 
the energy will go to the distant place. . . .

> . . . and would not work anyway, because the line
> going to the elevated terminal would work as an antenna, and irradiate
> most of the power. . . .

I agree the conductor that connects the resonator to the elevated 
terminal would radiate.  One question to be answered is how much of 
the power supply alternator's output would be lost as electromagnetic 
radiation from this conductor.  A possible solution is to use a 
higher aspect ratio extra coil and eliminate the conducting cylinder 
altogether, as is suggested in APPARATUS FOR TRANSMITTING ELECTRICAL 
ENERGY, U.S. Patent 1,119,732.

> . . . Unless the system worked at a very low frequency.
> But then, back to the construction problems and huge losses.

A 25 kHz type-one transmitter would be expensive, but not extremely 
hard to build.  Losses in the secondary and extra coil would be 
minimized by use of heavy wire.  The 1936 improved elevated terminal 
would be a requirement. Two of these machines have to be built for a 
proper system analysis.

> The idea of transmission through the ground falls back into a vertical
> monopole, a very standard type of antenna.

But the type-one and type-two transmitters do not incorporate a 
standard vertical monopole.  These launching structures are comprised 
of one or two top-loaded helical resonators, respectively.

> What it irradiates depends
> essentially on the vertical length of the system, no matter how the wire
> is coiled, what type of topload, etc. These determine only the frequency
> of the transmitted signal.

I can accept this statement for the time being.

> . . . If the length of the system is much smaller
> than the corresponding 1/4 wave length, very little energy is
> irradiated.

I'm okay with that.

> . . . The high current going into the ground doesn't mean
> anything. It just returns to the terminal by displacement current
> after moving just a bit away from the ground connection, without
> producing significant electromagentic waves. . . .

This is only the case when there is no receiver.  As stated in my 
previous post, a precisely tuned helical resonator type receiver has 
to used for a type-one transmitter function as it is intended.  To 
get the most meaningful results the transmitting and receiving 
facilities should be of identical construction. . . .

> Antonio Carlos M. de Queiroz

Gary Peterson