> Why are you trying to receive radio transmissions using a Tesla coil transmitter? . . . of course you will not receive an appreciable signal using conventional means.
Some are absolutely convinced that the only way to communicate wirelessly between two distant points is by means of radio waves as defined in the narrowest sense of the term, that is to say, far-field electromagnetic waves that are no longer associated with the launching structure, having totally closed back upon themselves with their E-field and H-field components completely in phase.
If it can be shown that the energy from a Tesla coil (TC) transmitter energy source can be received by a Tesla receiving transformer, but cannot be received [or is less well received] by a radio antenna [such as a balanced magnetic loop antenna] and receiver capable of detecting only radio waves [i.e., optimized for the reception of radio waves] then it will have been demonstrated that radio waves as defined above are not involved in the energy transfer process.
Two steps need to be performed in carrying out this proof: 1) establish the link between a TC transmitter and a distant Tesla receiving transformer, and 2) show that the received energy is not propagated in the form of radio waves. It appears that number one can be easily done. Number two can be demonstrated by showing that a radio-wave receiver capable of receiving a signal emanating from a radio-wave transmitter operating at the same frequency as the TC transmitter and at the same transmitter site is not able to receive the signal from the TC transmitter. A good radio-wave transmitter is needed to demonstrate that the radio-wave receiving antenna is working properly.
For this proof to be valid the TC transmitter has to be built in such a way as to minimize its output in the form of radio waves. Also, the radio-wave receiving antenna must be configured in such a way so that it interacts only with radio waves and not with the emanations of the TC transmitter. The radio wave antenna cannot be grounded. Even a counterpoise antenna will be susceptible to grounding due to capacitive-coupling. The grounding effect can be minimized by elevating it as far as possible above the earth's surface. The antenna could be a vertical 1/2-wave dipole with loading coils suspended high above the ground, or an air loop, or a tuned ferrite loop.
> What IS necessary is to pump the earth with waves at some multiple of the so-called Schumann resonant frequencies....
Tesla developed two slightly different techniques for wireless energy transmission. The first one, the “air-ground system” depends upon the passage of an electrical current through the earth between the two distant ground terminals and through the atmosphere between the two respective elevated terminals. According to Tesla's theory, this works because the density or pressure of the atmosphere at an elevation of 5 miles is sufficiently reduced to so that the air’s insulating properties can be impaired, allowing the electric current to flow. The denser atmosphere below 5 miles is also viewed as a propagating medium for the aboveground portion of the circuit, and, being an insulating medium, electrostatic induction is involved rather than electrical conduction.
We know that a powerful TC transmitter can charge an elevated
terminal to a point where the atmosphere around it becomes strongly
ionized. A vertical focused beam of
ultraviolet radiation could be used to facilitate the ionization process
directly above the terminal. This would
result in the formation of an electrically conducting path up to the
troposphere. This way, two distant
facilities could be linked together with a conducting atmospheric path. [Conceptual steps leading to this solution
included two balloon terminals,
“maintained at an elevation of not more than thirty thousand to thirty-five
thousand feet above sea-level” [“The Problem of Increasing Human Energy”] and a
large projection
positioned at the very apex of the two respective elevated terminals. [“Rare Notes from Tesla on Wardenclyffe,” L.I. Anderson, Electric Spacecraft Journal, Apr./May/Jun. Issue 26,
Keep in mind that the entire earth possesses a naturally existing negative charge or DC electrostatic potential with respect to the conducting region of the atmosphere, beginning at an elevation of about 50 kilometers. In operation, a grounded Tesla coil transmitter creates a local disturbance in this charge. This disturbance manifests itself as an annular deviation in the density of the background electric field that propagates away from the transmitter and diminishes in intensity as the distance from the transmitter increases. With a sufficiently powerful transmitter the field distortion propagates all the way to the antipode at which point the energy is reflected back towards its point of origin. The transmission of electrical energy across the entire globe and its reflection back to its source is the basis of the second technique, that is to say, the "earth resonance system."
The basic ground-air system requires that both a transmitter and a receiver be present; there can be no current between ground terminals and between elevated terminals if no receiver exists. The earth resonance system, on the other hand, can be implemented without any man-made receivers being installed. The earth itself fulfills the requirement that a receiver be present. It remains to be seen if the fundamental earth-resonance frequency precisely coincides with the fundamental Schumann resonance frequency, which, by the way, drifts around in the area between 7.5 - 7.9 Hz. I believe they will be found not to coincide.
We are focusing, for the time being, on an investigation of
the air-ground method at power levels insufficient to create a
high-altitude current flow. This leaves us only the
background charge disturbance to work with. Upon the activation
of a tuned receiving transformer that is within the area of the annular
disturbance created by an operating TC transmitter, an AC current begins
to flow between the two ground terminals, and also within the receiver's
helical resonator. The action that takes place at the respective elevated
terminals is less well defined. Perhaps a point-to-point connection
is established between the two elevated terminals such as occurs between
the two plates of a capacitor. Perhaps the interaction is somewhat
more localized, existing for the most part between each terminal and the
earth in its general vicinity and extending out a few wavelengths.
Perhaps what actually happens is some approximate combination of these two
hypothetical models. One can further envision a second annular
disturbance developing around the receiving transformer and with some
reflection of energy taking place back to the transmitter. This suggests a
standing-wave pattern establishing itself as part of the E-field
distortion. This pattern would be reinforced if the receiver were to be
replaced with another TC transmitter operating in an appropriate phase
relationship with the first TC transmitter. The next step would be to
place passive receivers at different points directly between the two
driven oscillators to see if nodes and antinodes can be observed. While
for a low-power system I don't think this would necessarily have to be an
earth-resonance harmonic, it would be worthwhile to sweep within a
few cycles of the operating frequency to see if anything pops up.
> . . . because they are the naturally harmonic waves of the earth. It would even be prudent to synchronize the impressed oscillations with those naturally occurring to 'add' to the existing waves, rather than canceling them.
I wonder if the ubiquitous and wide LORAN signal centered at 100 kHz is exciting an earth resonance (not Schumann resonance) mode?
> I have hopefully saved from my old computer a spreadsheet that lists all of the possible frequencies that would be usable.
It's my understanding that a strong earth resonance mode can be excited every 12 Hz or so all the way up to about 35 kHz, and that the region up to and beyond 137 kHz is still usable.
> If I am correct in my learning about Tesla’s ideas, the receiver must be in the correct location to get the maximum 'signal' . . .
I wouldn't be surprised if a single low-power TC transmitter worked in conjunction with a [single] passive receiver showed no sign of stationary waves.
> . . . but it would be an easy exercise to find out. In any case, I look forward to us making this happen.
I do too.
Gary Peterson
2005
> From:
"Tesla list" <tesla@xxxxxxx.com>
> To: <tesla@xxxxxxx.com>
> Sent:
> Subject: Tesla Coil RF Transmitter
>
> Hey all,
>
> How does a Tesla coil actually function like an RF Transmitter?
>
> Is it due to the fact that at the secondary topload,
the frequency of the
> output is very high - so much so that RF are produced?
>
> Can anybody introduce me a website that summarizes the principles of Tesla
> Coil (in say, 10 lines or less)? Most of the ones
I came across are really
> lengthy.
>
> Thanks!
> Sam
>
>
Hi Miles,
Most early radios were basically Tesla coils. At say 200kHz,
the 1/4 wavelength is 1230 feet. If you put a 1230 foot antenna on your
Tesla coil, it will transmit. Although real transmitters are far better
matched to the 50 ohm antenna load... But the key is our coils have very
poor transmitting properties due to being so small compared to the length of
antenna needed for our frequencies of operation.
Cheers,
Terry
************************************************************************************
A TC is an RF
transmitter as you have a large amount of RF power pushed into a short aerial
(secondary) so it will radiate as a transmitter will, although poorly (two
lines, but not very descriptive). . . . -- Derek
The TC is the
transmitter but it's the antenna that radiates. TC's
are very short helical antennas but as such the radiation is negligible.
If one were to design a coil for use as a transmitter the inductance would be
selected to resonate with the antenna capacitance if it were "direct
drive" such as Terry suggests. -- Ed
Tesla was
transmitting energy by pumping a charge into the ground itself. . . . The coil, all by itself, without an antenna, will transmit
if it is properly grounded. -- Dan
Paul Nicholson
responded:
The charge
'pumped' into the ground by the coil remains in the vicinity of the
transmitter. It doesn't spread evenly over the earth's surface, as I
think Tesla had claimed it would. Instead, the charge is trying to
return to the place (the topload and coil) where it
was taken from by the 'pump'. So it hangs around the transmitter, causing
spectacular effects and warming up the ground nearby. Tesla never did transmit any useful amount of
energy over any worthwhile distance - except by using wires to guide an
alternating field out of
> why is it so hard for anyone to believe that Tesla was transmitting by
conduction through the earth, and not propagation through the air?! -- Dan
Because, really they are the same thing!!! You
show me a system that is driving current through the earth, and I'll show you
that the fields which are driving that current are, in every respect, an EM
wave emitted by the transmitter.
Unfortunately, this is one of the cases in which nature just doesn't work
the way Tesla hoped it would. There just is no such thing as a 'true
conduction current' capable of coupling two TCs
beyond the range of their mutual field coupling.
************************************************************************************
Sam,
1.1 As Terry points out, many an early radio transmitter was simply a Tesla
coil with the topload replaced by a vertical piece of
wire, 1/4 wavelength long; using a flat-spiral Tesla coil was a popular way to
go. If the resonator's opposite terminal is grounded, then you have what
is called a grounded or "Marconi
antenna." This type of antenna behaves in a similar fashion to a 1/2
wavelength dipole in free space. Read up on antenna theory to learn how
these structures emit radio waves. Early on in his work Tesla himself
experimented with this type of transmitter.
1.2 There are two additional types of wireless transmitter that you can build
using a Tesla coil. [Both of these Tesla coil transmitters are
“radio-frequency” or RF transmitters, but not “radio wave” transmitters. The difference between a radio-frequency
transmitter and a radio-wave transmitter will become clear as you read on.] The first is quite similar to the classic Tesla coil that
nearly everyone on this list has assembled. The main difference is in the
placement of the topload. Instead of mounting
it close in, just above the resonator's top turn, the topload
is elevated somewhat above the top turn. Unlike the radio transmitter
described in paragraph 1.1, [the Tesla coil RF] transmitter requires that a
precisely tuned helical resonator type receiver be set in place in order for it
to function. This is why in the related wireless patents Tesla always
shows both the transmitter and the receiver (see http://www.teslaradio.com/images/645576-1a.gif
for example). In the case of this type transmitter, the transfer of
electrical energy is between the two ground terminals in the form of conduction
currents, and also between the elevated terminals. In a low power system,
the transfer of energy between the elevated terminals is, in effect, the result
of displacement currents, much like the transfer of electrical energy, which
takes place between the plates of a capacitor in an AC circuit. I call
this the type-one transmitter.
1.3 The second of the Tesla-type transmitters consists of a type-one
transmitter plus an unloaded helical resonator receiver, both placed in close
proximity to each other, each with an independent ground connection. Tesla first illustrates the improved type-two
transmitter in his
Gary Peterson
Antonio Carlos M. de Queiroz responded:
> 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. [In fact, only the transmitter described
in 1.1 above is intended for radio-wave transmission. The other two transmitters are not radio
transmitters; they are, however, “wireless transmitters.”]
> 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 top-loads.
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 unviable
construction, . . .
I assume you are referring 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
> . . . 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
[or at least useful]. 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 wavelength, very little energy is radiated.
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 electromagnetic 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. [The current flowing through the earth between the two
ground terminals is associated with an electromagnetic wave the strength of
which is proportional to the strength of the current.] To get the most meaningful results the
transmitting and receiving facilities should be of identical construction. . .
. [
Gary Peterson
Antonio,
What is the path of this current going into the ground, moving just a bit away
from the ground connection and then returning to the terminal?
Stork
Antonio answered:
It moves from
the ground connection in all directions, until the local electric field is
counterbalanced by the electric field attracting the current back to the top
terminal. The current then stops,
leaving the charges in the ground surface distributed as in a charged
capacitor, where one of the plates is the top terminal (with some influence of
the coil too) and the other plate is the ground. Some current moves away, as a ground wave
following an electromagnetic wave in the air above, but it is very small for
conventional Tesla coils, with dimensions much smaller than the wavelength of
the operating frequency.
Ed wrote:
> Hi all, this response isn't directed at any one in particular; I just have
a few observations . . . -- Dan
It is
impossible to believe that transmission was solely through the earth, as many
seem to believe. Take your example of a coax cable. The current
flow is through the center conductor with a return path through the inside of
the outer conductor. TWO-way circuit!!! In Tesla's case, at least
as we interpret it now, the current was to flow into the earth from the bottom
of the coil. Period. No return path.
No way at all this could work. I wonder if Tesla is being misinterpreted
and never intended to say that there was no return path for the current carried
through the earth. For sure his patents talk of a TWO-conductor
transmission path, with one conductor being the ionized "upper layer"
and the other being the ground. Always TWO conductors.
Just read the patents. When he speaks of "driving currents into the
ground" that may just be hyperbole.
> And Sam, you said the TC transmits poorly; considering that Tesla was
lighting up light bulbs with his receivers, seems his coils were transmitting
just fine...
No foundation for that statement. He did indeed light bulbs, probably
through inductive or capacitive coupling (unless you believe the stuff about
lighting many bulbs many miles a way, a statement with no proof at all and
apparently invented after his time). However, he never even mentioned how
much power was transmitted or being wasted. Probably most of it was
wasted. Efficiency was probably nil.
> Some of his earlier experiments involved running a loop of cable around
his laboratory. He would run RF through
it, and light up special bulbs anywhere in his lab. He
was constantly running experiments, probably hundreds of them by the time he
was through. If his transmitters actually needed an
Aerial, don't you think he would have figured that out? Why would he drop the earlier aerial (say that really quickly three times :) in favor of a capacitive
top load, if it performed worse? It's
not like he never tried an antenna!
>Dan
That was simple inductive coupling and not transmission. No mystery, no
miracle, no significant technical accomplishment except for the high frequency
involved and his method of generating it. You can do it just as well as
he did and the results will be just as good.
Ed
Antonio wrote:
Charges don't
flow freely in plasma. The resistivity
is significant. Note that the equivalent
linear resistance of the spark gap in our Tesla coils is easily of several
ohms, for distances of a few mm. This
improves with reduced pressures, but a wire can easily conduct the same current
with losses many orders of magnitude smaller.
Capacitive coupling decreases very fast with distance. It's
the "local field" of the antenna. Remember
that both coils have capacitance to ground, and this does not change
significantly if the coils are moved apart, while the capacitance between the
terminals decreases fast. The capacitance to ground of
the receiving coil and the capacitance between the terminals form a capacitive
voltage divider of huge ratio for quite small distances. If
the distance is comparable to the wavelength of the transmitted signal, we have
electromagnetic waves, far field.
> ”
Many people live at more than a mile above sea level, and do not see currents
flowing through the air...
> ”. . . You will then see something like an aurora
borealis across the sky, and the energy will go to the distant place. . . .” – Tesla
A few hundred feet away, except for the radiated energy.
> . . . 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. --
The shape of the conductor, straight or coiled, does not make significant
difference in the far field generated. The total
height of the system is the most important factor.
>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 wavelength would be 12 km. Something smaller than about 1 km would not radiate much. The local field would be usable up to a
distance similar to the height of the system.
Receiving antennas would have to be of similar size. Direct
connections would use less wire...
> 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 be 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. . . . –
How the
transmitter would be aware of the existence of a far receiver? People at that time may have been impressed
by the analysis of the basic double resonance system, where it is apparently
possible to transmit all the energy in a primary LC circuit to a secondary LC
circuit, no matter what is the coupling coefficient between the coils. If the coupling is low, the transfer just takes more
time. But in practice, losses eat all
the energy if the coupling is too low, before it has time to accumulate at the
receiver. And this does not consider
electromagnetic waves; that is what would excite the receiver if the distance
to the transmitter is large. They add
more dispersion, as irradiated energy that is not captured by the receiver is
lost, but produce far fields much larger than the local field.
The end is the radio systems that we use. Kilowatts of transmitted energy for
microwatts of received energy not very far away.
Antonio
[The
distance at which a Tesla receiving transformer can be “aware” of a TC RF
transmitter is directly related to the strength of that transmitter. The entire earth possesses a naturally
existing negative charge or DC electrostatic potential with respect to the
conducting region of the atmosphere, beginning at an elevation of about 50
kilometers. In operation, a grounded Tesla coil transmitter creates
a local disturbance in this charge. This disturbance propagates
away from the transmitter in the form of annular rings that diminish in
intensity as the distance increases. A Tesla receiving transformer within
this circular region will be “aware” of the transmitter. With a sufficiently powerful Tesla coil
transmitter the field distortion propagates all the way to the
antipode at which point the energy is reflected back towards its point of
origin. The transmission of electrical energy across the entire
globe and its reflection back to its source is the basis of the "earth resonance system." --
To the Tesla
List:
>
Capacitive coupling decreases very fast with distance. It's the "local field" of the
antenna. Remember that both coils have
capacitance to ground, and this does not change significantly if the coils are
moved apart, while the capacitance between the terminals decreases fast. The capacitance to ground of the receiving
coil and the capacitance between the terminals form a capacitive voltage
divider of huge ratio for quite small distances. If the distance is comparable to the
wavelength of the transmitted signal, we have electromagnetic waves, far field.
According to the patent SYSTEM OF TRANSMISSION OF ELECTRICAL ENERGY and Tesla's
article THE TRUE WIRELESS there is an interaction between the elevated
terminals of the transmitting and the receiving stations. This
interaction involves true electrical conduction and, in some cases,
electrostatic induction. In operation the elevated terminal functions as
one plate a capacitor. In opposition to the terminal are all other
objects in the environment, including the receiver's elevated terminal.
While more or less a majority of the field lines of a type-one transmitter are associated
with nearby objects, some of them, according to Tesla's theory of operation,
are associated with the elevated terminal of the other station. Tesla said,
"The elevated terminal charged to a high potential
induces an equal and opposite charge in the earth and there are thus Q lines
giving an average current I = 4Qn which circulates locally and is useless
except that it adds to the momentum. A relatively small number of lines q
however, go off to great distance and to these corresponds a mean current of I
sub e = 4qn to which is due the action at a distance. The total average
current in the antenna is thus I sub m = 4Qn + 4qn and its intensity is no
criterion for the performance. The electric efficiency of the antenna is
q/Q+q and this is often a very small fraction." [THE TRUE WIRELESS]
and
"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, 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 cannot travel
along this curve and get there, but 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."
[Nikola Tesla On His Work With Alternating Currents and Their
Application to Wireless Telegraphy, Telephony and Transmission of Power, pp.
128-130]
> Many people live at more than a mile above sea level, and do not see
currents flowing through the air...
One does not have to live at a high elevation to see Saint Elmo's fire,
lightning discharges, and the auroras.
> A few hundred feet away, except for the irradiated energy.
Tesla speculated about the illumination of an entire shipping lane, presumably
between
> The shape of the conductor, straight or coiled, does not make significant
difference in the far field generated. The total
height of the system is the most important factor.
I've been taught that with a base-loaded antenna the loading coil does not
contribute energy to the radiated field, only the straight section does this.
> . . . How the transmitter would be aware of the existence of a far
receiver? . . .
The transmitter would be aware of the receiver in the exact same way as a
generator does when an electrical load connected to it. In both cases
there is a closed circuit through which current flows. In a complete
type-one system using the "disturbed charge of ground and air method"
the earth comprises one half of the circuit through which the high current
associated with the transmitter's ground terminal flows. The other half
of the circuit is the medium of the upper half space, i.e., the earth's
atmosphere. Through this medium would
flow the high voltage, low current energy associated with the transmitter's
elevated terminal; I^2 R losses would be minimized. In a fully developed
ultra high-power system operating in a push-pull mode it is conceivable the entire
atmospheric path between the two stations would be ionized. And while
charges don't necessarily flow freely in plasma, and the path resistance can be
significant, all we are seeking to do is get fractionally more received energy
than a conventional radio receiver gets from a conventional radio transmitter
of equivalent power. Observing less of a
reduction in signal strength than that which is predicted by the inverse-square
law would be a significant experimental finding.
Best regards,
The Tesla Coil
List responds to Antonio:
> The end
is the radio systems that we use.
Kilowatts of transmitted energy for microwatts of received energy not
very far away. . . .
I think this
is a very important point. The
radio systems we have now are direct descendants of Tesla's wireless system
work. People like Marconi
found empirically that if you use a long wire antenna that radiates more of the
power, it actually works better.
If you think about it, our current radio systems must also be the best
possible in terms of transmitting power without wires. After all,
to transmit a message into the receiver you have to transmit power to it. So the more efficiently it transmits power,
the better it will transmit information.
The fact of the matter is just that the amount of power you can transmit
is very small.
One example that might be of interest to world wireless system fans:
The Radio 4 long wave transmitter in
Now the last Tesla coil I made just happens to resonate at 198kHz
(it was a pure coincidence). I live 300
miles away from the transmitter. So how
much power can I pick up?
The answer, experimentally, is not a lot.
If I plug the base of the secondary into one antenna connection of a
radio receiver, and ground the other connection, I get a storming good signal. I think I saw S9+20dB on the receiver's
signal strength meter after fiddling with the topload
to get it tuned. But that signal
strength corresponds to a captured power of only about 0.1 milliwatt. Hardly enough to light my
house even with phosphorescent tubes.
:^)
Wired power transmission certainly wins here- my nearest power station is a 2GW
unit about 50 miles away, and I can get 40 amps at 240V (10kW) any time I want
it. Even if the Radio 4 transmitter were
2GW, and only 50 miles away, and I built the biggest antenna that would fit on
my house, you can see from the above example that I wouldn't capture more than
a watt or two.
However, the same receiver- thanks to the wonders of Tesla's resonant circuits-
can give a usable signal with as little as 10 picowatts. Under good conditions you can receive a
signal from a 100-watt transmitter on the other side of the
Of course, this is all old news to any hams, pilots or ocean going yachtsmen
out there ;) It's just an ordinary HF
radio set. They are fast being made
obsolete by satellite phones, but still good fun to play with.
My point is that this is the state of the art, and I recommend that anyone with
an interest in Tesla's wireless system should get themselves a ham licence and have a play around. There is even a 136kHz ham band now, so you
can legally transmit on the same kinds of frequencies as Tesla did using the
same kinds of antennas, and then try higher frequencies with modern antennas
and see how much better they work. ;)
I know there are other hams on the list. I have been
off the air for a long time but I just got hold of a HF
rig and I hope to see some of you on 17 meters as soon as I get my station up
and running.
Steve Conner, GM0TET
Steve,
Very nice explanation. If Tesla coils as we configure them did
transmit RF power even with say 1 to 10% efficiency, we would be banned from
using them simply because the RF is very dirty like that of the spark gap
transmitter. Moral: DON'T connect an antenna to a
Tesla coil!
Chuck Hobson, G0MDK
Steve,
You wrote:
> There is
even a 136kHz ham band now, so you can legally transmit on the same kinds of
frequencies as Tesla did using the same kinds of antennas, and then try higher
frequencies with modern antennas and see how much better they work. ;)
That isn't a
ham band and requires a special license application. Look for "Part
5" under FCC rules and regulations. You don't need a license to
operate between 160 and 190 kHz if you keep your transmitter power to 1 watt
maximum. Not too much you can do with it, but guys are getting signals
across a couple of thousand miles with that power. Very slow speed
keying.
Ed Phillips
Ed,
Wasn't the
poster (i.e. Steve Conner, GM0TET) in
You might be able to get a waiver or STA for a
suitable historical demo, though. Now that GPS has
superseded Omega and Loran, there's not so much activity down there (you'd have
to show that you wouldn't interfere with LF and MF navigation beacons though)
Jim Lux
> The UK has an LF experimenters band. In the
Ed and Jim,
Sorry :-/ I am in the
> And, regardless, Type B (damped wave), e.g. Spark
gap transmitter, emissions are strictly forbidden.
I suppose I should have mentioned that, but I thought it went without saying. Quartz locked SSTCs only ;)
Steve
Ed wrote:
In the U.S. unlicensed transmission in the band from 160 kHz to 190 kHz is
legal, provided the maximum power input to the FINAL AMPLIFIER STAGE is less
than one watt and the maximum antenna length/height is 50 feet. A number of people have gotten experimental
licenses under Part 5 of the FCC regulations (forget the CFR
#) to operate in this band with large antennas and much more input power and
also more ERP. Ralph is one. Several other stations have gotten
experimental licenses to operate with similar powers in the band around 137
kHz. I don't remember exactly what the requirements are in
There are also a number of legal but unlicensed stations operating in the
vicinity of 13.555 MHz where the power is limited by a specification of maximum
radiated field strength. This limitation is about equivalent to allow a
maximum of 5 mW input to a half-wave dipole.
I'm sure that with the help of some creative statements on the experimental
license application some eager beaver could get a license to operate a CW (or
narrow band modulated) Tesla coil in one of these bands. In the
"good old days" the term Tesla transformer was often applied to the
RF transformer operated in a tuned primary tuned secondary type transmitter configuration
(secondary tuning capacitance was usually just that of the antenna) and was not
confined to the very high impedance secondaries being
used to generate impressive streamers.
Dan commented:
By the way, in
the
Malcolm Watts replied:
You could
answer your own question by doing some calculations bearing in mind that you
need to construct a low loss resonant circuit which can withstand some pretty
high voltages. I am not being rhetorical - it would be
an interesting exercise and I would be interested to see what you come up with.
>> The
idea of conducting current through the air is simply unworkable. -- Antonio
> I disagree. -- Gary
Ed wrote:
Fine; that's
your privilege. In defense of your belief I suggest you do a simple
calculation. Tesla was going to have his conducting layer at something
like 20 miles height, and expected it to cover the whole earth. Calculate
the capacitance between that conducting shell and the conducting earth - the
transmission path he proposed, remember. [To make the calculation simple
just assume an equivalent flat plate capacitor of the same area.]
Calculate its reactance at any frequency you can imagine, remember that he was
going to charge it to "100 million volts", and calculate the current
that would have to be fed into that capacitance to maintain that voltage.
After you do that sit and think for a bit, then report
the result of your calculations. It gets even more interesting after you
get that far, but that's a good starting point for a critical analysis of the
scheme.
Stork asked:
Does the current in the earth from the ground connection move as conduction
current also? Does one half cycle later current move back from the earth
as conduction current into the ground connection?
My question: Is current in the earth to and fro from the ground
connection conduction or displacement current? Is the earth itself a
conductor or dielectric?
Antonio
answered:
Yes. It is the same current that exits at the base of
the coil. It quickly reduces to nothing
(except for small waves that radiate) as it spreads, at some meters away, but
keeps essentially the same waveform.
Essentially conduction. The earth is a conductor, with
smaller or greater resistivity, depending on the
composition. Some displacement current exists too, as
in all conductors, but it can be ignored.
Tesla list
wrote:
Your contention that the current needs a two-way path is, I believe, incorrect. That would be true for DC currents, but not
AC. When the current is flowing from the
transmitter to the receiver, the charge accumulates in the top capacitance of
the receiver. When the current is
flowing back, it flows back out of the receiver’s capacitance, into the transmitters capacitance.
It is analogous to a hydraulic system, where instead of pumping the oil always
in one direction (you need two hoses to do this), you kept pumping the oil back
and forth. When you do that, you don't need a return hose,
because the oil can go into an accumulator at each end. Think about it.
In common household AC, the neutral is not really a return path either, but a
terminal to collect all three phases and add them together. By
definition, being neutral, the neutral does not carry any current (beyond the
utility pole, that is).
Dan
Tesla Coil
List responds:
Any current
flow can be considered to be in a single direction at some instant in time. Put another way, at any instant, a current flow can be
considered to be DC. (Y-N)?
Malcolm
Dan,
I can't agree with your statement here. You are correct in that the three
phase distribution lines do not have power flowing in other than just those
three wires. Once this goes through the step down transformer to your house,
you have either 220 volts ac on two wires where all the power flows just
through those two wires (for a 220 volt appliance such as a water heater) or
you have 110 volts ac between either of those 220 volt legs and a neutral
line. The full current for a lamp, toaster, etc. definitely flows in both
the hot lead and the neutral wire for 110 volt circuits.
Ed Sonderman
Dan,
It is
impossible to believe that transmission was solely through the earth, as many
seem to believe. Take your example of a coax cable. The current flow is through the center
conductor with a return path through the inside of the outer conductor.
TWO-way circuit!!! In Tesla's case, at least as we interpret it now, the
current was to flow into the earth from the bottom of the coil—period; no
return path. No way at all this could
work. I wonder if Tesla is being misinterpreted and never intended to say
that there was no return path for the current carried through the earth.
For sure his patents talk of a TWO-conductor transmission path, with one
conductor being the ionized "upper layer" and the other being the
ground—always TWO conductors. Just read the patents. When he speaks
of "driving currents into the ground" that may just be hyperbole.
> And Sam, you said the TC transmits poorly; considering that Tesla was
lighting up light bulbs with his receivers, seems his coils were transmitting
just fine...
No foundation
for that statement. He did indeed light bulbs, probably through inductive
or capacitive coupling (unless you believe the stuff about lighting many bulbs
many miles a way, a statement with no proof at all and apparently invented
after his time). However, he never even mentioned how much power was
transmitted or being wasted. Probably
most of it was wasted. Efficiency was probably nil.
> Some of his earlier experiments involved running a loop of cable around
his laboratory. He would run RF through it, and light
up special bulbs anywhere in his lab. He was
constantly running experiments, probably hundreds of them by the time he was
through. If his transmitters acutally
needed an Aerial, don't you think he would have figured that out? why would he drop the earlier aerial (say that really
quick three times :) in favor of a capacitive top load, if it performed worse? It's not like he never tried an antenna!
That was simple inductive coupling and not transmission. No mystery, no
miracle, no significant technical accomplishment except for the high frequency
involved and his method of generating it. You can do it just as well as
he did and the results will be just as good.
Ed Phillips
Tesla list
wrote:
>1 -- the earth is conductive, or we would not be grounding equipment in it.
. . .
Earth has varying conductivity from place to place. It’s somewhat lossy,
except in really large chunks. It’s not
used in transmitting power. There is a
range of conductivity, roughly:
silver
gold
copper
(big gap)
'earth' (wide range of values)
(big gap)
Glass
air
The first few are 'conductors', the last few
'insulators.' Materials can be found in all ranges.
>2 -- RF can be conducted thru a conductor, or coax would not exist.
Coax uses Really Good Conductors. Earth is an iffy, and poor, at best,
conductor. (The values can be looked up
in any standard engineering reference, the 'earth'
values will vary widely.)
>3 -- given the above statements, why is it so hard for anyone to believe
that Tesla was transmitting by conduction through the earth, and not
propagation through the air?! Just because you CAN
transmit RF through the air, doesn't mean it is the ONLY way to do it.
Transmission thru earth is lossy.
>When Tesla was working in
He had relatively primitive thermal detectors, cf the Colorado Springs Notes.
>Then he was also able to receive substantial currents (enough to light light bulbs) using a second Tesla coil tuned to the
transmitted frequency.
a) When the bulbs, etc, were outside the lab door.
b) at low
efficiency.
In any case, it’s straight RF. Can be duplicated near
any broadcast transmitter.
>Why would he need two different methods of receiving (one really sensitive,
and one brute force) if he was not transmitting in two different ways?
Standard radio can be received in lots of different
ways; some better then others, some better for specific uses.
>And, you said the TC transmits poorly; considering that Tesla was lighting
up light bulbs with his receivers, seems his coils were transmitting just fine.
Suggest reviewing:
power in
power out
distance.
>Some of his earlier experiments involved running a loop of cable around his
laboratory. He would run RF through it, and light up
special bulbs anywhere in his lab.
Can be done today. Not real
efficient, stray effects of large RF fields are unknown.
Best
D.W.P.
>>>
Your assertion that if you put a 1230 foot antenna on the thing, it will
transmit, is half right. The coil, all by itself,
without an antenna, will transmit if it is properly grounded.
Dan
>> That's true about a properly grounded Tesla Coil Dan, but the
Effective Radiated Power (ERP) would still be
miniscule, probably undetectable (electromagnetic waves) beyond about 500 to
1000 meters distance I would think. It
would be interesting to know if anyone has tried detecting Tesla Coil signals
with a good communications receiver.
Chuck
> We all know what he said, but that doesn't mean
it's true; in this case it can't be. This is one topic where he clearly
bent his pick and went off into the wild blue yonder. Remember that at
the time he was writing this he was stating with certainty that "Hertzian waves are dead and will soon disappear from the
scene." They still are king over 100 years later, and for a good
reason.
>
> If current flows into the ground an equal among MUST flow through whatever
you call the thing on top of the coil. There is no way his
configuration could have behaved other than as a transmitter with a short
top-loaded antenna. The circuit is clearly shown over and over again in
his patents. I'll agree that the radiated power would have been low
because it's a lousy design for transmitting but that's all it could do,
sorry. And the controversy goes on!
Ed
Many people
have tried to detect Tesla coil fundamental signals at a significant
distance. Any LW band receiver will work fine
with very high sensitivity. Richard Hull, I believe, got out to about a
city block. In general, a few hundred feet is pretty good for a large well-grounded
coil.
The much higher frequencies of RF noise given off buy the spark gap (1 to
1000++ MHz) can go much further and are the cause of TV interference and
such. At high frequencies, the small lead lengths of the primary wiring
can be significant transmitters.
Cheers,
Terry
Terry, ALL
Supporting Terry on this one.
Richard Hull tried to detect fundamental of Nemesis, max pickup distance was
< 2 city blocks. Also had fellow experimenter Bill Richards who is a lowfer HAM try to detect 54kHz fundamental on opposite side
of Richmond (~ 20 mi as crow flies)..
ZIP, ZERO, NADA.
Nothing was detected above white noise level.
Regards
Dave Sharpe, TCBOR/HEAS
Ed:
Tesla said that he measured standing waves set up by lightning discharges. He said he could also set up standing waves
with his transmitter. Standing waves can
only occur if the reflected wave coming back at you is substantially of the same
intensity as the transmitted wave. This
is of fundamental importance, because if the waves are the same strength coming
back as going out, Tesla was right when he said that the earth has negligible
attenuation.
So the big question is: Was Tesla right?
Did he in fact measure standing waves, or was it another phenomena? If he was
right, and you can indeed set up standing waves, it would mean that the energy
does not dissipate as you say. Otherwise
it does.
This question will not be settled until someone tries to duplicate Tesla's
experiments, and find out one way or the other.
Dan
> 1.2 ...
In the case of this type transmitter [a type-one transmitter with a Tesla
receiving transformer in place], the transfer of electrical energy is between
the two ground terminals in the form of true conduction currents, and also
between the elevated terminals. -- Gary Peterson
Paul Nicholson responded:
This is a
radio wave by another name; 'true conduction current' doesn't offer an
alternative to EM waves for transferring energy. There is only one type of current in
electrical engineering, and it always requires a field to drive it A current is a flow of charge (usually electrons) and they
are driven along by a field. There are
no grounds for believing that inefficient radiators such as described by
Attempts to revive Tesla's ideas for broadcasting power, by introducing
concepts such as:- cavity resonance using ionosphere
or artificial plasma layer, projecting Zenneck waves,
etc, are simply providing one mechanism or another to allow the field to
propagate further, and thus allow current to be 'transmitted'. Really, it is always the field that is
causing excitation of current in the receiver.
A receiving TC tuned to the same frequency as a transmitting coil will receive
well, but only to the extent that the
transmitting coil broadcasts its field. As the coils are moved further
apart, the coupling coefficient drops very rapidly. You may try to mitigate that by demanding
higher and higher Q factors, but it is the loaded Q that must rise, and of
course this means that you cannot apply much load to the receiving coil.
This relates to the fact that the receiving coil can, at most, only make
available the power that it can 'capture' from the field, by virtue of its
physical size in relation to the free space wavelength.
It matters little if the two TC ground terminals are joined together or
not by a common 'earth'.
The best method for transmitting power by EM waves is to guide it to its
destination, using a waveguide, a coax, or as in most
cases, a pair of wires - such as a mains cable. This is the efficient and
reliable system we already use: a system of guided waves operating at 50 or
60Hz called a national grid.
The bottom line is - there's no magic way to excite a current at the receiver
without projecting a field to the receiver. Even if you make a current by
shoveling charge into a lorry (truck!) and drive it to the receiver, I will
show that the energy conveyed is represented by the EM field of that
charge. (In such a case, the work of the lorry goes into the field as it
has to drag the load of charge away from the equal and opposite amount of
charge left behind at the transmitter.)
[If the
conductor is configured as an antenna and a time-varying current is applied to
it the associated fields assume the form of a radio wave and radiate away from
the conductor. Note that Paul’s
definition of the term “radio wave” also includes the form of electromagnetic
wave that propagates along an RF transmission line. This
is a mistake. While there are always
electric and magnetic fields associated with the flow of electrons through a
conductor, an ideal RF transmission line does not radiate any radio waves. If the conductor is part of a transmission
line the fields are confined and cannot radiate away as a radio wave. An ideal antenna is a 100% efficient
radiator. An ideal transmission line has
0% efficiency as a radiator. – Gary Peterson]
Paul,
You wrote:
> This is a
radio wave by another name . . .
In the case of
an operating Tesla-coil RF transmitting-receiving system using the ground and
atmospheric conduction method, I agree that electromagnetic waves are
involved. However, I do not believe these are "radio waves."
> 'true conduction current' doesn't offer an alternative to EM waves for
transferring energy. . . .
I use the term "true conduction current" only when I wish to make a
distinction between the electrical current which flows through a conductor
(such as a wire or highly ionized plasma) verses the so called
"displacement current."
There is an electromagnetic field associated with the electrical current that
flows through the earth between the ground terminal of the transmitter and the
ground terminal of the receiver. As with any electrical transmission line
there are loops and nodes or maxima and minima in the
EM field, distributed along the conductor, the distance between which
corresponds to the wavelength of the transmitted energy. Some of the
energy of this ground current and its associated EM field escapes
from the system in the form of "radio waves." I use this term
"radio waves" in its narrowest sense, i.e., far-field electromagnetic
waves that have closed back upon themselves and are no longer associated with
the launching structure. These "radio waves"
that are more than one wavelength from the launching structure, and have their
E and H components in phase are the "Hertz waves" to which Tesla
occasionally refers in his writings. These "radio waves" have
nothing to do with the transmission of energy through the earth between the
transmitting and receiving stations other than in the fact that they constitute
a mechanism for loss from the overall resonating system.
In addition to the alternating electrical current flowing through the ground,
there is also a flow of electrical energy between the elevated terminal of the
transmitter and that of the receiver. This occurs as a combination of
displacement current between the respective elevated terminals and the
conducting upper atmosphere beginning at about 7.5 kilometers up, and electrical
conduction through the conducting region spanning the distance between the two
locations. (Taking into account the powerful magnetic field developed by
each station's helical resonator, an embedded magnetic field might also be
involved.) While not an ohmic conductor, the
density or pressure of the upper atmosphere is sufficiently reduced so that
it's insulating properties can be impaired, allowing the electric current to
flow. The conducting region is developed through the process of
atmospheric ionization, in which the effected portions of the atmosphere are
modified to the plasma state. Tesla wrote about the possibility of using
powerful ionizing beams pointing upward from the elevated terminals to ionize
the atmosphere directly above the stations, leading to a flow of conduction
currents between the two terminals by a path up to and through the troposphere,
and back down to the other station. As with the terrestrial transmission
line mentioned above, EM waves are also associated with the atmospheric transmission
line as well. Because plasma is the conducting medium, these are either
electrostatic plasma waves or, assuming the presence of inter-connected
magnetic fields, magneto-hydrodynamic plasma waves. Note that propagation
of an ion acoustic wave in plasma bears a distinct resemblance to Tesla's
description of "the universal medium . . . a gaseous body in which only
longitudinal pulses can be propagated, involving alternating compressions and
expansions similar to those produced by sound waves in the air."
>It matters little if the two TC ground terminals are joined together or not
by a common 'earth'.
Actually, it makes all the difference in the world.
>The best method for transmitting power by EM waves is to guide it to its
destination, using . . . a pair of wires - such as a mains cable. . . .
>Paul Nicholson
Yes, a pair of conductors is the best way to go, and that's exactly what Tesla
had in mind with the ground and atmospheric conduction method:
"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, 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. . . ."
-- Nikola Tesla, 1916
Gary Peterson,
2005
Tesla was
trying to utilize a tropospheric phenomenon, NOT the
50+ mi high region that decades later was discovered to be the ionosphere. -- Matt Demming
[Tesla] talked about a conducting layer at an altitude low enough to be reached
by a balloon . . . The key words here are "Tesla was trying";
remember that he never succeeded . . . -- Ed
When you say
"Tesla never succeeded" . . . the one plant that would have decided
the issue one way or the other, was Wardenclyffe, and
it never got completed! He never got funding for anything else
approaching that scale after that. So I don't think the issue is settled
at all. Why won't anyone try to duplicate his experiments? All
anyone does is see how big of a spark they can make. . . . --
Dan
Plenty of guys have tried without any success [to
transmit energy to a distance using Tesla coil transmitting and receiving
apparatus]. Some have reported their results here. --
Ed
Gary Peterson
responded:
Tesla's work
in alternating current engineering began with development of the AC power
system. Even before this goal was fully realized, he began research into
the use of alternating electric currents for wireless telegraphy, telephony,
and power transmission -- the wireless transmission of electrical energy. . . . Remember . . . Tesla's work was directed towards the
development of a system that combined wireless telecommunications and
electrical power transmission.
"I had at that time already
perceived enough to get the idea that energy could be transmitted without wires.
It was of no consequence to me at that time whether it was to be used for
telegraphy, or telephony, or power transmission. I was on the problem of transmitting energy
without wires; and as it is my custom always to analyze scientifically every
problem that I undertake to solve, I devoted a great deal of thought to how to
attack that problem, and the following crystallized out. . . ."
".
. . If you have an antenna of a certain capacity
charged to 100,000 volts, you will get a certain current; charged to 200,000
volts, twice the current. When I spoke of these enormous potentials, I
was describing an industrial plant on a large scale because that was the most
important application of these principles [the wireless transmission of
electrical power], but I have also pointed out in my patents that the same
principles can be applied to telegraphy and other purposes. That is
simply a question of how much power you want to transmit."
-- Nikola Tesla, 1916
While Tesla viewed electrical power transmission as being of greater
importance, large-scale implementation of the Tesla system would have taken
place only after the feasibility of the basic concept had been
established. As Dan points out, the
premature decommissioning of the Wardenclyffe telecommunications plant left
this as an unanswered question.
Following Tesla's lead, a number of people have taken a stab at building
working models of Tesla's ground and air system for the wireless transmission
of electrical energy. They include Eric Dollard
(before 1990), myself (1990), Richard Hull (1991), Richard Quick (1994, see http://www.pupman.com/listarchives/2000/July/msg00761.html),
D.C. Cox, and Konstantine Meyl
(2003). Of course, it was Tesla who gave us the basic instructions about
the transmitting and receiving apparatus and their operation.
The object is to detect the fundamental tone of a precisely tuned non-sparking
Tesla coil by setting up a Tesla Coil transmitter in which the primary and
secondary oscillations are synchronized, and also a precisely tuned helical
resonator receiving transformer, set to exactly the same frequency. For a
detector most people will start out by using a small lamp of some sort; an NE2,
NE51, a fluorescent tube, an LED or a small low-voltage incandescent light are
all good indicators of the received energy. This is the same thing that
Tesla was doing at C/S. A small permanent-magnet dc motor with a diode
bridge rectifier also works. This is a great way to learn about the
tuning of both the transmitting and the receiving transformers.
Unfortunately this is where most people also stop-at least those who have
reported their work on this list and elsewhere.
Many are not interested in the easily performed, but less spectacular
feat of detecting the transmitted signal at 100 times-plus the distance using a
sensitive "radio-wave" receiver in conjunction with their receiving
transformer, instead of a "diminutive lamp."
Matt wrote:
>>. . . Not too many people want to invest their
life savings and decades of work . . .
The great thing is that meaningful results can be achieved without having to
spend a fortune. . . .
>>. . . in a project that 1) Is theoretically
unlikely to ever work.
But it does work. . . .
>>2) If successful, would destroy all global communications . . .
It will significantly improve global telecommunications. . . .
>>. . . and possibly all air traffic
Fully developed the World System will facilitate aviation by allowing the
propulsive energy to be transmitted to aircraft, which will then not have to
carry fuel.
>>3) Would have possibly terminally destructive environmental
consequences.
It will allow us [that is to say the
future inhabitants of the planet] to control the environment rather than
having the environment control us, as it does now. Also, pollution will
be reduced. . . .
>What will
[future aviators] do for a connection to the ground to utilize the current that
is "forced" into it? -- Ed
Gary Peterson
responded:
Tesla asserted
that his system for the wireless transmission of electrical energy could be
used for the propulsion of aircraft and
surface vehicles. In the case of an “airship,” the
connection to ground would be made through a trailing electrical conductor.
Writing to Benjamin F. Miessner in 1915 he stated,
"In an article in the Century Magazine . . . I have
related the circumstances which led me to develop the idea of a self-propelled
automaton. My experiments were begun sometime in '92 and from that
period, on, until '95, in my laboratory at
In the article "Nikola Tesla Tells How We May Fly Eight Miles High at
1,000 Miles an Hour" (Reconstruction, July 1919) he spoke about a possible
technological revolution in the transmission of propulsive power to aircraft
"through the air."
"For years I have advocated my
system of wireless transmission of power which is now perfectly practicable and
I am looking confidently to its adoption and further development. In the
system I have developed, distance is of absolutely no consequence. That
is to say, a Zeppelin vessel would receive the same power whether it was 12,000
miles away or immediately above the power plant. The application of
wireless power for aerial propulsion will do away with a great deal of complication
and waste, and it is difficult to imagine that a more perfect means will ever
be found to transport human beings to great distances economically. The
power supply is virtually unlimited, as any number of power plants can be
operated together, supplying energy to airships just as trains running on
tracks are now supplied with electrical energy through rails or wires.
"The transmission of power by wireless will do away
with the present necessity for carrying fuel on the airplane or airship.
The motors of the plane or airship will be energized by this transmitted power,
and there will be no such thing as a limitation on their radius of action,
since they can pick up power at any point on the globe.
"The advance of science to
this point, however, is attended with terrible risks for the world. We
are facing a condition that is positively appalling if we ever permit warfare
to invade the earth again. For up to the present war the main destructive
force was provided by guns which are limited by the size of the projectile and
the distance it can be thrown. In the future nations will fight each
other thousands of miles apart. No soldier will see his enemy. In
fact future war will not be conducted by men directly but by the forces which if
let loose may well destroy civilization completely. If war comes again, I
look for the extensive use of self-propelled air vehicles carrying enormous
charges of explosive which will be sent from any point to another to do their
destructive work, with no human being aboard to guide them. The distance
to which they can be sent is practically unlimited and the amount of explosive
they can carry is likewise practically unlimited. It is practicable to
send such an air vessel say to a distance of four or five thousand miles and so
control its course either gyroscopically or electrically that it will land at
the exact spot where it is intended to have it land, within a few feet, and its
cargo of explosive can there be detonated.
"This cannot be done by means
of the present wireless plants, but with a proper plant it can be done. We have here the appalling prospect of a war
between nations at a distance of thousands of miles, with weapons so
destructive and demoralizing that the world could not endure them. That
is why there must be no more war."
In the article "Faster Liners is Tesla's Dream" (New York Sun, June
5, 1935) he spoke about the transmission of propulsive power to ships at sea
"through the stratosphere."
"The principles of this high
tension power, generated by shore plants and transmitted through the upper
reaches of the air, illuminating the sky, turning night into day and at the
same time supplying power, have occupied Dr. Tesla's attention on and off now
for the past thirty-five years. . . .
"There is a method of
conveying great power to ships at sea which would be able to propel them across
oceans at high speed. . . .
"The principle is this.
A ray of great ionizing power is used to give to the atmosphere great powers of
conduction. A high tension current of 10,000,000 to 12,000,000 volts is
then passed along the ray to the upper strata of the air, which strata can be
broken down very readily and will conduct electricity very well.
"A ship would have to have
equipment for producing a similar ionizing ray. The current which has
passed through the stratosphere will strike this ray, travel down it and pass
into the engines which propel the ship."
-- Nikola Tesla
Gary Peterson
