Loop Antennas

A balanced magnetic loop antenna is used to characterize the output of the
Tesla coil transmitter in the form of electromagnetic radiation, i.e., "radio
waves."

The physical size of the loop affects the capture ability of the loop.  The
larger the winding size the greater the pickup.  In other words, the larger
the loop diameter, the greater the efficiency.

	 "A small loop antenna appears as a very large resonant circuit.  The
loop itself can be viewed as a large single turn inductor of this circuit.
Due to the large (relatively speaking) size of this inductor, radiation very
easily takes place.  Experimenters have noticed that the more turns there are
to this inductor, the less efficient it is.  For some low frequency loop
antennas several turns may be required to obtain resonance but radiation
efficiency usually suffers.  Basically, the radiation resistance increases as
the loop size increases.  The higher the radiation resistance, the higher the
efficiency assuming a constant loss resistance.  Increasing the number of
turns in a loop increases the inductance but also increased the loss
resistance.  Taken to the extreme, ordinary tank circuits don't radiate much
at all due to the small, multiturn inductors. . . .

	 "[Interestingly] There have been claims that a vertical small loop
does not suffer from the pseudo-Brewster angle notch-out effect that other
vertical antennas will have when installed over real ground.  I have not
uncovered any theory to back this up and my first thought would be that a
vertical small loop should act like any other vertical antenna in this
regard.  However, the real world experience of users would indicate that this
phenomenon may need further investigation. . . ." [
http://www.aa5tb.com/loop.html ]



G). The physical size of the Loop Tank Coil affects the overall pickup
(capture ability) of the loop.  The larger the winding size the greater the
pickup. Larger loops will also be easier to balance than smaller ones.

H). The Tuning Sharpness "Q" is determined by the size of the wire (surface
area).  The lower the resistance the higher the "Q" will be. The loading of
the Tank Coil also affects the "Q".  This more than wire resistance affects
the Transformer Coupled Loop.  In a Transformer Loop, the placement of the
Link Coil in relation to the main tank (distance) determines the amount of
coupling, and hence the loading of the tank circuit.  The point of critical
coupling can be found by varying the coupling link distance, while comparing
tuning sharpness and gain. the critical coupling point will be found at the
sharpest tuning before the gain starts to drop.  Tuning will continue to
sharpen (slightly), but gain will fall off more rapidly, as one couples more
loosely (moving the link physically farther from the Tank Coil).  Further
improvement can be had by matching the load impedance to the link coil with a
matching transformer.  This can be done as part of a balun, or following the
balun (lead-in side).  For optimum performance all impedance’s in the system
should be properly matched.

Source: http://www.frontiernet.net/~jadale/Loop.htm



A small loop antenna appears as a very large resonant circuit. The loop itself
can be viewed as a large single turn inductor of this circuit. Due to the
large (relatively speaking) size of this inductor, radiation very easily takes
place.  Experimenters have noticed that the more turns there are to this
inductor, the less efficient it is.  For some low frequency loop antennas
several turns may be required to obtain resonance but radiation efficiency
usually suffers.  Basically, the radiation resistance increases as the loop
size increases.  The higher the radiation resistance, the higher the
efficiency assuming a constant loss resistance.  Increasing the number of
turns in a loop increases the inductance but also increased the loss
resistance.  Taken to the extreme, ordinary tank circuits don't radiate much
at all due to the small, multiturn inductors. . . .

[Interestingly] There have been claims that a vertical small loop does not
suffer from the pseudo-Brewster angle notch-out effect that other vertical
antennas will have when installed over real ground.  I have not uncovered any
theory to back this up and my first thought would be that a vertical small
loop should act like any other vertical antenna in this regard.  However, the
real world experience of users would indicate that this phenomenon may need
further investigation. . . .

Construction of a small loop is pretty straight forward.  Simply choose the
desired loop diameter based upon materials available and performance desired.
The larger the loop diameter, the greater the efficiency.  If it is made
larger then about 1/10 wavelength in circumference it will no longer be
classified a small loop and its radiation pattern will begin to change. . . .

Also note that the programs will inform you of a maximum loop circumference
for the loop that will give you the so called small loop performance. If the
diameter of the loop is increased beyond this value the efficiency will
increase but the pattern will change. The extreme example of this would be if
you were to increase the size to a full wavelength. The efficiency would be
very high and the pattern (broadside pattern) would be opposite that of a
small loop. Many small loop antenna experimenters recommend circumference of
0.25 wavelengths as a good compromise between efficiency and useful pattern.

Source: http://www.aa5tb.com/loop.html

Here is a link to a good reference on loops for measuring signal strength:

     http://www.vk1od.net/shieldedloop/index.htm

Not very sensitive unfortunately.  More turns on larger loop = bigger
signal = more problems in interpreting measurements.

Ed

On Sun, 1 Feb 2009, Ed Phillips wrote:

>     Sorry, but as I've pointed outbefore that part about a small loop
> appearing as a "very large resonant circuit"  is dead wrong,

When was that?  The correct phrase is:  for absorbing incoming EM waves,
the effective aperature of an electrically small loop antenna is greatly
increased by having the loop be a part of a high-Q tank circuit.

To state this in simple terms for the general public, we'd say that small
receiving antennas "become larger" when resonance is added. (Obviously
this only works with electrically small loops where diameter << wavelength
of operation.)

General public aside, changes in the EA of absorbers really do mimic a
change in antenna
size in several ways.  Receiving aperture is not purely a mathematical
artifact or impedance change.  Receiver loops with large EAs will also
generate stronger local fields in the nearfield ...as if the antenna's
dipole length was physically longer.  And downstream of the antenna, a
larger "EM shadow" is being cast.

Ideally, quite a small receiving loop can behave the same as a longwire
halfwave dipole.  By "Ideally" I mean "if materials of sufficiently low
resistance were available."  Gedanken experiment: if Q value can be made
enormous, then even millimeter-sized point-like antennas can behave as
halfwave longwire antennas of any length desired.


Here are papers discussing the phenomenon as applied to classical EM
interactions with small suspended particles and with atoms:

    Abstracts of Bohren and Paul/Fischer papers
    http://amasci.com/tesla/dipole1.html



In the 1980s some guys at NASA managed to build an active loop antenna for
ELF frequencies by intentionally harnessing this same effect.  They say
they achived much higher S/N than they did by simply amplifying the
loop's output signal.





   I'd suggest consulting a reliable
> reference book on the real properties of "small loops", where small
> means diameter or other critical dimension  less than maybe 0.01 wavelength.
>
> Ed
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

(((((((((((((((((( ( (  (   (    (O)    )   )  ) ) )))))))))))))))))))
William J. Beaty                            SCIENCE HOBBYIST website
billb at amasci com                         http://amasci.com
EE/programmer/sci-exhibits   amateur science, hobby projects, sci fair
Seattle, WA  206-762-3818    unusual phenomena, tesla coils, weird sci

This feedback antenna circuit may increase sensitivity to low level 'Tesla wave' signals while at the same time minimizing the influence of stray capacitive and inductive reactances. The design is based upon the negative resistance, negative inductance circuit found in U.S. Patent No. 5,296,866, Mar. 22, 1994, Active Antenna, GSC-13449, J.F. Sutton (NASA).  See http://www.tfcbooks.com/articles/tws5.htm for additional information.

A regenerative Tesla coil receiver using modern components.

> In the 1980s some guys at NASA managed to build an active loop antenna for
> ELF frequencies by intentionally harnessing this same effect. They say
> they achived much higher S/N than they did by simply amplifying the
> loop's output signal. -- B.B.

Hello,

I just found this group while searching for parts for my next Tesla
experiment.  Since this is right up my ally, I thought I would join.
I started working on Tesla transmission this time last year.  However,
I've been researching Tesla's literature for nearly 3 years prior.

So far I've been able to light 25 Watt incandescent bulbs a max
distance of about 14-20 meters using a wire as my ground plane.
Unfortunately my first coil was constructed wrong.  My "Extra" coil
was too low an inductance and is basically swamped by my secondary.
This means my standing wave is too feeble to work with anything but
very conductive grounds.  My top capacity is also WAY too small.

I'm in the process of building a parts list for a more improved system
that will more closely resemble patent 1,119,732 - which I feel is the
proper construction for Tesla's system, both for receiving and
transmitting.  If anyone has suggestions in the way of components
(such as capacitors, power supplies, etc.) let me know.

Thanks,
Charlie

Hello,

I just found this group while searching for parts for my next Tesla
experiment. Since this is right up my ally, I thought I would join.
I started working on Tesla transmission this time last year. However,
I've been researching Tesla's literature for nearly 3 years prior.

So far I've been able to light 25 Watt incandescent bulbs a max
distance of about 14-20 meters using a wire as my ground plane.
Unfortunately my first coil was constructed wrong. My "Extra" coil
was too low an inductance and is basically swamped by my secondary.
This means my standing wave is too feeble to work with anything but
very conductive grounds. My top capacity is also WAY too small.

I'm in the process of building a parts list for a more improved system
that will more closely resemble patent 1,119,732 - which I feel is the
proper construction for Tesla's system, both for receiving and
transmitting. If anyone has suggestions in the way of components
(such as capacitors, power supplies, etc.) let me know.

Thanks,
Charlie"

     Very impressive!  Please give us a lot more details of this
experiment including power input, operating frequency, drawing or photo
of experimental setup, etc..

Ed

Hi Charlie,

Thanks for the pictures and the excellent descriptions - they help to
clarify your interesting setup. I think I understand why you have gotten
better results when not using an Earth ground instead of a direct wire.
Normally, displacement (capacitive) current that drives the topload is
balanced by a similar current from the base of the driver/resonator in
your transmitter. This current is typically amperes, or 10's of amperes
for larger coils.

If you remove this ground and instead connect the base of your
transmitter ONLY to the base of the receiver, the system behavior
becomes significantly more complex. RF energy now transfers directly
from the base of your transmitter to the base of the receiver and back
into the transmitter in a complex manner that is highly dependent on the
relative operating frequencies of the transmitting and receiving systems
and receiver loading. In a tuned system driven from a spark gap or solid
state switched system, you can actually see the transmitting resonator
ring down while the receiving resonator rings up (as energy transfers to
the receiver) and then vice versa (as energy transfers back to the
transmitter). With the direct wire connection and identically tuned
resonators, the two systems are actually quite tightly coupled. And,
because of the direct RF current path, performance is not very sensitive
to the distance between resonators. As one system drives the other,
there is significant current flowing through the common wire that links
them, and the peak voltage on the wire link may reach hundreds, or even
thousands of volts for larger systems.

A close analogy to this system is called a "bipolar twin": Two
resonators and toploads, tuned to the same frequency, have their bases
connected together and the coils are then operated 180 degrees out of
phase. Although most coilers drive both coils with separate primaries,
you can get almost identical performance by driving a single
("transmitting") resonator. Base current coming out of the transmitting
resonator directly feeds/drives the base of the receiver, and efficient
power transfer can occur without any need for a separate Earth ground.
The high base current that would have normally have flowed to Earth
ground (for a single resonator) now flows instead through the
interconnecting wire to drive the other resonator. The "return" path is
through the topload and resonator self-capacitances of both resonators
to ground

If you instead were to ground the transmitter, its displacement current
can now flow directly into the Earth and, at larger separation
distances, the two resonators will become quite loosely coupled. The
reduced coupling causes dramatic reductions in the amount of energy you
can draw from the receiving resonator. The system you currently have is
similar to a one-wire power transmission system proposed by Tesla. Tesla
eventually believed he could eliminate the interconnecting wire and
instead use the Earth to provide the connection between resonators
(i.e., Wardenclyffe). However, as you have seen, this approach tends to
dramatically reduce energy transfer efficiency with distance versus a
direct-wire connection.

In future experiments, you may want to try increasing the number of
turns on the transmitting and receiving coils so that you operate
significantly below commercial broadcast bands. Try using frequencies
below 100 kHz. You may want to use some Tesla Coil design tools to help
design your system. The Tesla Coil Mailing List would be a good start -
you can sign up at http://www.pupman.com. Check out the archives on the
site and also the recommended design tools, such as Bart Andersons's
Java TC or FANTC programs. Although you can use these to design entire
systems, they can also help you design just a secondary and topload.

By increasing the number of turns on the resonators, you'll dramatically
increase the Q of both. While this will make tuning more
sensitive/difficult, it will improve the observed energy transfer
efficiency of the overall system. Whether you use a magnifier (a bit
more difficult to tune) or a simple 2-coil system shouldn't matter with
respect to RF energy transmission experiments. Logistically, a 2-coil
transmitter may be easier to use.

Other comments are below:

Charles Van Neste wrote:
> Hi everyone,
>
> I've attached some pictures of my experiment.  At least I've attached
> them to this email.  Is there a more official way of posting pictures?
> Please don't laugh, I know its not the best Tesla coil ever made haha.
> The first two pictures show the setup.  This is one of the first
> experiments and the transmission distance is pretty close, about 2-3
> meters.  I'm in the second picture to give you an idea of how big the
> transmitter is (I'm about 6ft tall).

The pictures came through just fine. This is apparently one of the few
forums where posting of images via email is permitted.

>
> I wanted to talk about my ground wires a little.  Unfortunately, I
> haven't had good success using an earth ground.  I've used all types of
> wires as my ground though: bare, insulated, coax.  I've let them lay on
> the ground (both indoors and out), suspended them, placed metal objects
> on/around them in different directions, and even touched them with my
> hands (haha I don't advice this - atleast not with a well designed
> system, mine is crappy and I can get away with stupid stuff like that).
> They all give the same result with no difference.  The length of the
> ground wire (from what I've tested) didn't seem to affect it either..
> But I imagine you have to get very far before the ground wire length
> becomes an issue.

Yes, since it is a direct path for RF current to flow between tuned
resonators, there is considerably less attenuation with distance than
with a "wireless" system that uses independent local grounds on each
resonator.

>
> My T-coil is in a high voltage lab and I've dragged a wire down the
> hall, out the main door and into the parking lot (about 20 meters) and
> there was no difference in intensity.  As long as the ground connects
> the transmitter to the receiver, the light bulb turns on, if you
> disconnect it, the light bulb goes off.  This appears to tell me 2
> things, one is that it is not magnetic or electrostatic induction, and
> two, it is some sort of "ground wave" that propagates along the wire.

You're currently generating an RF current that directly links
("couples") the two resonators together. Each resonator is then
capacitively coupled to the Earth, completing the overall energy flow
"circuit". Grounding the common feed wire at any point will divert some
of the displacement current, reducing RF current flow through the direct
connection and reducing observed power transfer performance between
resonators. Removing the wire entirely reduces performance even more.

> I have tried to use an earth ground (the connection points separated by
> about 4 feet).  I ran a wire out the window of the lab and connected to
> a 3 foot spike in the ground outside.  4 feet away another spike was
> placed and the receiver's ground wire was attached to that.  It sort of
> worked but you could barely see any light from the bulb.  I recently
> tried using a creek as my ground wire (the water in the creek anyway).
> But the water measured a resistance of about 15 Mega Ohms and the bulb
> again did not light.  My Tesla coil is a horrible design (it was my very
> first).  I really think that is where all my failures derive from -
> faulty design.

I suspect your design is fine - grounding the system effectively reduces
the coupling between the two resonators, reducing energy transfer
efficiency.

>
> I need a stronger standing wave since it appears the strength of the
> standing wave in the transmitter is what generates a good ground wave.
> I say this because my first design used 750kHz and had a standing wave
> voltage of about 150kV (pretty crappy for a Tesla coil).  When I lowered
> the height of my extra coil, the frequency dropped to 580kHz but the
> standing wave voltage became something like ~250kV and the efficiency of
> the system went from about 10% to about 50%.

Using a larger tank capacitor and more efficient (higher inductance)
resonators will help. Lowering the frequency may also help to reduce
other losses in the system.

>
> Earlier I said I didn't think it was electrostatic induction because my
> receiver is just a coil, it has no top load at all.  The coil is the
> same resonant frequency as the transmitter and that seems to be the only
> requirement (that and a good ground connection).  I think lowering my
> operating frequency and actually building a REAL Tesla coil will allow
> me to transmit through the earth/water/sea.

Even an open vertical resonator (no topload) will have a very well
defined set of resonant frequencies due to the distributed capacitance
of the windings versus ground. Directly base-driving this resonator at
its natural frequency will allow it to ring up and store energy almost
as well as resonator with a topload. Adding a topload and increasing
resonator inductance should improve efficiency no matter which coupling
methods you use.

>
> I will be presenting a Tesla experiment I'm working on at an
> international IEEE conference in Italy this June.  I'm always learning
> something new about Tesla transmission, just when I think I have it
> figured out I get thrown a curve ball haha.  But I believe that Tesla
> had 2 modes of transmission.  In the beginning he tried using the
> ionosphere to transmit, but later in Colorado Springs he discovered the
> ground technique.  The ground technique does not use the air directly,
> it uses those ground waves I talked about earlier.  In his later
> writings the ground technique is all he seems to mention.

I agree. He actually proposed many systems of RF power transmission
including single wire (US Patent #000593138), rarefied gas (#000645576,
000649621), various Earth/media systems (000685953, 000685954,
000685955, 000685956, 000723188, 000725605, 000787412), culminating in
the Wardenclyffe system (001119732). I suspect that Tesla realized that
the rarefied conduction approach was technically impractical, and he
focused instead on more potentially feasible approaches.

> Also reading Tesla's work, it makes me think these waves are reactive.

Yes - the energy that's rung up and stored within the resonator is
purely reactive (except for losses).

> Meaning real power is not used until a load is placed on the receiver.

Yes (except for losses in the reactive circuits)

> At this point the receiver pulls the energy out of the system,
> otherwise, the transmitter does not disapate energy as in radio
> transmission.

Close... The Tesla transmitting coil "sees" a local environment that is
primarily reactive ("near-field" inductance and capacitance associated
with the resonator and topload). Because of the long wavelength versus
resonator length, there is very little energy actually "lost"
(transmitted) as electromagnetic radiation. However, there are still
some losses associated with winding resistance, skin effect, ground
resistance, etc.


> It is well known that low frequency radio will also
> couple to the ground and can be transmitted very far in this fashion.

As an EM wave, yes. But, that is not what you are seeing.

> However, this is radiated energy that is lost (already pulled from the
> system upon generation).

True for a radiating EM system.

> This makes the Tesla system way more
> efficient.  Plus, I don't think long distance radio has ever powered
> light bulbs haha!

I suspect you're seeing direct RF conduction, where the far end tuned
resonator "looks" like an RF conjugate "load" to the transmitter - a
mirror image of the transmitter, 180 degrees out of phase. This allows
significant energy to be transfered from transmitter to receiver and
back (if you're lightly loading it). Energy not drawn by the receiver's
load, is effectively reflected back to the transmitter since the two
systems so tightly coupled. This coupling is dramatically reduced if you
independently ground the transmitter and receiver and remove the direct
wire link. Although it is still possible to transfer energy between the
two systems via the weaker electrostatic coupling between toploads and
decreasing voltage fields in the resistive soil around the transmitter,
the coupling and efficiency is no longer anywhere close to that of the
one-wire directly linked system.

BTW, folks who live near radio transmitters often have a lighting
problem - their fluorescent lights may not fully turn off due to the
E-field of the nearby transmitting antenna(s)... :^)

>
> I hope this answered some of your questions.  Unfortunately, these are
> the only pictures I can offer at this time and they are not very
> impressive - sorry.  Let me know if you have more - and please remember
> I still learning and what I think now could be drastically different in
> 3 months time.
>
> Charlie

I am very impressed with your setup, research, and experiments. I wish
you good luck with future experiments and continued success in your
career. Please keep us posted of future experiments or if you have any
questions.

Best wishes,

Bert Hickman
Stoneridge Engineering
--
***************************************************
We specialize in UNIQUE items! Coins shrunk by huge
magnetic fields, Lichtenberg Figures (our "Captured
Lightning") and out of print technical Books. Visit
Stoneridge Engineering at http://www.teslamania.com
***************************************************

Charlie:

     Your last two notes are very interesting are are clear enough about
how you are doing your experiments.  How about sending along Bert's
private note?  I suspect his conclusions were about the same as mine as
to what your  experiment really represents but I'd like to check before
making my own comments and suggestions.  I do have one general
suggestion though.  Use metallic electrodes for your spark gap rather
than the carbon - I think they'll work a lot better.

Ed

Sure wish I had that much free lab space!!!!!!!!!!!!!!!!!!!

Within the framework of Classical Electrodynamics (CED) it is common practice to choose freely an arbitrary gauge condition with respect to a gauge transformation of the electromagnetic potentials.  The Lorenz gauge condition allows for the derivation of the inhomogeneous potential wave equations (IPWE), but this also means that scalar derivatives of the electromagnetic potentials are considered to be unphysical. 

A GENERALIZATION OF CLASSICAL ELECTRODYNAMICS FOR THE PREDICTION OF SCALAR FIELD EFFECTS
http://www.teslaradio.com/pages/electrodynamics.pdf

Koen J. van Vlaenderen
Institute for Basic Research

(2008)

Abstract

Within the framework of Classical Electrodynamics (CED) it is common practice to choose freely an arbitrary gauge condition with respect to a gauge transformation of the electromagnetic potentials.  The Lorenz gauge condition allows for the derivation of the inhomogeneous potential wave equations (IPWE), but this also means that scalar derivatives of the electromagnetic potentials are considered to be unphysical.  However, these scalar expressions might have the meaning of a new physical field, S.  If this is the case, then a generalised CED is required such that scalar field effects are predicted and such that experiments can be performed in order to verify or falsify this generalised CED. The IPWE are viewed as a generalised Gauss law and a generalised Ampe`re law, that also contain derivatives of S, after reformulating the IPWE in terms of fields.

Since charge is conserved, scalar field S satisfies the homogeneous wave equation, thus one should expect primarily sources of dynamic scalar fields, and not sources of static scalar fields. The collective tunneling of charges might be an exception to this, since quantum tunneling is the quantum equivalent of a classical local violation of charge continuity. Generalised power/force theorems are derived that are useful in order to review historical experiments since the beginning of electrical engineering, for instance Nikola Tesla's high voltage high frequency experiments. Longitudinal electro-scalar vacuum waves, longitudinal forces that act on current elements, and applied power by means of static charge and the S field, are predicted by this theory.  The energy density and field stress terms of scalar field S are defined.

Some recent experiment show positive results that are in qualitative agreement with the presented predictions of scalar field effects, but further quantitative tests are required in order to verify or falsify the presented theory. The importance of Nikola Tesla's pioneering research, with respect to the predicted effects, cannot be overstated.

Classical electrodynamics deals with electric and magnetic fields and interactions caused by macroscopic distributions of electric charges and currents. This means that the concepts of localised electric charges and currents assume the validity of certain mathematical limiting processes in which it is considered possible for the charge and current distributions to be localised in infinitesimally small volumes of space.

ELECTROMAGNETIC FIELD THEORY
http://www.teslaradio.com/pages/electromagnetics_2008.pdf

Bo Thidé

Swedish Institute of Space Physics
Uppsala, Sweden

and

Department of Astronomy and Space Physics
Uppsala University, Sweden

and

LOIS Space Centre
School of Mathematics and Systems Engineering
Växjö University, Sweden

(2008)
 
1

Classical Electrodynamics

Classical electrodynamics deals with electric and magnetic fields and interactions caused by macroscopic distributions of electric charges and currents. This means that the concepts of localised electric charges and currents assume the validity of certain mathematical limiting processes in which it is considered possible for the charge and current distributions to be localised in infinitesimally small volumes of space. Clearly, this is in contradiction to electromagnetism on a truly microscopic scale, where charges and currents have to be treated as spatially extended objects and quantum corrections must be included. However, the limiting processes used will yield results which are correct on small as well as large macroscopic scales.  It took the genius of JAMES CLERK MAXWELL to unify electricity and magnetism into a super-theory, electromagnetism or classical electrodynamics (CED), and to realise that optics is a subfield of this super-theory. Early in the 20th century, Nobel laureate HENDRIK ANTOON LORENTZ took the electrodynamics theory further to the microscopic scale and also laid the foundation for the special theory of relativity, formulated by Nobel laureate ALBERT EINSTEIN in 1905. In the 1930s PAUL A.M. DIRAC expanded electrodynamics to a more symmetric form, including magnetic as well as electric charges. With his relativistic quantum mechanics, he also paved the way for the development of quantum electrodynamics (QED) for which RICHARD P. FEYNMAN, JULIAN SCHWINGER, and SIN-ITIRO TOMONAGA in 1965 received their Nobel prizes. Around the same time, physicists such as Nobel laureates SHELDON GLASHOW, ABDUS SALAM, and STEVEN WEINBERG managed to unify electrodynamics with the weak interaction theory to yet another super-theory, electroweak theory. The modern theory of strong interactions, quantum chromodynamics (QCD), is influenced by QED.

In this chapter we start with the force interactions in classical electrostatics and classical magnetostatics and introduce the static electric and magnetic fields and find two uncoupled systems of equations for them. Then we see how the conservation of electric charge and its relation to electric current leads to the dynamic connection between electricity and magnetism and how the two can be unified into one `supertheory', classical electrodynamics, described by one system of coupled dynamic field equations—the Maxwell equations.

At the end of the chapter we study Dirac's symmetrised form of Maxwell's equations by introducing (hypothetical) magnetic charges and magnetic currents into the theory. While not identified unambiguously in experiments yet, magnetic charges and currents make the theory much more appealing for instance by allowing for duality transformations in a most natural way.

"The scientist makes use of a whole arsenal of concepts which he imbibed
practically with his mother's milk; and seldom if ever is he aware of
the eternally problematic character of his concepts.  He uses this
conceptual material, or, speaking more exactly, these conceptual tools
of thought, as something obviously, immutably given; something having an
objective value of truth which is hardly even, and in any case not
seriously, to be doubted. . . . In the interests of science it is
necessary over and over again to engage in the critique of these
fundamental concepts, in order that we may not unconsciously be ruled by
them."

My secondary coil is roughly a 500 meter long AWG 14 wire and should resonate at
approximately 150 kHz. I am "measuring" roughly 300 kHz with an oscilloscope
some distance away.

Is the coil operating in Lambda/2 instead of Lambda/4 mode?
Am I seeing just a harmonic on the oscilloscope but why am I not seeing the
primary frequency?
Is the primary coil operating at the wrong frequency?

The secondary is grounded to the house water pipe. The primary's "sweet spot"
was found through experimenting, drawing the longest spark by far to ground. The
coil is operated with a grounded light bulb near the top terminal but not close
enough to draw sparks but close enough to "draw energy" and to make the system
less susceptible to capacitive changes in its environment (i.e. myself moving
around nearby).

Any ideas on how to explain the higher frequency would be appreciated.
Thanks
Gerhard

Need much better details of the coil.  Diameter, length, wire size,
spacing between turns?????  Have you excited it at the base to measure
all of the resonances starting with low frequency and going higher?

Ed

"My secondary coil is roughly a 500 meter long AWG 14 wire and should
resonate at approximately 150 kHz. I am "measuring" roughly 300 kHz with
an oscilloscope some distance away.

Is the coil operating in Lambda/2 instead of Lambda/4 mode?
Am I seeing just a harmonic on the oscilloscope but why am I not seeing
the primary frequency?
Is the primary coil operating at the wrong frequency?

The secondary is grounded to the house water pipe. The primary's "sweet
spot" was found through experimenting, drawing the longest spark by far
to ground. The coil is operated with a grounded light bulb near the top
terminal but not close enough to draw sparks but close enough to "draw
energy" and to make the system less susceptible to capacitive changes in
its environment (i.e. myself moving around nearby).

Any ideas on how to explain the higher frequency would be appreciated.
Thanks
Gerhard

Hi Gerhard,

What is the diameter of your secondary and coil winding length, and what
   are you using for a topload?

In addition to resonating at the fundamental frequency, your secondary
will also resonate at various higher frequency harmonics. These higher
order modes will result in voltage peaks occurring inside the winding as
well as near the top. A badly tuned system (say where the primary is
resonant at half the natural frequency of the secondary), will still
excite the secondary. However, not as efficiently, and possibly with
secondary flashovers or primary-to-secondary flashovers as well.

Bert
--
***************************************************
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Lightning") and out of print technical Books. Visit
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meintesla wrote:
> My secondary coil is roughly a 500 meter long AWG 14 wire and should
> resonate at approximately 150 kHz. I am "measuring" roughly 300 kHz
> with an oscilloscope some distance away.
>
> Is the coil operating in Lambda/2 instead of Lambda/4 mode? Am I
> seeing just a harmonic on the oscilloscope but why am I not seeing
> the primary frequency? Is the primary coil operating at the wrong
> frequency?
>
> The secondary is grounded to the house water pipe. The primary's
> "sweet spot" was found through experimenting, drawing the longest
> spark by far to ground. The coil is operated with a grounded light
> bulb near the top terminal but not close enough to draw sparks but
> close enough to "draw energy" and to make the system less susceptible
> to capacitive changes in its environment (i.e. myself moving around
> nearby).
>
> Any ideas on how to explain the higher frequency would be
> appreciated. Thanks Gerhard
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>

Ed:
Thanks for trying to help out.

The secondary is wound on a 88 cm high wooden whiskey barrel 56 cm diameter on
top and bottom, 65 cm in the middle. All iron rings have been removed from
barrel.

Bare wire diameter 1.6 mm, the wire is insulated, with insulation:2.7 mm
diameter. Bare wire spacing ~ 1.4 mm on average. 276 windings

The primary is a cylindrical (top diameter slightly larger than bottom diameter)
coil starting at a height of about 12 cm from the bottom going up to 24 cm
height with 5 windings of 6 AWG wire at a distance of 9 - 12 cm from secondary
coil.

Topload is a 20 cm diameter steel sphere 33 cm above last winding

I have tried to excite the secondary at the base with a frequency generator (to
measure coil resonance) but it turned out that the generator had bands with no
output so the results were not conclusive.

Hope this helps a little
Gerhard


--- In wireless_energy_transmission@yahoogroups.com, Ed Phillips <evp2@...>
wrote:
>
>     Need much better details of the coil.  Diameter, length, wire size,
> spacing between turns?????  Have you excited it at the base to measure
> all of the resonances starting with low frequency and going higher?
>
> Ed
>
> "My secondary coil is roughly a 500 meter long AWG 14 wire and should
> resonate at approximately 150 kHz. I am "measuring" roughly 300 kHz with
> an oscilloscope some distance away.
>
> Is the coil operating in Lambda/2 instead of Lambda/4 mode?
> Am I seeing just a harmonic on the oscilloscope but why am I not seeing
> the primary frequency?
> Is the primary coil operating at the wrong frequency?
>
> The secondary is grounded to the house water pipe. The primary's "sweet
> spot" was found through experimenting, drawing the longest spark by far
> to ground. The coil is operated with a grounded light bulb near the top
> terminal but not close enough to draw sparks but close enough to "draw
> energy" and to make the system less susceptible to capacitive changes in
> its environment (i.e. myself moving around nearby).
>
> Any ideas on how to explain the higher frequency would be appreciated.
> Thanks
> Gerhard
>

Hi Gerhard,

It's possible that the combination of your tank capacitor and primary
winding can't be tuned low enough to be in tune with your
secondary/topload. You didn't mention the size of your tank capacitor so
I can't model your primary circuit to see if this might be the problem.

The added capacitance of your topload will also lower the operating
frequency of your secondary. If you don't have enough primary turns to
lower the primary frequency to match, then you may end up tuning your
primary so that it resonates with the next higher harmonic of your
secondary. In this case you will get some output, but not nearly as much
as when you are in proper tune. You could try increasing the size of
your tank capacitor or adding some more turns to your primary to see if
you can bring it into proper tune.

Bert

meintesla wrote:
> Ed: Thanks for trying to help out.
>
> The secondary is wound on a 88 cm high wooden whiskey barrel 56 cm
> diameter on top and bottom, 65 cm in the middle. All iron rings have
> been removed from barrel.
>
> Bare wire diameter 1.6 mm, the wire is insulated, with insulation:2.7
> mm diameter. Bare wire spacing ~ 1.4 mm on average. 276 windings
>
> The primary is a cylindrical (top diameter slightly larger than
> bottom diameter) coil starting at a height of about 12 cm from the
> bottom going up to 24 cm height with 5 windings of 6 AWG wire at a
> distance of 9 - 12 cm from secondary coil.
>
> Topload is a 20 cm diameter steel sphere 33 cm above last winding
>
> I have tried to excite the secondary at the base with a frequency
> generator (to measure coil resonance) but it turned out that the
> generator had bands with no output so the results were not
> conclusive.
>
> Hope this helps a little Gerhard
>
>
> --- In wireless_energy_transmission@yahoogroups.com, Ed Phillips
> <evp2@...> wrote:
>> Need much better details of the coil.  Diameter, length, wire size,
>>  spacing between turns?????  Have you excited it at the base to
>> measure all of the resonances starting with low frequency and going
>> higher?
>>
>> Ed
>>
>> "My secondary coil is roughly a 500 meter long AWG 14 wire and
>> should resonate at approximately 150 kHz. I am "measuring" roughly
>> 300 kHz with an oscilloscope some distance away.
>>
>> Is the coil operating in Lambda/2 instead of Lambda/4 mode? Am I
>> seeing just a harmonic on the oscilloscope but why am I not seeing
>>  the primary frequency? Is the primary coil operating at the wrong
>> frequency?
>>
>> The secondary is grounded to the house water pipe. The primary's
>> "sweet spot" was found through experimenting, drawing the longest
>> spark by far to ground. The coil is operated with a grounded light
>> bulb near the top terminal but not close enough to draw sparks but
>> close enough to "draw energy" and to make the system less
>> susceptible to capacitive changes in its environment (i.e. myself
>> moving around nearby).
>>
>> Any ideas on how to explain the higher frequency would be
>> appreciated. Thanks Gerhard
>>

Hello Charlie:

This is good advice and I can understand the effect that the hand would have
when placed near the upper half of the secondary.

How would this procedure help me understand why the coil would not resonate at
Lambda/4 of its wire length? In other words if the wire length is 500 meters why
would it not resonate around 150 kHz but rather at around 300 kHz? (Probably a
very naive question but I had to ask)

Gerhard

--- In wireless_energy_transmission@yahoogroups.com, Charles Van Neste
<cwvanneste@...> wrote:
>
> Try placing the primary with the secondary (the primary near the bottom of the
secondary), then exciting the secondary with a function generator at the
bottom.  Hook the primary up to an oscilloscope and sweep the function generator
from low frequency to high.  When you see the voltage peak on the o-scope,
that's usually the fundamental frequency (and it is usually the largest).  When
you find the first large peak, you can move your hand from the bottom of the
secondary coil to the top.  At the bottom, nothing should happen in the o-scope
reading when you move your hand, but at the top your hand should make a drastic
disturbance.  If you excite any higher harmonic standing wave, you'll find parts
along the coil that your hand effects and other areas (the nodes) where your
hand doesn't. 
>
> I have found that when you ground the secondary, the frequency will shift a
bit, but it keeps close to that range.
>
> Charlie
>
>

Hello Bert:

That was my initial thought too you could be right I probably tuned it to the
2nd harmonic.

Gerhard

--- In wireless_energy_transmission@yahoogroups.com, Bert Hickman
<bert.hickman@...> wrote:
>
> Hi Gerhard,
>
> It's possible that the combination of your tank capacitor and primary
> winding can't be tuned low enough to be in tune with your
> secondary/topload. You didn't mention the size of your tank capacitor so
> I can't model your primary circuit to see if this might be the problem.
>
> The added capacitance of your topload will also lower the operating
> frequency of your secondary. If you don't have enough primary turns to
> lower the primary frequency to match, then you may end up tuning your
> primary so that it resonates with the next higher harmonic of your
> secondary. In this case you will get some output, but not nearly as much
> as when you are in proper tune. You could try increasing the size of
> your tank capacitor or adding some more turns to your primary to see if
> you can bring it into proper tune.
>
> Bert
>
> meintesla wrote:
> > Ed: Thanks for trying to help out.
> >
> > The secondary is wound on a 88 cm high wooden whiskey barrel 56 cm
> > diameter on top and bottom, 65 cm in the middle. All iron rings have
> > been removed from barrel.
> >
> > Bare wire diameter 1.6 mm, the wire is insulated, with insulation:2.7
> > mm diameter. Bare wire spacing ~ 1.4 mm on average. 276 windings
> >
> > The primary is a cylindrical (top diameter slightly larger than
> > bottom diameter) coil starting at a height of about 12 cm from the
> > bottom going up to 24 cm height with 5 windings of 6 AWG wire at a
> > distance of 9 - 12 cm from secondary coil.
> >
> > Topload is a 20 cm diameter steel sphere 33 cm above last winding
> >
> > I have tried to excite the secondary at the base with a frequency
> > generator (to measure coil resonance) but it turned out that the
> > generator had bands with no output so the results were not
> > conclusive.
> >
> > Hope this helps a little Gerhard
> >
> >
> > --- In wireless_energy_transmission@yahoogroups.com, Ed Phillips
> > <evp2@> wrote:
> >> Need much better details of the coil.  Diameter, length, wire size,
> >>  spacing between turns?????  Have you excited it at the base to
> >> measure all of the resonances starting with low frequency and going
> >> higher?
> >>
> >> Ed
> >>
> >> "My secondary coil is roughly a 500 meter long AWG 14 wire and
> >> should resonate at approximately 150 kHz. I am "measuring" roughly
> >> 300 kHz with an oscilloscope some distance away.
> >>
> >> Is the coil operating in Lambda/2 instead of Lambda/4 mode? Am I
> >> seeing just a harmonic on the oscilloscope but why am I not seeing
> >>  the primary frequency? Is the primary coil operating at the wrong
> >> frequency?
> >>
> >> The secondary is grounded to the house water pipe. The primary's
> >> "sweet spot" was found through experimenting, drawing the longest
> >> spark by far to ground. The coil is operated with a grounded light
> >> bulb near the top terminal but not close enough to draw sparks but
> >> close enough to "draw energy" and to make the system less
> >> susceptible to capacitive changes in its environment (i.e. myself
> >> moving around nearby).
> >>
> >> Any ideas on how to explain the higher frequency would be
> >> appreciated. Thanks Gerhard
> >>
>

Hello Charlie:

This is good advice and I can understand the effect that the hand would
have when placed near the upper half of the secondary.

How would this procedure help me understand why the coil would not
resonate at Lambda/4 of its wire length? In other words if the wire
length is 500 meters why would it not resonate around 150 kHz but rather
at around 300 kHz? (Probably a very naive question but I had to ask)

Gerhard"

     Best answer is that the Lambda/4 business is more or less a myth for
most coil geometries.  A small-diameter grounded vertical antenna  will
be self-resonant at close to the quarter-wave frequency, probably
starting the myth.   The actual resonant frequency depends on coil
inductance and distributed capacitance [and also any toploading
capacitance].  I'm laid up at the moment but am intending to calculate
the expected resonant frequency of your secondary based on the geometric
information you sent.

Ed

Gerhard:

     I made a rough estimate of the resonant frequency of your coil,
assuming the sphere was somewhat higher than you say.  I get a resonant
frequency of about 180 kHz [not far from your estimate of 150] and a
ratio of wire length to wavelength of about 0.34, which appears to be
typical for a coil of that general length/width.  Resonant frequency
should be around 213 kHz without the coil and inductance should be
around 19.5 mH..  Numbers very approximate because of the shape of the
coil.  Didn't try to estimate primary inductance since you didn't give
the primary capacitance.

Ed

"Ed:
Thanks for trying to help out.

The secondary is wound on a 88 cm high wooden whiskey barrel 56 cm
diameter on top and bottom, 65 cm in the middle. All iron rings have
been removed from barrel.

Bare wire diameter 1.6 mm, the wire is insulated, with insulation:2.

7 mm diameter. Bare wire spacing ~ 1.4 mm on average. 276 windings

The primary is a cylindrical (top diameter slightly larger than bottom
diameter) coil starting at a height of about 12 cm from the bottom going
up to 24 cm height with 5 windings of 6 AWG wire at a distance of 9 - 12
cm from secondary coil.

Topload is a 20 cm diameter steel sphere 33 cm above last winding

I have tried to excite the secondary at the base with a frequency
generator (to measure coil resonance) but it turned out that the
generator had bands with no output so the results were not conclusive.

Hope this helps a little
Gerhard"

Charles:
As soon as I get my hand on a new frequency generator I will try that thank you.
Gerhard

--- In wireless_energy_transmission@yahoogroups.com, Charles Van Neste
<cwvanneste@...> wrote:
>
> Ed is right, the quarter wavelength stuff just gives a really gross estimate
and it all depends on the inductance and capacitance of the coil.  In my first
(and only for the moment) coil, the wire length is 150 meters (~500 feet), which
would give a quarter wave resonance at around 500kHz.  However, without the top
load, the quarter wave resonance is 800kHz!  With the top load, its 580kHz.  I'm
sure larger top loads would bring it down even more.
>
> Also, the technique I was advising would just let you know if your 300kHz is
really a quarter wave resonance since you could quickly determine with your hand
if you had the fundamental standing wave or harmonics there of.  Also what might
help is placing the o-scope across the primary winding, and apply the function
generator across the capacitor (shorting your spark gap if your using that). 
This way the capacitor and inductor looks like a tank circuit and you apply the
power from the function generator across the capacitor (in parallel with the
capacitor).  Then if you sweep the frequency, when the o-scope shows the highest
voltage peak, this will let you know what your primary circuit is resonating at
and you can adjust things from there (I'm not a fan of separating the primary
from secondary when determining resonances since I feel this gives a better
picture as to how things will act when in operation).
>
> Charlie
>
> --- On Tue, 3/10/09, Ed Phillips <evp2@...> wrote:
>
> From: Ed Phillips <evp2@...>
> Subject: Re: [wireless_energy_transmission] Re: Advice needed - details
> To: wireless_energy_transmission@yahoogroups.com
> Date: Tuesday, March 10, 2009, 5:08 PM
>
>
>
>
>
>
>
>
>
>
>
>
>             Hello Charlie:
>
>
>
> This is good advice and I can understand the effect that the hand would
>
> have when placed near the upper half of the secondary.
>
>
>
> How would this procedure help me understand why the coil would not
>
> resonate at Lambda/4 of its wire length? In other words if the wire
>
> length is 500 meters why would it not resonate around 150 kHz but rather
>
> at around 300 kHz? (Probably a very naive question but I had to ask)
>
>
>
> Gerhard"
>
>
>
> Best answer is that the Lambda/4 business is more or less a myth for
>
> most coil geometries.  A small-diameter grounded vertical antenna  will
>
> be self-resonant at close to the quarter-wave frequency, probably
>
> starting the myth.   The actual resonant frequency depends on coil
>
> inductance and distributed capacitance [and also any toploading
>
> capacitance] .  I'm laid up at the moment but am intending to calculate
>
> the expected resonant frequency of your secondary based on the geometric
>
> information you sent.
>
>
>
> Ed
>

http://www.ttr.com/corum/index.htm

See part III for a guide to measure your coil's characteristics.

From
Class Notes: Tesla Coils and the Failure of Lumped-Element Circuit Theory by
Kenneth L. Corum and James F. Corum, Ph.D. © 1999 by K.L. Corum and J.F. Corum

I am not claiming to understand this..

Charlie asked, 'would capacitive coupling not work in this case?'

Capacitive coupling is one of the proposed mechanisms for explaining the operation of Tesla wireless system demonstration apparatus in the absence of radio waves.  See WIRELESS TRANSMISSION THEORY ( http://www.teslaradio.com/pages/wireless_102.htm ) for an annotated list of the proposed mechanisms.

The principle objective at this time is to determine if data collected with our experimental realizations matches up with predictions based upon the 'theoretical capacitive coupling model' presently being advanced by Ed Phillips.

Regarding my July 2002 measurement of the Tesla coil transmitter's ordinary radio wave output, this was only one of a series of measurements taken on a series of Tesla coil transmitters, each existing in a more advanced state of refinement.  It was found that as the Tesla wireless system transmission range increased the output in the form of radio waves decreased.

Gary

--- In wireless_energy_transmission@yahoogroups.com, Charles Van Neste <cwvanneste@...> wrote:
>
> That is interesting Gary.  You could detect a signal at 1km but the radiation died away after 60 feet [meters]?  You know, doesn't capacitive coupling follow the same "inverse of the radius squared" law as magnetic coupling?  So wouldn't capacitive coupling not work in this case?
>
> Charlie
>
> --- On Mon, 3/16/09, Gary Peterson pete@... wrote:
>
> From: Gary Peterson pete@...
> Subject: [wireless_energy_transmission] EXPERIMENTAL REALIZATION OF A SMALL-SCALE TESLA WIRELESS SYSTEM
> To: wireless_energy_transmission@yahoogroups.com
> Date: Monday, March 16, 2009, 12:30 PM
>
>
>
> Ed,
>
> I continue to work on SCALING DOWN TESLA'S WIRELESS ENERGY TRANSMISSION SYSTEM FOR EXPERIMENTATION [ http://www.teslaradio.com/pages/scaling.htm ] in an effort to make it more understandable.
>
> I spent some time yesterday evening calibrating my DX-302 LF receiver's S-meter--the one that I used to collect the data from my July 27, 2002 1-kilometer Tesla wireless system demonstration (see http://www.teslaradio.com/pages/sstc-a.htm for the details).
>
> I have established a mimimum limit of 3.92E-12 watts of power output from the Tesla coil receiving transformer, with a maximum limit of 24 watts input to the Tesla coil transmitter.
>
> There were no measureable radio waves at 60 meters from the Tesla coil transmitter.
>
> I would be interested to learn what your theoretical capacitive coupling model predicts for comparison with my 2002 experimental realization.  Perhaps you could create an Excel Spreadsheet to perform the calculations?
>
> Gary
> ------------ --------- --------- --------- --------- --------- --------- --------- -----
> From: "Ed Phillips" evp@...
> Sent: Friday, March 13, 2009 3:46 PM
> To: g.peterson@...
> Subject: Re: You can call me on Thursday.
>
> Gary:
>
> Will call you if I feel like it . . .
>
> Ed
>

boxa wrote: no the inductive/capacitive effect going on does not follow the square laws of fields, thats why teslas system is alot different than basic radio and em radiation. from the research i have done the energy effect is just decreased over a distance instead of the square of distance, but when you obtain resonance of the system even distance has alot less of an effect, tesla even said it before, something like "there will be no distance to great for man using this system of communication and energy" something like that, obviously this system would have characteristics not associated with the em spectrum.. i didnt know you guys do this stuff on this site, i am happy i joined it! i got some great stuff comming along as well, i hope you guys will like it, i have shown the one wire transmission models on the small scale which is impressive because you obviously see that the energy travels down the small wire without loss but also thousands of feet of wire without loss that i have done experimentally on my own which is so exciting and further supports teslas wireless energy transfer, ok nice talking to other tesla enthusist...
 
boxa

Thanks for your response.  Now we need a mathematical capacitive-coupling model to compare with our experimental systems.  Any thoughts?

Regards, Gary

Mar 16, 2009 12:45:24 PM, wireless_energy_transmission@yahoogroups.com wrote:

That is interesting Gary.  You could detect a signal at 1km but the radiation died away after 60 feet?  You know, doesn't capacitive coupling follow the same "inverse of the radius squared" law as magnetic coupling?  So wouldn't capacitive coupling not work in this case?

Charlie

--- On Mon, 3/16/09, Gary Peterson <pete@...> wrote:

From: Gary Peterson <pete@...>
Subject: [wireless_energy_transmission] EXPERIMENTAL REALIZATION OF A SMALL-SCALE TESLA WIRELESS SYSTEM
To: wireless_energy_transmission@yahoogroups.com
Date: Monday, March 16, 2009, 12:30 PM

Ed,

I continue to work on SCALING DOWN TESLA'S WIRELESS ENERGY TRANSMISSION SYSTEM FOR EXPERIMENTATION [ http://www.teslaradio.com/pages/scaling.htm ] in an effort to make it more understandable.

I spent some time yesterday evening calibrating my DX-302 LF receiver's S-meter--the one that I used to collect the data from my July 27, 2002 1-kilometer Tesla wireless system demonstration (see http://www.teslaradio.com/pages/sstc-a.htm for the details).

I have established a mimimum limit of 3.92E-12 watts of power output from the Tesla coil receiving transformer, with a maximum limit of 24 watts input to the Tesla coil transmitter.

There were no measureable radio waves at 60 meters from the Tesla coil transmitter.

I would be interested to learn what your theoretical capacitive coupling model predicts for comparison with my 2002 experimental realization.  Perhaps you could create an Excel Spreadsheet to perform the calculations?

Gary