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John KN5L,
?So far it looks like you are the only one to have actually run with the ball.
?Do have any thoughts about actually building this in an instrument?
As always once you get to 1MHz and up strays become
important to minimize, but, apparently a Q meter can be built that does this.
? I ask because, I would want a variable capacitor, I would also have a difficult time
measuring a 6 inch diameter coil on the small pcb you have.
?I made the suggestion that unless we can find a better way to make the 50 to 1 transformer so it is wideband,
?we may have to have 3 switchable transformers for low, medium, and high frequencies. The OPs design goal was
1.5MHz to 150MHz. I received no response on the idea. I have enjoyed this thread and your posts.
?????????????????????????????????????????????????????? Mikek
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You might find Jeri Ellsworth's work interesting :
On Mon, Sep 26, 2022 at 1:01 PM Steve Hendrix < SteveHx@...> wrote:
I love this kind of "kitchen table
science" and teaching it to youngsters. Would there be any
possibility of getting her science fair report?
Steve Hendrix
On 2022-09-01 09:35 AM, Jeff Green
wrote:
I? meant to add this to my post.
I realize it sounds impossible to do at home but our daughter won
a regional science fair by making a transistor in the high school
art room.
Was it a good transistor??
Define good. It was much better then the first 2N device,
The 2N23.?
Consider Japan used young women to hand assemble transistors for
their first transistor radios.
I wrote a report for an economics class explaining how thinking
outside the box allowed Japan to get a jump start on the US/West
for transistors. I had a nice book by a British EE that showed all
the steps.?
If you are determined enough, you can make a lot more stuff "on
the kitchen table" then you'd believe.
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I love this kind of "kitchen table
science" and teaching it to youngsters. Would there be any
possibility of getting her science fair report?
Steve Hendrix
On 2022-09-01 09:35 AM, Jeff Green
wrote:
toggle quoted message
Show quoted text
I? meant to add this to my post.
I realize it sounds impossible to do at home but our daughter won
a regional science fair by making a transistor in the high school
art room.
Was it a good transistor??
Define good. It was much better then the first 2N device,
The 2N23.?
Consider Japan used young women to hand assemble transistors for
their first transistor radios.
I wrote a report for an economics class explaining how thinking
outside the box allowed Japan to get a jump start on the US/West
for transistors. I had a nice book by a British EE that showed all
the steps.?
If you are determined enough, you can make a lot more stuff "on
the kitchen table" then you'd believe.
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Added to:
is section "Prototype Q-Meter Analysis"
which evaluates difference between VNWA S11, Prototype Q-Meter, and
shape of Q-Curve using Rs and Rp values.
This analysis indicating Prototype Q-Meter is about 10% low when
compared to VNWA S11 measurement.
A limitation of the Q meter is High resonating capacitance for low
frequencies. For these measurements, a total of three C0G capacitors are
added. Suggesting Additional Q errors below 2.5MHz.
Using: , 33" #20 at 1MHz = 0.1 Ohm.
SimSmith model has R1M = 0.17 Ohm. Well within limits of wire proximity
RF skin effects.
John KN5L
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Hi Mikek:
Thanks very much.
--
Have Fun,
Brooke Clarke
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
-------- Original Message --------
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On Sun, Sep 25, 2022 at 10:34 AM, Brooke Clarke wrote:
Can you tell me if the 660/46 is a single bundle or is
it a group of bundles?
?After taxing my old eyeballs counting and coming up with about
26 wire in each bundle of 5 times,
?then not getting the math to work out to 660. I see he gave you
the formula.
0.04*
660(0.04*26*3+0.04*27*2)*5
It deciphers to wire diameter is 0.004", there are 660 wires, 3
bundles have 26 wires and 2 bundles have 27 wires, these 5 are
twisted together,
there are 5 bundles like the one just mentioned.
This is 3x26 + 2x27 = 132 wires and you have 5 of those bundles,
so 5 x 132 = 660
? Hope that helps.
?????????????????? Mikek
?
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On Sun, Sep 25, 2022 at 10:34 AM, Brooke Clarke wrote:
Can you tell me if the 660/46 is a single bundle or is it a group of bundles?
?After taxing my old eyeballs counting and coming up with about 26 wire in each bundle of 5 times,
?then not getting the math to work out to 660. I see he gave you the formula.
0.04* 660(0.04*26*3+0.04*27*2)*5
It deciphers to wire diameter is 0.004", there are 660 wires, 3 bundles have 26 wires and 2 bundles have 27 wires, these 5 are twisted together,
there are 5 bundles like the one just mentioned.
This is 3x26 + 2x27 = 132 wires and you have 5 of those bundles, so 5 x 132 = 660
? Hope that helps.
?????????????????? Mikek
?
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Hi Mikek:
I asked the eBay seller to clarify his claim of Type 2 Litz with his
designation of 660/46 which is a single bundle (Type 1) of 46 AWG
wires.? But his answer was to copy and paste something that did not
survive in his email.
Can you tell me if the 660/46 is a single bundle or is it a group of
bundles?
---------------------
Product
Number Strands Conductor Diameter?? *Strands Number????????Twisted
structure?????Measured breakdown voltage (V)?Copper conductor
cross sectional area (mm2)?Maximal Resistance (¦¸/m
at20¡æ)?Enamel-insulated wire maximum overall diameter??
(mm)?Envelope of the maximum diameter?? (mm)
Equivalent AWG?Every kilograms of length (feet-Meter/Kg)?????SDQAJ
0.04*
660(0.04*26*3+0.04*27*2)*5¡µ250¡Ö0.260.0186-0.0247¡´0.049¡´1.7118¡Ö436ft=133M/KGThe
maximum operating temperature of this litz wires is 155 degrees
Celsius.
-------------------------------
--
Have Fun,
Brooke Clarke
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
-------- Original Message --------
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Show quoted text
On Sat, Sep 24, 2022 at 02:00 PM, Brooke Clarke wrote:
Do you have a link to "The Litz man's page"?
Sellers name is mkmak222. He also has rods and toroids of the low
loss R40C1 ferrite material.
?or
?????????????????? Mikek
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Aargh! (Forehead slap!)
Of course you are right. I did not look closely enough at the output load.
Thanks for the correction, Alan.
Cheers
Tom
Sent from my iThing; please forgive the typos and brevity
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On Sep 25, 2022, at 03:30, Alan <g8lco1@...> wrote:
?Bootstrapping
The V301 valve in the Boonton Q meter is NOT a cathode follower but an " infinite impedance detector" due to the capacitor C302. So you cannot bootstrap at AC.
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On Sat, Sep 24, 2022 at 03:05 PM, John KN5L wrote:
Correct, As wire spacing decreases, there is skin effect squeezing,
which will increase RF resistance.
?I would think that is why my 5 coil test does not show that a 15 TPI coil would have the highest Q and it shows Q starts to drop at 12TPI, at least with coils wound with 660/46 on a 6" form.
Looked at wire chart, #46 is skin saturated in this frequency range.
Therefore wire Q is a function of frequency.
?? That's the design criteria of Litz wire, use all the available copper for current flow, without having any copper with less current density, then just add more wires to reduce losses. ? Your latest graph is now taking the shape of the 5 coil graph I posted. 
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On Sun, Sep 25, 2022 at 03:29 AM, Alan wrote:
Impact of 100M ohm
With a receive frequency of 1MHz and a Q=1000 that would? produce a -3dB audio bandwidth of 500Hz with an AM broadcast. A Q=100 would give a much better sounding bandwidth in a receiving application.
?? The 100M¦¸? as you say adds a very small reduction in Q, but the tube also adds losses especially at high frequencies as shown in this graph from the 260A manual. ? Note: the input impedance is down to 4M¦¸ at 4MHz. So, even if it was possible to bootstrap the tube, it would not eliminate the loading of the tube. ? But, the OP wants to build a Q meter for the frequency range 1.5 MHz to 150 MHz, that will take need a high input impedance voltmeter that will hold up it's high impedance up to 150MHz. Although Qs at 150MHz are generally lower that what is possible at 1MHz, so the input impedance can be somewhat relaxed without causing as much reduction in Q.  The only quibble re the 1000Q coil and BW, after you add the losses of the other components and load the coil enough to extract an audio signal you can hear, the loaded Q will be lower. If audio BW is ever a problem it is easy to spoil the Q, not so easy to improve it after the Q coil is finished. ?I'll remain a bit skeptical on the litz in AM radios, what I have seen is not a large litz, using only about 7 strands. But, I will need to check and to be sure the strands are actually insulated from each other. ??????????????????????????????????????????????????????????????????????????????????? Thanks,? Mikek
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BootstrappingThe V301 valve in the Boonton Q meter is NOT a cathode follower but an " infinite impedance detector" due to the capacitor C302. So you cannot bootstrap at AC. It would be possible to add a parallel cathode follower and bootstrap that however this is in the land of diminishing returns as it only impacts inductors of exceptional Q at MF. Impact of 100M ohm A simple work around is to measure Q of a coil then to add 100M ohms in parallel then retune and take a second Q reading then calculate out the 100M ohm first reading. However most? measurements don't need such a process because the 100M ohm loading is <1% Q reduction.? If you have an excellent 100uH inductor? Xl=628 ohms at 1MHz, so for a Q=2000? the parallel loss will be 1.26M ohm . Adding 100M ohm in parallel to 1.26M produces 1.2443, a 1.26% drop from Q=2,000 to 1975.? In reality a large coil near to the metalwork of a Q meter will read low Q because of eddy currents, in my experience the Q drop due to eddy currents is often far greater than 1%! ? Although it is interesting to make hi Q coils for the sake of interest a 6 inch diameter coil would need a large screen to avoid stray pick up while preserving Q. It would have about the same sensitivity as a ferrite rod antenna to real world signals so screening could be important in many applications. Real world Ferrite antenna QWhilst a few ferrite rods in broadcast receivers were wound with Litz most were not for very good reasons.?
- Raising the Q makes tracking very much more difficult.
- Litz is very expensive.
- You have to tin every strand both ends and not break any strands to realise the possible Q.
- Using thin solid wire produces sufficient Q but without excessive sideband cutting.
- The radio sounds much better so you sell more!
With a receive frequency of 1MHz and a Q=1000 that would? produce a -3dB audio bandwidth of 500Hz with an AM broadcast. A Q=100 would give a much better sounding bandwidth in a receiving application. Regards, Alan G8LCO
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Hi Mikek:
Thanks.? I've made a table of those Litz wire sizes and put all the
combinations with the same bundle diameter in the same column (+/-
for odd bundle AWG numbers).
For example these all are about 18 AWG bundle diameter: 100/48,
660/46, 405/44, 270/42, 170/40, 100/38/ 65/36, 32/33, 17/30 or
10/28.? That's to say a coil would with any of these would have the
same inductance.
--
Have Fun,
Brooke Clarke
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
-------- Original Message --------
toggle quoted message
Show quoted text
On Sat, Sep 24, 2022 at 02:00 PM, Brooke Clarke wrote:
Do you have a link to "The Litz man's page"?
Sellers name is mkmak222. He also has rods and toroids of the low
loss R40C1 ferrite material.
?or
?????????????????? Mikek
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Correct, As wire spacing decreases, there is skin effect squeezing,
which will increase RF resistance.
Looked at wire chart, #46 is skin saturated in this frequency range.
Therefore wire Q is a function of frequency.
New plot updated with equations:
Rpt = 0.0098
XL(MHz) = 2*pi*MHz*240
Qwire(MHz, turn) = XL(MHz) / (turn*Rpt)
Qcore(MHz) = 2.5e6 / XL(MHz)
Qtotal(MHz, turn) = 1/(1/Qwire(MHz,turn)+1/Qcore(MHz))
John KN5L
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On Sat, Sep 24, 2022 at 02:12 PM, John KN5L wrote:
As wire spacing decreases, there is skin effect squeezing, which will
reduce RF resistance.
I'm sure you meant will increase RF resistance
Not sure how this relates to Litz wire,
Litz wire increases Q because it has much more surface area than a single wire of the same diameter. Its frequency is limited though and if you look thru the the litz man's listings you will see that for each frequency range there is an optimal diameter wire.
as there are already close spaced wires.
These closely spaced wires are would in a special way for ?
- Mitigation of Skin Effect
- Mitigation of Proximity Effect
- Minimum eddy current losses
- From, https://www.newenglandwire.com/litz-wire-benefits-and-applications/
One would need to measure Q to evaluate
?? It's been done. in fact if you look at old am radios with ferrite rods, they all use litz wire to improve efficiency. ???????????????????????? Mikek
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Hi Mikek,
Added to Q as a function of tpi graph is 15tpi.
As wire spacing decreases, there is skin effect squeezing, which will
reduce RF resistance. Not sure how this relates to Litz wire, as there
are already close spaced wires. One would need to measure Q to evaluate
extent.
John KN5L
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On 9/24/22 3:55 PM, Mikek wrote: wire I used 660/46 litz wire, it is 0.065" in diameter, meaning 8 TPI
with be very close to 1 wire spacing. Close wire spacing is just over 15
TPI.
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On Sat, Sep 24, 2022 at 02:00 PM, Brooke Clarke wrote:
Do you have a link to "The Litz man's page"?
Sellers name is mkmak222. He also has rods and toroids of the low loss R40C1 ferrite material. ?or ?????????????????? Mikek
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Hi Mikek:
Do you have a link to "The Litz man's page"?
I think 2.46? comes from taking the differential of a simple
equation for the inductance of a single layer cylindrical coil.
--
Have Fun,
Brooke Clarke
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
-------- Original Message --------
toggle quoted message
Show quoted text
On Sat, Sep 24, 2022 at 01:16 PM, Brooke Clarke wrote:
Self capacity is a very important factor.? Hence the
experiments related to TPI.? But for me it's hard to make sense
of TPI.? So mentioning the physical wire diameter, or the
equivalent the maximum TPI for a close would coil, would help.
?The wire I used 660/46 litz wire, it is 0.065" in diameter,
meaning 8 TPI with be very close to 1 wire spacing. Close wire
spacing is just over 15 TPI.
EBAY Litz supplier,
The old books I referenced when winding AM broadcast
coils talked about a spacing of one wire diameter.? This is easy
to do using a loop of wire with a weight.? Note any dielectric
material near the coil adds capacity, and for some insulators
even adds resistive loss.
Styrene is high on the list of low loss materials. I would have
liked to made the walls of the coupler much thinner, but I had
someone volunteering the work, 5 coils, 5 different threads, so I
didn't ask him to remove a lot of material. I also made the the
thread cut just the minimum, so the wire wasn't surrounded by
styrene.
Getting the minimum wire length for a given single
layer cylindrical coil inductance, like the ones shown in recent
posts, depends on the form factor.? AFAICR making the diameter
about 2.5 times the length is near optimum.? That's to say for a
6" diameter form the coil length should be about 2.4" long.?
The 2.5 ratio was not what my experiment came up with, My test
showed 1.97. The Litz man's page shows a test of a 1.9 ratio coil
with a peak Q of 1472 (805kHz), but he adds, 2.46 is the best
ratio. I don't know if that would hold up over all diameter coils.
???????????????????????????????????????? Mikek
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On Sat, Sep 24, 2022 at 01:16 PM, Brooke Clarke wrote:
Self capacity is a very important factor.? Hence the experiments related to TPI.? But for me it's hard to make sense of TPI.? So mentioning the physical wire diameter, or the equivalent the maximum TPI for a close would coil, would help.
?The wire I used 660/46 litz wire, it is 0.065" in diameter, meaning 8 TPI with be very close to 1 wire spacing. Close wire spacing is just over 15 TPI. EBAY Litz supplier, https://tinyurl.com/mr2aw5zm
The old books I referenced when winding AM broadcast coils talked about a spacing of one wire diameter.? This is easy to do using a loop of wire with a weight.? Note any dielectric material near the coil adds capacity, and for some insulators even adds resistive loss.
Styrene is high on the list of low loss materials. I would have liked to made the walls of the coupler much thinner, but I had someone volunteering the work, 5 coils, 5 different threads, so I didn't ask him to remove a lot of material. I also made the the thread cut just the minimum, so the wire wasn't surrounded by styrene.
Getting the minimum wire length for a given single layer cylindrical coil inductance, like the ones shown in recent posts, depends on the form factor.? AFAICR making the diameter about 2.5 times the length is near optimum.? That's to say for a 6" diameter form the coil length should be about 2.4" long.?
The 2.5 ratio was not what my experiment came up with, My test showed 1.97. The Litz man's page shows a test of a 1.9 ratio coil with a peak Q of 1472 (805kHz), but he adds, 2.46 is the best ratio. I don't know if that would hold up over all diameter coils. ???????????????????????????????????????? Mikek
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Hi:
Self capacity is a very important factor.? Hence the experiments related to TPI.? But for me it's hard to make sense of TPI.? So mentioning the physical wire diameter, or the equivalent the maximum TPI for a close would coil, would help.
The old books I referenced when winding AM broadcast coils talked about a spacing of one wire diameter.? This is easy to do using a loop of wire with a weight.? Note any dielectric material near the coil adds capacity, and for some insulators even adds resistive loss.
Getting the minimum wire length for a given single layer cylindrical coil inductance, like the ones shown in recent posts, depends on the form factor.? AFAICR making the diameter about 2.5 times the length is near optimum.? That's to say for a 6" diameter form the coil length should be about 2.4" long.? In The Colorado Springs Notebook by Tesla the loading coil was maybe 15 feet in diameter and about 3 or 4 feet long/high.? So the "Tesla Coils" that are sold to schools that have a 2" diameter close would coil that's 8" tall probably have a Q of about 1.
--
Have Fun,
Brooke Clarke
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
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