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Hi

I am a little confused, my 1/1 balun done with FT140-43 2x10 turns with 1mm wire as illustrated by photo attached, i want to measure losses by S21 Logmag function after a good thru calibration, with renormalizing the coax Zc impedance from 50 Ohm to 78.5 Ohm it gives me the double of losses with 78.5 Ohm coax compared to 50 Ohm coax Z, i can not explaine this ? why ? see S21 responses attached , knowing that i measured the caracteristic impedance of the balun it is around 62 Ohm as showen by graphic attached here , any help ?

H4 + 1.2.40
73's Nizar

Please compare at the same frequency. Your 50-ohm (actually 52-ohm)
measurement is at 27.7 MHz. Your 72-ohm measurement is at 14.2 MHz.
Please repeat at the same frequency and get back with us.

Dave - W?LEV

On Sun, May 11, 2025 at 4:47?PM Team-SIM SIM-Mode via groups.io <sim31_team=
[email protected]> wrote:

Hi

I am a little confused, my 1/1 balun done with FT140-43 2x10 turns with
1mm wire as illustrated by photo attached, i want to measure losses by S21
Logmag function after a good thru calibration, with renormalizing the coax
Zc impedance from 50 Ohm to 78.5 Ohm it gives me the double of losses with
78.5 Ohm coax compared to 50 Ohm coax Z, i can not explaine this ? why ?
see S21 responses attached , knowing that i measured the caracteristic
impedance of the balun it is around 62 Ohm as showen by graphic attached
here , any help ?

H4 + 1.2.40
73's Nizar

--

*Dave - W?LEV*


--
Dave - W?LEV

Hi Dave
Thanks
Pse take a look to the graphic curve , the losses difference is huge over all the band from 50Khz to 30Mhz , marker value not so important here .
73's Nizar

Hi All

i tryed to change the balun designe with the same FT140-43 but with 1X12 turns this time , I measure the charateristic impedance of the balun is around 142 Ohm ( see Smith shart focused on the graph center) , but this time with 78.5 Ohm renormalized coax impedance it gives the half with 50 Ohm normal coax , huge diffrence around 1db at 30Mhz , in add this new balun seems have much more losses -2.5 db compared to the first one -0.2db , why ?? what is not correct with this second balun , see illustration below .
73's Nizar .

Instead of reading where the plot intersects, read the numbers at the top
of the screen which is where your cursor is placed. You have:

-0.774 dB loss at 54.6 + j 35.2 ohms equivalent of 64 ohms for the
total impedance
-0 440 dB loss at 80.7 + j 24.8 ohms equivalent of 84 ohms for the
total impedance

The total impedance is derived by calculating the SQRT of the SUM of the
SQUARES.

Note that using the reflection measurement option as illustrated in the
first image, the total loss is 0.5 of the measured value as the RF must
pass twice through the network. The ratios above don't change.

So the loss at nominally 54 ohms real is 0.167 dB greater at 81 ohms real.

Also note that due to the non 50-ohm or non 72-ohm Zo of the transmission
line transformer (common mode choke), the Zo of the choke will transform
either resistance to something else between 50 and 80-ohms.

What you are using for your 50 and 72 ohm non-reactive loads for the load
in your common mode choke - the disc in the first picture?

How did you measure the impedance of our common mode choke? I usually take
two measurements to determine this:

1) Measure the capacitance with the far end of the choke open terminated.
This will give you the capacitance of the windings (pretty close).

2) Measure the inductance with the far end of the choke short terminated.
this will give you the inductance of the windings (pretty close).

Measure both of these using the Smith Chart and the cursor.

Then calculate the characteristic impedance of the transmission line choke
(common mode choke) using the following:

Zo = SQRT [Measured Inductance in Henries / Measured Capacitance in Farads]

NOTE: 1 ?H = 1E-6 H and 1 pF = 1E-12 F

Dave - W?LEV



both the

On Sun, May 11, 2025 at 6:03?PM Team-SIM SIM-Mode via groups.io <sim31_team=
[email protected]> wrote:

Hi All

i tryed to change the balun designe with the same FT140-43 but with 1X12
turns this time , I measure the charateristic impedance of the balun is
around 142 Ohm ( see Smith shart focused on the graph center) , but this
time with 78.5 Ohm renormalized coax impedance it gives the half with 50
Ohm normal coax , huge diffrence around 1db at 30Mhz , in add this new
balun seems have much more losses -2.5 db compared to the first one
-0.2db , why ?? what is not correct with this second balun , see
illustration below .
73's Nizar .

--

*Dave - W?LEV*


--
Dave - W?LEV

Hi Dave

Thanks
I do not use any external artifact to take S21 Losses measurements with equivalent 78.5 Ohm coax Z0 , i just use the DiSlord Z0 renormalisation option on Display menu, this option take on consideration all computing's needed to acte as a real 78.5 Ohm NanoVNA .

For measuring characteristic impedance of my Balun i use My owne purely experimental methode , no computing nor modeling just measuring the resistor value that focused the Smith diagram on one dote (resistor trimmer termination) and read the renormalized impedance value that make it exactly on the center of the the shart, it's easy methode, reliable and accurate enougth without any computing errors and estimation, only direct experimental measurement , see screenshoot illustration.

73's Nizar

Hi Dave

as asked here below the attached new measurements with renormalized Z0 coax 78.5 Ohm and 50 Ohm ( first balun Zc= 62 Ohm) , cursor at the same frequency 14.125Mhz .

73's Nizar .

Nizar,
The renormalization makes some assumptions that may not apply to your balun, in particular that S11=S22.
This is often close to true for things like ceramic filters, but is probably not close for your balun.
--John Gord

Hi Jhon

In fact I redo the measurement of the characteristic impedance of the first balun with more care of bad contactes, i measure Zc=60 Ohm see screenshoot below , wich gives SWR = 1.2 with 50 Ohm coax and 1.3 with 78.5 Ohm Coax wich explaine the more losses with 78.5 Ohm renormalized coax , I think the renormalized impedance function on Dislord firmware + H4 is accuracy enought here to give a correct results , we assume here that coax has 78.5 Ohm and antenna has also 78.5 Ohm S11 = S21 , No problem right now about firmware modeling , butit will be appreciated if we can renormalise also the port2 impedance independly of port1 one on the future firmwares: it will be really wonderfull .

One important conclusion : if we want to fully optimize out ferrit balun we should measure it's characteristic impedance with a resistor trimmer terminaison and adjust it to much as near as possible the coax characteristic impedance to have less losses , NanoVNA H4 + DiSlord firmware should help a lot .

73's Nizar

Hi Jhon

A graphical X4 zoom option on the future firmware around the center of the Smith shart can help to show more easily the impedance focusing on the center plot of Smith diagram .

73's Nizar

On Tue, May 13, 2025 at 06:42 AM, Team-SIM SIM-Mode wrote:

it will be appreciated if we can renormalise also the port2 impedance independly of port1

Nizar, this program will do that:



Brian

Hi Brian

Thank you , and great work , i am still not familiar to , it seems great and can be developped more , if any youtube video can help us step by step how to use it , it will be very helpfull . I need a real time plotting to adjust in real time the reisistor trimmer terminaison to focus the impedances on one graphical dot as small as possible on smith shart to measure characteristic impedances of coax's or baluns , wondering if your software can download S11 and S12 data's on real time from nanoVNA as Nano-App does ?

Congratulation for your good Work.
73's Nizar .

On Tue, May 13, 2025 at 11:25 AM, Team-SIM SIM-Mode wrote:

wondering if your software can download S11 and S12 data's on real time from
nanoVNA as Nano-App does ?

No. It runs from .s1p or .s2p files only. See splot.txt for details.

Brian

Thanks Brian

Hope it will be a real time plotter one day soon , it's a dream.

73's Nizar

On Tue, May 13, 2025 at 12:37 PM, Team-SIM SIM-Mode wrote:

Hope it will be a real time plotter one day soon

I'm not going to write another NanoVNA-Saver or NanoVNA-App. Someone can incorporate the features they like into those programs if they wish.

Brian

How about a pipe? The sender doesn't even have to be aware of the pipe's
existence.

WIKIPEDIA - Named Pipe (Software)


73 de Andrew/N5ASE

On Tue, May 13, 2025 at 4:37?PM Team-SIM SIM-Mode via groups.io <sim31_team=
[email protected]> wrote:

Thanks Brian

Hope it will be a real time plotter one day soon , it's a dream.

73's Nizar