开云体育

Thanks a lot Dave.

Shall go through it and get back to you.

73
Jon, VU2JO

On Fri, May 16, 2025 at 4:49?AM W0LEV via groups.io <davearea51a=
[email protected]> wrote:

I've had several requests on reading the values of inductors and capacitors
using the NANOVNAs. I've put that together in the attachment to this
email. If you want to learn how it's done using the NANOVNA's and the
Smith Chart presentation, the attachment should be of interest to you. For
the write-up, I've used the H4 version of the NANOVNA, but everything
should be applicable to any version of the NANOs or professional VNAs. So,
don't belabor the point that .....waaahhhh....waaahhhh......I don't have
the H4. The technique is applicable to any vector network analyzer.

So, if interested, have a read of the attachment.

Dave - W?LEV


--
Dave - W?LEV

Okay! Great! Thank you!

Yahoo Mail: Search, Organize, Conquer

On Thu, May 15, 2025 at 13:35, Team-SIM SIM-Mode via groups.io<sim31_team@...> wrote: Hi Roger

Thanks , I re do the measure of my 25m of RG213 at 100Mhz? (Span 5Mhz ) by this cicle methode see illustration below with graphical renormalized Z0 to center impedances circle around center smith shart.
73's Nizar








--
73
Karl
KI4ZUQ

I've had several requests on reading the values of inductors and capacitors
using the NANOVNAs. I've put that together in the attachment to this
email. If you want to learn how it's done using the NANOVNA's and the
Smith Chart presentation, the attachment should be of interest to you. For
the write-up, I've used the H4 version of the NANOVNA, but everything
should be applicable to any version of the NANOs or professional VNAs. So,
don't belabor the point that .....waaahhhh....waaahhhh......I don't have
the H4. The technique is applicable to any vector network analyzer.

So, if interested, have a read of the attachment.

Dave - W?LEV


--
Dave - W?LEV

Please let us know where you are going with this

Simply trying to take the data from the graphic presentation and try to provide an
appropriate explanation and interpretation. The power of any GRAPHIC as opposed to looking '
at a bunch of data is to try to deduce "what does this mean?"

On Thu, May 15, 2025 at 11:44 AM, W0LEV wrote:

Please let us know where you are going with this

Dave, I think Alan is pointing out that I'm using port 1 data for a component measured between the two ports. True, but I'm just using the data to exercise my program, not to draw conclusions about the part.

As long as we're chasing anomalies, here's a good one. It's an MA magnitude/angle file where the VNA botched a point near 180 deg. I'm guessing it was attempting some sort of averaging and wound up with an angle of -1.3 deg when it should be near 180 (or -180). The bad point is in the middle of the data listing.

Brian

Please let us know where you are going with this:

QUOTE: s11 measure in series mode between the channels.

S11 and S22 are reflection measurements.

Dave - W?LEV

On Thu, May 15, 2025 at 6:17?PM alan victor via groups.io <avictor73=
[email protected]> wrote:

s11 measure in series mode between the channels.

--

*Dave - W?LEV*


--
Dave - W?LEV

Hi Roger

Thanks , I re do the measure of my 25m of RG213 at 100Mhz (Span 5Mhz ) by this cicle methode see illustration below with graphical renormalized Z0 to center impedances circle around center smith shart.
73's Nizar

On Thu, May 15, 2025 at 11:17 AM, alan victor wrote:

s11 measure in series mode between the channels.

Does this explain the trace gap? I assume that's what you're referring to.

Brian

s11 measure in series mode between the channels.

Those interested in more detail on my last post will find this article informative. The graphs at the end show what should be expected when making measurements of characteristic impedance of coaxial cables.

Nizar,
What I pointed out in my previous post is that your characteristic impedance measurements were not in accordance with well defined transmission theory.

Your results showed a rise in characteristic impedance and then considerable rolloff especially near 100 MHz. What should be observed is a slow decrease which flattens out at VHF. This can be seen in the graphic I posted.

After a few MHz the equation is Zc = SQRT (L/C) where L and C are the inductance and capacitance per unit length respectively. C can be considered constant with frequency while L decreases with frequency. L consists of internal and external inductance. The skin effect and the fact that internal inductance of the inner conductor decrease to zero at high frequencies are the prime reasons for this.

Yes, they can be pretty good for testing at HF if properly chosen and
measured. That's exactly what I do to "quailfy" potentiometers for use at
HF frequencies. It works!

Dave - W?LEV

On Thu, May 15, 2025 at 4:48?PM Team-SIM SIM-Mode via groups.io <sim31_team=
[email protected]> wrote:

Hi Dave

To be Honest , this is graphical results of my used potentiometre
illustrated with NanoVNA attached screenshoots : +j3 Ohm max at 30Mhz

73's Nizar .

--

*Dave - W?LEV*


--
Dave - W?LEV

Hi Dave

To be Honest , this is graphical results of my used potentiometre illustrated with NanoVNA attached screenshoots : +j3 Ohm max at 30Mhz

73's Nizar .

Any potentiometer used in the process can easily be verified to be
non-inductive using the VNA. That's how I choose the proper potentiometer.

Dave - W?LEV

On Thu, May 15, 2025 at 4:34?AM Team-SIM SIM-Mode via groups.io <sim31_team=
[email protected]> wrote:

Hi Roger

Thanks, its not assumed that test terminaison resistor should be a pure
real resistive value nor an accurate Zc muched impedance but just to be
approximatly reduced to a relatively focused and small circle of
impedances , what we measure in final is the circle center graphically
value with help of graphical renormalisation option added by DiSlord
without using Marker or cursur numerical displayed values over the desired
freq band , circle impedances has obviosly reactive impedances values but
turning graphically around the good center value to take on the end.

Hi Dave , Thanks , i have no offensive to mathematical approches, just i
prefer that mathematical threads can be taken by firmware as possible ( as
Dislord try to do) to facilitate nanovna use simply graphically especially
on using magical circles of Smith plots .

73s Nizar

--

*Dave - W?LEV*


--
Dave - W?LEV

This is a s21 measure with DUT in series with the channels.
At DC low freq begins at 50 then goes anti resonant and above that
an array of parasitic responses.

Hi Dave

Here My graphical illustrations of :

1) a 50 Ohm resistor thru a 1/1 balun Zc = 62 Ohm : real & X values change just a bit cross the 30Mhz band.

2) Same 50 Ohm resistor thru a 1/1 balun Zc=142 Ohm: real & X values change a lot cross the 30Mhz band , we need to adjust again the antenna to have a good SWR over the bands .

Both have a 50 Ohm pure resistor at Low frequency's .

That what I mean by impédances changes with this below illustrated graphical data's , John have the good question , did we really need a mutched CRC impedance to the system ?
My hunble response : Yess it's prefered to have a muched CRC impedance , otherwise we may need to retouch the antenna dimensions to tune again the overall system .

73's Nizar .

Here are the images.

Brian

Here's another issue revealed by trace dots. The data is for a Johanson 390 nH inductor. Note the trace gap at about 7 o'clock. The frequency steps are uniformly 1 MHz so the gap is not due to a frequency jump. Something changed dramatically in the VNA as the frequency crossed 7500 MHz. I wonder which side of the gap is correct. Or is either? If the application was important, I would trust any part of this data.

I had looked at this file several times with a normal trace, as shown in the second image, and I never noticed the flat spot that shows up as a gap with dots.

Brian

Hi Roger

Thanks, its not assumed that test terminaison resistor should be a pure real resistive value nor an accurate Zc muched impedance but just to be approximatly reduced to a relatively focused and small circle of impedances , what we measure in final is the circle center graphically value with help of graphical renormalisation option added by DiSlord without using Marker or cursur numerical displayed values over the desired freq band , circle impedances has obviosly reactive impedances values but turning graphically around the good center value to take on the end.

Hi Dave , Thanks , i have no offensive to mathematical approches, just i prefer that mathematical threads can be taken by firmware as possible ( as Dislord try to do) to facilitate nanovna use simply graphically especially on using magical circles of Smith plots .

73s Nizar

Another suggestion: Make the chart so that the outer boundary circle is say 1.5:1 or 2:1. I have a chart that is either 1.5:1 or 2:1 somewhere in my clutter.