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I was only able to find on the UK ebay the COILCRAFT TTWB1015
0,07MHz-225MHz Wideband RF Transformer 1 : 1.5
(

)
Which I bought.
I would have liked to buy the 2010 (or -B) versions (to have the 1:1 while
the secondary winding has a centre tap).. -Or 3010 (or -C).
But so be it, I hope I can rewind the 1015 easily...

All the best,

Victor

Op vr 22 jul. 2022 om 15:14 schreef Miro, N9LR via groups.io <m_kisacanin=
[email protected]>:

My "formula" are used to perform calculations in Excel; for example, to calculate 'L' adapters. The algebraic form is easier to copy, especially when you have to pay attention to cells with $.

The "mathematical" calculation is done only once to establish the cooking recipe.

I find that the use of Greek letters complicates the pedagogy a lot. Many don't even know how to vocalize the letter, making it difficult to read line online. When to use them on this forum it's a hassle.

I was disappointed that Excel did not know how to draw a sequence of complex numbers (a+jb) in the form of a graph. It is necessary to break down the real part into the imaginary part. So I don't use these functions.

Good day to all
73
--
F1AMM (Fran?ois)

Hi Francois,

Your development to conclusion appears correct.

To be sure use some test values to check it.

You might find an alternative approach less mathematically demanding:

Addition and subtraction of complex numbers are very easy to perform in rectangular form, whilst multiplication and division are easy to perform in polar form.



So first calculate the top line of the equation in rectangular form, then the bottom line of the equation in the same way.

Next, convert both to polar form and perform the division.

Finaly, if required convert polar to rectangular.

Hope that helps

Ed, G8FAX

And S11 (vector) is indeed identical to Gamma (vector), or S11 and the Reflection Coefficient
are one and the same.

Hello

** I agree gamma=S11 **

In effect

If we use Z = Zo * (1+gamma) / (1-gamma) that means:
Zo + Zo.gamma = Z - Z.gamma
gamma.(Zo+Z) = Z - Zo
gamma = (Z-Zo)/(Z+Zo)

But the question was how to calculate S11 from the impedances and you didn't explain how you calculated gamma if Z=A+jB

Your formulation gamma = (Z-Zo)/(Z+Zo) misled me and stupidly I thought it meant
gamma (A-Zo)/(A+Zo) + j (B-Zo)/(B-Zo)

To answer the question, if the impedance is Z=A+jB it is necessary to continue the development of gamma = (Z-Zo)/(Z+Zo) and that gives:

gamma = (A?+B?-Zo?+2jBZo) / ((A+Zo)?+B?)

Is this correct ?

It is indeed a pity that nanovna-saver only indicates |S11| on the screen. You have to go to the .S1P file to find
S11 = a+jb
a and b are then the coordinates of the point representing the impedance in the Smith diagram (xOy mark centered on the chart with the unit corresponding to the large outer circle).
x=a and y=b

Is this correct ?

Sorry to have contradicted you by mistake but, in addition, my language is French and I have to make BIG efforts to write in English (thanks Google). I am not a teacher but an old OM who tries to find his way between what he measures (with his nanoVNA-F + nanovna-saver), what he calculates as an adapter for example, what he realizes practically and the observed results (measurements).
--
F1AMM (Fran?ois)

-----Message d'origine-----

De la part de AG6CX (Edward San Francisco)
lundi 25 juillet 2022 00:58

Re comment:

“But S11 is not the equivalent of gama.“

Indeed Gamma (a vector) is calculated by the quotient of (Zload-Zo)/(Zload+Zo)
with Zload and Zo both complex numbers.

The result Gamma of this complex division may be expressed in Cartesian form
Gamma= a + jb.

Gamma is easily converted to polar form where Gamma = rho angle Theta, where Theta = arctan(b/a)

rho is the SQRT of a*a + b*b

Magnitude of Gamma or IGammaI = rho

And S11 (vector) is indeed identical to Gamma (vector), or S11 and the Reflection Coefficient are one and the same.

Refer to RF Formulas One Port Systems by Olivier Pilloud HB9CEM 2005-06-28

At pilloud.net/op_web/one_port.pdf

Ed McCann
AG6CX

For Z2S and S2Z for S11 and S21 I made this one up.

It might help a bit.




73

Arie

Two years ago I have built the enclosed spreadsheet in ODS format (Libre Office) for education purpose. Maybe it can helpful, and also be easily modified or adapted. Blue fields are input ones. The main interest is that it follows the label names used for the NanoVNA.

As an example I have fed it on line 5 (cells I5 and J5) with the previous results from Jim Lux. These are reverse calculations, and final results are highlighted in E5 and F5 cells, and it perfectly matches !

F6EGK Jean-Roger

On Sat, Jul 23, 2022 at 03:57 PM, Jim Lux wrote:

in Excel, IMARGUMENT returns the angle (in radians), IMABS is the magnitude

Thanks Jim, I had forgotten about those converter functions.

Anyone not familiar with Excel functions, "DEGREES" converts radians to degrees..

Kind regards

Ed, G8FAX

I think I found where the error is.

You wrote : ? The S1P files contains the real and imaginary parts of the reflection coefficient, Greek letter ‘gamma’. ?

But S11 is not the equivalent of gama.

We did everything to complicate this matter of reflection coefficient starting with the identifier:

- Either with the Greek letter gamma when it has a complex value like A+jB
- Either with the Greek letter rho ρ when using the module

We will use a synonymous identifier: S11 which comes from the S parameters of a quadripole. It should say "S one one" but "S eleven" is common. We will not dwell on the parameters S which find their origin in the matrix calculation. The interest of this synonym is that:
? If we talk about the complex value we write S11
? If we talk about the module we write |S11| remembering that :
? nanovna-saver displays this parameter |S11|
? nanovna-saver saves S11

It is in fact the reduced coefficient because we will retain as definition
If Z = A + jB

Then

z = Z/Zc = A/Zc + j B/Zc

in most cases Zc = 50

S11 = (z-1)/(z+1)

To complicate everything, we invented the ROS (which some unfortunately still call the TOS, as in the bottom of many Smith charts) while it is almost impossible to know this relationship between the maximum and minimum voltage generated by a standing wave

ROS = (1 + |S11|) / (1-|S11|)
And
|S11| = (ROS-1)/(ROS+1)

In everyday life: VSWR = SWR = ROS so we avoid talking about TOS, it's simpler

--
F1AMM Fran?ois

On 7/23/22 8:07 PM, F1AMM wrote:

The complex impedance Z is given by Zo * (1+gamma) / (1-gamma)

Please can you explain me where is my mistake; I am like Saint Thomas.
Here is the digital test data (my antenna)
S11 = -0,310484238 +j 0,011489099
Zo = 50
With the formula
Z = Zo * (1+gamma) / (1-gamma)
it gives
Z = 95,02931686 + j 48,86414014
With my formula, it gives
Z = 26,3018063 +j 0,66894279
and this is what nanovna-saver displays
I must still have missed something :(
73

I get the same answer you do 26.4+j 0.669
using Excel

S11 -0.31048 0.011489
complex -0.31048+0.011489i
1+S11 0.68952+0.011489i
1-S11 1.31048-0.011489i
divide 0.526041061787863+0.0133788274211592i
*50 26.30205309 0.668941371

The complex impedance Z is given by Zo * (1+gamma) / (1-gamma)

Please can you explain me where is my mistake; I am like Saint Thomas.

Here is the digital test data (my antenna)
S11 = -0,310484238 +j 0,011489099
Zo = 50

With the formula
Z = Zo * (1+gamma) / (1-gamma)
it gives
Z = 95,02931686 + j 48,86414014

With my formula, it gives
Z = 26,3018063 +j 0,66894279
and this is what nanovna-saver displays

I must still have missed something :(

73
--
F1AMM Fran?ois

-----Message d'origine-----

De la part de Jim Lux
dimanche 24 juillet 2022 00:58

On 7/23/22 8:41 AM, Ed G8FAX wrote:

The S1P files contains the real and imaginary parts of the reflection coefficient, Greek letter ‘gamma’.
The complex impedance Z is given by Zo * (1+gamma) / (1-gamma)

Excel has the capability of working and manipulating complex numbers, so the spreadsheet formulae can be simplified and use directly the values from the S1P file.

I believe complex number feature also exists in LibreOffice.
To obtain the impedance magnitude after this requires conversion to polar form.

ATAN2 is a useful function to use.

in Excel, IMARGUMENT returns the angle (in radians), IMABS is the magnitude

I can do the math.... I taught electronics including L - R- C circuits and conversions for 17 years. I was just looking for a quick way to find them on the Nano. And |Z| was my main interest.

Although I must say, the equations shown in the pdf look nothing like what I taught.... Mine was simply going back and forth between R +jX and Z Θ, normally using Pythagoras and trig functions.

I fired up a laptop with NanoVNA Saver and was able to get what I needed.

Thanks to all.

The S1P files contains the real and imaginary parts of the reflection coefficient, Greek letter ‘gamma’.

The complex impedance Z is given by Zo * (1+gamma) / (1-gamma)



Excel has the capability of working and manipulating complex numbers, so the spreadsheet formulae can be simplified and use directly the values from the S1P file.



I believe complex number feature also exists in LibreOffice.

To obtain the impedance magnitude after this requires conversion to polar form.



ATAN2 is a useful function to use.




Kind regards

Ed, G8FAX

On 7/22/22 10:50 PM, F1AMM wrote:

Admitting that it is of interest to examine the phase of the impedance, it is indeed necessary to start from the Touchstone S11 file (.s1p). It is an ASCII file where you find, on each line: the frequency, the real of the S11 then the imaginary of the S11. in the first line there is the standardization impedance (50 Ohms in general)
If you are interested, I have restored the "formulas" allowing you to recalculate the A+jB of the load from S11. It's not trivial even if it's quite simple if we start from the right bases. I do this in Excel.
I don't know how to pass this type of information on the forum.

You could just post a sample excel file.. (of maybe the first 10 lines of a S1P). That's what I've done.

Interesting discussion. I used to work for HP. Later sold Cascade probe stations. Calibration was always "difficult". Especially on wafer: how far do you overdrive (i.e. press the probe down), how many times has that standard been used, etc etc.

Seems to me we're expecting a bit too much from the nanovna. As someone already posted, its not a lab grade instrument. To me its a "how close am I" kind of tool. If I REALLY care I will use a better tool (I am fortunate enough to have an 8753).

Ron
N4XD

Hi Wayne,

Mark at QSL Communications sells several VNAs including the Hugen NanoVNA-H and the Deepelec NanoVNA-F (now DeepVNA-101).

This is the VNA page
Do your homework on overseas vendors.

Cheers...Bob VK2ZRE

I don't know how to pass this type of information on the forum.

Maybe it works with just the attached document.

The original document, more readable, is a .docx in French
--
Fran?ois

I've written a Windows utility that checks Touchstone files for |S11| > 1. It handles version
1.1 files, the kind NanoVNAs generate, as well as version 2.0. It lists maximum |S11| and the
number of frequencies where |S11| > 1. This utility may come in handy if you experience odd
problems processing NanoVNA data as I did.

Thanks a lot.

README.TXT is only for GND.EXE

Do you have help files for AVG.EXE and S11.EXE?
--
F1AMM Fran?ois

-----Message d'origine-----

De la part de Brian Beezley
Envoyé : samedi 23 juillet 2022 02:12

Admitting that it is of interest to examine the phase of the impedance, it is indeed necessary to start from the Touchstone S11 file (.s1p). It is an ASCII file where you find, on each line: the frequency, the real of the S11 then the imaginary of the S11. in the first line there is the standardization impedance (50 Ohms in general)

If you are interested, I have restored the "formulas" allowing you to recalculate the A+jB of the load from S11. It's not trivial even if it's quite simple if we start from the right bases. I do this in Excel.

I don't know how to pass this type of information on the forum.
--
F1AMM Fran?ois