Tesla Coil Geometry and Cylindrical Coil Design

Tesla used a range of different coil geometries throughout his experimental work, including flat[1], cylindrical[2], conical[3] , and separated cylindrical secondary with an extra coil[4]. Each of these different geometries present different advantages and different limitations, and hence it is important for any experiment using a Tesla coil or TMT system to choose a coil geometry best suited to the type of experiment at hand. Different experiments are designed to study different aspects of electrical phenomena and qualities including, displacement and transference of electric power, radiant energy and matter, wireless, single wire, and low-loss transmission, longitudinal modes and cavity effects, plasma and dielectric effects etc.

The electrical dynamics and properties of different Tesla coil geometries is a complex and involved field, and has been much explored both theoretically and practically in the prior art, and notably including Dollard[5,6] and Corum et al.[7,8]. In the first part of this post we review some of the most important experimental considerations for coil geometry that I have observed and encountered throughout my research so far. In the second part we take a look at a cylindrical coil design suitable for plasma effects and other discharge phenomena when combined with an extra coil, and similar to a design by Eric Dollard for his cosmic induction generator.

Figures 1 below show the final cylindrical coil design in a variety of configurations, including a TMT system for transference of electric power experiments, induction generator plasma experiments, and both driven using the Quad 811A tube board. The detail of these experiments, phenomena and measurements will be reported in subsequent posts.

Coupling and Free Resonance

A Tesla coil can be considered to be a resonant air-cored transformer when excited by a linear sinusoidal drive to the primary coil. As such it is fundamentally important to ensure that as much energy as possible from the generator, is transferred from the primary coil to the secondary coil as quickly as possible, so the coupling between the two coils is maximised. At the same time, at least the secondary coil must be able to freely resonate according to the nature of its design and geometry, and with maximised quality factor and minimised resistive losses, requiring minimised coupling between the two coils. In some cases both the primary and secondary coils are arranged to resonate in tune with each other whilst maximising the resonant properties of the secondary. These two fundamental requirements of Tesla coils present a trade-off or balance that must be optimally struck in any TC design, and according to the intended application.

Maximising coupling of the primary and secondary implies tightly coupled coils which are in close proximity to each other, and that maximise the enclosed area of intersection of the magnetic field of induction, Φ. Increased coupling reduces the ability of the secondary coil to freely resonate at its fundamental resonant frequency, as it becomes increasingly driven by the primary, quenching the Q of the coil system, and tending towards a standard, magnetically coupled, non-resonant transformer.

The secondary coil on its own will freely resonate with maximum Q and impedance at the fundamental resonant frequency according to its design, geometry, and the materials used in its construction. As a primary coil is brought into proximity with the secondary the coupling starts to increase from zero and the properties of the two coils start to interact. With a non-zero coupling coefficient energy can now be transferred between the two coils, but the freely resonant properties of the secondary also start to change, influenced by the impedance characteristics of the primary, resonant or not.

The most optimum balance between these two requirements can be established in a separated secondary induction and extra coil arrangement, where tightly coupled induction can occur between the primary and secondary, whilst the free resonator properties of the coil system are maintained by the extra coil. This coil geometry is considered in more detail later in this post.

Field Distribution. Magnification and Compression

Magnification of the dielectric field of induction, Ψ, occurs from turn-to-turn of the secondary, starting from those turns most tightly coupled to the primary and enclosing the largest area of intersection with Φ from the primary. This magnification of Ψ is influenced by the geometry of the secondary through compression of the field distribution. In a cylindrical coil each turn moving away from the coupling region describes the same area and path length, which in principle leads to a uniform exponential increase in the magnification of Ψ.

In contrast, in a flat coil geometry each turn becomes smaller than the last as the turns move away from the outer coupling region. In this case Ψ is progressively compressed towards the centre of the coil increasing the magnification non-linearly towards the centre high-end of the coil, and leading to a highly non-linear dielectric induction field distribution. For the same number of turns Ψ is measurably higher towards the high-end in a flat coil, than for the same turn measurement in a cylindrical coil.

For coils designed to explore phenomena related to the imbalanced magnification of the dielectric field of induction Ψ e.g. attractive and repulsive forces, low temperature light emission and “cold” electricity, charge accumulation and storage, and “fern” effect discharges, then compression is particularly important in the geometry of the required coil. In this case a flat coil with many smaller turns to the centre, or a conical coil with turns concentrated towards the cone tip, are more suited to investigation of these kinds of phenomena.

Cylindrical coils, or separated secondary induction and extra coils, are better suited for experiments requiring a balance between Ψ and Φ e.g. for experiments in the displacement of electric power with a non-linear impetus, telluric and single wire transference of electric power in a TMT system, and plasma phenomena.

Charge Distribution, Conductor Volume and Surface Area, and boundary Conditions

If we consider the secondary coil to be a continuous metal conductor, at a typical resonant frequency between 10kc – 10Mc, then geometry effects considerably the charge storage and distribution across its surface. In the case of a flat coil the largest proportion of conductor is closer to the outer coupling region, and hence the distribution of charge on the conductor is biased towards the outer perimeter of the coil with less towards the centre. The effect of this is to electrically damp the resonant properties of the secondary towards the centre, so less energy can be stored and released in each resonant cycle, which in turn effects the amount of energy that can be coupled to the longitudinal mode within the cavity described by the secondary coil system.

In my own research I have found it to be critically important in coil design, for the purpose of investigating displacement events and their related phenomena e.g. radiant energy emissions, to ensure that we create a system which is best suited to sustain for as long as possible the coherent balance and continuity between the dielectric and magnetic fields of induction. In this way we so arrange our design to ensure that any generated displacement events occurring from or within the generator, from or within the medium conveying the electric power, and from or within any load thus designed to receive or utilise this power, will sustain the event for as long as possible and with amplitude such that it can be investigated and measured. Tesla[9] suggested and established this requirement clearly, in that the conducting boundary conditions for Ψ and Φ must ensure the maximum balance, continuity, and coherence for these two inter-dependent fields when moving from one section of an electrical system to another. In this way he established that the requirement between the primary and secondary of a magnifying transformer should be made from equal volumes of conductor.

From further investigation by others, notably Dollard[5,10], where the density of the conductor in the primary and secondary is the same, (e.g. for a primary and secondary both with copper as the conductor), equal volumes of the conductors can be considered equivalent to equal weights of the conductors, and has been found to apply best when working at lower frequencies where the skin effect does not have a significant effect on the impedance of the conductor, e.g. when working with normal copper or aluminium conductors at a frequency < 3000kc. At higher frequencies where the skin-effect can dominate the impedance of the conductor, balancing the bounding conditions for the two fields of induction can be better accomplished by equal surface area of the conductors.

In any calculation of equal weights or surface areas of the system conductors it is necessary to consider the overall resonant system of both the primary and secondary. For example, if the primary is tuned by a vacuum variable capacitor then this and the inter-connection conductors must be added to the calculation. If the secondary coil includes a top-load e.g. metal toroid, multi-wave oscillator resonator, or other conductive arrangement this must also be added to the calculation for the secondary. Empirically any conductor that contributes to the resonant circuit of the coil needs to be factored into the equation.

It is also empirically suggested that this calculation is adequate for the dielectric field of induction Ψ, and that for complete continuity there must be a balance in magnetic materials as well. Normally magnetic materials are to be avoided or eliminated in the design of a TC in order to prevent reduction and/or distortion of the magnetic coupling between the primary and secondary, and parasitic inductive losses. If magnetic materials are deliberately placed in the design e.g. when using a magnetic disruptor to quench the primary spark gap, which also forms part of the primary resonant system, then this should be balanced out magnetically in the secondary load circuit.

Geometry and the Longitudinal Mode Cavity

One of the unique qualities of any TC geometry is that a longitudinal cavity is established between the outer boundary conditions of the secondary coil. The Longitudinal Magneto-Dielectric (LMD) mode has been considered both theoretically and experimentally in the prior art[10-12], and appears to develop within the secondary coil primarily as a result of the geometrical inter-action between the distributed inter-turn mutual inductance, and the inter-turn mutual capacitance. It is conjectured that the ratio and balance of this distributed inductance and capacitance determines the cavity properties, and hence the formation of a pressure wavefront, where Ψ and Φ establish and maintain a phase alignment to each other. The outer boundary conditions of the longitudinal cavity are dynamically defined, where significant electrical reflections from impedance mismatch will collapse the phase alignment between Ψ and Φ, and lead to dissipation of the LMD mode.

In a typical TC the boundary conditions of this longitudinal cavity usually occur at the top-load at the high or inner-end of the coil, and the low or outer-end plus any single wire extension, load in the single wire extension, and termination load at the end of the wire extension, whether this be open-circuit, ground, or other defined load. In a matched TMT system, as in my transference of electric power experiments, the longitudinal cavity can be extended all the way from the “transmitter” cavity through the transmission medium to the “receiver” cavity. In principle when the longitudinal mode is established stably in this cavity, electric power can be passed between the source and load over very great distances, (in the far field condition), and is considered to be a key principle in Tesla’s telluric transmission of wireless power.

The LMD mode of transmission forms as a standing wave between the transmitter and receiver coils of a TMT system. In successive cycles of the generator oscillations, electrical energy is coupled from the generator into the cavity. The pressure of the wavefront in the longitudinal mode moves backwards and forwards as it traverses the cavity from the transmitter to the receiver, reflected from the top load of the receiver and back again towards the transmitter where it is amplified or suppressed by coupling from subsequent cycles from the generator. Whether the longitudinal wavefront is amplified or suppressed depends on the tuning of the system and hence the longitudinal wavelength in the cavity.

At the correct point of tuning the amplitude of the wavefront is reinforced by successive cycles from the generator. The magnitude of this longitudinal wavefront reaches an equilibrium in the cavity based on the impedance characteristics of the cavity medium, its tuning, and dissipation of the stored power to both the transmission medium, and to the surrounding environment. The longitudinal wavelength within the medium is longer than that of the generator excitations, which represents a lower frequency of oscillation for the longitudinal mode. This puts the phase aligned Ψ and Φ wavefront at different phase relationships to any transverse components throughout the length of the cavity, a property of the longitudinal mode that can be measured in the cavity region.

At the correct point of tuning Ψ and Φ in the LMD mode form a standing wave in the cavity which results from the longitudinal wavelength, where the boundaries of the cavity are defined by the high impedance, high potential, points at the top-loads of the coils, and one or more null points form inside the cavity. At the fundamental frequency of the LMD mode, (not the same frequency as the fundamental resonance of the secondary coils or the generator oscillations), only a single null will exist in the centre of the cavity, and when the coils are closely spaced in the near-field. At higher order harmonics, and dependent on spacing between the coils multiple null points can form.

Empirically through observation and measurement in the various experiments in my research, and particularly in Transference of Electric Power, and Tesla’s Radiant Energy and Matter, a trade-off exists in the geometry of the coil, and the LMD mode. With tight and closely wound turns in a coil with significant magnification, and where height to width ratio > ~ 2, e.g. a conventional tall and narrow streamer coil, the LMD mode can easily be established within the secondary coil, but appears to diminish and tend quickly to zero in any single wire extension from the low end, even when the extension is left open-circuit, (complete wavefront reflection). In this case this type of coil geometry is unsuitable for transference of electric power experiments even in the near-field case. In the close mid-field region, (the boundary of which starts at approximately twice the secondary coil diameter), a TMT with reciprocal and transverse tuned transmitter and receiver coils, the power transferred through to the receiver load would be very low e.g. for 500W of power supplied from the generator only a few watts of power is available at the final load. In the far-field region the coils appear as unconnected from each other, even with a lower impedance single wire extension connected between both low ends of the transmitter and receiver secondary coils. In this geometry case telluric transference of electric power does not appear possible, even when the transmission medium is a relatively low impedance, (less than the combined impedance of the secondary coils at the transverse resonant frequency).

With loosely wound turns where the turn spacing is equal to or greater than the wire diameter, when the magnification secondary to primary turns ratio is lower e.g. 10-15 : 1, and where the height to width ratio is <~ 1, the LMD mode appears to have a lower intensity in the secondary coil, but can extend over very large distances and easily into the far field. In this case, and using a suitable flat or cylindrical coil TMT system the longitudinal mode can be extended across the entire cavity in any extent, near, mid or far-field. Substantial electric power can be transferred from the generator to the receiver load through a low impedance single wire extension, through a telluric channel, or other suitably arranged low impedance or resonant transmission medium, and as demonstrated in transference of electric power experiments.

Hybrid Coils and Turn layering

In some cases a combination of coil geometry, or hybrid coil, has proven to be the best choice for the experiment in hand. An example of this would be the flat coil originally demonstrated by Dollard et al.[11], and used extensively in my own research and particularly in experiments on the transference of electric power, and telluric transference of electric power. In this flat coil geometry turn layering is used to produce two flat coil spirals closely spaced to each other, and providing a combination of properties from the flat and cylindrical designs. In particular the magnification of the coil can be increased, without damping the free resonant properties of the coil, and emphasising the compression properties that accentuate dielectric induction field phenomena.

Flat coils with turn layering up to as many as 5 layers can demonstrate excellent magnification and compression whilst retaining loosely wound turns and hence a good longitudinal cavity mode. Such a multi-layered coil is well suited to intense dielectric phenomena, such as Eric Dollard’s “fern” discharge experiment. The disadvantage of progressive turn layering is in the imbalance created between Ψ and Φ, and with each additional turn the rapidly increasing risk of breakdown at the winding return point. Whilst the longitudinal cavity in a TMT system appears to remain well established where a typical null point can be measured in transmission medium, the amount of power that can be transferred between generator and receiver load appears greatly diminished.

This reduction in transferred electric power is most likely as a result of the geometry imposed imbalance between Ψ and Φ, where Ψ has been significantly accentuated, and Φ has been suppressed by the hybrid and turn layered geometry. Maximum power transfer in a TMT system appears to occur when Ψ and Φ are maintained in dynamic balance, through optimal geometry of the TMT coils, transverse tuning to match the resonant frequencies of transmitter and receiver, and longitudinal mode tuning through obtaining a clearly defined standing wave within the cavity, (accomplished primarily through adjusting the electrical path length of the transmission medium to obtain a strong simultaneous null point for Ψ and Φ at the cavity centre).

Secondary Coil Induction and Extra Coil Resonance

This coil geometry and arrangement is probably the best for resolving the fundamental trade-off between coupling and free resonance, and appears to be Tesla’s[4] own choice of system arrangement for large scale transmission of electric power. In this coil arrangement the induction between primary and secondary is separated from the free resonator or extra coil. This allows the primary and secondary to be tightly coupled and designed to maximise transfer of energy between the generator and primary coil and the secondary coil. The air-core of this primary-secondary induction transformer allows it to operate at a higher frequency than a conventional iron-cored power transformer, whilst retaining resonant properties that improve impedance matching to the generator. The tuned high or low input impedance presented to the generator through correctly matching this arrangement, allows optimal generator drive from a wide range of different source types, including linear sinusoidal oscillators, spark-gap discharges, and other transient and impulse generators.

In Tesla’s case this was driven through very powerful uni-directional disruptive discharges from energy stored in large tank capacitors, and charged by high voltage DC dynamos. In this case the primary-secondary induction transformer requires a very low input impedance, maximising impulse primary currents, which in turn produces very strong magnetic induction field coupling between the primary and secondary. In this case the secondary is arranged in close proximity to the primary, of the same diameter to maximise intersection of the magnetic field of induction, and the number of turns kept minimal to prevent magnification and compression of the dielectric induction field, whilst minimising electrical losses in the secondary, and preventing premature leakage of energy through discharges from the secondary high-end.

The high-end of the secondary induction coil is directly connected to the low-end of the extra coil. The extra coil can be considered in this arrangement as a free resonator, often physically displaced from, or orthogonal to the secondary coil, but can also be driven centrally on axis to the secondary as in Tesla’s Colorado Springs apparatus[5,9]. The extra coil in this arrangement has an optimal electrical length of λ/4, and when combined with the primary – secondary induction transformer, the complete Tesla coil geometry is a tuned system with length 3λ/4, or generally nλ/4 where n is an odd positive integer. When arranged in this fashion the extra coil produces considerable magnification as a free resonator whilst maintaining a good balance between Ψ and Φ. Interesting variations on the standard high aspect ratio, (tall and narrow for high magnification), cylindrical extra coil geometry, include conical and golden ratio designed coils.

Ultimately the optimal design of this geometry as a resonant magnifying transformer is resolved by impedance matching the various stages of the system from generator to primary, primary to secondary, secondary to extra, and extra to extension and top-load. If a cavity is to be generated at the low end of the secondary coil, then impedance matching from the secondary to the cavity, and any additional circuit elements in the cavity, is also important. This approach to Tesla transformer design is notably explored in the prior art by Dollard[5,12], and within my own research through looking at TC and TMT system impedance, tuning, and matching using a vector network analyser.

An interesting alternative consideration arises regarding Tesla’s intended purpose for the extra coil, when we take into account that the Colorado Springs apparatus was designed around 1900, and specifically to be driven by powerful impulse disruptive discharges. When the extra coil is arranged to resonate at the third harmonic of the secondary induction system, and where the quality factor (Q) of the extra coil is very high, the output from the top-end of the extra coil will be a very powerful, low distortion, sinusoidal oscillation at a single frequency. This form of output is ideally suited to radio transmission as the carrier wave, and has been selected from a wide spectral bandwidth discharge.

The multitude of frequencies contained within a disruptive discharge are highly unsuitable for radio transmission due to the interference created across bands, and the large amount of energy dispersed across the spectral bandwidth, as demonstrated by the early spark-gap radio transmitters used in the very early 20th century. High power single frequency oscillators for radio transmitters became standard with the development of the vacuum tube in the early 20th century, but before this, and at the time of the Colorado Springs research, Tesla had found a unique way to create a powerful single frequency carrier wave from a wide-band disruptive discharge generator. As an alternative interpretation of his work at this time, the extra coil was ideally suited to both select and tune the output of a very high power transmitter to a single frequency.

Coil Geometry Comparison Summary

Flat Coil (loosely wound with 2 layers): Good compression and magnification of the dielectric field of induction, generally suitable for transference of electric power experiments as a TMT system with a secondary to primary turns ratio around 20:2. Shows moderate dielectric induction field phenomena such as attractive and repulsive forces and capacitor charging. Maintains a good longitudinal cavity for LMD experiments when correctly tuned, and the efficiency for the transference of electric power appears moderate around 60%+ when carefully tuned in the transverse modes, and balanced to maintain a longitudinal null point at the centre of the single wire transmission medium.

This coil geometry gives a good general purpose experimental base, the imbalance in Ψ and Φ due to the compression of Ψ limits the efficiency in power transfer, but yields a range of interesting phenomena. Can be readily matched in the primary circuit to either a linear sinusoidal oscillator or a spark discharge generator.

Cylindrical Coil (loosely wound): Best geometry to maintain the balance between Ψ and Φ, and hence highest efficiency in the transference of electric power experiments. In the near to mid-field with correct tuning and balancing efficiency can be > 90%. In a coherent arrangement where the longitudinal mode is established across the entire TMT system from generator to load it may, in principle, be possible to establish 100% displacement of electric power from source to load, although this remains a work in progress to demonstrate and validate.

When combined with an extra coil into the Colorado Springs experimental arrangement, and with suitable Telluric tuning and matching, then far-field longitudinal transference of electric power may also be possible, and appears to remain one of the ultimate goals of this field of energy research. In my research so far I have measured far-field Telluric power transfer, (at ~ 3 miles between transmitter and receiver), of around 10dBm in the 80m amateur band from the upper resonant frequency of a carefully tuned TMT system.

The cylindrical coil geometry, again due to its well balanced Ψ and Φ, and with a secondary to primary turns ratio between 20:2 and 20:3 also appears best suited to plasma based experiments, such as Dollard’s cosmic induction generator design. This geometry also forms a good induction pump for a wide range of extra coils. A conical extra coil added to a cylindrical coil induction generator greatly improves the compression and magnification of this geometry, accentuating Ψ, and yielding good dielectric induction field phenomena.

When mounted on separate support structures the primary and secondary can be moved and positioned relative to each other, which gives free and variable adjustment over the coupling between the primary and secondary coils. In a TMT system where the coupling can be adjusted in both transmitter and receiver, very fine balancing can be accomplished between coupling and primary tuning, and hence the possibility for increased transference of electric power efficiency.

Streamer Coil (tightly wound): A high aspect ratio tall and narrow cylindrical coil which is usually more tightly coupled to the primary. This geometry has excellent voltage magnification, and when combined with an accumulator at the high or top-end of the secondary coil can achieve considerable energy storage at very high potentials. Most often used for discharge streamer entertainment, or as a high frequency, high voltage power supply in research, this TC geometry can reach many MVs of voltage magnification and deliver many kWs of power continuously.

Due to the tight coupling and huge magnification, dielectric induction field phenomena can be very strong in this arrangement. Longitudinal cavity phenomena and the LMD mode appear to be small in this arrangement, that is, they can be so small as to easily go undetected. This coil geometry is unsuitable for transference of electric power, and experiments where a balance and tuning needs to be maintained between Ψ and Φ.

Golden Ratio Geometry

This is a particularly interesting geometry and could lead to a wide range of interesting phenomena yet to be explored. The golden ratio (GR) is very widely treated in the prior art and the following references constitute further reading on this subject[13-15]. From the perspective of TC and TMT systems the golden ratio can be conceived in a variety of different ways, including the aspect ratio for any of the coil geometries, and in particular the cylindrical and/or extra coils that can have there height to width ratios according to GR, the wire diameter to turn period according to GR, the primary coil as a spiral defined on GR proportions, and the electrical length of the primary, secondary, and extra coils according to GR, and even the ratio between the longitudinal  and transverse modes (including the cavity ratio) according to the GR.

It is conjectured that perhaps the most interesting GR relationship would exist directly between Ψ and Φ, which could be arranged through geometry, tuning, and generator and load characteristics. This area of research and investigation requires considerable further work, and remains work in progress at this time, and to be reported at a future point.

Displacement, Non-linear Dynamics, and Geometry

There is a very important distinction to be made in this area, which for me results from the sum total of my research so far, and all the experiments, observations, and measurements that have accompanied this journey. I would assert that Displacement and the observable phenomena that are emitted through the principle and mechanism of displacement e.g. Tesla’s Radiant Energy and Matter, do NOT originate as a result of the coil geometry of the experimental system. To clarify, I conjecture that displacement is an underlying coherent principle and mechanism within the inner workings of electricity, and that it is a displacement event that gives rise to the emission of various phenomena, including radiant energy. Displacement seems to be most effectively revealed by driving the experiment in a non-linear or transient fashion e.g. from a cylindrical TC with moderate coupling, driven by an impulse or disruptive discharge generator of at least a moderate power e.g. > 500W.

Therefore I am discriminating between displacement events and their associated phenomena, and the different properties of Tesla coils and TMT systems that result from the difference in balance between the differentiated dielectric and magnetic fields of induction, that are brought about by varying coil geometries. Said in yet another way, Tesla’s Radiant Energy and Matter, and other coherent electrical phenomena are not the product of coil geometry, but rather underlying coherent processes that constitute the inner, and as yet unexplored, workings of electricity. Whilst this conjecture may be difficult for some to acknowledge without considerable additional supporting evidence and results, something my research is actively engaged in acquiring, it would appear to me completely as common sense that there are underlying processes of a coherent nature that emit coherent forms of phenomena. These coherent phenomena are as yet manifestly unexplained by even the best current understanding of transference, which arises from the differentiated dielectric and magnetic fields of induction, and which constitutes electrical properties relating to common circuit characteristics and transmission.

This said, coil geometry and careful design are most important in balancing or preferentially accentuating Ψ and Φ. The relative balance or imbalance of Ψ and Φ, which results from a particular coil geometry and experimental system arrangement, results in a specific coil geometry being better suited to different types of experiment e.g. a flat coil for dielectric induction phenomena, a cylindrical coil based TMT system for maximum transference of electric power and plasma effects, Tesla’s Colorado Springs TMT system for far-field telluric transference of electric power etc.

The distinction between geometry based phenomena, and displacement based phenomena can be directly compared and contrasted when the TC or TMT system is driven by a linear sinusoidal source, or a non-linear transient impetus. The non-linear transient impetus will reveal displacement based phenomena related to the undifferentiated coherent induction field. The linear sinusoidal drive will reveal phenomena related to the balance of the differentiated induction fields Ψ and Φ, through the balance between the transverse and longitudinal modes, and the tuning and boundary conditions of the longitudinal cavity established in the system. Transverse tuning is about selectively coupling as much energy as possible from the generator to the transmitter, and from the receiver to the load, whereas tuning of the longitudinal cavity and its properties, is about transferring as much energy as possible between the transmitter and receiver.

In summary, this is a vast, and probably one of the most fascinating areas of electrical phenomena, that arise from Tesla coil based systems, and warrants considerable further research, observation, and measurement. Suffice to say for now, I would conjecture that the distinction between the undifferentiated and differentiated induction fields, is in my view key to discriminating between phenomena that relate to displacement (coherent and inner), and those that relate to transference (incoherent and outer). For me the purpose of the Tesla coil is very much as a fine tunable instrument with which to experiment, observe, and measure qualities that will progressively reveal the inner nature and workings of electricity.

For further exploration and discussion on what is presented on this page, please see the Energetic Forum[16].

Cylindrical Coil Design and Construction

This cylindrical coil was designed to be suitable for plasma experiments including induction generator arrangements, transference of electric power, and as a suitable induction pump for various extra coil configurations. The secondary coil was intended to have its fundamental resonant frequency, the lower frequency when coupled with the primary coil, in the 160m amateur band between 1.8-2.0Mc, and the upper frequency as close to, or tunable into, the 80m amateur band at 3.5-4.0Mc. For induction generator experiments it was decided to keep the diameter of the secondary coil close to that originally designed by Dollard.

The period of the turns in the secondary was kept at the empirical boundary of 2 x the outer conductor diameter of the secondary wire, which appears to maximise the Q of the secondary coil, whilst maintaining good coil longitudinal cavity properties by not excessively loading the inter-turn mutual capacitance of the windings. The wire for the secondary is the many stranded outer shield of RG316 coax, in order to minimise losses in the secondary coil through the skin effect, whilst maximising secondary conductor surface area. The outer diameter of RG316 is 2.5mm, and turn period of 5mm was empirically set as optimal for the intended experimental applications.

When driven by a primary with coupling coefficient to the secondary of ~ 0.1-0.3 the lower resonant frequency can become shifted down from the resonant phase change, set by the wire length, by as much as 500kc, and the upper resonant frequency shifted up by as much as 1500kc. This being the case then the resonant phase change of the secondary, from the wire length, would be set at around 2.2 – 2.3Mc. This will arrange with primary tuning, and adjustment of the coupling coefficient, for the lower resonant frequency to be well within the desired 160m band, and the upper to be close to and tunable into the 80m band.

Tccad 2.0 was used for a rapid and approximate indication of the electrical and resonant characteristics of the secondary coil, the detailed results of which are shown below in figure 2. The parameter “Winding Height of Secondary Coil” on the turn period of 5mm, (“Wire Diameter” 2.5mm +  “Spacing Between Windings” 2.5mm), was used to adjust the number of turns in the secondary until the “Approximate Resonant Frequency” and “Secondary Quarter Wavelength Resonant Frequency” were closest to the desired 2.2Mc.

The secondary was arranged to be 24 turns in total, 23 RG316 coax turns + 1 1/8” copper tube shield and capacity turn. This turn is spaced further away from the end of the coax turns to reduce the possibility of high-end discharge to lower turns, and is also intended to shield distortions to the dielectric field of induction at the high-end of the secondary, and particularly when operated in close proximity to another cylindrical coil or extra coil. The shield turn presents a uniform continuous metal conductor surface at the high-end of the coil, with a more uniform charge distribution, and to a limited degree providing some accumulation at the top-end without excessively loading the resonant frequency of the secondary. This capacity turn is included in the resonant frequency calculation on Tccad as it directly impacts the wire length and hence the resonant phase change of the secondary coil.

The primary design was intended to fully fit inside the secondary for maximum coupling experiments, reducing the outer diameter of the primary to 390mm. This does introduce a distortion in the magnetic field of induction as compared with a primary the same diameter as the secondary, and standing-off a physical distance below the secondary bottom-end winding. For the intended experiments the primary was set as a fixed 4 turns of  1/8” copper tube on a turn period of 9mm, and which have 4 fixed taps, and of course a variable tap can be used on the bare copper tube for very accurate tuning adjustments if needed. The fixed taps allow the primary coil to be electrically varied between 1 and 4 turns.

In this case where the intended experiments are firstly plasma phenomena, it was more important to have easily adjustable taps to flexibly change the primary characteristics, than maintain the need for equal weights of conductor in the primary and secondary coils. Even if the copper turn is not electrically used in the current path of the primary, the electrically unused copper places boundary conditions on the fields of induction, and hence must be factored in for experiments that require this balanced boundary condition from equal weights or volumes of conductor e.g. in achieving very high efficiency in the transference of electric power, and for establishing a strong and extended longitudinal LMD mode in the secondary cavity.

For reference, the equal weights of copper (< 3.0Mc) from primary to secondary calculation is as follows:

Secondary wire length for the 23 turns of RG316 coax = 32.52m

Measured unit weight of RG316 outer braid only: 6.150 kg/km

Secondary RG316 wire weight = 6.150 x 32.52 / 1000 = 0.200 kg

Secondary wire length for the 1/8” copper tube single turn = 1.41m

Measured unit weight of 1/8” copper tube: 50.3 kg/km

Secondary 1/8” copper tube weight = 50.3 x 1.41 / 1000 = 0.071 kg

Total conductor weight of secondary coil = 0.271 kg

Primary wire length per turn @ 390mm diameter = 1.23m

Primary turn 1/8” copper tube weight = 50.3 x 1.23 / 1000 = 0.062 kg

Number of turns in the primary required to equal the secondary coil weight: 0.271 / 0.062 ~ 4.4 turns

If we now factor in the weight of the vacuum variable capacitor copper plates and interconnection of the primary to this capacitor, which constitute the parallel resonant circuit of the primary:

Total approximated weight of copper in the capacitor plates and interconnections ~ 0.125 kg

Number of turns in the primary required to equal the secondary coil weight, (including primary resonant circuit):

(0.271 – 0.125) / 0.062 ~ 2.4 turns

Two to three turns of the primary is considered an optimum match to the mid-range tuned position of the vacuum variable capacitor at ~ 600pF, and with a coupling coefficient between primary and secondary of ~ 0.2. The primary inter-connections are made from copper plate, and 8 AWG (1600/0.08) micro-stranded silicone coated wire. The same wire is used to connect both primary coils to the generator for push-push, push-pull, and quadrature drive, and forms a good low impedance, low inductance connection for power transfer between the generator and the primary coils.

Figures 3 below show some of the construction features of the cylindrical coil design, including the support frame interleave arrangement, the secondary coil windings, the primary coil taps and tuning capacitor mounting, and the primary circuit inter-connections.

The overall design and construction of this cylindrical coil provides a simple yet versatile Tesla coil which can be used in a range of different experiments, including plasma phenomena and as an induction generator, and transference of electric power in a TMT system. By extending with extra coils, or by specifically designed primary coils e.g. equal weights of copper, or a Golden Ratio spiral, the useful range of experimental phenomena can be extended to include high efficiency transference of electric power, and telluric transference of electric power in the far-field. The detail of these experiments, phenomena and measurements will be reported in subsequent posts.

Click here to continue to cylindrical coil input impedance – TC and TMT Z11 measurements.


1. Tesla, N., System of Transmission of Electrical Energy, US Patent US645576A, March 20, 1900.

2. Tesla, N., Experiments with alternate currents of very high frequency and their application to methods of artificial illumination, American Institute of Electrical Engineers, Columbia College, N.Y., May 20, 1891.

3. Tesla, N., Nikola Tesla on his work with alternating currents and their application to wireless telegraphy, telephony and transmission of power: an extended interview, 1916 Interview – ISBN 1-893817-016, Twenty First Century Books, 1992.

4. Tesla, N., Apparatus for Transmitting Electrical Energy, US Patent US1119732A, January 18, 1902.

5. Dollard, E., Condensed Intro to Tesla Transformers, Borderland Sciences Publication, 1986.

6. Dollard, E., Theory of Wireless Power, Borderland Sciences Publication, 1986.

7. Corum, K. & Corum, J., Tesla Coils and the Failure of Lumped-Element Circuit Theory, TCBA News, Vol. 19, No. 2, 2000.

8. Corum, K. & Corum, J., RF Coils, Helical Resonators and Voltage Magnification by Coherent Spatial Modes, TELSIKS University of Nis, Sept. 19-21, 2001.

9. Tesla, N., Colorado Springs Notes 1899-1900, Nikola Tesla Museum Beograd, 1978.

10. Dollard, E. & Brown, T., Transverse & Longitudinal Electric Waves, Borderland Sciences Video, 1987.

11. Dollard, E. & Lindemann, P. & Brown, T., Tesla’s Longitudinal Electricity, Borderland Sciences Video, 1987.

12. Dollard, E., A common language for electrical engineering – lone pine writings, A&P Electronic Media, 2013.

13. Herz-Fischler, R., A Mathematical History of the Golden Number, New York: Dover, 1998.

14. Huntley, H., The Divine Proportion, New York: Dover, 1970.

15. Bogomolny, A., Golden Ratio in Geometry, Cut the Knot, 2018.

16. Forum Members, Eric Dollard Official Forum -> Eric Dollard, Post #2819 onwards, Energetic Forum, 2020.


 

Negative Resistance and the Self Generating Discharge – Part 1

Negative resistance is a feature of the I-V characteristic of a discharge between two electrodes, and if correctly utilised can lead to unusual electrical phenomena within an electrical circuit. In this first part on this topic we explore the I-V properties of the negative resistance (NR) region of a carbon electrode spark gap (CSG), or carbon-arc gap. When the CSG is biased into the correct region, and combined with a switched (non-linear) impetus from the generator, the impedance of the circuit can be seen to reduce from the conventional short-circuit case, increasing the current in the circuit and intensifying the light emitted from an incandescent lamp load.

The negative resistance characteristics of a spark gap where explored and utilised by Chernetsky[1] in order to demonstrate what he called the self-generating discharge (SGD). The SGD is a state of discharge where he claimed that the energy consumed from the generator was reduced, yet the power dissipated in the load was increased, and where the additional energy in the electrical circuit was “inducted” from the surrounding medium, or what is commonly referred to as the Aether[2], a “gaseous” medium that is all pervasive throughout space, and is also considered to extend beyond the physical realm. As such Chernetsky claimed an over-unity (OU) phenomena where the total output power was greater than that supplied to the circuit by the generator. This experiment has been replicated by others, including Frolov[3], and Dawson[4], who also claim to have measured OU output. This sequence of posts investigates these principles, attempts to measure the claimed OU output, and further explore its possible origin. Ultimately the studied phenomena forms part of the continuing central research, of revealing the inner workings of electricity, and hence the displacement and transference of electric power.

When investigating over-unity claims good experimental and scientific method is critically important. I have found many situations where OU has been attributed to unusual phenomena without being supported by good and well measured experimental data. OU most often appears to arise in non-linear systems, which owing to their transient nature are also difficult to measure reliably, especially when output power is to be accurately measured. Input power is usually quite straight-forward to measure accurately as it is supplied by dc sources such as batteries and power supplies, or drawn from the mains utility supply which is a low-frequency sinusoidal input. In these cases electrical instruments can be arranged to accurately determine real and reactive input power.

Where the generator produces a non-linear output through switching, pulses, impulses, or chopping an otherwise dc or low-frequency sinusoid the dissipated output power can become a complex transient, with many high-frequency components, and many different phase relationships within the experimental circuit. When this is combined with high voltage and/or current magnification , multi-resonant elements, different transmission modes both transverse and longitudinal, cavity and termination effects, and hence significantly changing boundary conditions on the dielectric and magnetic fields of induction, the final accurate determination of output power, even with sophisticated instrumentation, is exceedingly complex, and can very easily lead to substantial errors and mis-understandings. As such, and due to the complexity of these measurements, the phenomena themselves are easily attributed to OU directly without further detailed assessment, and videos show the qualitative results of the phenomena without significant quantitative supporting evidence. It is not surprising given the often lacking experimental method, and lack of detailed supporting measurements, that conventional science so often holds a cautious and pessimistic view of the OU field.

Having stated this, OU is a very important exploration into the unknown, in the search for a truly sustainable, re-generative power source, and one that attracts wide and diverse forms of research and endeavour. My own research is orientated towards revealing the inner workings of electricity, and through co-operating with life’s natural processes, reveal the re-generative and inclusive nature of these under-lying processes. In this sense my own research strives for best scientific method, and well quantified supporting measurements, which then make it possible to either refute or support established claims, whilst making it possible for me to venture new claims of my own as to the origin, principle, and mechanisms of the explored phenomena. Often one experiment leads to another, as in the case of the experiment that is presented in this post. Whilst interesting phenomena are observed, explored, and measured, further experiments will be required to validate Chernetsky and others’ claims, that the additional energy in the OU experimental system is induced from a medium external to the electrical circuit. In my experiments in this post I find the additional energy that intensifies the luminance of the load, is drawn through the generator from the line supply, and directly as a product of biasing the CSG to utilise the NR properties in the abnormal glow region of the discharge.

Figures 1 show the experimental apparatus and circuit, and some of the different types of measurements taken as part of the experiments.

The generator for this experiment is a single HV transformer in the High Voltage Supply (HVS), the output is rectified and connected directly to one electrode of the CSG via an RF ammeter, (Weston 425 200mA FSD). The other electrode of the CSG is connected to a two lamp series incandescent load (2 x 25W = 50W) and then back to the other terminal of the HVS transformer. The CSG has fan assisted cooling, and is shunted in parallel by a 3kV 10A vacuum relay, which enables the CSG to be switched in and out of the circuit for impedance and load power comparisons. The fan and vacuum relay are driven by a low voltage 15V output provided again by the HVS. The input power to the HVS transformer is continuously measured using a Yokogawa WT200 Digital Power Meter.

The process of ionisation in the region between two electrodes with a high electric field, is well studied in the prior art[5]. Liberated electrons within the discharge region are accelerated by the electric field between the electrodes, and in the process of moving towards the anode cause further ionisation of atoms, leading to an electron avalanche effect known as a Townsend discharge.  Figure 2 below shows the typical current-voltage (I-V) characteristics for a Townsend discharge transposed from Abdelrahman et al.[6]. The negative resistance characteristics utilised in this experiment result from biasing the CSG to the correct region of this I-V curve, around the abnormal glow region between points D-E-F-G . The interesting and unusual phenomena presented in this experiment result from the reduction in circuit impedance, when the biased CSG is combined with a suitable load circuit (incandescent lamps), and driven from a non-linear transient high voltage generator at the line frequency.

The following video introduces the apparatus, experiments, and phenomena associated with the negative resistance of a CSG, and demonstrates aspects of the following:

1. A qualitative observation of the discharge produced in the CSG when biased into different regions of the I-V characteristic, including open-circuit, short-circuit, abnormal glow (D-E-F), and arc discharge (G) regions.

2. Adjusting and biasing the spark gap into the abnormal glow region to utilise the negative resistance properties within the electrical circuit.

3. The change in impedance of the circuit when switched between short-circuit conduction and spark gap discharge.

4. The change in circuit current and dissipated power in the load with switched impedance, and the effect on the input power to the generator from the line supply.

5. A comparison of adjusting and biasing the circuit when driven from a non-linear transient input, and a linear sinusoidal.

6. Measurement of the generator output using an oscilloscope both in the non-linear and sinusoidal cases, and showing the switching transients generated when the CSG is biased into the negative resistance region.

7. An experimental investigation of the I-V characteristics of the CSG using a Tektronix 576 curve tracer.

Figures 2 below show in detail some of the additional measurements made during the experiment including the overall impedance properties Z11 of the experimental circuit from the perspective of the generator, the different drive conditions applied from the generator, and the NR characteristics of the CSG measured on the Tektronix 576 I-V curve tracer.

To view the large images in a new window whilst reading the explanations click on the figure numbers below:

Fig 3.1. Here we look at the low frequency small signal input impedance Z11 from the perspective of the generator, using the HP4195A network analyser. The circuit was measured and compared in two conditions, firstly with the carbon electrodes touching at the ends forming a short-circuit, and secondly with the electrodes parted and the vacuum relay activated to shunt the electrode gap with a short-circuit path through the relay. In both of these cases the impedance measured was the same in magnitude and phase and shows that above 25Hz and up to 200Hz the circuit is completely resistive at a constant 379.5Ω, and constant phase of ~ 0° (-14.4 mdeg @ 100.1Hz). Below 25Hz will also be a continuous constant resistive impedance but requires considerably reduced resolution bandwidth to remove the measurement noise observed. A reduced resolution bandwidth in this case represents a considerably increased scan time for the measurement. This measurement shows that there are no unusual impedance characteristics at the base drive line frequency, no resonant characteristics, and that the circuit appears as a constant resistive load that results almost entirely from the cold resistance of the incandescent lamp filaments, 2 x 25W in series, (in the range 175 – 200Ω each).

Fig 3.2. Shows the HF small signal input impedance Z11 from the perspective of the generator up to 10Mc, using the HP4195A network analyser. The SCR in the HV supply creates a switched output from the incoming sinusoidal line supply, (see Fig. 3.1 here for detailed input and output waveforms), which means there are many higher frequencies present at the output of the HV transformer. This constitutes a non-linear transient drive to the experimental circuit, which is the summation of many higher frequencies, and hence higher frequency characteristics of the circuit impedance contribute to the overall circuit operation, and may play a part in the observed phenomena. This is then combined with the high frequency transient switching in the spark gap itself, which adds a much wider band of available frequencies, and the all important impulse-like currents in and around the abnormal glow discharge region.  We can see from this measurement that the resistive impedance rises gradually with frequency reaching ~ 434Ω @ 5Mc, and ~503Ω @ 10Mc. There are no significant features in the measured band, the circuit is not self-resonant up to 10Mc, and the overall circuit is largely resistive with a small amount of series stray inductance from the the wiring.

Fig 3.3. Shows the oscilloscope waveforms both for the input to the HV transformer at the output of the SCR (green), and the output of the HV rectifier at the input to the experimental circuit (yellow), where the circuit is set with the vacuum relay closed across the CSG. The SCR output shows how the line sinusoid is chopped into a small section, in this case part of the negative half of the cycle, providing pulses of input current to the HV transformer. The output of the HV rectifier is a voltage magnified pulse train up to ~ 2kV, and set at ~1.3kV peak for this experiment. This output level is sufficient to generate discharges in the CSG, whilst low enough to allow fine control of the I-V characteristics through electrode gap adjustment.

Fig 3.4. Here the vacuum relay has been opened and the CSG adjusted to utilise the NR region around the abnormal glow section of the I-V characteristics. The basic form of the waveforms are the same as in Fig. 3.3 with the addition of some impulse currents from discharges in the CSG, an increase in peak voltage at the output of the HV transformer ~ 1.8kV, and a slight increase in the “on” cycle of the SCR from ~ 4ms to 5ms. This corresponds to increased brightness in the lamp loads, an increased current in the experimental circuit from ~ 100mA to 125mA, and an increase in the power drawn from the line supply ~ 50W to 80+ W. The bias adjustment of the SCR remains the same as for the condition in Fig 3.3, yet clearly by operating the CSG around the abnormal glow region of its characteristics more power is drawn in through the line supply, reflecting a reduction in impedance in the experimental circuit below that of the normal short-circuit impedance at the CSG electrodes or through the vacuum relay. When the experimental circuit is biased at this point the region between the carbon electrodes is mostly dark and visibly discharge free, with the occasional momentary white flash as a discharge occurs across the electrodes when point G (Fig. 2) is reached.

Fig 3.5. Shows the I-V characteristics of the CSG as measured on a Tektronix 576 curve tracer. The advantage of a purely analog curve tracer like this is that negative resistance can be easily visualised through the unusual movement of the beam spot, which through the thickness and luminescence of the trace shows the speed of movement, and through the path of the spot often in arcs and loops, the unusual characteristics of NR regions and transitions. In this test the output power of the tracer is limited to 2.2W at maximum voltage bias of 1500V. With the current in the CSG restricted with a high series resistance (300kΩ) arc discharge does not occur, and the electrical characteristics can be explored prior to the arc discharge at point G. Here the voltage across the electrodes has been increased to the full 1500V output. At the transition voltage the gap enters the NR region and the trace rapidly sweeps negative in a wide arc before coming back toward the centre bias point at around 80mA of current, and still prior to arc discharge. The low luminescence of the arc shows the very rapid transition through this region, and the length of the arc right across to the far left of the screen, shows how the NR effect magnifies the  voltage across the high series resistance in the test circuit.

Fig 3.6. Here the output power of the tracer is set to 10W limit, with a series resistance of 65kΩ. At 1200V output the transition to the NR region is reached, but here the transition is even quicker which less voltage magnification to the left of the screen, and a tighter and more direct path to the same centre bias point of around 80mA of current prior to arc discharge. Without current limiting in the circuit the transition through the NR region is very rapid, which makes biasing a circuit to maintain characteristics at this point both tricky and mostly unstable, as could be seen in the video experiment. It is better to establish a circuit that oscillates around the NR region and hence utilising its unusual properties in a more stable manner, then trying to bias statically to one individual bias point within the NR region.

Fig 3.7. Here the output power of the tracer is set to 50W limit, with a series resistance of 14kΩ. At 1100V output the CSG transitions rapidly to arc discharge, indicated by the bright region at about 50V 80mA. The loops of the negative resistance region are just visible, and show now how rapidly the onset of arc discharge occurs when the circuit current is less restricted.

Fig 3.8. Shows the full development of the arc discharge curve at the maximum power output limit of 220W, with a series resistance of 3kΩ. The wide arcs of the negative resistance region are just visible, but the transition through this region is very rapid and in this case utilisation of that region would become very difficult as the characteristics of the CSG are dominated by the arc discharge. With the arc discharge fully developed in region G+ (Fig. 2) it is interesting to note that the impedance presented by the circuit is now higher then the short circuit case, the lamps are dimmer, and a lower current is drawn from the line supply. The impedance of the circuit can be further lowered by shorting the CSG with the vacuum relay, which increases the brilliance of the lamps to the CSG short-circuit case. The impedance of the circuit can be further lowered from the CSG short-circuit case by opening the vacuum relay, and adjusting the electrode spacing to bias the characteristics into the negative resistance region. At this point the lowest impedance of the circuit is presented to the HV supply, drawing the maximum current and hence power from the line supply.

The negative resistance characteristics in the discharge region, and the ability to adjust and utilise this region, appear to be strongly influenced by two material factors in the circuit:

1. The electrode material used for this experiment is carbon which shows a negative resistance region over an adjustable range. It is repeatedly possible, as demonstrated in the video, to adjust and maintain the CSG into the abnormal glow region of the curve and observe unsual phenomena in the circuit. When the carbon electrodes were replaced with tungsten electrodes it became very difficult to adjust the CSG into a region where the NR characteristics could be maintained. Adjustment to the correct bias could only be accomplished momentarily before reverting to the arc discharge region, or the open circuit condition. This suggests that the bias region for the abnormal glow is much narrower and hence much more difficult to select in a metal such as tungsten. As such the properties of carbon are identified as a more suitable material for the I-V characteristics that lend themselves to the utilisation of negative resistance within non-linear electrical systems.

2. The gaseous medium within the discharge region between the electrodes. In this first part on this topic, and for simplicity in the video, experiments were demonstrated with air in the discharge region, but considerably better results have been obtained when the electrodes are in a vacuum region or inert gas inside a glass tube. Two mechanisms have been tested to demonstrate this, the first a vacuum relay where the gap between the electrodes could be adjusted by applying a dc current to the relay’s exciter coil, and secondly a 1B24 TR cell, a cold cathode tube RF spark gap, where the internal gap can be adjusted by an external screw. A TR cell is a gas discharge tube which is used typically as an electronic switch, or as in the case of the 1B24, to protect the sensitive receiver of a radar system from damage by the strong transmit pulse. This method in radar is now long obsolete, the 1B24 being used in, and just after, the second world war. The tube used here has a manufacture date of May 1944 printed on the glass.

Figures 3 below shows the arrangement of the 1B24 TR cell which was used in experiments to enhance the phenomena presented in this post.

In the case of the vacuum relay it was found that a very small gap could be controlled by adjusting the dc current in the relay exciter coil. At a certain level of bias the contact would start to switch between closed and a very tiny gap, both exploiting the negative resistance in I-V characteristics, whilst introducing another transient switching source in the circuit. In this case the overall resistive impedance in the circuit fell considerably lower than that experienced with the correctly biased CSG. The current in the secondary circuit went up as far as 200mA, the lamps where illuminated with a very high brilliance, and the input power drawn from the generator increased considerably to reflect this rapid decrease in circuit impedance. This bias method and utilisation of NR whilst intensified, was difficult to maintain, and would quickly destabilise to normal circuit impedance. However, this experiment shows that the utilisation of NR properties is strongly dependent on the degree of transient switching and hence non-linearity in the circuit, and combined with a clean discharge region, in this case the vacuum relay contact gap, considerable intensification of the phenomena is possible.

Summary of the results and conclusions so far

The phenomena observed in this experiment and demonstrated in the video, and combined with additional supporting measurements,  appears to result from a reduction in circuit impedance below that of a short-circuit condition, when the CSG is adjusted into the negative resistance region surrounding the abnormal glow section of the I-V characteristic. When adjusted to this region, and combined with a non-linear transient drive from the generator, the overall impedance of the circuit drops, and the current rises as more power is drawn from the generator. In this experimental case the increase in brilliance of the incandescent lamps results from additional power drawn from the generator, over and above that drawn when the CSG is directly short-circuited by the vacuum relay. From this we can ascertain that the negative resistance region of the CSG reduces the overall circuit impedance presented to the generator in non-linear transient cases. In this experiment there is no evidence of additional energy being drawn into the circuit from any source other than the generator, and all changes in energy can be accounted for by measurement of that supplied into the HV supply, and that dissipated in the load.

In comparison, when the HV supply was driven using a linear sinusoidal from a variac, rather than a non-linear switched SCR controller, the phenomenon could not be adjusted, observed, or measured in the same experiment, and the impedance of the circuit under all conditions using the CSG is greater than the short-circuit of the vacuum relay, or carbon electrodes. From this it is clear that to utilise the unusual properties of negative resistance they must be combined with a non-linear impetus, which also suggests a process that may be related to underlying displacement events. It is always in the presence of a non-linear condition that the mechanism of displacement can be engaged or observable within the electrical properties. It appears to surface in non-linear scenarios where the boundaries of the dielectric and magnetic fields of induction would lead to a discontinuous condition in the electrical properties of the circuit. It is conjectured that displacement appears to “act” in order to rebalance this discontinuous condition and restore dynamic equilibrium between the induction fields within the circuit.

With regard to the phenomenon observed in this experiment, it is conjectured that the apparent reduction in circuit impedance below that of a short-circuit primarily results from a coherent inter-action between the dielectric and magnetic fields of induction. The analogy is drawn to both the superconducting state in metals at low temperature[7,8], and also to ballistic electron transport in a high mobility electron gas[9], also at low temperature. In the case of the superconducting state two electrons became weakly bound together through exchange of a lattice phonon. In so doing they form Cooper pairs where the coherent phonon exchange extends across the entire material on a macroscopic scale. This coherent phonon exchange, and subsequent binding together of Cooper pairs, leads to a band-gap opening in the conduction band of the material, and hence electron-pairs can traverse the dimension of the material without scattering in this band. In this way conduction of a current via electron movement through the superconducting material has zero resistance, and is considered to be coherent.

In the second case of ballistic electron transport, the electronic energy band structure of the semiconductor is so arranged to provide a quantum well, narrower than the phonon wave number, at the fermi level within the well. This confines electrons to a 2D sheet in the well, reducing scattering and increasing the mean free path. Further confinement laterally leads to a 1D wire where the scattering with the lattice is further reduced and the mean free path of an electron becomes longer than the injection contacts at either end of material. In this case, and at low temperature, electrons can travel ballistically from one terminal to the other (e.g. in a quantum wire channel). The ballistic conduction reduces the resistance between the contacts below that normally expected for the diffusive condition, since the scattering with the lattice has been reduced to a point where the electron path between the contacts can be considered as coherent.

In both of these analogies reduction in impedance of the transmission medium is considered the result of a coherent conduction process. In the experiment reported here I conjecture that the reduction in impedance results from the coherent inter-action of the dielectric and magnetic fields of induction, where that coherent configuration is brought about by a displacement event. The displacement event is in itself revealed through the non-linear drive to the experiment, and “mixed” through the negative resistance properties of the CSG. The final product of the displacement event through the negative resistance characteristics, is to re-balance the electrical dynamics of the circuit by coherently aligning the dielectric and magnetic fields of induction yielding a reduced circuit impedance. This conjecture, based on the results so far, requires considerable further work to establish its scope of validity, and would also ideally benefit from a suitable mathematical treatment, when such a form of mathematics is available to describe the properties and processes under exploration.

For further exploration and discussion on the results and phenomenon from this experiment please see the Energetic Forum[10].

In the experiments of Chernetsky[1], and others[3,4], the SGD occurred when the carbon electrodes were adjusted, presumably, into the negative resistance region of their I-V characteristics. The generator for this experiment was a switched fly-back transformer, (transient driven), between 25-100kc, and the secondary circuit incorporated a tank capacitor charged from a half-wave rectified output from the secondary coil of the fly-back. The load was formed with incandescent lamps in series with a carbon electrode gap, and connected in parallel with the secondary tank capacitor. When the carbon arc gap was properly adjusted in the experimental circuit, the current supplied to the fly-back primary was seen to fall, whilst the lamp load was illuminated with greater brilliance, and no discharge arcs where visible between the carbon electrodes. The additional energy in the circuit to maintain the brilliance of the lamps was attributed to energy drawn into the circuit from the Aether and the circuit is claimed to be OU in performance.

The experimental circuit explored in this preliminary investigation of negative resistance is different to that of Chernetsky and others for the following main reasons:

1.  It operates at the line frequency of 50Hz, much lower than the 25-100kc of the fly-back transformer.

2. It does not include a tank capacitor in the secondary, which made lead to additional resonant circuit and/or magnification phenomena in the secondary, and possibly cavity effects and hence longitudinal modes formed between the secondary of the fly-back and the external circuit.

3. A bridge rectifier is utilised instead of half-wave rectification of the secondary output.

Differences 1 and 2 may certainly be significant to the overall result and performance of the circuit. On this basis it is not possible yet to support or refute the OU claims for this circuit. Certainly the non-linear negative resistance phenomena explored in this experiment does not result in an OU condition. In the next part of this experimental sequence the same CSG is used in a circuit equivalent to that presented by Chernetsky and others, and its overall performance measured in detail.


Update

A recent replication of this experiment by Bierbaumer[11] demonstrates that in a very similar experimental arrangement, the increased light intensity observed in the lamps, and the measured additional power drawn from the supply, is most likely to occur due to a slight preferential phase shift between the voltage and current waveforms in the SCR envelope. In this experiment the phase shift appears to be brought about by impulse noise generated by discharges in the carbon spark gap, which effects the triggering conditions of the SCR in the most basic trigger circuit. It is subsequently demonstrated that improvement of the SCR triggering circuit, to make it less susceptible to impulse noise generated by the spark gap, suppresses the observed phenomena of increased lamp intensity and additional consumed power.

Bierbaumer also uses an alternative approach to the replication of the negative resistance I-V characteristics, using a digital and analogue oscilloscope in X-Y mode, and series connected carbon-silicon spark gaps. In this experiment he demonstrates anomalously high “shoot-through” or impulse currents, which are considerably larger than expected from the measured circuit impedance, and appear to occur right at the point where the spark gap transitions between the abnormal glow region at region E (ref. Fig. 2 at the top of the post), through the transition from glow to arc at region F, and finally into the arc at G. The result of this demonstration appears to show that despite the considerable current limiting in the discharge circuit from a low inductance, high resistance load, high intensity impulse currents and the associated magnetic induction field can be generated around the negative resistance region of the carbon-silicon spark gaps.

In my own experiments I have measured similar large anomalous impulse currents in the I-V characteristics when the previously mentioned B1B vacuum relay,  or the 1B24 cold cathode RF spark gap, were connected in parallel with the existing carbon-arc gap, and adjusted to the critical region on the I-V characteristrics at E-F-G. The result was much larger than expected impulse currents that could not be accounted for through SCR waveform phase relationship changes, or the measured impedance of the experimental circuit. The generation of excess impulse currents is an area that requires further investigation and careful quantitative measurement to establish if it is directly the result of negative resistance characteristics, or part of other non-linear phenomena that can arise from displacement of electric power.


1. Chernetsky, A., About physical nature of biological energy phenomenons and its modeling, All-Union Correspondence Polytechnical Institute, Moscow, 1989.

2. Whittaker, E., A History of the theories of aether and electricity, Longman, Green and Co., 1910.

3. Frolov, A. Self-generating electrical discharge, Pegasus Research Consortium, 1996.

4. Dawson, D. Notes on the Impulse discharge, Post #2765, Energetic Forum, 2020.

5. Little, P., Electron-emission – Gas discharges, Handbuch der Physik XXI,  Springer-Verlag, 1956.

6. Abdelrahman, M. & El-Khabeary, H., Study of Three Different Types of Plasma Ion Sources, Plasma Science and Technology, Vol.11, No. 5, Oct. 2009.

7. Bardeen J. & Cooper, L. & Schrieffer, J., Theory of Superconductivity, Physical Review, Vol. 108, pg. 1175, 1957.

8. Marsh, A. & Williams, D. & Ahmed, H., Supercurrent transport through a high-mobility two-dimensional electron gas, Vol. 50, No. 11, Physical Review B (Rapid Communications), September 1994.

9. Marsh, A., Superconducting contacts and Supercurrent Flow in a GaAs/AlGaAs Heterojunction, Ph.D. Thesis, Cambridge University, July 1995.

10. Forum Members, Eric Dollard Official Forum -> Eric Dollard, Post #2807 onwards, Energetic Forum, 2020.

11. Bierbaumer, W., Negative Resistance and the Self Generating Discharge – Experimental Replication, YouTube, 2021.


 

Vector Network Analyser – DG8SAQ

This post on the Vector Network Analyser, the DG8SAQ by SDR-Kits[1-3], is the first in a sequence looking at how to use advanced test equipment to measure the properties, characteristics, and electrical parameters associated with Tesla coils and TMT transmission systems. The small signal ac input impedance characteristics Z11, and also the transfer impedance characteristics Z21, are used a lot in the experiments and measurements presented in this website, and yield a lot of fascinating and intricate dynamic data that can assist in the design, operation, matching and tuning of experimental apparatus suitable for experiments in the displacement and transference of electric power.

Vector network analysis is a vast and well-documented subject which covers the vector response of an electrical network to a frequency stimulus, and analyses the real and imaginary components of both the reflected and transmitted components of that stimulus. The results of this frequency analysis are detailed measurement data of the magnitude and phase of reflected and transmitted scattering parameters such as S11 and S21, which combined with a known and carefully measured calibration, yield impedance measurement parameters like Z11 and Z21 which can be displayed and stored in a variety of different formats.

The purpose of this post is not to cover in detail the theory and prior-art of vector network analysis, which is more than adequately treated in the field, but rather to demonstrate how to use a vector network analyser to gain practical measurements from Tesla and TMT based systems. Some good references[4-7] for further study of this subject area are presented at the end of this post. The usb VNA demonstrated in this post is both sufficiently accurate, and yet affordable, for the expert amateur inventor, researcher, experimenter, or engineer. The results obtained using this instrument, and presented on many of my posts on this website, have been found to correspond with good accuracy and feature detail, when compared to measurements taken using a professional grade VNA, a Hewlett-Packard (HP) 4195A[8].

The 4195A although from the late-80s, and very much an HP flag-ship at the time with a list price, including accessories, in that era of over $50k, and is still actively used in some research labs due to its high accuracy, high dynamic range, and measurement mode flexibility (network, spectrum, and impedance) from 10Hz – 500MHz. Fully working and calibrated examples can still fetch as much as $5k on Ebay and from used test equipment suppliers. The HP 4195A will be presented and compared in another post in this equipment sequence.

The following videos looks in detail at the setup, calibration, software, and measurement of a cylindrical Tesla coil using the usb connected DG8SAQ VNWA, and is intended as a practical introduction to start using a VNA to gain useful measurement data. The first video focuses on the practical setup, calibration, and measurement, and considers and demonstrates the following:

1. An introduction to Tesla coil measurements using a usb connected vector network analyser (VNA).

2. Connecting the VNA directly to the secondary of a Tesla coil for series-fed measurements.

3. Connecting the VNA to the primary of a Tesla coil to measure Z11, the small signal input impedance from the perspective of the generator (the VNA).

4. Connection considerations and methods when using coaxial, and twisted-pair cables.

5. Consideration of calibration reference plane, and techniques to extend the reference plane directly to the primary coil inputs.

6. Calibration of the VNA for Z11 measurements using a short, open, and 50Ω termination.

7. Calibration and measurement procedure for a primary driven cylindrical Tesla coil.

8. Calibration and measurement procedure for a series-fed cylindrical secondary coil.

Figure 2 below shows the schematic for the series-fed and primary driven VNA measurement setup. The high-resolution version can be viewed by clicking here.

The second video focuses on using the DG8SAQ software to calibrate, measure, display, and store the data , and demonstrates the following:

1. Calibration preparation in setting frequency scan bandwidth, number of data points in the scan, and hence the scan rate.

2. Calibration of the VNA for Z11 measurements using a short, open, and 50Ω termination.

3. Display forms including cartesian, polar, and smith chart, trace scaling, and display parameter selection for the measured data.

4. Calibration, measurement procedure, and display of results for a primary driven cylindrical Tesla coil.

5. Calibration, measurement procedure, and display of results for a series-fed cylindrical secondary coil.

6. Data exporting to file, and loading from file to display.

In summary, the SDR-Kits DG8SAQ VNWA has proven to be a reasonable cost, good accuracy, and flexible addition to the lab test equipment, and is capable of a wide range of different measurements, which contributes useful data in the design, implementation, and operation of Tesla coils and TMT transmission systems.


1. Baier, T., A Small, Simple, USB-Powered Vector Network Analyzer Covering 1 kHz to 1.3 GHzQEX Jan/Feb 2009

2. SDR-Kits, Introducing the DG8SAQ VNWA 3 Low Cost 1.3 GHz Vector Network Analyzer, SDR-Kits DG8SAQ

3. SDR-Kits, Software & DocumentationSDR-Kits DG8SAQ Documentation

4. Keysight Technologies, Understanding the Fundamental Principles of Vector Network AnalysisApplication Note 5965-7707

5. National Instruments, Introduction to Network Analyzer Measurements, Fundamentals and BackgroundNI RF Academy

6. Baier, T., Experiments with the DG8SAQ VNWA and the SDR-Kits Test BoardSDR-Kits DG8SAQ Tutorial

7. Baier, T., Your RF Cable, The Unknown EntityHam Radio 2018

8. Keysight Technologies, Network Analyzers, Combined Network/Spectrum Analysis, 10 Hz to 500MHz, HP 4195A


 

Transference of Electric Power – Part 2

In this second part on the transference of electric power we take a look at the differences that arise when a spark gap generator (SGG) is used as the power source for the experiment rather than a single frequency oscillator as used in part 1. It is recommended to study  part 1 before this second part, in order to gain an underlying understanding of the overall experiment, phenomena, results, and suggested interpretation of the experimental results, that are characteristic to the practical investigations in the transference of electric power.

Unlike a single frequency oscillator or linear amplifier generator, a spark gap generator produces a very broad range of frequencies which result from the abrupt and impulse-like discharge that occurs at the spark gap. Frequencies generated by such a spark gap discharge, range from the very low in the 10s of Hz, all the way up to 100s of MHz, and beyond into GHz frequencies. With such a wide frequency band the stored energy available in the tank capacitors, which are charged at each half-cycle of the HV supply, is distributed across this wide band leading to two significant factors. Firstly that considerably less energy is available from the source at the resonant frequency of the transmitter coil, and secondly, tuning of the TMT transmission system has considerably less effect on the transference of electric power between the generator source and the receiver load.

The experimental work in this part is intended to investigate and demonstrate aspects of the following:

1. Tuning measurements using a vector network analyser to measure Z11, the small signal ac input impedance for the experimental system, from the perspective of the spark gap generator.

2. Tuning indifference when powering a load either in the single wire transmission line or at the output of the receiver.

3. Reduced power available in the single wire transmission line.

4. Reduced power available in the receiver load.

5. Tesla radiant energy and matter phenomena.

6. Transference of electric power between the transmitter and receiver in the near field.

Figures 1 below show an overview of the experimental arrangement which consists of two flat coils used as transmitter and receiver and joined via the base of the secondary coils by a single wire transmission line with an inline 60W four incandescent lamp load, (4 x 15W 240V pygmy lamps). The transmitter primary is connected to the Spark Gap Generator via a matching unit which consists of two compound series tank capacitors, shunted 4 x 1B22 hydrogen-argon spark gap modulator tubes, and a 1200pF vacuum variable capacitor in parallel with the 2 turn copper strap primary.

The receiver primary is tuned by another parallel connected 1000pF vacuum variable capacitor which in turn is connected to a 50W two incandescent lamp load. The outer end terminal of the receiver primary is connected directly to RF ground via a low inductance ground strap. As in part 1 the secondary coils of the transmitter and receiver are positioned facing each other on axis 1.5m apart, and are counter-wound to each other in order to produce a balanced and reciprocal cavity arrangement.

Figure 2 below show the schematic for the transference of electric power experiment powered by the SGG. The high-resolution version can be viewed by clicking here.

The principle of operation and matching requirements are somewhat different between the vacuum tube generator (VTG) and the SGG. In the VTG maximum power transfer between the generator and primary is accomplished when the impedance of the primary resonant circuit is equal to the  combined vacuum tube internal impedance, when oscillating at the designed and configured operating point, (class C amplifier), for the tuned primary frequency, and run in CW (continuous wave) mode. In this case the primary circuit is not arranged to resonate at the same frequency as the secondary, where oscillating primary currents would be far too large and lead to destruction of the vacuum tubes. Rather the correct impedance match between the primary and tube oscillator facilitates maximum transfer of power from the non-resonant tube tank circuit to the tuned primary circuit, whilst keeping vacuum tube power dissipation under the maximum combined rating for the tubes.

In the SGG case it is in principle optimal to arrange the resonant frequencies of the primary tank circuit, and the secondary coil to be the same. In this case bursts of very large and maximal oscillating currents are generated in the primary tank circuit, which in turn result in strong magnetic coupling to the secondary circuit, and hence maximum power transfer between the resonant primary tank, and the secondary resonant coil. In practice matched primary tank and secondary coil resonant frequencies cause considerable operating issues when running, as the very high oscillating currents, in the high-Q low impedance primary, result in a very aggressive, unstable, and erratic spark discharge. The de-tuning of the circuit, by deliberate mis-match of the primary tank circuit resonant frequency and the secondary resonant frequency, reduces the Q considerably of the primary, reduces slightly the coupling between the primary and the secondary, whilst considerably stabilising the spark gap discharge to be suitable for experiments in the transference of electric power through a high-Q TMT transmission system.

In the case where a Tesla coil is being used for maximum streamer discharge, it is accepted as best practice to match the primary tank resonant frequency as close as possible to the secondary coil resonant frequency. Here maximum energy is coupled into the secondary and dissipated through the top-load accumulator. In this case the primary frequency is usually de-tuned slightly below the secondary frequency to maximise power transfer during streamer discharge, which leads to very white-hot powerful discharges. For example for a coil arranged to resonate with suitable top-load at 1.7Mc/s the primary resonant tank circuit would be tuned to resonate between ~ 1.5-1.6Mc/s, (~10% lower to compensate for secondary frequency drop on discharge). This case requires a very powerful and robust spark gap that will operate very aggressively, unstably, and producing large amounts of heat, light and noise.

In the case for a TMT transmission system using two or more Tesla coils matched and tuned together in a high-Q narrow bandwidth arrangement, and connected with a single wire and operated in a balanced LMD transmission mode, the primary resonant tank frequency is optimally arranged to be lower in frequency than the secondary resonant coil frequency. In this case there is only a small measured difference in total power being transferred from the generator to the final receiver load as a result of the deliberate primary resonant tank and secondary coil resonant frequency mis-match. For example for a coil arranged to free resonate into a single wire transmission line at 1.7Mc/s the primary resonant tank circuit would be tuned to resonate between ~ 1.0-1.3Mc/s.

The 1B22 hydrogen-argon spark gap tubes were shunted out of the circuit for experiments in the transference of electric power to the receiver load, as their higher internal resistance reduces the primary currents, causing a reduction in the total transmitted power. The shunts are made from copper sheet which remove the tubes from the circuit without increasing the inductance of the primary tank circuit.  In experiments relating to Tesla’s radiant energy and matter it is possible to obtain improved results, (amplified phenomena), when the 1B22 tubes are included in the circuit. It is conjectured that the slight dioding action[1,2] as a result of the ionizing radioactive (Radium Ra-226) trigger element, and the improved pulse response of the primary tank circuit, improves the uni-directional energy supply from the tank circuit to the TMT system. This improved uni-directional energy supply increases the intensity of the LMD mode wavefront in the single wire cavity, amplifying radiant energy and matter phenomena.

A correctly triggered and functioning 1B22 will emit a dark purple spark discharge within the aluminium can of the cathode terminal, which is quickly quenched by the rarefied hydrogen-argon gas mix. A defective 1B22 with a leak to air will still work as a spark gap but will generate a brighter green-yellow discharge as aluminium is combusted from the cathode surface. The discharge sustains for longer causing considerable burning of the electrodes, and rapid over-heating causes distortion of the glass tube, with finally destruction of the electrodes.

The following video introduces the experimental setup, instrumentation, and readings, and looks in detail at Z11 the small signal impedance characteristics of the experiment from the perspective of the spark gap generator. It concludes with a range of experiments in the transference of electric power using a spark gap generator, combined with a preliminary introduction to Tesla’s radiant energy and matter experiments.

Figures 3 below show the detailed Z11 impedance measurements that were presented in the video, and will be referred to in the consideration of the experimental results.

Figures 4 below show the oscillating voltages and currents in the primary transmitter tank circuit, and also those measured at the single wire load. In both the green and red traces the current amplifier is calibrated at 50A/div, showing the large oscillating currents that occur in the primary, and those transferred to the burst in the secondary.

The principle of operation of the transmitter coil primary tank circuit is explained in detail in the post Spark Gap Generator – Part 2. In fig. 4.2 the current (red) in the single wire medium has become far more impulse-like in nature, rather than the oscillating sinusoidal established in the primary coil ring-down as the tank capacitors discharge in the series resonant tank circuit. It is conjectured that these impulse-like currents may be indicative of the burst wavefront constituting the LMD mode, within the cavity formed between the transmitter and receiver coil top-loads. It may also indicate more clearly why it is possible to observe radiant energy and matter phenomena more easily in a SGG driven TMT system, compared to a VTG or linear amplifier driven TMT system. That is, the nature of the burst currents generated in the primary resonant tank circuit by the SGG generator lend themselves more readily, when induced into the secondary cavity, to the LMD mode in the form of impulse-like, uni-directional bursts. These more uni-directional bursts in turn lead to an intensified wavefront in the cavity and the clearer observation of Tesla’s radiant energy and matter phenomena. This experimental area will be explored in much more detail in subsequent posts, but for now serves as an empirical introduction to these fascinating phenomena.

Fig. 4.1. shows the oscillating voltage and currents generated by the SGG in the primary resonant tank circuit. The oscillating currents (green) are a product of the stored energy in the tank capacitors repeatedly transferred backwards and forwards between the tank capacitors and the inductance of the primary coil. As the stored energy is consumed by transfer to the secondary circuit, and by dissipation as heat, light, and noise in the spark gap, and the series resistances of the primary tank circuit, the envelope of the primary current decays until all stored energy in the current cycle is expended. The oscillating nature of the current when transferred from the primary to the secondary tends to cause “dragging” or “smearing” of the LMD wavefront in the secondary cavity reducing the potency and impact of the pressurised wavefront.

In the most ideal case the wavefront would constitute a single pulse of very large amplitude and with very short pulse width, resembling as closely as possible a true impulse function. This pulse wavefront would traverse the cavity in a uni-directional manner with no reflections or dispersion leading to a singular and positive acting pressure wave with both the di-electric and magnetic fields of induction coherently in phase. In this ideal case the transfer of electric power could be 100% between transmitter and receiver, or if radiant energy phenomena are so arranged by a suitable load or emitter in the single wire transmission medium of the cavity, 100% wireless transfer of electric power could be arranged between many points. The intense radiant energy burst from the strong wavefront may also generate a wide range of unusual and hitherto unexplored electrical and matter phenomena, which may in turn also assist in the experimental exploration of the displacement of electric power, the hidden underlying coherent guiding principle of the undifferentiated electric and magnetic fields of induction.

This most ideal case requires that in the primary tank circuit all the energy stored in the tank capacitor per cycle is transferred to the secondary within the first half-cycle of the ring-down. This would create a single pulse from each cycle where all energy available in the tank circuit is transferred to the secondary, in effect driving the primary with a pulse generator. In order to do this it would be necessary to quench the spark gap after the first half-cycle of the discharge, and also ensure that the impedance of the primary circuit was sufficiently low that all the stored energy in the tank could be discharged in this first half-cycle. Both of these requirements present very challenging practical implementations, and will be explored in more detail in subsequent posts.

Tank circuit capacitance optimisation

In the current primary circuit the tank capacitance was adjusted in three different configurations in order to find the optimum operating point for the experiments in the transference of electric power powered by the SGG. The circuit diagram in figure 2 shows the arrangement of the tank capacitor in these three configurations:

1. 2.3nF 16kV from two series MMC units of four capacitors each. This is the tank capacity used in the video experiment and is very stable with only a very small reduction in the amount of power transferred to the receiver load. From figs. 3.3 and 3.4 the resonant frequency of the series primary tank at M1 is 1.09Mc/s. Good stable operation could be established up to ~800W.

2. 1.9nF 20kV from two series MMC units of four and six capacitors respectively. This tank capacity increased slightly the amount of power transferred to the receiver load over configuration 1, but the unbalanced capacity either side of the primary coil, (4 cap. unit one side, 6 cap. unit the other side), was found to lead to more instability in the spark discharge including “popping” and material ejection at the electrodes at powers only up to 500W. The resonant frequency of the tank circuit in this configuration is ~ 1.2Mc/s

3. 1.6nF 24kV from two series MMC units of six capacitors each. This was found to be the lowest practical tank capacity when running at powers up to 1kW. Lower than this the spark gap became too aggressive and erratic for good accurate measurements and stability in the transference of electric power. The resonant frequency of the tank circuit in this configuration is ~ 1.3Mc/s

Overall, configuration 1 was selected for most experiments in the transference of electric power, providing the best balance between longer-term stable and reliable operation of the spark gap, and with acceptable energy transfer to the transmitter secondary coil.

The other feature of the tank circuit was to minimise the inductance of the connections and components. The optimum condition is for all the current in the tank circuit to contribute to generating a magnetic field only within the primary coil itself, which maximizes the magnetic field coupling to the secondary coil. In practise magnetic fields are also created around the inductance of the tank circuit connections and components, storing some of the available tank circuit energy, and reducing the magnetic field generated within the primary coil. The inductance of the tank circuit components is kept minimum by keeping connection wires short and made from large many stranded conductors, by using copper busbars, and solid aluminium or copper mounting blocks for larger components. In the circuit diagram of fig. 2 the low inductance parts of the tank circuit extend from the spark gap to the primary coil and are indicated by thicker connecting wires.

Tuning indifference when powering a load

One of the most notable differences between the experiments in part 1 and 2, is that power dissipated in the both the single wire load and the receiver load varies only slightly with large changes to the transmitter and receiver primary tuning capacitor. The transmitter tuning capacitor was varied over the range 20-1200pF which in figs. 3.1 and 3.2 shows very large changes to the frequency spectrum of the TMT system. However when powered from a properly adjusted spark gap generator the bulbs in the single wire transmission medium remain well-lit over much of the tuning range. This is in stark contrast to part 1 where power dissipated or transferred in the various loads were very dependent on the tuning condition of the transmitter and receiver, and to the matching conditions of the VTG to the primary of the transmitter.

In fig. 4.2 we see that currents in the single wire transmission medium are much more impulse-like and consist of many narrow pulse excitations and rapid bursts. The spectral content of this time-domain signal will be very wide with energy distributed over a very broad-bandwidth, and consistent with the properties of the spark gap stimulus in the primary circuit. With such a wide bandwidth of frequencies present at the single wire load we would expect the bulbs to be illuminated irrespective of the tuning in the transmitter primary. Many frequencies are being transferred from the primary to the secondary circuit which is characteristic and typical of the properties of this experiment when driven from a spark gap based generator.

Given the above as a broad comparison with the experiment in part 1, tuning around the upper and lower resonant frequencies of the flat coil transmitter causes a slight increase in brightness for the single wire load, showing that more energy is selectively coupled at these frequencies from the generator as would also be expected from part 1, and from the frequency characteristics measured in figs. 3.1-3.4.

Reduced power in the single wire load and receiver load

The spread of energy over a very wide bandwidth results in less energy being dissipated in both the single wire load and also in the receiver load, as compared the single frequency oscillator experiment in part 1.

1. In the case of the single wire load, the bulbs can still be lit to almost full brightness since all the power from all transferred frequencies is being dissipated in this load. The bulb brightness showing the average power dissipation over many bursts coming from the spark gap generator. At an input power of 300W to the HV supply it was possible to illuminate the single wire load to around two-thirds of its maximum rating, so ~45W. At 500W the load could be illuminated fully to ~60W.

2. In the case of the receiver load, much less power could be coupled into this load even when tuned correctly as a complete TMT system, as shown in figs. 3.3 and 3.4. The single wire load had to be first removed to prevent power dissipation at this load, and then the receiver load could be illuminated to maximum ~0.5 of its total power e.g. about 25W. From the wide-band of frequencies available in the single wire transmission medium only a very narrow range at the resonant frequency of the receiver flat coil are transferred from the single wire to the receiver load. It should however be noted that the receiver bulb loads where illuminated dimly over the entire tuning range of the transmitter primary and the receiver primary. This again shows that a little of that wide bandwidth of energy is coupled to the receiver irrespective of the tuning, again tuning indifference based on the spectral content of the source energy.

In this case the spark gap generator is far from optimal for the transference of electric power, where for the same input power as in part 1, less energy is transferred to the single wire load, and very much less energy can be transferred to the receiver load. This proves to be the case even when the TMT system is optimally tuned as shown in figs. 3.3 and 3.4, and by further comparison with the optimal tuning results in part 1 of this experiment.

Tesla radiant energy and matter phenomena

These phenomena form some of the most interesting and unusual aspects of this TMT experiment using a spark gap generator. Whilst these effects can also be observed in the same experiment using a single frequency oscillator, linear amplifier, or other oscillating source they are much reduced in intensity when compared with a spark gap generator, burst oscillator, pulse generator, or properly designed and operated impulse or displacement generator. The exploration of these phenomena in this experiment is only as an introduction to these effects, and properly requires a much more detailed experimentation and consideration, which will be presented in a subsequent post along with very much magnified phenomena results.

The preliminary phenomena observed in this experiment include:

1. Attracting metals to the surface of an incandescent bulb in the single wire cavity, where the bulb acts as an emitter of radiant energy.

2. Amplification or intensification of a radiant energy event by interaction with a living organism, (human hand).

3. Charging a capacitor with radiant energy by bringing it close to the emitting bulb.

4. Radiant matter pressure waves emanating from the emitting bulb and impacting on a living organism, (human hand).

It should be noted here that improving the uni-directional pulse nature of the generator system by, for example, including components such as 1B22 spark gap modulator tubes in the tank circuit, early magnetic quenching of the spark discharge, or other impulse/pulse/burst generation methods, considerably magnifies the observed phenomena. It is also important to note that these types of phenomena are best observed when  a cavity has been established using a resonant transformer, such as a Tesla coil, and where a longitudinal pressure wavefront is established within the cavity, preferably in an LMD type mode, or ideally with direct displacement.

Summary of the results and conclusions so far:

The transference of electric power experiment using the tuned TMT flat coil system has produced considerably different results when powered using a spark gap generator, as compared with the single frequency feedback oscillator in part 1. The key differences and results include the following:

1. Tuning indifference occurs due to the wide spectral bandwidth of the energy transferred from the generator to the final receiver load, and impacting on all parts of the TMT transmission system between these points.

2. Considerably reduced levels of transferred electric power both to the single wire transmission medium load, and the receiver load, for the same nominal input power to the HV supply of 300W. Again this is attributed to the diffuse spectral energy content when a wide bandwidth generator is connected to a narrow bandwidth high-Q TMT transmission system.

3. Tank circuit tuning configurations have shown that a de-tuned primary and secondary resonant frequency in the transmitter primary leads to the best balance between transferred electric power, and stable, consistent, and long-term reliable operating conditions.

4. Radiant energy and matter phenomena have been observed in the experiment, and indicate components and optimizations, including different generator configurations, that will intensify and maximise these unusual observations.

5. Generator configurations and types that improve the impulse/pulse/burst nature of the transferred energy may intensify radiant energy phenomena by generating a more uni-directional pressure wavefront in longitudinal system, which may also provide additional insight into the preliminary investigations into the displacement of electric power.

The results for the transference of electric power in the near-field using a spark gap generator indicate that this form of generator is not well suited for energy transmission in the narrow bandwidth high-Q TMT system. A very large and robust spark gap generator would be required to transfer adequate power from generator to load, with considerable losses at the spark gap, huge electromagnetic interference to the surrounding medium, and invasive and unstable operating conditions. However this form of generator does appear to lend itself to phenomena that arise from the longitudinal pressure wavefront generated in the cavity of a resonant transformer, such as a Tesla coil. As such it is conjectured that this form of generator may be useful in the exploration of displacement, the hidden underlying coherent guiding principle of the undifferentiated electric and magnetic fields of induction.


1. Dollard, E. & Lindemann, P. & Brown, T., Tesla’s Longitudinal Electricity, Borderland Sciences Video, 1987.

2. Dollard, E. and Energetic Forum Members, Energetic Forum, 2008 onwards.