Peter, whatever happened with Eric P. Dollard?

[7imix]

I think the reason for the 62% spacing is because you have to think of each pair of windings as a capacitor. As the windings get further apart, the distributed capacitance between every turn starts to add up. The farther the plates of a capacitor are apart, the smaller the capacitor. Therefore, the farther the turns in a coil are apart, the smaller the distributed capacitance of the coil. You can see tesla calculating this and talking about it in "Colorado Springs Notes."

And yes, the relation to fibonacci sequence is highly likely.

Most "tesla" coils that people build have narrow diameters, close-spaced turns and many, many, many turns, making for a much greater capacitance relative to inductance. It seems tesla was trying to do the opposite, make the inductance as large and the capacitance as small as practical, while still matching the inductance to capacitance for quarter-wave resonance.

[dR-Green]

Audio signal

[dR-Green]

Notes on the Crystal Set

When measuring the velocity difference between underground and our ground, the two seperate receivers can be brought into phase unison by the use of a test oscillator. Both receivers must have a primary tank circuit, here you can place your measurement equipment.

The detected AM output, audio frequency, signal is immune to receiver phase shift. This is a property of A.M. detection. Use the audio to measure propagation delay.

Using more than one method of testing to reduce the margin of error as much as I can. Radio station is broadcasting at 882kHz. 555 signal generator is not 100% stable, multiple readings taken. Fluke scope doesn't display actual reading in Scope mode but seems to round it up or down (varies between 862-892kHz but won't display 882kHz as it will do in Meter mode). Audio signal of the normal receiver was very poor with a lot of noise so software scope shots are also included. Under ground receiver required up to -18.31dB and over ground receiver required +6.02dB gain to get the levels somewhat equal to my ear. PicoScope when not running is displaying current value reading of the whole sample, not the average.

Test oscillator signal







Waveform A (Blue) (Left audio channel) = Tesla receiver
Waveform B (Red) (Right audio channel) = Normal receiver

Receivers in phase unison











Received radio signal

[Kokomoj0]

I noticed that too, it may be a coincidence though.

yeh same here, 1.6, .6, numbers I use in acoustic design, Fibonacci popped into my head too.

Fibonacci number - Wikipedia, the free encyclopedia

[madhatter]

apperantly editing isn't working...
Update to the 62%

It seems very related to the skin effect and maybe Erics calculation for the proximity effect. As the skin effect is related to 1/e and 63% of the current in the depth, possibly this was the relation.

[pnajafi]

Pancake shape

pnajafi,

"Does anyone know why pancake coils generate more voltage than an standard coil between each turn?"

I think it is caused from distributed capacity or mutual-capacity K. We have e, or voltage seen from mutual capacity, E, the reactance voltage, and finally, ((i+I)r) or the voltage drop due to current flow against a resistance. e & E can add depending upon their phase orientation, whereas ((i+I)r) is always a voltage drop. So bringing it altogether; ((j(i+I))r)-j(e+E)=Volts (induced voltage would be negative), the phases of the currents i & I and voltages e & E need to be taken into account for this equation to be useful. Note that this is very different from a parallel or series LC circuit, and could be seen as a type of parallel LK circuit, even though we think of it as just another inductor. My 2cents, hope it helps.



Garrett M

Thanks. This gives me more clues and connection on what to look for. Do you know whether Tesla experimented more and used just intuition to come up with it or he actually was aware of these mathematical theories,etc and worked from there?

[madhatter]

I do not know why.

<two cents>
But I do notice that 62%, 0.62, is an approximation of 2 / (1 + sqrt(5)), or 0.618 (rounded to 3 digits), which is the inverse of the Golden Ratio, (1 + sqrt(5))/2
</two cents>

I noticed that too, it may be a coincidence though.

[lessismore]

I do not know why.

<two cents>
But I do notice that 62%, 0.62, is an approximation of 2 / (1 + sqrt(5)), or 0.618 (rounded to 3 digits), which is the inverse of the Golden Ratio, (1 + sqrt(5))/2
</two cents>

[Kokomoj0]

That's what brought me out of the closet.

Why the spacing?????? Eric Please why??

I was thinkin it has something to do with the capacitance between windings. when you move 2 surfaces farther apart the working capacitance reduces. I just assumed he is attempting to make a coil as purely inductive as possible? The problem of course is that it will also reduce the inductance, so maybe 62% is the best compromise distance?

[jake]

There's some issues with the equations for the extra coil, not sure if it's just a misprint or haste. I've worked through the secondary coil dimensions and although at first blush they work out, they are also the basis for the extra coil. The Eq Eric has for the spacing factor seems odd. I'm working on the fundamentals of the math behind the dimensions still, hope to have something by morning.

That's what brought me out of the closet.

Why the spacing?????? Eric Please why??

[Web000x]

Thank you Eric, I think that cleared up a great amount of confusion! What may I ask is in Morro Bay? Before you leave, check your paypal, I made a donation last night. Please check in with us when possible, I'll do my best to get this up and running asap. Thank you for all your help.

Do you have gear to get on 40m CW? I know you used to do daily transmissions there, will you be reachable via 40m CW? If you need a radio / tuner / antenna, I'll help you out.

Regards,
Mike

73 DE WX9HV

Hey Mike,

Eric was gone to Lone Pine when you made that post. He contacted me a few days ago updating me of his situation and told me that he had seen your post from a friend's computer. He has no working HAM equipment to transmit right now. He said that if you could get him a working PRC-47 that he would be able to broadcast.

Good luck,

Dave

[madhatter]

There's some issues with the equations for the extra coil, not sure if it's just a misprint or haste. I've worked through the secondary coil dimensions and although at first blush they work out, they are also the basis for the extra coil. The Eq Eric has for the spacing factor seems odd. I'm working on the fundamentals of the math behind the dimensions still, hope to have something by morning.

[dR-Green]

I posted a calculator for the tesla resonant calculator over in the yahoo group N6KPH because excel file are not allowed here.

Problem is I get a negative number with the calculation for conductor spacing on the extra coil. I get this when I do it manually as well.

Has anyone calculated their extra coil with the "tentative equations" given earlier?

Yes you are right, negative number here as well. The equation subtracts a big number from a smaller number so immediately goes negative (d - N).

[jake]

TRT calculator

I posted a calculator for the tesla resonant calculator over in the yahoo group N6KPH because excel file are not allowed here.

Problem is I get a negative number with the calculation for conductor spacing on the extra coil. I get this when I do it manually as well.

Has anyone calculated their extra coil with the "tentative equations" given earlier?

[garrettm4]

Pancake Coil

pnajafi,

"Does anyone know why pancake coils generate more voltage than an standard coil between each turn?"

I think it is caused from distributed capacity or mutual-capacity K. We have e, or voltage seen from mutual capacity, E, the reactance voltage, and finally, ((i+I)r) or the voltage drop due to current flow against a resistance. e & E can add depending upon their phase orientation, whereas ((i+I)r) is always a voltage drop. So bringing it altogether; ((j(i+I))r)-j(e+E)=Volts (induced voltage would be negative), the phases of the currents i & I and voltages e & E need to be taken into account for this equation to be useful. Note that this is very different from a parallel or series LC circuit, and could be seen as a type of parallel LK circuit, even though we think of it as just another inductor. My 2cents, hope it helps.



I did some more thinking on this topic and came to some conclusions and thought I would share them with everyone here. The "pancake coil", or any coil for the sake of discussion, has different modes of propagation, axial & radial, dependent upon how it is driven and wound. One mode is called Forced Oscillation, seen as waves of a continuous level in cycles per second, this can be achieved by direct 2-wire connection or mutual induction, this is the 'normal' method of driving circuit elements today. An alternative mode is called Free Oscillation (sometimes known as "ringing"), seen as dampened waves or a changing level in cycle-decibels per second (similar to but NOT AM modulation), this method is almost NEVER used or even discussed except for the transient case where the phenomena is a "problem" that is worked out of the design. In almost all of the later Tesla apparatus I have examined he uses "Dampened Waves", or Free Oscillations, and Impulses to control and drive his experiments. In the pancake coil we can drive it in two differing modes both via mutual induction, this seen as a free coil not hooked up to anything. In the free oscillation mode where impulses of mutual induction are impressed upon the coil, the coil having a larger than normal mutual-capacity has a larger than normal capacity current which cuts across the coil winds through the insulating portions this in per radians per second, much like a drop of water falling into a calm pool of water, the disturbance is radial. The self inductance of the coil is axial and thereby moves along the entire length of the coil, this in radians per second. If we take this further we could talk about the self induced mutual magnetic induction of each turn, another radial phenomena in per radians per second, and the self-capacity, an axial phenomena in radians per second, of the entire coil to a conducting surface such as the earth or a ground plane. I believe this is why Mr. Dollard makes a very large emphasis on his Four Quadrant Theory of Electrical Waves. e E i & I are needed to describe the effects of L C M & K, which is quite hard to do with the usage of only V & I. Furthermore the radial or axial directions of propagation and the normal direction of rotation of the subsequent vector quantities gives rise to some interesting considerations when talking about a coil and what it is doing per unit time.

Garrett M