Wireless Power? (The work of Nikola Tesla)

[Meizirkki]

jim, in one of my posts I explained why Tesla coils have such high Q and that it's exactly what "excess energy" seeking people get so exited about. I hope it didn't give you the wrong impression that I would think there is excess energy. I see what you say and I completely agree. Also, thanks for the compliment :) but I must note that Tesla coils are not directional antennas in the traditional sense. They are more like plates of a capacitor, the entire space between them being the dielectric. A properly operated Tesla coil doesn't create large magnetic fields.

and sophiecentaur, sorry for not being clear enough in my previous posts. The resistor were of same type, 10 ohm (very close, measured with a multimeter) and the coils as identical as possible. The impedances were same and that's why I didn't bother mentioning current or power. Voltages are true RMS measured with an oscilloscope.

I don't think I'm leading any of my fellow students down a wrong path.. I'm an experimenter, not a theorist. I'm not one to tell people how things are, instead I show off Even our teacher was surprised when we lit up fluorescent lamps by holding them in our hands ;) (a joule thief buzzing in the background.)

 

[jim hardy]

"They are more like plates of a capacitor, the entire space between them being the dielectric. "

I did not do well in fields or vector calculus courses so can't offer any worthy commentary.
"... A properly operated Tesla coil doesn't create large magnetic fields.""
Yet i have read that E and B fields are inseparable..
So i just make mental note of experiments like yours , and if Fate ever wants me to understand fields better one of them will be an epiphany.
"When the student is ready a teacher will appear".
Meantime i just watch while folks like Sophie and Yungman and Bassalisk et al enjoy the advanced math.


Maybe we'll get back to an Aether and maybe it'll be anisotropic... some of my friends over at Neutron Repulsion toss about such ideas. I feel like Charley working in that bakery...(Flowers for Algernon)
Thanks for the clarification and thanks to all for letting me share your playground..

 

[sophiecentaur]

jim, in one of my posts I explained why Tesla coils have such high Q and that it's exactly what "excess energy" seeking people get so exited about. I hope it didn't give you the wrong impression that I would think there is excess energy. I see what you say and I completely agree. Also, thanks for the compliment :) but I must note that Tesla coils are not directional antennas in the traditional sense. They are more like plates of a capacitor, the entire space between them being the dielectric. A properly operated Tesla coil doesn't create large magnetic fields.

and sophiecentaur, sorry for not being clear enough in my previous posts. The resistor were of same type, 10 ohm (very close, measured with a multimeter) and the coils as identical as possible. The impedances were same and that's why I didn't bother mentioning current or power. Voltages are true RMS measured with an oscilloscope.

I don't think I'm leading any of my fellow students down a wrong path.. I'm an experimenter, not a theorist. I'm not one to tell people how things are, instead I show off Even our teacher was surprised when we lit up fluorescent lamps by holding them in our hands ;) (a joule thief buzzing in the background.)

But the 10Ω is not the Load, is it? It is surely just a current sensing resistor, not a power meter. Certainly you wouldn't light LEDs with 400mV. So how did you actually measure the POWER transfer involved? What was your load impedance and what was your source impedance, for a start?
I get the impression that your attitude to this business is tailor made for the Tesla religion. Just approximate enough to feel you understand the arm waving but not rigorous enough to use the Equations to tell you what exactly is going on and to keep you on the rails.

You are a student, I realize. It is great that you have enthusiasm. If you really want to follow this fondness for Science to take you into a career, you will need to go through the pain of formal treatment of all these things. You will then be able to see what you have read in its context. Take it from me, conventional EM is NOT WRONG. The terms you are bandying about have much more exact meanings than you seem to realize. When you have got some substantial knowledge of the topic then you can usefully take the subject into 'paid employment'.

If you want to beat 'em then you will have to join 'em first - like all the successful and celebrated workers have done. You seem to have a good, healthy disregard for 'excess energy', in principle - and that reassures me.But I think you need to see the overall picture and that a lot of what you are describing is, in fact, just that. These Energy Sources are not actually Sources - they are just (Low-grade) Energy Levels. There is loads of thermal energy in the Arctic Ocean - it's just not a lot of use because the temperature is so low. Likewise with your 'unspecified' energies that exist in the World. The Energy sources you hint at don't actually represent energy that can be utilised. Like I said, the Conservation Laws and thermodynamics can't be ignored. The Numbers count: use 'em.

 

[Meizirkki]

Okay, now I see that I wasn't clear enough. Sorry.

The LED test and the efficiency test were two separate tests. In the efficiency test, the 10 ohm resistor was the load impedance. The only component connected across the terminals of the primary coil, which means all the current in the primary goes though it. At the transmitter end, a 10 ohm resistor was connected in series with the primary and function generator, again all the current from the function generator goes though the 10 ohm resistor. My teacher was following the experiment and I can assure you I did everything with great care.

I hope I didn't upset you. I don't have a fraction of the knowledge and experience you have. I'll take your advice and learn more :)

I hope to take pictures and more accurate measurements of my new setup when it's finished.

 

[sophiecentaur]

Never upset - don't worry.
My point is that your 10Ohm resistor measurement will not tell you the power unless you know source and load impedances. If you have resonant systems it is even less easy. So, apart from the fact that you lit your diodes, you cannot know the efficiency.

But there are two entirely separate issues here. You have shown that it is possible to get good coupling between a source and load, using a transformer but that has nothing to do with the notion of getting energy from other, unspecified, sources of RF energy. You did not take my point about Conservation Laws, but they apply here the same as anywhere else and they are the basic objection to 'excess energy' and also to this. Going back a bit, you are actually suggesting the equivalent to a 'Maxwell Demon', which has been put to bed long ago.

 

[Meizirkki]

Never upset - don't worry.
My point is that your 10Ohm resistor measurement will not tell you the power unless you know source and load impedances. If you have resonant systems it is even less easy. So, apart from the fact that you lit your diodes, you cannot know the efficiency.

But there are two entirely separate issues here. You have shown that it is possible to get good coupling between a source and load, using a transformer but that has nothing to do with the notion of getting energy from other, unspecified, sources of RF energy. You did not take my point about Conservation Laws, but they apply here the same as anywhere else and they are the basic objection to 'excess energy' and also to this. Going back a bit, you are actually suggesting the equivalent to a 'Maxwell Demon', which has been put to bed long ago.

In my last two posts I have apologized for causing all these misunderstadings by not making my posts clear enough. No, it's not that. I read several previous posts of mine and I don't understand which part of them makes you think that:

- I am not familiar with the laws of thermodynamics and the conservation of energy.
- I have claimed that my coils would "collect energy"

I never claimed that Tesla coils had something to do with "collecting energy" nor did I make the slightest implication that my coils were in any way associated with the whole subject.

I didn't comment on your point about energy conservation laws and thermodynamics because I wasn't ignorant to them in the first place. You say that I was "suggesting the equivalent to a 'Maxwell Demon'".. I do not recall making such a suggestion.

Also, I must say I am slightly offended by your refusal to believe that I and the teachers of my school know how to measure efficiency.

 

[sophiecentaur]

Rather than saying the coils 'collect energy' it would be more appropriate to say that the 'couple energy' from one to another. That is a mutual effect involving 'near fields' and your receiving coil is getting its energy from a relatively high power source nearby. This is nothing to do with Mr Tesla but is good fun and a worthwhile experiment / demo.
Any structure will receive RF energy and radiate it in the same way that it will absorb and radiate thermal energy, in fact it's the same thing. The net gain or loss of energy will depend upon the total energy from all outside sources and the noise energy generated naturally within the structure due to the energy stored in it. It makes no difference whether you have a high Q or low Q, the totally energy available 'to use' from the receiving structure will just be equal to the flux of energy it can intercept. Any excess energy will be re-radiated. If you consider that the total amount of noise and interference energy (unless you happen to live just down the road from a powerful transmitter) passing through the area intercepted by a small antenna (or any structure) will be such that it will need amplification before it's easily detectable. Crystal sets are operating with relatively powerful signals and are the only 'passive' receivers you can make. These only make use of a mW or less of energy, from one or more powerful mf transmitters,not too distant. The net energy from all transmissions is of no use for powering any device but a sensitive earphone. No useful free energy. You would need to specify what other 'sources of energy' could provide any more than this. Magnetism is not a source of energy any more than the Earth's gravitational field is, on its own.

I question your measurement of efficiency because what you have described is not a valid way to find it.

Your contributions imply a connection between Tesla (you have championed his cause) and the results of your experiments. If there is no connection then perhaps a separate thread would have been better.

Your response to my objection involving Conservation Laws implies that you do not see the bigger picture and where they come into play.

 

[Meizirkki]

Hello again. I have a work trip to germany the next month, so I hurried to finish my new coils and take measurements before that.

Unfortunately for me, the efficiency was not at all what I expected. At first I couldn't believe my own calculations, since the results were so much better with the old coils. I checked photos of the earlier experiment and BUM. I found that in the earlier experiment, I had accidentally connected the scope probe in a way that short circuited the resistor I was measuring voltage from. The fact that both funtion generator output and scope probe are connected via PE ground had apparently crossed my mind. Thanks to the PE ground being such poor conductor for HF signal I still got results and considered the experiment a huge success.

https://docs.google.com/document/d/1QirnU-yX7XPJY_1MaW0UqU-egkO3-6WoxhcDQ3yiOyE/edit?pli=1

Thinking about it now, I find my own claim of 95% efficiency absurd. More than 5% is certainly lost already in the induction between the primary and the secondary. bah. I feel so stupid for not seeing that myself. Sorry.

My new coils aren't a complete failure though. Even with notable inconsistencies in the coils and sinewave input, the transmission did work. The efficiency, while being only a fraction of my previous claim, could never be achieved with magnetic induction at that distance (I tried that too), and with major improvements to design will definitely challenge radio transmission esp. at longer ranges. (correct me if I'm wrong)

At the very last, I hope this experiment provides enough evidence to show Tesla's transmission system is not "all moonshine".

I'm looking forward to improving the coils and designing a solid state power supply for the transmitter. Apart from improving the efficiency, I'm going to test whether distance has any effect on the transmission. If I can find faraday cages I will place the coils in them just to show the transmission is not based on EM waves and all energy radiated is energy lost.

Peace.

 

[sophiecentaur]

At the very last, I hope this experiment provides enough evidence to show Tesla's transmission system is not "all moonshine".

I'm looking forward to improving the coils and designing a solid state power supply for the transmitter. Apart from improving the efficiency, I'm going to test whether distance has any effect on the transmission. If I can find faraday cages I will place the coils in them just to show the transmission is not based on EM waves and all energy radiated is energy lost.

Peace.

Why should the basic working of a transformer system be attributed to Tesla? You may as well attribute it to Faraday - the only difference is the Iron core and the frequency.

I don't see why you would need a Faraday cage if you're planning to achieve 90% efficiency. Why should you care where the odd 10% is going? If you put it in a metal box, they you have even less idea about how the coupling is achieved and it would barely qualify for the name 'wireless' - more like a waveguide.

If you are using the separation distances that are referred to in 'that paper', you will be in the near field, in any case, so it won't be the radiated power but the 'coupled' power. When you say that it's not based on em waves, I'm not sure what you can mean. Do you mean 'free waves'? Because, if the power is not transferred by electromagnetism then you would have to invent a new set of fields to account for it. Is that feasible?

I can see that you think I am being a 'wet blanket' concerning Mr Tesla but do you not consider the possibility that you are re-inventing a wheel that has been re-invented many times before (including Tesla). If you want to optimise performance then you really need to look into the matching problem and what is basically an Impedance Matrix involving the self and mutual impedances of the two structures. Do some reading round and, apart from the term 'wireless' that has been hijacked recently, this sort of thing has been looked at many times. The difference in the situation these days is mainly the availability of cheap and efficient amplification and rectification and low power requirements for modern electronic equipment - which is probably why it is taking off again.

BTW, my ageing rechargeable toothbrush uses Wireless Power - but, as it's at 50Hz and needs to be small, the distance involved is not great.

 

[Meizirkki]

Why should the basic working of a transformer system be attributed to Tesla? You may as well attribute it to Faraday - the only difference is the Iron core and the frequency.

I'm only talking about Tesla all the time because this thread is about him and it's his work I'm trying to replicate. It's not my purpose to praise Tesla.

I don't see why you would need a Faraday cage if you're planning to achieve 90% efficiency. Why should you care where the odd 10% is going? If you put it in a metal box, they you have even less idea about how the coupling is achieved and it would barely qualify for the name 'wireless' - more like a waveguide.

I would do that only to show the energy is not transferred via radio waves.

If you are using the separation distances that are referred to in 'that paper', you will be in the near field, in any case, so it won't be the radiated power but the 'coupled' power. When you say that it's not based on em waves, I'm not sure what you can mean. Do you mean 'free waves'? Because, if the power is not transferred by electromagnetism then you would have to invent a new set of fields to account for it. Is that feasible?

Sorry, I'm confusing terms again. By EM waves I meant radio waves. I'm curious to how large this near field is, and how far it could be "stretched" with higher voltages and Earth grounding. And I forgot to mention, but that paper was made by me.

I can see that you think I am being a 'wet blanket' concerning Mr Tesla but do you not consider the possibility that you are re-inventing a wheel that has been re-invented many times before (including Tesla). If you want to optimise performance then you really need to look into the matching problem and what is basically an Impedance Matrix involving the self and mutual impedances of the two structures. Do some reading round and, apart from the term 'wireless' that has been hijacked recently, this sort of thing has been looked at many times. The difference in the situation these days is mainly the availability of cheap and efficient amplification and rectification and low power requirements for modern electronic equipment - which is probably why it is taking off again.

I might be reinventing a wheel that has been reinvented many times but I don't mind it. Even though the near field coupling is widely known and used, I haven't found anyone trying to do the same over long distances with the help of Earth and atmosphere. The only way to find out whether "Tesla was right" is to try do it myself.

With this more specific testing I've come to notice the same thing you say, the impedance and top/self capacitances of the coils should be exactly the same to achieve the best performance, but it's rather hard to do. It was obvious to me that my coils were somewhat out of tune when the output power could be improved by bringing my hand near the transmitter. I was tempted to take results while holding my hand there but I couldn't see the reading of output voltage on the other side of the room

 

[Meizirkki]

uhh I meant to say inductance, not impedance. (can't I edit my posts?)

 

[HallsofIvy]

The problem with wireless power transmission is that you lose an awful lot of power through leakage to the atmosphere. Tesla could transmit power from one end of a stage to the other but not much further. (That's why "electrical engineering" used to be referred to as "power engineering" and "electronic engineering" as "signal engineering".)

The problem of loss is less with microwaves but there are other problems (it is far more dangerous to stand in front of a microwave beam than in front of a radio beam).

 

[billbaty]

The problem with wireless power transmission is that you lose an awful lot of power through leakage to the atmosphere. Tesla could transmit power from one end of a stage to the other but not much further. (That's why "electrical engineering" used to be referred to as "power engineering" and "electronic engineering" as "signal engineering".)

The problem of loss is less with microwaves but there are other problems (it is far more dangerous to stand in front of a microwave beam than in front of a radio beam).

That's just not true. Tesla transmitted power over a hundred and fifty mile radius. He invented fluorescent lighting tubes that he placed on farms and ranches so he could monitor the transmission. These tubes were placed as far as 150 miles away from his tower and were to be witnessed by the farmers and ranchers. Tesla was hoping that the power transmission would extend at least 100 miles but tubes 150 miles away lit up. I have not read where he ever commented on how far the power could reach.

 

[sophiecentaur]

You would have to provide substantial evidence than that about your claim about Tesla's demonstration. It's such an outrageous claim that you would need a lot more than some lines from a book.
It just has to be nonsense or you'd have to reject everything from Maxwell onwards in order to believe it.
This is supposed to be a Scientific discussion with its feet firmly on the ground and not fantasy.

 

[sophiecentaur]

uhh I meant to say inductance, not impedance. (can't I edit my posts?)

Is there not an Edit button at the bottom of your posts? I can always find one on my latest posts. It's on the same line as the 'Quote' button.

Yep - this is an edit.

 

[Meizirkki]

I've seen the button. I guess it just disappears after a while since I can't edit any of my posts now.

EDIT: Except for this one I just made. ;)

 

[ontour]

An Australian inventor is claiming to have found the solution to Tesla's Underground Wireless Transmission and is looking for input from experienced people in this field.
They are encouraging Universities to get involved by building a cost effective apparatus to demonstrate "proof of principle"
There is a google blog link in the "Serious activities Begins" section on the home page

[crackpot link deleted]

 

[sophiecentaur]

When that "Australian Inventor" has some theory or results to publish then I'm sure PF will be all eyes and ears. Until that, it's still Science fiction (by definition) and is not a part of PF world.

btw, only one conductor is needed to carry a guided wave. I thought simply everyone had heard of a Goubeau Line. That link doesn't seem to have heard of it, yet they're pontificating about 'earth return'. Probably not a good source of serious info.

 

[Meizirkki]

Solution? Pff. Like there ever was a problem? :P

EDIT: How on Earth is this something "that no one has ever been able to do before?" You only need two coils ffs. Should I call universities to see my coils too?

EDIT2: And he claims "all energy is transmitted via ground"? Not true.. I should contact him.

 

[ontour]

Please do...I'm sure your input would be welcomed

The blog

[crackpot link deleted]

 

[sophiecentaur]

I'm amazed about the claim of 90% efficient transfer of power from one coil to another. What if another coil were put nearby? Would that get 90% of the power too? 180% of the input power would appear. That would be amazing good value.

 

[Meizirkki]

No. The input power would be shared between the two receivers. Tesla coils are "transponders" rather than transmitters and receivers.

 

[sophiecentaur]

No. The input power would be shared between the two receivers. Tesla coils are "transponders" rather than transmitters and receivers.

It's a transformer, in fact. Where's the magic in that? Not all transformers are made of iron and handle mains electricity.
I wish someone could tell me what's supposed to be different about these things with the name 'Tesla' attached to them. Transformer windings are essentially magnetically coupled coils because it is a near field effect and the impedance is not the same as for free space.
This way of close-coupling small pieces of equipment to a power source could have useful applications (subject to the interference levels being controlled). A 'charging table' would be another step up from 'the dock'. Efficiency need not be high because low power is involved.

But there seems to be some confusion about the distance over which this type of coupling exists. It is only in operation within a wavelength or so from the primary / transmitter. Only a 'free wave' will propagate over longer distances and energy can only be 'directed' using a large aperture antenna. Furthermore, the mutual impedance between wide spaced transmit and receive array is low (a receive antenna can't "suck" energy from the source). You cannot avoid 'wasting' most of your power and it is a brave man who disputes Maxwell's Equations.

People go and spoil it all by extrapolating a near-field process to long distance high power transmission as if it's the same thing. Tesla had a number of totally off the wall patents which are fully available for development but have never been (they were duff); there is no implication that a patented idea will actually work. Likewise, there may well have been uninformed pen-pushers in the Pentagon (or whatever it was called at the time) who decided that one or two of his untested ideas were a potential threat. There was no need to justify these decisions on rigorous technical grounds. Once declared secret, they were hidden from normal scrutiny and are not available for a healthy scrutiny /de-bunking. They just sit there, proving to the gullible that they are suppressed by that great conspiratorial body they love to hate. Tesla must be chuckling in his grave.

 

[gushovard100]

Tesla coils joined in single base wire connection format connect by conduction. Tesla lodged his first patent application that said transmission and then set out another Patent with virtually the only difference being the word conduction. It appears that the engineers at the time didn't get the conduction thing. And he didnt mean by EM he meant by wire connection. A simple single wire system I have built demonstrates conduction through one wire not magnetic transfer of power since both coils are 180 degrees out of phase. If they were acting as a transformer or by electromagnetic connection they would need to be out of phase to transmit energy using magnetic energy. It uses voltage and Amperage to do the job. Sure, it puts out a little EM radiation but very limited and usesless in the process since it is out of phase.

 

[sophiecentaur]

Tesla coils joined in single base wire connection format connect by conduction. Tesla lodged his first patent application that said transmission and then set out another Patent with virtually the only difference being the word conduction. It appears that the engineers at the time didn't get the conduction thing. And he didnt mean by EM he meant by wire connection. A simple single wire system I have built demonstrates conduction through one wire not magnetic transfer of power since both coils are 180 degrees out of phase. If they were acting as a transformer or by electromagnetic connection they would need to be out of phase to transmit energy using magnetic energy. It uses voltage and Amperage to do the job. Sure, it puts out a little EM radiation but very limited and usesless in the process since it is out of phase.

Welcome
I suppose you acknowledge that Maxwell's Equations describe all there is to know about the way Electric and Magnetic Fields behave. In which case, if you attempt to give an 'explanation' of an electromagnetic phenomenon, it should follow from those equations.

Whatever the "conduction thing" is, Maxwell governs what happens. Maxwell applies to a simple battery and bulb circuit, a transformer, a coax cable, waveguide, near field - far field EM power transmission - everything. If you want to quote from a Patent as a form of proof of your ideas then that is not valid. There are millions of Patents based on absolute nonsense; we all know that.

Your simple "single conductor" system would need some more detailed description, along with measured results, to a reasonable standard.

"wire connection" involves EM just as much as a Radio transmitter. Read your EM theory. Not all EM waves are radiated waves.

 

[Meizirkki]

It's a transformer, in fact. Where's the magic in that?
...
I wish someone could tell me what's supposed to be different about these things with the name 'Tesla' attached to them.

Is there supposed to be magic in that? I'm really having some hard time here trying to understand your hate for Mr. Tesla. Yes Tesla coils are a sort of transformer and there is no magic.

I can (once again) try to explain you the major differences between Tesla coils and a conventional transformer:

- The secondaries can be far away from each other. Farther than magnetic induction used in conventional tranformers can reach.

- The secondaries do not need a conductor between them. The single wire used in my efficiency test can be replaced with a capacitor or a capacitance of natural medium such as water (I expect Earth grounding to work too, but I haven't tested it yet). I will provide test results for this later.

- Thanks to their structure, Tesla coils store energy in the oscillating field. This is rarely the case in conventional transformers.

- Conventional transformers tend to work with a wide range of frequencies, depending on their structure. Tesla coils work with only one frequency (though, input signal can be a harmonic of the oscillating field). The frequency of the oscillating fields is determined by the physical size and shape of the coil.

- Conventional transformers usually have many layers of wire on top of each other. Tesla coils can not operate if there is more than one layer. This is not a problem with isolation, but a necessity for the operation. The propagation of high frequency signal is very different in single and multilayer coils.

Hope this helps you understand the differences.

 

[sophiecentaur]

I don't "hate" Mr T at all. What I do hate is the attitude that people have towards him. It is irrational and sycophantic. No one ever give me any solid evidence that his inventions are actually of any use (except the high voltage generator, which I have made and which is very impressive). The existence of Patents or 'suppressed secrets' are no evidence at all and neither are stories of American farmers experiences - with respect, they could have been persuaded that they had seen anything that Mr T told them they'd seen.

Transformers ("Understanding of"): I did not say that the Tesla design of transformer was conventional. The air core and the tuning are both significant differences between it and a mains transformer. Have you seen the transformer coupling that is used in radio IF strips or have you seen the transformer coupling that is used in Radio transmitters? No iron there, either and usually, a narrow band of operation. You mention specifics of coil design. If you look in radio engineering publications from the last century, you will find all sorts of wrinkles about how to wind the most effective and lossless coils for MF filtering and matching. It's very hard to characterise these structures (or at least it was, before computers were available).

As you haven't provided a drawing (schematic or otherwise) I can't comment on how this 'single wire coupling' operates. If you can't explain what is going on in terms of conventional EM theory then that doesn't mean anything special except that you haven't analysed what is going on. You are surely not trying to say that Maxwell doesn't apply to coils with a 'T' marked on their design.

'Storage of energy in an oscillating Field' is an example of Resonance. Inductive loop communication systems often to use resonance to improve efficiency.

You haven't said how you were measuring the Power in your experiment. It is extremely easy to confuse measured Voltage with Power and it is the bugbear of reliable RF power system appraisal. If those measurements are not bombproof then an apparent 90% could be a much lower real value. What did this efficiency test consist of? How did you ascertain the power that your source was delivering? What sort of separation have you made your system operate over?

a capacitance of natural medium such as water

This phrase rings alarm bells with me. I reads a bit 'new age' to be included in a serious discussion about an Engineering topic. What is it supposed to mean and how would it be implemented?

 

[Meizirkki]

This phrase rings alarm bells with me. I reads a bit 'new age' to be included in a serious discussion about an Engineering topic. What is it supposed to mean and how would it be implemented?

I did not mean the capacitance of water, sorry. I meant to say that it is possible to use capacitor in the place of wire, and natures own materials can be exploited to form this capacitor.

In his patents, Tesla has connected the sedondaries of his coils to Earth. I have not been able to test this yet, but I have (today) used water to form this capacitor. It is as simple as cutting the wire between secondaries and dropping the wires to a pot of water. They wire does not need to be stripped from insulating material. When both wires touch the water, it is enough to form the capacitor.

Air can not be used to form the capacitor explained above, because air is already used to form another capacitor at the top end of the coils. (Big spheres should be used at the top end, big surface area = more capacitance = longer distances)

Tesla called this "Disturbed ground and air method", which makes perfect sense to me.

 

[sophiecentaur]

I did not mean the capacitance of water, sorry. I meant to say that it is possible to use capacitor in the place of wire, and natures own materials can be exploited to form this capacitor.

In his patents, Tesla has connected the sedondaries of his coils to Earth. I have not been able to test this yet, but I have (today) used water to form this capacitor. It is as simple as cutting the wire between secondaries and dropping the wires to a pot of water. They wire does not need to be stripped from insulating material. When both wires touch the water, it is enough to form the capacitor.

Air can not be used to form the capacitor explained above, because air is already used to form another capacitor at the top end of the coils. (Big spheres should be used at the top end, big surface area = more capacitance = longer distances)

Tesla called this "Disturbed ground and air method", which makes perfect sense to me.

It would really help if you were to draw a diagram of what you see is going on here. The capacity between two spheres, separated by a few metres is extremely small ( a few tens of pF). The 'other ends' of the coils would be 'grounded' in some way, I imagine. With a stake in the ground or in a pool of water would make little difference. It's just an Earth connection between the two bases which would usually be best with a 'copper' plane between the two coils but a few wires would be almost as good.

There will be a mutual inductance between the two coils and a (tiny but finite) capacitance between them. That will be the coupling mechanism between the two in the near field. The far (radiated) field will not have established itself for a small separation but the currents in the two coils will be the result of the Impedance Matrix - self and mutual impedances and the 'drive point' voltage. Having resonant structures will give you effectively much bigger 'elements'. This is just an extension of the idea of top or bottom loading short monopole antennae.

btw, what sort of Q do you reckon you are finding for these coil / ball structures?

 

[Meizirkki]

It would really help if you were to draw a diagram of what you see is going on here. The capacity between two spheres, separated by a few metres is extremely small ( a few tens of pF).
...
btw, what sort of Q do you reckon you are finding for these coil / ball structures?

Here. This is how I think it works.

The capacitance is indeed very small. A friend of mine did some calculations and said it would be very unlikely for my coils achieve distances beyond ~100 meters. And this was for my first set of coils which operated at ~14MHz.

I can think of three ways to improve the distance: raising the voltage, installing a bigger sphere on top of the coils and using higher frequency.

I have not been able to test the Q of my coils in operation. I don't even know how to do it. If I remember correctly the LCR tester thingy showed a Q ratio of 5.5 for each of the secondary coils and 5 for the primaries. I am not sure about this though, and I don't know whether the tester is accurate.

Luckily my boss here in Germany is interested in this kind of "lost inventions" too. He provided me with materials and let me wind pancake coils for demonstration this week. I thought I wouldn't be able to do any testing this month, but thanks to him I've been able to test the "water capacitor" and try a bit longer distances. The function generator here can go only up to 1MHz which is just enough to achieve the transmission somewhat out of tune. I won't be measuring efficiency, but I can post here any tests that can be made without accurate measurements. (Demonstrating the water trick and longer distances).