28 MHz Tesla coil.
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28 MHz Tesla coil.
Hello.
A Tesla coil is a large very high voltage transformer.
Tesla was able to send power 20 miles, without wires, in the 1890's.
But, early Tesla coils operated on very low frequencies, and so are large, huge in fact.
The higher the frequency, the smaller the coils.
I am thinking of 28 MHz for a Tesla coil, for a full power unit.
At a few kHz, a Tesla coil can wipe out communications for thousands of feet, wired unshielded, radio, everything.
It does this by ionizing the air, making it conductive.
Flash overs are not desirable.
But, at a few kHz, a Tesla coil the size of a briefcase is very inefficient.
300 watts can wipe out communications for a few thousand feet, but for power transfer, not very effective.
A Tesla coil would need to be much higher in frequency to be efficient as a small unit.
So, now, the question, what would be the good frequency to efficiency to size?
Remember that this is a theory and a math model, not an actual device.
I picked 28 MHz as it is in the ham band, so 1500 watts is legal, and power MOSFETs work there, but that is the upper limit for a non RF transistor, and they have ratings of 1000 volts and higher.
Again, this is a model in theory, and the goal is the transfer of as much energy from point A to point B.
One can transfer in the HF band with small antennas, Near Field Communications does that with 13.56 MHz with hand held devices, but at a very short range.
And it is very very inefficient.
The other problem is things like Tasers will explode if subjected to a strong Tesla coil, the problem seems to be sudden battery failure.
We can not have exploding Tasers! no matter how much one might hate the things!
It might be that the extending wires act as a dipole and get to resonance at some point, but why do the wires not burn up?
Again, this is a theory, not a produced project.
I have played with RF tank circuits at 28 MHz and so far it looks promising.
The idea is to couple as much energy into space as possible, just as any transmitter and antenna, but at very high voltage.
One would be best served by reading about what a Tesla coil is for a better understanding of what I am dealing with.
A Tesla coil is a large very high voltage transformer.
Tesla was able to send power 20 miles, without wires, in the 1890's.
But, early Tesla coils operated on very low frequencies, and so are large, huge in fact.
The higher the frequency, the smaller the coils.
I am thinking of 28 MHz for a Tesla coil, for a full power unit.
At a few kHz, a Tesla coil can wipe out communications for thousands of feet, wired unshielded, radio, everything.
It does this by ionizing the air, making it conductive.
Flash overs are not desirable.
But, at a few kHz, a Tesla coil the size of a briefcase is very inefficient.
300 watts can wipe out communications for a few thousand feet, but for power transfer, not very effective.
A Tesla coil would need to be much higher in frequency to be efficient as a small unit.
So, now, the question, what would be the good frequency to efficiency to size?
Remember that this is a theory and a math model, not an actual device.
I picked 28 MHz as it is in the ham band, so 1500 watts is legal, and power MOSFETs work there, but that is the upper limit for a non RF transistor, and they have ratings of 1000 volts and higher.
Again, this is a model in theory, and the goal is the transfer of as much energy from point A to point B.
One can transfer in the HF band with small antennas, Near Field Communications does that with 13.56 MHz with hand held devices, but at a very short range.
And it is very very inefficient.
The other problem is things like Tasers will explode if subjected to a strong Tesla coil, the problem seems to be sudden battery failure.
We can not have exploding Tasers! no matter how much one might hate the things!
It might be that the extending wires act as a dipole and get to resonance at some point, but why do the wires not burn up?
Again, this is a theory, not a produced project.
I have played with RF tank circuits at 28 MHz and so far it looks promising.
The idea is to couple as much energy into space as possible, just as any transmitter and antenna, but at very high voltage.
One would be best served by reading about what a Tesla coil is for a better understanding of what I am dealing with.
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Re: 28 MHz Tesla coil.
Hello.
This covers the material a bit.
http://amasci.com/tesla/tesceive.html
Remember that the author is going from atoms and light to Tesla coils, an interesting concept.
And, remember that a Tesla coil of any size can kill!
TV flyback transformers are only good to a few thousand volts.
What we need is something like the Pi tank circuit in a tube transmitter, but for far more voltage on the secondary, not a step down to 50 ohms.
This is all possible, but what would be the most efficient at this point?
Remember, the higher the frequency, the greater the losses but the smaller the circuit.
And, we are taking several mega Volts so it is going to have to have insulators of a minimum size.
This is a mental exercise, something that requires several factors to be considered at once.
The upper limit on RF out is 1500 watts.
The bands available are all USA ham bands.
This covers the material a bit.
http://amasci.com/tesla/tesceive.html
Remember that the author is going from atoms and light to Tesla coils, an interesting concept.
And, remember that a Tesla coil of any size can kill!
TV flyback transformers are only good to a few thousand volts.
What we need is something like the Pi tank circuit in a tube transmitter, but for far more voltage on the secondary, not a step down to 50 ohms.
This is all possible, but what would be the most efficient at this point?
Remember, the higher the frequency, the greater the losses but the smaller the circuit.
And, we are taking several mega Volts so it is going to have to have insulators of a minimum size.
This is a mental exercise, something that requires several factors to be considered at once.
The upper limit on RF out is 1500 watts.
The bands available are all USA ham bands.
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Re: 28 MHz Tesla coil.
Can you find the parts in the back of an old TV too?
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Re: 28 MHz Tesla coil.
here we go again cowpat,
power transfere of that kind uses very high Q self resonant coils not tank circuits not musical tesla coils,
conventional tank circuits use the lossy transverse electromagnetic hertzian waves we all use that travel @ ( velocity of light x velocity factor of the medium ),
tesla used none electromagnetic longitudinal impulse waves that travel @ ( pi/2 x velocity of light ),
tv lopt are useless,
you don't know much about tank circuits for a guy tha claims to build rf amplifiers,
tank circuits in typical tube amps have no secondary, they are designed to have a Q of about 10 to minimise circulating currents, the exact OPPOSITE of what you need,
high Q in your tank circuit creates huge circulating currents that melt your tank coil,
erric dollard is the only guy alive today i know of that has replicated some of tesla's longitudinal wave experiments.
power transfere of that kind uses very high Q self resonant coils not tank circuits not musical tesla coils,
conventional tank circuits use the lossy transverse electromagnetic hertzian waves we all use that travel @ ( velocity of light x velocity factor of the medium ),
tesla used none electromagnetic longitudinal impulse waves that travel @ ( pi/2 x velocity of light ),
tv lopt are useless,
you don't know much about tank circuits for a guy tha claims to build rf amplifiers,
tank circuits in typical tube amps have no secondary, they are designed to have a Q of about 10 to minimise circulating currents, the exact OPPOSITE of what you need,
high Q in your tank circuit creates huge circulating currents that melt your tank coil,
erric dollard is the only guy alive today i know of that has replicated some of tesla's longitudinal wave experiments.
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"An antenna with a poor ground using few radials cannot have a support mast grounded to the radial common point (at least it shouldn't if designed properly) There is no exception to this!
"An antenna with a poor ground using few radials cannot have a support mast grounded to the radial common point (at least it shouldn't if designed properly) There is no exception to this!
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Re: 28 MHz Tesla coil.
Hello.
First off, hundreds of Tesla coils have been built, just go on You Tube.
Second, I pointed out the differences of a tank coil and that of a Tesla coil, and a Tesla coil being a one band device.
Finally, there is nothing about speed or anything else, it is just a theory at this point.
The idea is only to discover what would be the best compromise between size and efficiency.
At UHF, antennas are shorter than at HF. that is a given, 27 MHz vs that tiny UHF talkie.
Most Tesla coils operate at a few kHz.
Again, there are hundreds of Tesla coils out there.
The question now is, what works best?
Tesla did his experiments long before the thermonic valve, or electron tube.
He used a spark gap.
Most Tesla coils use spark gaps, simply following the original design.
But there is no reason a Tesla coil could not be produced for nearly any frequency.
Now, with that said, what would be the ideal frequency?
Going off into some tangent does not answer the question.
Thank you.
First off, hundreds of Tesla coils have been built, just go on You Tube.
Second, I pointed out the differences of a tank coil and that of a Tesla coil, and a Tesla coil being a one band device.
Finally, there is nothing about speed or anything else, it is just a theory at this point.
The idea is only to discover what would be the best compromise between size and efficiency.
At UHF, antennas are shorter than at HF. that is a given, 27 MHz vs that tiny UHF talkie.
Most Tesla coils operate at a few kHz.
Again, there are hundreds of Tesla coils out there.
The question now is, what works best?
Tesla did his experiments long before the thermonic valve, or electron tube.
He used a spark gap.
Most Tesla coils use spark gaps, simply following the original design.
But there is no reason a Tesla coil could not be produced for nearly any frequency.
Now, with that said, what would be the ideal frequency?
Going off into some tangent does not answer the question.
Thank you.
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Re: 28 MHz Tesla coil.
"First off, hundreds of Tesla coils have been built, just go on You Tube."Cowthief wrote:
everybody and his dog has seen the singing tesla coils on youtube,
"Second, I pointed out the differences of a tank coil and that of a Tesla coil, and a Tesla coil being a one band device."
no you did not point out the difference, tube tank circuits are exactly the opposite in Q of what you need and they don't usually use a transformer with a secondary winding,
"Finally, there is nothing about speed or anything else, it is just a theory at this point."
speed is everything with what you want to investigate and its not theory,
look at wheatstone's work and teslas own words, do some research,
"The idea is only to discover what would be the best compromise between size and efficiency"
if coils that fit in your handbag were any good tesla would not have built wardenclyffe,
"At UHF, antennas are shorter than at HF. that is a given, 27 MHz vs that tiny UHF talkie.
Most Tesla coils operate at a few kHz. Again, there are hundreds of Tesla coils out there.
The question now is, what works best?"
best to do what?,
transmit electrical power with very little loss over large distances without wires ?
transmit electrical power without loss over a single wire returning the energy on the opposite half cycle?
or make arcs that play music for youtube videos?
i did that when i was ten years old using pencil leads as a spark gap and smoked one channel of my stereo by transmitting to my dads car radio 150ft away down the yard and every other AM radio in the area,
"Tesla did his experiments long before the thermonic valve, or electron tube.
He used a spark gap. Most Tesla coils use spark gaps, simply following the original design."
tesla did not use a spark gap like a spark plug from your moped or my pencil leads, he used the principle of the disruptive discharge,
tesla had full control over frequency and pulse width many years before other guys, do some research,
"But there is no reason a Tesla coil could not be produced for nearly any frequency."
correct
"Now, with that said, what would be the ideal frequency?"
certainly not 28mhz but we know why you chose to stir the fcc/hammy pot with that diatribe don't we speedy,
tesla used many frequencies including very high frequencies,
it has been claimed he used what we now call schumann resonance frequencies for his wireless power transmitter, do some research.
"Going off into some tangent does not answer the question"
point out the tangent cowpat, you are the master of obfuscation and not answering the question not me,
i can't tell you how to do that i don't want the men in black visiting me.
Last edited by MrWeetabix on 11 Sep 2014, 15:08, edited 3 times in total.
Reason: Edited for clarity by MrWeetabix
Reason: Edited for clarity by MrWeetabix
W8JI
"An antenna with a poor ground using few radials cannot have a support mast grounded to the radial common point (at least it shouldn't if designed properly) There is no exception to this!
"An antenna with a poor ground using few radials cannot have a support mast grounded to the radial common point (at least it shouldn't if designed properly) There is no exception to this!
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Re: 28 MHz Tesla coil.
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Re: 28 MHz Tesla coil.
Hello.
The reason I picked 28 MHz is not to "stir the pot" but that is a legal frequency band in the USA and allows 1500 watts.
And, right now, 10 meters is dead, the solar cycle and all.
Tesla did all sorts of neat things, with the technology at the time.
What I want to know is, going higher in frequency, what is the trade off?
And, the Pi network in a tube radio, such as an FT-101, is configured to match the high impedance of the tube to that of 50 ohms.
http://www.suws.org.uk/images/1/1a/FT-101E.pdf
I picked that site as it is the UK.
I looked at the FT-101 as it is a very simple, straightforward, radio.
Most have had the TV sweep tube unit replaced, updated to some Russian tubes or a drop-in solid state replacement.
The question is very straight forward, what will be the best compromise for maximum power transfer?
Tesla wanted to power the world, I am thinking more local.
Remember that a Tesla coil is NOT a multi frequency device, you build it for an intended target frequency.
To build one for 28 MHz and 1500 watts, what would be the ideal primary? secondary? coil spacing?
What would be the drawbacks of 28 MHz?
Would 6 meters be better?
All are questions that in theory can be answered in theory.
I decided to see what sort of answers I might find here.
The reason I picked 28 MHz is not to "stir the pot" but that is a legal frequency band in the USA and allows 1500 watts.
And, right now, 10 meters is dead, the solar cycle and all.
Tesla did all sorts of neat things, with the technology at the time.
What I want to know is, going higher in frequency, what is the trade off?
And, the Pi network in a tube radio, such as an FT-101, is configured to match the high impedance of the tube to that of 50 ohms.
http://www.suws.org.uk/images/1/1a/FT-101E.pdf
I picked that site as it is the UK.
I looked at the FT-101 as it is a very simple, straightforward, radio.
Most have had the TV sweep tube unit replaced, updated to some Russian tubes or a drop-in solid state replacement.
The question is very straight forward, what will be the best compromise for maximum power transfer?
Tesla wanted to power the world, I am thinking more local.
Remember that a Tesla coil is NOT a multi frequency device, you build it for an intended target frequency.
To build one for 28 MHz and 1500 watts, what would be the ideal primary? secondary? coil spacing?
What would be the drawbacks of 28 MHz?
Would 6 meters be better?
All are questions that in theory can be answered in theory.
I decided to see what sort of answers I might find here.
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Re: 28 MHz Tesla coil.
you are hilarious cowpat,
erric dollard devised new maths to calculate what you need when he was at borderland sciences, i don't know if he is correct or not, all those kinda guys sound more crazy than doc brown,
you won't find any of this stuff in any school or university book as they teach us electricity is electron flow,
they even changed their mind over which way they flow since i was in school,
tesla did not think electricity was electron flow, he thought electrons were the resistance getting dragged along much slower than the flow of electricity, like rocks in a river or the rocks in your head,
tesla did not agree with hertz or lorentz's chopped down version of maxwells work,
http://www.youtube.com/watch?v=QKggql3aYkc
http://www.youtube.com/watch?v=TttHkDRuyZw
erric dollard devised new maths to calculate what you need when he was at borderland sciences, i don't know if he is correct or not, all those kinda guys sound more crazy than doc brown,
you won't find any of this stuff in any school or university book as they teach us electricity is electron flow,
they even changed their mind over which way they flow since i was in school,
tesla did not think electricity was electron flow, he thought electrons were the resistance getting dragged along much slower than the flow of electricity, like rocks in a river or the rocks in your head,
tesla did not agree with hertz or lorentz's chopped down version of maxwells work,
http://www.youtube.com/watch?v=QKggql3aYkc
http://www.youtube.com/watch?v=TttHkDRuyZw
W8JI
"An antenna with a poor ground using few radials cannot have a support mast grounded to the radial common point (at least it shouldn't if designed properly) There is no exception to this!
"An antenna with a poor ground using few radials cannot have a support mast grounded to the radial common point (at least it shouldn't if designed properly) There is no exception to this!
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Re: 28 MHz Tesla coil.
TL:DR Pics or it didn't happen etc.
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Re: 28 MHz Tesla coil.
Hello.
The theory of relativity has issues, the universe seems to be expanding faster than light.
There is this theory that gravity is by far faster than light.
All fine and well, but this has little to do with the issues at hand, what is the ideal balance between Frequency, Efficiency, and Size, of a Tesla coil?
So, far, I have not found any Tesla coil on 28 MHz or above.
28 MHz is a nice, easy to produce, frequency.
It would be 100% legal at or under 1500 watts.
If I input 1000 volts at 28 MHz and the coil does 150 to 1, that is 150 thousand volts, is that enough?
But, if the coil does 1500 to 1, that is 1500 thousand, and it is RF at 28 MHz.
With 35 turns in the primary, the secondary would have a lot of turns for 1500 to 1.
So, you can see, a LOT of effort.
The theory of relativity has issues, the universe seems to be expanding faster than light.
There is this theory that gravity is by far faster than light.
All fine and well, but this has little to do with the issues at hand, what is the ideal balance between Frequency, Efficiency, and Size, of a Tesla coil?
So, far, I have not found any Tesla coil on 28 MHz or above.
28 MHz is a nice, easy to produce, frequency.
It would be 100% legal at or under 1500 watts.
If I input 1000 volts at 28 MHz and the coil does 150 to 1, that is 150 thousand volts, is that enough?
But, if the coil does 1500 to 1, that is 1500 thousand, and it is RF at 28 MHz.
With 35 turns in the primary, the secondary would have a lot of turns for 1500 to 1.
So, you can see, a LOT of effort.
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Re: 28 MHz Tesla coil.
you still don't get it do you cowpat, all i can see is you killing yourself with the WRONG kind of electricity.
http://www.youtube.com/watch?v=FUemx2ZabOw
http://www.youtube.com/watch?v=DFa-IymyWHM
http://www.youtube.com/watch?v=FUemx2ZabOw
http://www.youtube.com/watch?v=DFa-IymyWHM
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"An antenna with a poor ground using few radials cannot have a support mast grounded to the radial common point (at least it shouldn't if designed properly) There is no exception to this!
"An antenna with a poor ground using few radials cannot have a support mast grounded to the radial common point (at least it shouldn't if designed properly) There is no exception to this!
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Re: 28 MHz Tesla coil.
This guy is into "free energy".
I am interested in what Tesla did, and what the limits are.
I have built a portable Tesla coil in the past, in fact, this bit with used TV sets was an effort to build a Tesla coil.
MOSFETs can work to 30+ MHz, the power MOSFETs.
The problem is that I do not know what the limits are, for a Tesla coil or the transmission medium.
I am interested in what Tesla did, and what the limits are.
I have built a portable Tesla coil in the past, in fact, this bit with used TV sets was an effort to build a Tesla coil.
MOSFETs can work to 30+ MHz, the power MOSFETs.
The problem is that I do not know what the limits are, for a Tesla coil or the transmission medium.
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Re: 28 MHz Tesla coil.
There must be more uneducated rubbish talked about Tesla than anyone else. You CANNOT wirelessly transfer (or 'broadcast') useful amounts of power over any meaningful distance. It's not anything special, it's just radio and it obeys the same laws of physics as anything else. Just look at AM and FM broadcast transmitters - they gobble up hundreds of KW and just a few miles away the power received is not enough to power anything beyond a crystal set. People go on about Tesla as if he was some kind of genius, but he was just misguided and his system never achieved anything useful and it never will.
You know what they say about a little knowledge.
You know what they say about a little knowledge.
'SOMEONE GET ME A SAW!'
Andy.
Andy.
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Re: 28 MHz Tesla coil.
Hello.
Tesla had light bulbs illuminated from 20 miles away from the transmitter.
The problem with the Tesla power transmission scheme is not that it does not work, but how do you meter it?
Anyone could build a receiver and absorb power.
With that said, increasing the voltage seems to be the key.
A common transmitter uses a monopole tuned to around 50 ohms.
The Tesla coil is a transformer tuned circuit, but the secondary must have a very high impedance.
That seems to be the key, not just an efficient radiation of RF, but also the voltages radiated.
With that said, I can get about 12 amps from a SWER line at 120 volts about 300 feet away.
http://www.telegraph.co.uk/technology/3 ... icity.html
http://en.wikipedia.org/wiki/Single-wire_earth_return
I am getting good at getting power from SWER!
The trick is to have a good ground and good antenna.
The antenna for 60 Hz is not a monopole but a large section of sheet copper.
I would get a zap whenever I would walk to my car, so I figured, why not harness this power?
That was around 90 volts.
So, I got to cracking, and put a common steel trash can on the roof of the house, 1500 volts no load but 97 volts at 300 watts, to ground.
Next, what is the length of a wave at 60 Hz? several thousands of feet.
So, what would be the ideal antenna? loop?
Turns out the a section of copper aligned with the power line is more than enough.
But, there must be a constant load, or the voltage rises.
Directly under this power line, with a loop, 1500 watts is easy!
Everyone insists that the power being radiated is safe, less than the power required in a flash light.
OK, so I should not be able to do this, right?
Something is wrong.
From here, I am looking at Tesla coils.
I want to send several kilowatts from a point of reception to a point of use.
Safe? that is what they say.
Effective? that is a matter of opinion.
Tesla had light bulbs illuminated from 20 miles away from the transmitter.
The problem with the Tesla power transmission scheme is not that it does not work, but how do you meter it?
Anyone could build a receiver and absorb power.
With that said, increasing the voltage seems to be the key.
A common transmitter uses a monopole tuned to around 50 ohms.
The Tesla coil is a transformer tuned circuit, but the secondary must have a very high impedance.
That seems to be the key, not just an efficient radiation of RF, but also the voltages radiated.
With that said, I can get about 12 amps from a SWER line at 120 volts about 300 feet away.
http://www.telegraph.co.uk/technology/3 ... icity.html
http://en.wikipedia.org/wiki/Single-wire_earth_return
I am getting good at getting power from SWER!
The trick is to have a good ground and good antenna.
The antenna for 60 Hz is not a monopole but a large section of sheet copper.
I would get a zap whenever I would walk to my car, so I figured, why not harness this power?
That was around 90 volts.
So, I got to cracking, and put a common steel trash can on the roof of the house, 1500 volts no load but 97 volts at 300 watts, to ground.
Next, what is the length of a wave at 60 Hz? several thousands of feet.
So, what would be the ideal antenna? loop?
Turns out the a section of copper aligned with the power line is more than enough.
But, there must be a constant load, or the voltage rises.
Directly under this power line, with a loop, 1500 watts is easy!
Everyone insists that the power being radiated is safe, less than the power required in a flash light.
OK, so I should not be able to do this, right?
Something is wrong.
From here, I am looking at Tesla coils.
I want to send several kilowatts from a point of reception to a point of use.
Safe? that is what they say.
Effective? that is a matter of opinion.