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Re: NanoVNA port renormalization
Roger,
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Here are screenshots of tests with a ceramic filter and a crystal filter at 10.7 MHz (different spans). Each is shown at 50 ohms and again at a higher Z that gives a better match. Also shown is the test fixture and the filters I tested. There is no matching added to the fixture, just direct connections with coax leads about 3cm long. The small headers on the test fixture are the 50 ohm and short used in calibration. Not shown in the photo is the thru jumper. --John On Sun, Feb 9, 2025 at 02:40 PM, Roger Need wrote:
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Re: Smith Chart acting up in calibration
As a followup on this, I see the chip specific files from Huygen, but not Dislord . . . . fwiw . . .
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- Tim On February 9, 2025 8:41:26 PM EST, Tim Dawson <tadawson@...> wrote:
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. --
Sent from my Android device with K-9 Mail. Please excuse my brevity. |
Re: NanoVNA port renormalization
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. |
Re: After firmware update my nano-vna-h is behaving bizarrely.
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 firmware update my nano-vna-h is behaving bizarrely.
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 |
Re: Smith Chart acting up in calibration
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.
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- Tim On February 9, 2025 8:26:04 PM EST, "Bryan Curl via groups.io" <bc3910@...> wrote:
Absolutely....thanks Tim. Somehow I missed your post. --
Sent from my Android device with K-9 Mail. Please excuse my brevity. |
Re: Smith Chart acting up in calibration
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. |
Re: Nanovna-h and Windows 11
On Sun, Feb 9, 2025 at 11:18 AM, Stan Dye wrote:
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. |
Re: Smith Chart acting up in calibration
Thanks for the shout out, and glad that I could help!
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- Tim On February 9, 2025 2:41:19 PM EST, "Roger Need via groups.io" <sailtamarack@...> wrote:
On Sun, Feb 9, 2025 at 10:34 AM, Bryan Curl wrote:Bryan - The first one to suggest this was Tim Dawson so he gets the credit not me... --
Sent from my Android device with K-9 Mail. Please excuse my brevity. |
Re: NanoVNA port renormalization
On Sun, Feb 9, 2025 at 02:04 PM, John Gord wrote:
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 |
Re: NanoVNA port renormalization
Roger,
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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 10:40 AM, Roger Need wrote:
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Re: NanoVNA port renormalization
On Sun, Feb 9, 2025 at 11:45 AM, Tony Scaminaci wrote:
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 |
Re: NanoVNA port renormalization
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:Hopefully |
Re: Smith Chart acting up in calibration
On Sun, Feb 9, 2025 at 10:34 AM, Bryan Curl wrote:
Bryan - The first one to suggest this was Tim Dawson so he gets the credit not me... Roger |
Re: Nanovna-h and Windows 11
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 |
Re: Types oif NanoVNA
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-- *Dave - W?LEV* -- Dave - W?LEV |
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