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OverUnity Research > Benches > Itsu (Moderator: Itsu) > Smudge proposed NMR experiment replication.
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Author Topic: Smudge proposed NMR experiment replication.  (Read 126975 times)
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Re: Smudge proposed NMR experiment replication. « Reply #300 on: 2020-07-17, 09:18:13 »

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I have some power meters (Bird 43 and a Gotting), but both are for higher frequency (Gotting) and/or for higher power (500W) at 4Mhz (Bird 43), so won't show much on the ±5W on 4Mhz we are dealing with.
But what i see on them is that in our system we have almost as much reflected power as power going in.


Got my litz wire and made the 2x 3mm thick plexiglas formers (150mm by 150mm square), so i am ready to wind them.
Aiming for 14 turns (0.93mm litz wire), so will cover an area of OD: 113mm, ID:87mm.

Just need to know the winding scheme, Weave 1 or Weave 2.


Regards Itsu
   
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Re: Smudge proposed NMR experiment replication. « Reply #301 on: 2020-07-17, 14:46:12 »

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Quote from: Itsu on 2020-07-17, 09:18:13
Just need to know the winding scheme, Weave 1 or Weave 2.
They are very similar but Weave1 should generate a more symmetric H-field.  I did not confirm it experimentally, though, so please get a 2nd opinion on that from Smudge or another expert.

I did not post the TDR scopeshots of the picopulse yet because I blew up my only 2N2369 transistor and I have only the following high-frequency BJTs in stock:
BF199
BC547B
2N3904
CX237B
MPS2907A
BC556B
   
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Re: Smudge proposed NMR experiment replication. « Reply #302 on: 2020-07-17, 16:45:33 »

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Ok, so i would go for Weave1, so please Smudge or any other expert, can you confirm?

Here a link to the both coils, Coil2.png = weave2, coil.png = weave1:
https://www.overunityresearch.com/index.php?topic=3924.msg83193#msg83193
 

 
Bummer that you blew up your 2N2369, Alltransistors.com gives some equivalents, but none in your list.

2N3227     Si     NPN     0.36     40     20     4     0.5     200     500     4     100     TO18
2N4137     Si     NPN     0.36     40     20     4     0.2     200     500     4     40     TO18
2N4873     Si     NPN     0.36     40     15          0.2     200     600     4     110     TO18
2N5272     Si     NPN     0.36     40     20          0.2     200     500     4     100     TO18
2N915A     Si     NPN     0.36     70     50     5     0.2     200     600     4     50     TO18
BSX20       Si     NPN     0.36     40     15     5     0.5     200     500     4     40     TO18
BSX93       Si     NPN     0.36     40     15     4     0.5     200     500     4     40     TO18
CV7555     Si     NPN     1.2       40     15     4.5    0.2  200     500     4     40     TO18
FT2369     Si     NPN     0.36     40     15     4     0.2     200     500     4     40     TO18

Itsu
   
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Re: Smudge proposed NMR experiment replication. « Reply #303 on: 2020-07-17, 21:12:04 »

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Quote from: Itsu on 2020-07-17, 16:45:33
Bummer that you blew up your 2N2369, Alltransistors.com gives some equivalents, but none in your list.

2N3227     Si     NPN     0.36     40     20     4     0.5     200     500     4     100     TO18
2N4137     Si     NPN     0.36     40     20     4     0.2     200     500     4     40     TO18
2N4873     Si     NPN     0.36     40     15          0.2     200     600     4     110     TO18
2N5272     Si     NPN     0.36     40     20          0.2     200     500     4     100     TO18
2N915A     Si     NPN     0.36     70     50     5     0.2     200     600     4     50     TO18
BSX20       Si     NPN     0.36     40     15     5     0.5     200     500     4     40     TO18
BSX93       Si     NPN     0.36     40     15     4     0.5     200     500     4     40     TO18
CV7555     Si     NPN     1.2       40     15     4.5    0.2  200     500     4     40     TO18
FT2369     Si     NPN     0.36     40     15     4     0.2     200     500     4     40     TO18
That list helped  O0
It jogged my memory that I have seen a BSX transistor in my Mom's old CRT TV ~20 years ago. Don't ask me how I remember that.
She never throws anything away, so I will have it tonight.

Anyway, I found the attached Pushing Tool very helpful with winding these pancake coils.
Also, using a low-viscosity SuperGlue (cyanoacrylate) in an insulin syringe w/ integrated needle (from a pharmacy), is very useful for securing the Litz wire around the wire crossings, because this glue polymerizes instantly when subjected to pressure from the pushing tool.
   
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Re: Smudge proposed NMR experiment replication. « Reply #304 on: 2020-07-18, 08:55:38 »

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How did you remember that!  ;D

Yes, people seem to store the strangest things in their heads, now this comes in handy.
Now where did your mom store that old CRT TV......


Ok on the winding tool, i don't like superglue on plexiglas as it tends to give smears and dirty up the whole thing, but in this case i probably need to.

Itsu
   
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Re: Smudge proposed NMR experiment replication. « Reply #305 on: 2020-07-18, 13:31:02 »

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Quote from: Itsu on 2020-07-18, 08:55:38
How did you remember that!  ;D

Yes, people seem to store the strangest things in their heads, now this comes in handy.
Now where did your mom store that old CRT TV......
I got the BSX20! It was in the attic ..with everything else

Quote from: Itsu on 2020-07-18, 08:55:38
Ok on the winding tool, i don't like superglue on plexiglas as it tends to give smears and dirty up the whole thing, but in this case i probably need to.
Yup, but the insulin syringe gives you so much control, with such small amounts that it doesn't spread around.
   
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Re: Smudge proposed NMR experiment replication. « Reply #306 on: 2020-07-19, 02:31:24 »

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So I reconstructed the Picopulser with the BSX20 transistor and 3pF cap ( actually 2x1.5pF ).
With a 100VDC supply, it generates 7.3VP-P, 492ps pulse (FWHM).
« Last Edit: 2023-09-10, 23:30:45 by verpies »
   
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Re: Smudge proposed NMR experiment replication. « Reply #307 on: 2020-07-19, 09:05:07 »

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Thats a very clean pulse, so the BSX20 might be performing better then the original 2N2369 as the diagram for the LT1073 calls for a 350ps risetime pulse  O0

Itsu
   
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Re: Smudge proposed NMR experiment replication. « Reply #308 on: 2020-07-19, 09:25:10 »

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This was with a 50Ω coax directly to a 50Ω input of LowZ scope.
It wasn't so clean when I was probing it with a 1MΩ probe set to 10x.  The probe's capacitance took time getting charged ...and distorted the pulse.
   
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Re: Smudge proposed NMR experiment replication. « Reply #309 on: 2020-07-19, 10:33:54 »

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Quote from: Itsu on 2020-07-17, 16:45:33
Ok, so i would go for Weave1, so please Smudge or any other expert, can you confirm?

Here a link to the both coils, Coil2.png = weave2, coil.png = weave1:
https://www.overunityresearch.com/index.php?topic=3924.msg83193#msg83193
 


Seems we are not getting a second opinion on your Weave* coils from Smudge or any other coil expert which is disappointing.

So i will go for Weave1 next week as currently i am trying to repair a P6302 current probe which suffer from broken wires in its plug which is a pain to get open.

 
Itsu
   
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Re: Smudge proposed NMR experiment replication. « Reply #310 on: 2020-07-19, 10:42:36 »

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Quote from: Itsu on 2020-07-19, 10:33:54
I am trying to repair a P6302 current probe which suffer from broken wires in its plug which is a pain to get open.
...and I wasted the entire day yesterday fixing a broken firmware in the scope.
   
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Re: Smudge proposed NMR experiment replication. « Reply #311 on: 2020-07-19, 11:32:25 »

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Broken firmware!?  So you went in, debugged the firmware then reflashed it?

Sounds like the manufacturer could be interested in it.

Itsu
   
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Re: Smudge proposed NMR experiment replication. « Reply #312 on: 2020-07-19, 13:13:27 »

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Quote from: Itsu on 2020-07-19, 11:32:25
Broken firmware!?  So you went in, debugged the firmware then reflashed it?
Yeah, with IDAPro and JTAG flasher.

Anyway, below are the waveforms of these two pancake coils (with the middle break open, although the photo shows the break bridged by a pot).
The upper trace is of Weave1, and the lower trace is of Weave2.

Notes:
These are not unprocessed traces.  First, the pulse response of all the interconnects was saved to a reference waveform designated as M1.
Next, the opened Weave1 pancake coil was connected to Ch1 and the difference of Ch1-M1 was saved to a upper reference waveform M2.
Finally, the opened Weave2 pancake coil was connected to Ch1 and the difference of Ch1-M1 was displayed as the lower trace F1.

« Last Edit: 2020-07-19, 16:13:59 by verpies »
   
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Re: Smudge proposed NMR experiment replication. « Reply #313 on: 2020-07-19, 14:11:05 »

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And below is an illustration of the difference that a termination makes.
As before, the upper trace (M2) depicts the pulse response of a Weave1 pancake coil with the middle break opened, and the the lower trace (F1) illustrates the same coil with a termination of 200Ω at the middle break.

As you can see, the largest difference is around +10ns, which is approximately the round trip delay of ½ of the wire length used to wind this coil (...or the length of the wire up to the middle break).
« Last Edit: 2020-07-19, 15:44:39 by verpies »
   
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Re: Smudge proposed NMR experiment replication. « Reply #314 on: 2020-07-19, 15:43:51 »

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And below is an illustration of the difference that a termination makes...but this time with Weave2
The upper trace (M2) depicts the pulse response of a Weave2 pancake coil with the middle break opened, and the the lower trace (F1) illustrates the same coil with a termination of 200Ω at the middle break.

As you can see, the largest difference is still around +10ns, which is approximately the round trip delay of ½ of the wire length used to wind this coil (...or the length of the wire up to the middle break).
   
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Re: Smudge proposed NMR experiment replication. « Reply #315 on: 2020-07-19, 16:42:55 »

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Nice screenshots, they show almost no difference between weave1 or weave2.

Is one coil more easy to build then the other, or are they similar difficult?
   
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Re: Smudge proposed NMR experiment replication. « Reply #316 on: 2020-07-19, 18:23:08 »

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Quote from: Itsu on 2020-07-19, 16:42:55
Is one coil more easy to build then the other, or are they similar difficult?
There is a difference but it is only mental.  Apparently it is easier for my brain to keep track of Weave 2. There is no mechanical difference.

There should be a difference in their H-field symmetry, though.
   
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Re: Smudge proposed NMR experiment replication. « Reply #317 on: 2020-07-20, 08:59:46 »

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Ok,  is one more symmetric (better) then the other?
   
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Re: Smudge proposed NMR experiment replication. « Reply #318 on: 2020-07-20, 12:38:09 »

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Yes
   
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Re: Smudge proposed NMR experiment replication. « Reply #319 on: 2020-07-20, 15:18:57 »

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Quote from: Itsu on 2020-07-19, 10:33:54
Seems we are not getting a second opinion on your Weave* coils from Smudge or any other coil expert which is disappointing.

Sorry about that.  Having just recently moved house my time has been spent laying paving slabs and moving furniture around, I haven’t really paid much attention to OUR.  I have to say that I am not sure that such finesse in coil design is needed, but I am no expert.  I am pleased that you and verpies are doing this work and long for the day when you actually discover the proton spin absorption peak or trough.  I understand verpies’ concerns that the signal could be too difficult to find until you have mastered the problems of getting high current into the pancake coils and have eliminated (as far as possible) unwanted magnetic and electric coupling from the pancake coils to the toroidal coil.  I think my investigative approach would have been different, I would have spent more time just searching for the proton resonance then, having found it, I would work at that fixed frequency fine-tuning the system.  But that may well have ended in failure in not finding the proton resonance.

You asked earlier what proton frequency would occur in your latest build.  If we had some way of measuring the permanent magnet field between the pancakes we could give you an accurate answer.  My FEMM result for your magnet separation of 21mm is a field very close to 0.1 Tesla that gives a frequency of 4.258 MHz, but FEMM is not a 3D simulator.

Smudge
   
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Re: Smudge proposed NMR experiment replication. « Reply #320 on: 2020-07-20, 15:23:45 »

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Quote from: Itsu on 2020-07-14, 21:37:46
H-probe measurement (0 to 50Mhz) on the front pancake middle of windings using the TG and SA
Could you do it again but with the the H-probe positioned between the 2 pancake coils (connected in series opposing) ?
Prior to the sweeps, please find the one H-probe orientation and position, which gives you the strongest signal between the coils and mechanically fix the H-probe in that orientation and position for all sweeps. (a photo of this position would be nice to see, too).

Anyway, if you decide to do this, please make these 6 sweeps:
  • pancake coils powerd by the PA, through a symmetrizing 1:1 balun and the parallel cap (Smudge's style).
  • pancake coils powerd by the PA, and the parallel cap (Smudge's style).
  • naked pancake coils powerd by the PA through a symmetrizing 1:1 balun.
  • naked pancake coils powerd by the PA.
  • pancake coils powered by the PA and a cap in series (Partzman's style).
  • pancake coils powered by the PA, through a symmetrizing 1:1 balun and a cap in series (Partzman's style but w/balun).

Use long sweep times so the ringing resonant systems have the time to settle.
   
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Re: Smudge proposed NMR experiment replication. « Reply #321 on: 2020-07-20, 16:40:42 »

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Quote from: Smudge on 2020-07-20, 15:18:57
Sorry about that.  Having just recently moved house my time has been spent laying paving slabs and moving furniture around, I haven’t really paid much attention to OUR.  I have to say that I am not sure that such finesse in coil design is needed, but I am no expert.  I am pleased that you and verpies are doing this work and long for the day when you actually discover the proton spin absorption peak or trough.  I understand verpies’ concerns that the signal could be too difficult to find until you have mastered the problems of getting high current into the pancake coils and have eliminated (as far as possible) unwanted magnetic and electric coupling from the pancake coils to the toroidal coil.  I think my investigative approach would have been different, I would have spent more time just searching for the proton resonance then, having found it, I would work at that fixed frequency fine-tuning the system.  But that may well have ended in failure in not finding the proton resonance.

You asked earlier what proton frequency would occur in your latest build.  If we had some way of measuring the permanent magnet field between the pancakes we could give you an accurate answer.  My FEMM result for your magnet separation of 21mm is a field very close to 0.1 Tesla that gives a frequency of 4.258 MHz, but FEMM is not a 3D simulator.

Smudge

Smudge,

no problem there, sorry for being impatient, you have enough on your head right now, take your time.

Thanks for the new data, its an approximate which we can work with.

Itsu
   
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Re: Smudge proposed NMR experiment replication. « Reply #322 on: 2020-07-20, 16:45:45 »

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Quote from: verpies on 2020-07-20, 15:23:45
Could you do it again but with the the H-probe positioned between the 2 pancake coils (connected in series opposing) ?
Prior to the sweeps, please find the one H-probe orientation and position, which gives you the strongest signal between the coils and mechanically fix the H-probe in that orientation and position for all sweeps. (a photo of this position would be nice to see, too).

Anyway, if you decide to do this, please make these 6 sweeps:
  • pancake coils powerd by the PA, through a symmetrizing 1:1 balun and the parallel cap (Smudge's style).
  • pancake coils powerd by the PA, and the parallel cap (Smudge's style).
  • naked pancake coils powerd by the PA through a symmetrizing 1:1 balun.
  • naked pancake coils powerd by the PA.
  • pancake coils powered by the PA and a cap in series (Partzman's style).
  • pancake coils powered by the PA, through a symmetrizing 1:1 balun and a cap in series (Partzman's style but w/balun).

Use long sweep times so the ringing resonant systems have the time to settle.


Ok,  i can do that,    do you mean between pancake coils with the toroidal coil removed?
   
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Re: Smudge proposed NMR experiment replication. « Reply #323 on: 2020-07-20, 16:57:22 »

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Quote from: Itsu on 2020-07-20, 16:45:45
...do you mean between pancake coils with the toroidal coil removed?
Yes

Quote from: verpies on 2020-07-20, 15:23:45
Prior to the sweeps, please find the one H-probe orientation and position, which gives you the strongest signal between the coils
Because the probe is sensitive not only at its end and maybe also to E-fields, I am concerned about the probe picking up something else than just the magnetic flux spanned by the Litz loop.

Thus, I have to revise my phrase in the sentence above, from "the strongest signal" to:
"the largest ratio of the signal amplitude with the Litz loop inside the probe vs. with the Litz loop removed (empty probe)" -  for the same probe position and orientation, of course.

This should eliminate any false readings not contributed to by the Litz loop.
   
img  Itsu
Re: Smudge proposed NMR experiment replication. « Reply #324 on: 2020-07-20, 17:24:53 »

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Ok, but the problem is that i do not have that much room to manoeuvre as the gap between the pancakes is small.
For maximum pickup i need to have the litz loop on the opposite side / curve of the pancakes, but it won't fit.

Will see what i can do....

Itsu
   
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