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Hi
This is my point of view : Z--> option does not change the physically pot2 impedance , it remaine always at 50 Ohm +/- 1 ohm value, just firmware by computing way can display S11 or S21 as its at 75 ohm or 300 ohm , for example seting it at the accurate physically port2 50.45 ohm will gives more accurate S11 S21 displayed results , but if DUT does not run smoothly on physically 50 Ohm load , computing compensation will loos sens , so its rather to have the two Z port option one for port1 and second for port2 .
73s Nizar.

If your nanovna-H is an MS version (rather than older SI version - see label on back for hardware revision number) - then you need to go into 'expert settings' and change the 'mode' to 'MS5351', then do 'save config'.
See if that is the problem.
Stan KC7XE

After calibrating after upgrading to new firmware NanoVNA-H.v1.2.40.dfu from dsilord, the nano vna is showing what seems to be crazy flickering SWR values even after recalibrating and trying to find any setup that needs to be repeated.

Is this a known thing? Is it indicative that my device, labelled Nano-VNA-H and running a slightly earlier DSILord 1.2.x (1.2.30 I think) should go back to 1.2.30?

Warren VA7 WPX

At one time there were specific binaries which set that flag (but otherwise identical) Not sure if they still exist or not, since it's so easy to set.

- Tim

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Absolutely....thanks Tim. Somehow I missed your post.

One thing Ill have to remember now is that a reset will revert it back to SI...even if I save the config.

Fred, Yes, the sma connectors are weak sauce. They are always my first suspect. My next one may have N type...but adapters may cost more than the nanovna. hi hi.

On Sun, Feb 9, 2025 at 11:18 AM, Stan Dye wrote:

Please see the detailed steps I provided for getting the correct driver
installed in the .pdf file at the following link. This is in the files section
of this group. Let me know if it doesn't clearly explain the solution, and
I'll update it:
/g/nanovna-users/files/Miscellaneous/DFU-mode%20Driver%20for%20Win10Win11

Stan KC7XE

I have been using the STM32 Cube Programmer (latest is now 2.19).

Thanks so much for the docs and driver so I can now switch back and forth. I'm so used to the STM32 way but it's nice to be able to use the NanoVNA-App as well.

Thanks for the shout out, and glad that I could help!

- Tim

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.

On Sun, Feb 9, 2025 at 02:04 PM, John Gord wrote:

A crystal (or ceramic) filter response is correctly transformed by the
renormalization; I have used this feature several times.

Interesting... What was the design impedance of the filter?

I am surprised at your results because the loading greatly affects the crystal filter characteristics. The usual way is to use a series resistance, L pad or transformer on input and output if the crystal filter is designed for a higher impedance and then recalculate the response from the measured results factoring this in. Doing this is not the same as directly connecting a 50 ohms VNA and then doing a S parameter transformation (Port Z function) like the one in the NanoVNA. I am interested in your results so please explain the test setup and your results.

Roger

Roger,
Most filters are passive and linear.
A crystal (or ceramic) filter response is correctly transformed by the renormalization; I have used this feature several times.
I agree that an active circuit might not be stable if presented with 50 ohm loading when designed for another impedance.
The basic idea is that a passive two-port can be fully represented in a number of different ways like Z-parameters, Y-parameters, H-parameters and S-parameters normalized to various impedances. There are formulas to convert from one parameter type to another.

--John Gord

On Sun, Feb 9, 2025 at 11:45 AM, Tony Scaminaci wrote:

Both the link DiSlord provided and your original link work fine for me. It
may be your email provider chopping up the link.

Thanks -- I don't get the emails from this group. I just log into the Web site for groups.io. It may be the way it formats on the Web.

Roger

Hi Stan,

Shortsightedness on my part and I hadn't looked well enough and found your instructions which worked perfectly, thank you ever so much, Pete

Roger,

Both the link DiSlord provided and your original link work fine for me. It
may be your email provider chopping up the link.

Tony

On Sun, Feb 9, 2025 at 12:45?PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

On Sun, Feb 9, 2025 at 10:40 AM, Roger Need wrote:

Unfortunately the link you provided was cutoff and did not work.

Hopefully

groups.io formats this one correctly...

(z)-c.html

Groups.io cutoff my link as well. Here is another attempt...


Roger

On Sun, Feb 9, 2025 at 10:34 AM, Bryan Curl wrote:

Roger,
Resolved: You nailed the issue. I thought for sure I was an SI type but sure
enough the HW version is 4.3_MS. The flash changed it to SI.

Bryan - The first one to suggest this was Tim Dawson so he gets the credit not me...

Roger

Just a crazy thought from someone with very little VNA experience .....
SMA connectors are known to have a quite limited number of insertion cycles.
Is it possible you have a connector that is no longer working reliably;y?

Pete, you are having a driver problem. Windows11 has the most recent driver from ST, so it thinks it is the best one to use, and doesn't try to install the older driver that works with DfuseDemo and nanovna-app. (This driver does work with the latest STMCubeProgrammer from st.com.)

Please see the detailed steps I provided for getting the correct driver installed in the .pdf file at the following link. This is in the files section of this group. Let me know if it doesn't clearly explain the solution, and I'll update it:
/g/nanovna-users/files/Miscellaneous/DFU-mode%20Driver%20for%20Win10Win11

Stan KC7XE

For the HR'ers in the group, the H4 seems most popular. But get the LARGE
SCREEN choice of any of them.

Dave - W?LEV

<>
Virus-free.www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Sun, Feb 9, 2025 at 2:20?PM CLIFTON HEAD via groups.io <aecret=
[email protected]> wrote:

For a newie using wanting to use NanoVNA which is better the NanoVNA F V2
or the H4

--

*Dave - W?LEV*


--
Dave - W?LEV

On Sun, Feb 9, 2025 at 10:40 AM, Roger Need wrote:

Unfortunately the link you provided was cutoff and did not work. Hopefully
groups.io formats this one correctly...

(z)-c.html

Groups.io cutoff my link as well. Here is another attempt...


Roger

On Sun, Feb 9, 2025 at 01:23 AM, DiSlord wrote:

Here is renormalization in coppermountaintech
Analysis > Fixture Simulator > Port Z Conversion
(z)-c.html

Unfortunately the link you provided was cutoff and did not work. Hopefully groups.io formats this one correctly...

(z)-c.html

Copper mountain Provides for several Fixture Simulations. Here is the link to the topic.


The current Port Z function in the NanoVNA changes the reference impedance using only the real part with imaginary set to zero.. The measurement is still made using 50 ohms on Port 1 (CH0) and Port 2 (CH1) and a mathematical conversion of the matrix of S-parameters measured at 50 ohms to the matrix of S-parameters with a reference impedance entered by the user is generated. In my opinion there is a limitation to this method in that the DUT is being driven and loaded by 50 ohms and that only linear passive devices will yield correct results. Non linear devices or active circuits will not be tested with the impedance they are designed to operate with and simulation using this method will not yield correct results. So a 300 ohm resistive attenuator would measure OK but a crystal filter circuit that was not designed to work in a 50 ohm system would not.

Roger

Roger,
Resolved: You nailed the issue. I thought for sure I was an SI type but sure enough the HW version is 4.3_MS. The flash changed it to SI.

The unit will now calibrate with a stimulus of 50khz to 1.5G with no issues.

Thanks for all the help guys.

Bryan, N0LUF

On my older firmware, the menu selection is config/expert setting
settings/more/mode. The mode setting toggles between Si5351 and MS5351.
This path may be different in 1.2.40.

Tony AC9QY

On Sun, Feb 9, 2025 at 12:18?PM Tony Scaminaci via groups.io <tonyscam=
[email protected]> wrote:

The label on the back does indicate if it’s using the MS5351. Someone (and
I can’t remember whom) mentioned that firmware 1.2.40 included support for
both the Si5351 and MS5351. After flashing, there is a setting in a menu
(can’t remember this either) to select the proper chip. If I can find that
menu setting, I’ll post it.

Tony AC9QY



On Sun, Feb 9, 2025 at 11:58?AM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

On Sun, Feb 9, 2025 at 09:13 AM, Tim Dawson wrote:

I have lost your initial message, but if this is an -H4, isnthe MS/SI

option

ser correctly?

That can change when flashing.

Yes that setting is important. IF the OP bought his H4 a few years ago

it

is the SI version. I thought the label on the back indicated if it was

an

MS version It is easy enough to try both settings and see if one works
better than the other.

The other issue is that some of the chips will not operate up to 300 MHz.
You can change the upper limit by going into Config-Expert Settings and
changing the limit under Threshold.

Roger