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Here!! Here!!. We should have been more persistent in the 1960 when the USA
tried to move to the metric system.
*Clyde K. Spencer*



On Sat, Jan 30, 2021 at 5:34 PM David Eckhardt <davearea51a@...>
wrote:

Personally, I'm more at home in metric than our "kings foot" set of units!
However, if I had used metric, all the hams over here in the good 'ol USofA
would bellyache they couldn't deal with 2.54 cm/inch (conversion is on most
calculators) or, heaven forbid, Kelvins instead of degrees F. When
presenting, I warn the audience up-front that miles per hour has no place
in Fields and Waves in specifying c, only 3E8 m/sec and other metric units
shall be used.

Dave - W?LEV
(Born a Nerd, Always a Nerd........)


On Sat, Jan 30, 2021 at 7:24 PM Jean-Denis Muys via groups.io <jdmuys=
[email protected]> wrote:

Very interesting. I was quite shocked that you didn’t use metric units

for

the calculations though. This would be my suggestion: use metric units.

JD

On Jan 30, 2021, at 07:23, Barry Feierman <k3euibarry@...>

wrote:

?Hello NANO VNA folks
I keep updating my NANO VNA talk after presenting at different club

meetings. I've had my Nano VNA for about four months now, and each time I
play with it I learn something new.

Questions raised by viewers made me reconsider how to explain PHASE and

RESONANCE and especially what the SMITH CHART reveals.

It feels like PHASE is greatly misunderstood, with antennas.
I tried to come up with a simple mechanical analogy: GRAMPY pushing

GRANDCHILD on a swing.

Even little grandkids know that GRAMPY has to push the swing at just

the

right time (PHASE) to increase the amplitude of the kid's swinging.

We all "know" that. If Grampy does not push at the right time, the

grandkid complains.

Do antennas work the same way, with the feed line pumping in energy at

just the "right time" to increase the current in the antenna?

The rig does not supply the electrons to the antenna (they were already

in those copper or aluminum atoms).

The rig supplies, via the feed line, the instructions as to WHEN to

push

those electrons.

Think of the feed line like GRAMPY pushing the GRANDKID.


We use the Nano VNA most likely in our (warm) shack. But perhaps we are

really interested in what the readings are at the ANTENNA junction.

By changing the feed line by a few feet (on 10 meters) I was able to

convince myself that adding about a 1/4 wavelength of RG213 (6 feet)

did

ROTATE the impedance values on the Smith Chart. I "knew" what was going

to

happen, but still smiled when I saw it with my own eyes. Yet, adding 6
feet of coax (to a 100 ft feed line) did absolutely nothing to the SWR
readings on 10m (28-29 MHz) to the REFLECTION COEFFICIENT, and to the
RETURN LOSS.

So I added these slides to my newest PDF file.

The attachment is my latest rendition of a NANO VNA talk (as pdf

slides).

If any clubs are looking for a speaker, I am all in. I learn a lot by

giving a talk on a topic (I'm at a 9th grader understanding of the VNA)

73 and TU for all of the helpful suggestions. Feel free to pass on

these

PDF slides to others.

de Barry Feierman k3eui





<Nano VNA Analyzer Jan 28.pdf>

--
*Dave - W?LEV*
*Just Let Darwin Work*

Personally, I'm more at home in metric than our "kings foot" set of units!
However, if I had used metric, all the hams over here in the good 'ol USofA
would bellyache they couldn't deal with 2.54 cm/inch (conversion is on most
calculators) or, heaven forbid, Kelvins instead of degrees F. When
presenting, I warn the audience up-front that miles per hour has no place
in Fields and Waves in specifying c, only 3E8 m/sec and other metric units
shall be used.

Dave - W?LEV
(Born a Nerd, Always a Nerd........)


On Sat, Jan 30, 2021 at 7:24 PM Jean-Denis Muys via groups.io <jdmuys=
[email protected]> wrote:

Very interesting. I was quite shocked that you didn’t use metric units for
the calculations though. This would be my suggestion: use metric units.

JD

On Jan 30, 2021, at 07:23, Barry Feierman <k3euibarry@...> wrote:

?Hello NANO VNA folks
I keep updating my NANO VNA talk after presenting at different club

meetings. I've had my Nano VNA for about four months now, and each time I
play with it I learn something new.

Questions raised by viewers made me reconsider how to explain PHASE and

RESONANCE and especially what the SMITH CHART reveals.

It feels like PHASE is greatly misunderstood, with antennas.
I tried to come up with a simple mechanical analogy: GRAMPY pushing

GRANDCHILD on a swing.

Even little grandkids know that GRAMPY has to push the swing at just the

right time (PHASE) to increase the amplitude of the kid's swinging.

We all "know" that. If Grampy does not push at the right time, the

grandkid complains.

Do antennas work the same way, with the feed line pumping in energy at

just the "right time" to increase the current in the antenna?

The rig does not supply the electrons to the antenna (they were already

in those copper or aluminum atoms).

The rig supplies, via the feed line, the instructions as to WHEN to push

those electrons.

Think of the feed line like GRAMPY pushing the GRANDKID.


We use the Nano VNA most likely in our (warm) shack. But perhaps we are

really interested in what the readings are at the ANTENNA junction.

By changing the feed line by a few feet (on 10 meters) I was able to

convince myself that adding about a 1/4 wavelength of RG213 (6 feet) did
ROTATE the impedance values on the Smith Chart. I "knew" what was going to
happen, but still smiled when I saw it with my own eyes. Yet, adding 6
feet of coax (to a 100 ft feed line) did absolutely nothing to the SWR
readings on 10m (28-29 MHz) to the REFLECTION COEFFICIENT, and to the
RETURN LOSS.

So I added these slides to my newest PDF file.

The attachment is my latest rendition of a NANO VNA talk (as pdf

slides).

If any clubs are looking for a speaker, I am all in. I learn a lot by

giving a talk on a topic (I'm at a 9th grader understanding of the VNA)

73 and TU for all of the helpful suggestions. Feel free to pass on these

PDF slides to others.

de Barry Feierman k3eui





<Nano VNA Analyzer Jan 28.pdf>

--
*Dave - W?LEV*
*Just Let Darwin Work*

Roger:

Thank you for the SimSmith circuit and explanation. You have solved one of
the mysteries in all this for me. My measured DM CMC loss did not
correlate with the amount of heating (actually very little heating) I
experienced at power. I believe your little article explains why. Also,
the values are measured in a 50-ohm system. If the CMCs are installed In a
system other than 50 ± j0, the attenuation may not be what is measured in a
well defined system impedance. That's why I carefully state everything in a
50-ohm system. With my antenna/Xline system, the chokes never are
embedded in a 50-ohm system! There are 'matches' outside the ham bands,
but not within. The whole reason for parallel conductor feeders and the
CMCx.

As far as 50 ± j0 at both sides of the CMC is concerned, only if the
section of transmission line on the toroid is, itself, 50 ± j0 or
electrically 1/2-wavelength long. The 1/2-wavelength requirement would
render then narrow band devices which none of us really want to deal with.
The older antenna matching units address the problem of a CM to DM
transition in obvious manner: Link Coupling. It's also good for getting
RF through windows without poking holes in the wall. But, these are
narrowband devices.

As most of us know, and written in Mr. Sevick's books, it is rather
difficult to wind a 50-ohm section of line on these toroids. I believe
Sevick resorted to tape windings to get close to a 50-ohm section. As
pointed out in a previous post, my Xline on the core I measured with the
NANO amounted to about 85 ohms. I have some #12 Teflon insulated wire
(Teflon thickness enough to withstand 10 to 20kV) coming from Surplus Sales
of Nebraska with which I may be able to lower the Zo of the Xline on the
cores without breakdown. Hopefully, next week.

Dave - W?LEV

On Sat, Jan 30, 2021 at 7:32 PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

Something to consider when determining loss in a common mode choke by this
method.



Roger

--
*Dave - W?LEV*
*Just Let Darwin Work*

The NanoVNA-F also has the capability of saving the S1p and S2p without the
need of the SD card modification.

On Sat, Jan 30, 2021, 2:03 PM Dragan Milivojevic <d.milivojevic@...>
wrote:

You need to get one with a SD slot (or hack one) and install dislords
firmware
to enable that feature.

On Sat, 30 Jan 2021 at 21:23, rezonanzz <bajaguilin@...> wrote:

Does the nano-vna have the ability to save s-parameter files in

Touchstone

format?

You need to get one with a SD slot (or hack one) and install dislords
firmware
to enable that feature.

A minor correction: the authors are Dr. Howard Johnson and Martin Graham.

They authored two books (including the one cited below) and they are both excellent.

DaveD

Does the nano-vna have the ability to save s-parameter files in Touchstone format?

Barry,

I thought you might enjoy this description of the resonant swing set by Graham Johnson in his book . - High Speed Signal Propagation - Advanced Black Magic (1993).

Roger

Something to consider when determining loss in a common mode choke by this method.



Roger

Very interesting. I was quite shocked that you didn’t use metric units for the calculations though. This would be my suggestion: use metric units.

JD

An addition at the beginning and a few minor 'fixes'. Going to sleep last
night I kept mulling over changes I wanted to make. See attachment.

Dave - W?LEV

I am happy with my VNA -F.Good luckSent from my Verizon, Samsung Galaxy smartphone

Barry, great slide presentation.?
However, you ask questions in a number of the slides and have a few quizzes but don't provide an appendix or any presentation notes with the answers.?
Can you please add either of those to the end of the slides to make them a great standalone educational tool?
Thanks
Larry


On Sat., 30 Jan. 2021 at 10:20 a.m., Barry Feierman<k3euibarry@...> wrote: Hello NANO VNA folks
I keep updating my NANO VNA talk after presenting at different club meetings. I've had my Nano VNA for about four months now, and each time I play with it I learn something new.

Questions raised by viewers made me reconsider how to explain PHASE and RESONANCE and especially what the SMITH CHART reveals.
It feels like PHASE is greatly misunderstood, with antennas.
I tried to come up with a simple mechanical analogy:? GRAMPY? pushing GRANDCHILD? on a swing.
Even little grandkids know that GRAMPY has to push the swing at just the right time (PHASE) to increase the amplitude of the kid's swinging.
We all "know" that.? If Grampy does not push at the right time, the grandkid complains.
Do antennas work the same way, with the feed line pumping in energy at just the "right time" to increase the current in the antenna?
The rig does not supply the electrons to the antenna (they were already in those copper or aluminum atoms).
The rig supplies, via the feed line, the instructions as to WHEN to push those electrons.
Think of the feed line like GRAMPY pushing the GRANDKID.


We use the Nano VNA most likely in our (warm) shack. But perhaps we are really interested in what the readings are at the? ANTENNA? junction.
By changing the feed line by a few feet (on 10 meters) I was able to convince myself that adding about a? 1/4 wavelength of RG213? (6 feet) did ROTATE the impedance values on the Smith Chart.? I "knew" what was going to happen, but still smiled when I saw it with my own eyes.? Yet, adding 6 feet of coax (to a 100 ft feed line) did absolutely nothing to the SWR readings on 10m? (28-29 MHz) to the REFLECTION COEFFICIENT, and to the RETURN LOSS.
So I added these slides to my newest PDF file.

The attachment is my latest rendition of a? NANO VNA talk (as? pdf slides).
If any clubs are looking for a speaker, I am all in.? I learn a lot by giving a talk on a topic (I'm at a 9th grader understanding of the VNA)

73 and TU for all of the helpful suggestions. Feel free to pass on these PDF? slides to others.
de? Barry Feierman? k3eui

Hello NANO VNA folks
I keep updating my NANO VNA talk after presenting at different club meetings. I've had my Nano VNA for about four months now, and each time I play with it I learn something new.

Questions raised by viewers made me reconsider how to explain PHASE and RESONANCE and especially what the SMITH CHART reveals.
It feels like PHASE is greatly misunderstood, with antennas.
I tried to come up with a simple mechanical analogy: GRAMPY pushing GRANDCHILD on a swing.
Even little grandkids know that GRAMPY has to push the swing at just the right time (PHASE) to increase the amplitude of the kid's swinging.
We all "know" that. If Grampy does not push at the right time, the grandkid complains.
Do antennas work the same way, with the feed line pumping in energy at just the "right time" to increase the current in the antenna?
The rig does not supply the electrons to the antenna (they were already in those copper or aluminum atoms).
The rig supplies, via the feed line, the instructions as to WHEN to push those electrons.
Think of the feed line like GRAMPY pushing the GRANDKID.


We use the Nano VNA most likely in our (warm) shack. But perhaps we are really interested in what the readings are at the ANTENNA junction.
By changing the feed line by a few feet (on 10 meters) I was able to convince myself that adding about a 1/4 wavelength of RG213 (6 feet) did ROTATE the impedance values on the Smith Chart. I "knew" what was going to happen, but still smiled when I saw it with my own eyes. Yet, adding 6 feet of coax (to a 100 ft feed line) did absolutely nothing to the SWR readings on 10m (28-29 MHz) to the REFLECTION COEFFICIENT, and to the RETURN LOSS.
So I added these slides to my newest PDF file.

The attachment is my latest rendition of a NANO VNA talk (as pdf slides).
If any clubs are looking for a speaker, I am all in. I learn a lot by giving a talk on a topic (I'm at a 9th grader understanding of the VNA)

73 and TU for all of the helpful suggestions. Feel free to pass on these PDF slides to others.
de Barry Feierman k3eui

Nice write-up of your method.

Only a comment on the measurement outcome itself.
In the Smith Chart it becomes clear that the transmissionline impedance (the sort of twinlead windings on the core) is about 85 ohms that introduces the varying SWR in the S21 measurement.
Ofcourse, this can be overcome.
At 500 kHz (also on the Smith Chart) I expected the trace to start closer to 50 ohm.

73,

Arie PA3A



Op 29-1-2021 om 23:24 schreef David Eckhardt:

On Fri, Jan 29, 2021 at 03:02 PM, Mel Farrer wrote:

In my book any serious engineering comparisons like that, are done at one
sitting, N O changes in setup PERIOD.

Yes, in an ideal world, all tests would be done with no changes in the setup. Unfortunately, we - at least most of us - don't live in an ideal world, we live in the real world. A number of NanoVNA users have compared their Nanos to HP equipment and have found that the Nanos, while by no means equivalent to HP equipment, are pretty darn good. If we needed to know to a fraction of an ohm the common mode impedance of a particular choke, we'd be out of luck. But most of us don't need that kind of accuracy, and the NanoVNAs suit us just fine.

“It is the mark of an instructed mind to rest satisfied with that degree of precision which the nature of the subject admits, and not to seek exactness where only an approximation of the truth is possible.” - Aristotle

Thank you for sharing.

Looking forward to seeing your process for measuring common mode attenuation through a CMC :-)

--
VE6WGM

Don't yield to unreasonable people, that's what they want.

OK. you clearly do not understand. I quit.......

Dave - W?LEV

On Sat, Jan 30, 2021 at 1:40 AM Mel Farrer via groups.io <farrerfolks=
[email protected]> wrote:

So why use them as a comparison with multiple variables? NO THE SETUPS
need to be the same to be a real comparison. Do your home work.
Mel, K6KBE
On Friday, January 29, 2021, 04:24:59 PM PST, David Eckhardt <
davearea51a@...> wrote:

Setups HAD to change. The initial measurements were made with the HP
8753C. Those I put out today with the procedure are made using the NANOVNA
and SAVER. Of course the setups are DIFFERENT!!!!!! ENTIRELY DIFFERENT
INSTRUMENTS!!!!!!

Dave - W?LEV

On Fri, Jan 29, 2021 at 11:02 PM Mel Farrer via groups.io <farrerfolks=
[email protected]> wrote:

David, thanks for the good work, but I have one question,
1. With all of the equipment and access to the testing site, did you

make

the measurements at different times and different calibrations? Sort of
defeats the accuracy right off the get go. In my book any serious
engineering comparisons like that, are done at one sitting, N O changes

in

setup PERIOD. Sorry, my stick.

Mel, K6KBE
On Friday, January 29, 2021, 02:25:24 PM PST, David Eckhardt <
davearea51a@...> wrote:

With all my recent measurements of CMCs, I've been encouraged by several
readers to put together a procedure for the various measurements I've

made

with the HP 8753C, but using the NANOVNAs and SAVER. The attachment is

the

first installment which presents a procedure using the NANOs and SAVER to
measure the DM loss through any CMC. It is also useful for measuring

other

two-terminal transmissive devices such as filters, attenuators, active
stages, and.......

Have a look at my first cut. I'd invite anyone to make suggestions to

make

things clearer and/or correct any errors I've made in the write-up.

Have a

read of the attachment.

The next installment will address measuring the bulk CM impedance

presented

by the CMCs using the NANOs and SAVER (another day, please) which have

been

previously measured using the HP equipment.

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*

--
*Dave - W?LEV*
*Just Let Darwin Work*

So why use them as a comparison with multiple variables?? ?NO THE SETUPS need to be the same to be a real comparison.? Do your home work.
Mel, K6KBE