Hendershot Replications

[morpher44]

mutual inductance

If mutual inductance is a reasonnably a possibility, why do we notice that the distance between the two tanks is never the same on most pictures ? Is it possible that the final effect of all this stuff would be a tuner (mysterious 5MHz ?), a phase shifting to get a significant signal difference between the two tanks and finally (i know it's an audacious thought...) a global resonance of the tanks to each other to make a high power LF amplifier ? Hendershot son talked about wholes in the ceiling if I'm not wrong... Maybe because his father unfortunately got perfect resonance which, we know, has very destructive... power. Of course I speculate...

@Nomdi,

Yes ... good point.
In the various photos, do we ever notice the distance between
the two cylinders to be greater than one diameter?
On the photo showing the device actually operating, with the
light bulb glowing, the cylinders appears to be less than
one diameter apart from each other.

I guess I need to study a bit more about the relationship
between distances here and mutual induction.

One experiment I was doing last night, which I was trying to
upload to youtube ... but youtube is having some problems ...
is using two 5 inch basket weave coils in a Joule Thief circuit.
The LED lights and things work .. until I move the coils
to greater than one diameter distance apart from each other.
As soon as that threshold is crossed, mutual inductance
no longer occurs effectively ... the Joule Thief no longer
oscillates.

I was surprised to see this occur at one diameter distance.
Was this a coincidence .. or does the math work out that way
always.

This is very interesting for another aspect of the Hendershot
design ... and that is with the inter-dowel distance.
If these dowels are too close, the wire-loop around the dowel
will inductively couple with the nearby dowel loops.
If on the other hand they are spaced just right ...
they will be prevented from inductively coupling with each other.
So the question can be asked

"Did Hendershot select 57 dowels to enhance or
prevent mutual inductive coupling between dowels?"

I think that mutual inductive coupling between
dowels is another thing to consider.

If it was me, I would work out the minimum number
of dowels I would have to use to achieve my goal.
So anything less than 57 might cross some
threshold here in terms of mutual inductance between dowels.

[NOMDI]

@morpher44

I was thinking the inductance and capacitance of the
tank circuit was the dominant set of values for tuning as well.
But now I'm not so confident in that assumption.

The 120uH you assume is not actually what will be seen
by the tank circuit.
Inductance is a funny thing in that it is influenced
by mutual induction as well.
So since we have a 64-turn coil UNDER that "tank" coil,
it behaves like a transformer.
The other side of that transformer has several other
inductances hooked up in series.
The tank circuit, therefore sees a much larger inductance ...
upwards into the millihenries, since we
are dealing with those 5:1 transformers, etc.
Again, I'm no expert in circuit analysis ... and
all this crazy mutual inductance makes the problem
quite complex.

I have clued into the fact that if you can make
all these inductances experience the same rising and
falling magnetic field (up and down the sign wave),
you utilize the phases to create a nice
180 degree phase shift. One transformer ... gives you 90 degrees.
A 2nd transformer gives you another 90 degrees, resulting in 180.
With a 180 phase shift you can then do "regeneration"
of the waveforms ... adding their amplitudes...

So if the waveform -- arriving to the left-hand side were to be
run through essentially two transformers -- each shifting phase
90 degrees .... when that arrives to the right-hand side,
it too would produce magnetic fields that go up and down
in the same way. The left and right could be made to
synchronize in this way since their fields are moving in
unison up and down on the same plane. They
would be able to exchange mutual inductance ... producing
an even larger effect in terms of feedback.

I suspect the Hendershot device is using mutual inductance to
some advantage.

It is easily demonstrated that two coils that have their
cylinder mouths oriented UP, when placed next to each
other, can inductively couple -- just as effectively as if
their mouths were facing each other.

If mutual inductance is a reasonnably a possibility, why do we notice that the distance between the two tanks is never the same on most pictures ? Is it possible that the final effect of all this stuff would be a tuner (mysterious 5MHz ?), a phase shifting to get a significant signal difference between the two tanks and finally (i know it's an audacious thought...) a global resonance of the tanks to each other to make a high power LF amplifier ? Hendershot son talked about wholes in the ceiling if I'm not wrong... Maybe because his father unfortunately got perfect resonance which, we know, has very destructive... power. Of course I speculate...

[morpher44]

divide or multiply?

Hendershot coil will resonate at all this frequencies.
1823 * 4 =7294 m, 41126 Hz
L=120uH
C=0.1248uF (Not 1.3 as mentioned on note, 1 decimal off)
divide by 32 = 56.949265 meters, 5264202.452715 hz ~5.26MHz (Moray was using his device with 5MHz)

@mlurye
Ok. Looks like your multiplying wavelength by 4 there
to go to a lower frequency.

re: frequencies in the 1Mhz to 6Mhz range.
In the 60s, space satellites were used to investigate the
RF spectrum and it was found that most radiant energy
arriving to earth from space lies in the 1Mhz to 6Mhz range.
You can pick this interference up on your AM band or
if you have a short-wave radio, you can listen to the
stuff that arrives from 1.6Mhz upwards to 6Mhz.
It arrives day and night ... but at night you can
really pick it up nicely.
Also, the signal strength from any transmitting
source out there will vary as the Earth rotates around
and providing good line-of-sight or not to the transmitting
object. The sun is obviously one important "transmitter"
out there ... and depending upon storms on the sun, etc.
you can pick up varying amounts of energy.

[morpher44]

the tuning...

NOMDI based on this number I can make one assumption, they were using the same frequency to tune in to. And with info available for Hendershot device we can calculate it as close as possible.
May be if we will scan in 5264197.63332369 area we can find source of energy that was used by those devices.

@mlure and @NOMDI

I was thinking the inductance and capacitance of the
tank circuit was the dominant set of values for tuning as well.
But now I'm not so confident in that assumption.

The 120uH you assume is not actually what will be seen
by the tank circuit.
Inductance is a funny thing in that it is influenced
by mutual induction as well.
So since we have a 64-turn coil UNDER that "tank" coil,
it behaves like a transformer.
The other side of that transformer has several other
inductances hooked up in series.
The tank circuit, therefore sees a much larger inductance ...
upwards into the millihenries, since we
are dealing with those 5:1 transformers, etc.
Again, I'm no expert in circuit analysis ... and
all this crazy mutual inductance makes the problem
quite complex.

I have clued into the fact that if you can make
all these inductances experience the same rising and
falling magnetic field (up and down the sign wave),
you utilize the phases to create a nice
180 degree phase shift. One transformer ... gives you 90 degrees.
A 2nd transformer gives you another 90 degrees, resulting in 180.
With a 180 phase shift you can then do "regeneration"
of the waveforms ... adding their amplitudes...

So if the waveform -- arriving to the left-hand side were to be
run through essentially two transformers -- each shifting phase
90 degrees .... when that arrives to the right-hand side,
it too would produce magnetic fields that go up and down
in the same way. The left and right could be made to
synchronize in this way since their fields are moving in
unison up and down on the same plane. They
would be able to exchange mutual inductance ... producing
an even larger effect in terms of feedback.

I suspect the Hendershot device is using mutual inductance to
some advantage.

It is easily demonstrated that two coils that have their
cylinder mouths oriented UP, when placed next to each
other, can inductively couple -- just as effectively as if
their mouths were facing each other.

[mlurye]

Very interesting ! I guess you've found the best theory about the mysterious 1.3 origin Do you have any idea about the meaning of this Hendershot and Moray 5 Mhz common value ?

NOMDI based on this number I can make one assumption, they were using the same frequency to tune in to. And with info available for Hendershot device we can calculate it as close as possible.
May be if we will scan in 5264197.63332369 area we can find source of energy that was used by those devices.

[NOMDI]

wavelength

1823 * 4 =7294 m, 41126 Hz
L=120uH
C=0.1248uF (Not 1.3 as mentioned on note, 1 decimal off)

divide by 32 = 56.949265 meters, 5264202.452715 hz ~5.26MHz (Moray was using his device with 5MHz)

Very interesting ! I guess you've found the best theory about the mysterious 1.3 origin Do you have any idea about the meaning of this Hendershot and Moray 5 Mhz common value ?

[mlurye]

I'm still not following.
I get f = 164506 hz with those values ... but you already have C = 7.8nF.
Wavelength is 1822.376 meters.

divide by 4 = 455.594116 meters, 658025.306589 hz
divide by 16 = 113.898529 meters, 2632101.226357 hz
divide by 32 = 56.949265 meters, 5264202.452715 hz
Now what?

Hendershot coil will resonate at all this frequencies.

1823 * 4 =7294 m, 41126 Hz
L=120uH
C=0.1248uF (Not 1.3 as mentioned on note, 1 decimal off)

divide by 32 = 56.949265 meters, 5264202.452715 hz ~5.26MHz (Moray was using his device with 5MHz)

[morpher44]

hmmm...

morpher,
L=120uH , C=0.0078uF based on this I calculated wave length.
Wave length / 4 or /16 or /32 you can get resonant frequency and get C for it.

I'm still not following.
I get f = 164506 hz with those values ... but you already have C = 7.8nF.
Wavelength is 1822.376 meters.

divide by 4 = 455.594116 meters, 658025.306589 hz
divide by 16 = 113.898529 meters, 2632101.226357 hz
divide by 32 = 56.949265 meters, 5264202.452715 hz
Now what?

[mlurye]

@mlurye

Could you explain your math in a bit more detail. I'm not following how you derive this.

-morpher44

morpher,
L=120uH , C=0.0078uF based on this I calculated wave length.
Wave length / 4 or /16 or /32 you can get resonant frequency and get C for it.

[morpher44]

the math

Hendershot, did his calculations based on 1/16 of wave length for (0.0078uF) and 1/32 of wave length for (1.3uF). Or maybe he calculated it for 1/4, but it operated in 1/16. Played with numbers for 1.3uF it's different (not related) wave length then 0.0078uF, not even close. Correct value would be 0.1245uF or ~0.13uF (for 1/4 wave length), ~1.99uF (for 1/16 wave length). Looks like Hendershot was of on one decimal point.

@mlurye

Could you explain your math in a bit more detail. I'm not following how you derive this.

-morpher44

[mlurye]

Hendershot, did his calculations based on 1/16 of wave length for (0.0078uF) and 1/32 of wave length for (1.3uF). Or maybe he calculated it for 1/4, but it operated in 1/16. Played with numbers for 1.3uF it's different (not related) wave length then 0.0078uF, not even close. Correct value would be 0.1245uF or ~0.13uF (for 1/4 wave length), ~1.99uF (for 1/16 wave length). Looks like Hendershot was of on one decimal point.

[mlurye]

Yes my thoughts exactly.
re: the 1.3 mF, it definitely looks like MFD ... but this
little note here has no context...

Calculations on this note are done in kilocycles (first line). The rest is destroyed

[morpher44]

high voltage spikes

we can speculate he did it only to get a very high voltage capacitor. It seems to be logical because the LC cell is made to be tuned a the resonance point, which means high voltage pikes. Can we suspect that every replication made with a single layer capacitor (made of paper which is not as good as actual plastic films for insulation) has "dead born" capacitors ?

I also guess that this could explain the value of 1.3 mF (we've seen in his son document), which could be in fact 13 nf, almost twice the value of the 7.8 nF he could have first experiment with a parallel double layer capacitor...

Yes my thoughts exactly.
re: the 1.3 mF, it definitely looks like MFD ... but this
little note here has no context...

[mlurye]

Another observation.
Look at this picture, do you see buzzer? Hendershot balancing the load. May be replacing buzzer with 60W bulb will be sufficient.

[NOMDI]

Standard caps do not affect HF resonance much, with double layer there is much better response in tuning.

Thanks for advice !