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On Mon, Feb 22, 2021 at 08:46 AM, Zack Widup wrote:

I have a general question. What is the deal with the # symbols in the
subject line, in this case, "#features #nanovna-saver"? Is it some kind of
a secret code?

It's called a hashtag. A trendy, modern thing. I have not found a use for it.

--
Doug, K8RFT

On Mon, Feb 22, 2021 at 05:24 PM, Manfred Mornhinweg wrote:

NanoVNA-H in DFU mode, connected it, but NanoVNA-App doesn't see it.

As I remember doing it, NanoVNA-App does not use Dfuse mode. Try using NanoVNA-App without running Dfuse.
Just use the NanoVNA-App by itself. Run the app (with the correct port settings) to connect to the device, and Click the "double up arrows" icon - it has the tooltip "upload vna firmware".

--
Doug, K8RFT

What "same" problem?

Great Thread .... starting to understand this stuff ....:)

--
Cheers,
Ian
Melbourne, Australia

Does DfuSE find it when it shows up as STM32 BOOTLOADER? - If so it's only a matter of selecting the firmware file with choose, then clicking upgrade. I don't see that as any less friendlier :)

Mike,

Personally, I always use NanoVNA-App for firmware updates, rather than
DfuSE... much friendlier.

Could you perhaps help me in this? I was told to update the firmware in mine, but today I tried for about three hours and had no success. For some reason the driver doesn't seem to work. I downloaded the driver from the ST website as instructed in the user manual, installed it, it told me that all is fine, then I put my NanoVNA-H in DFU mode, connected it, but NanoVNA-App doesn't see it.

Checking in the Windows Device Manager, the NanoVNA shows up as "STM32 BOOTLOADER", with no driver installed.

I removed and reinstalled the ST driver, same result.

I saw that NanoVNA-App comes with a Zadig driver, I tried to run that one, but it tells me that it's not a valid Win32 application.

So, how is this done? Which is the correct driver to update the firmware from NanoVNA-App in Windows XP 32 bit?

The ST driver is claimed to be compatible with Windows XP, but maybe NanoVNA-App doesn't work with it?

Manfred

On Fri, Feb 19, 2021 at 12:44 AM, Adnan Yousaf wrote:

I want to use NanoVNASaver for continuously reading and storing S1.p data i.e.
automating my experiments for long duration tests (few hours). Since there is
no LabVIEW tool available for NanoVNA, I tried to use the Saver version v0.3.8
but with no success.
Would be great if someone has already a tip or solution in this context.

There is a Labview package for the NanoVNA V2+ and V2+4 written by joeqsmith. It is discussed on the eevblog at the link below which is the most recent discussion. He originally did not release this software because he did not want to offer user support. He has kindly released it and a manual BUT do not ask him for support. You can read his posts and the user manual and figure it out yourself.

eevblog link -
manual link -
software download - multiple zip files -

I have not used this software so I can't provide any more info. You will have to modify it to record the files but if you are a Labview user that should not be much trouble.

Good luck - Roger

This post is about measuring low resistances using the S11 method and testing the ESR of capacitors. It is surprising how well the NanoVNA can measure resistances that are much higher or lower than the system impedance of 50 ohms using the S11 method to calculate complex impedance R+/-jX.

For this test I used a SMA connector test jig, like the one I posted earlier, to measure a 1 ohm 0805 SMD resistor. The resistance of the part (soldered to a pin header) was first measured using a 4 wire Kelvin resistance meter at the following frequencies: DC - .990 ohms and at 100 kHz. - .995 ohms. Then it was connected to the SMA test jig. The sweep was from 10 kHz to 1 MHz. and there was excellent agreement with the Kelvin measurement. The graph is attached below.

The measurement of low resistance is something we are interested in when testing electrolytic capacitors. The equivalent series resistance ESR is an important parameter when using electrostatics in power supply filtering and in certain bypass applications. It is desirable to have a low value of ESR and a high ESR is one of the ways that an electrolytic can be checked for failure or selected for use in a circuit. Electrolytic capacitor manufacturers rate these components at a low frequency with 100 Hz. and 120 Hz. being the most common. The NanoVNA does not measure that low but recent firmware has been developed that goes down to 10 kHz. or lower.

A 10uF 50 V electrolytic from my parts bin was selected for this test. It's characteristics were first measured on a DE-5000 LCR meter. Note how capacitance and ESR both decrease with frequency.

100 Hz. 10.2 uF ESR of 6.5 ohms
1 kHz. 9.5 uF ESR of 2.0 ohms
10 kHz. 8.7 uF ESR of 1.3 ohms
100 kHz. 6.5 uF ESR of 1.2 ohms

The capacitor had 1" (2.5 cm) leads that were inserted into the pin header of the SMA test jig at the reference plane.

The results were very close to those obtained with the LCR meter (which is optimized for low frequency operation). Graphs are posted below. The rising "apparent capacitance" in the graph is due to the 1" lead inductance increasingly affecting the value of reactance measured as the frequency increases. This can clearly be seen in a test I did some time ago on a small 10 pf capacitor that was measured with long leads which were then shortened for comparison.

I hope this post has illustrated how a NanoVNA can be used to accurately measure capacitors if a decent test jig is used.

Roger

You started a new thread so it is not clear what the
"same problem" is.

I’m having exactly the same problem and this only started following the latest update V 1.0.45

I enjoyed the discussion and thank the contributors. Think about how load impedance was measured in the "old days".
The slotted line technique was used in practice before the Smith Chart was invented. Now, as an RF engineer, I am not old enough to have first hand experience in having to perform these measurements as a matter of course professionally, but my "Microwaves 401" professor worked with Phil Smith back in the day.
There were no calculators or other modern conveniences and things were done manually or with a slide rule. These were tedious computations. Load impedances were often measured with a slotted line to give the reflection coefficient and the Zload was calculated from that. Accordingly, Phil thought that it would be a great idea to have a graphical aid to map the Zload onto the reflection coefficient so one could read Zload from the chart and the Smith Chart was developed.
A few resources in print or on the Web that tell how this was done may shed some light on the subject for better understanding.

Two more sources are;
Pozar, Microwave Engineering, pp70
and see: by Ahmed M. Attiya

I made a short 2 page note on how this was (probably) done and include it here as an attachment along with the Excel spreadsheet to do the math. There are two tabs in the spreadsheet. One simply calculates the Zload from a given Reflection Coefficient and the other starts with the Slotted Line measurements and goes through the calculation of the reflection coefficient then the Zload. The example follows the numbers used in the Pozar book and the Youtube video.

FWIW, I hope somebody might see this stuff as useful to help understand the subject. We are all lucky to have such a versatile tool as the NanoVNA !

I have a general question. What is the deal with the # symbols in the
subject line, in this case, "#features #nanovna-saver"? Is it some kind of
a secret code?

73, Zack W9SZ

On Fri, Feb 19, 2021 at 2:44 AM Adnan Yousaf <adnan.yousaf@...> wrote:

Dear All,
I want to use NanoVNASaver for continuously reading and storing S1.p data
i.e. automating my experiments for long duration tests (few hours). Since
there is no LabVIEW tool available for NanoVNA, I tried to use the Saver
version v0.3.8 but with no success.
Would be great if someone has already a tip or solution in this context.

Best Regards
Adnan

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

@mirskym thank you for you thoughtful response. I will give it a try and let everyone know the results. 73 de W6MGV Coxsackie, NY, USA

Bundle of thanks for your reply.

The NanVNA app seems to work for continuous recording (s2p along with s1p) up to 1 GHz, however I am using NanoVNA v2 and the measurement frequency of interest is between 2-2.5 GHz. Is there any other similar app available for the aforementioned frequency range?


Best Regards
Adnan

I had the same problem. This guide helps you through it. /g/nanovna-users/files/Absolute%20Beginner%20Guide%20to%20The%20NanoVNA

Good article. The author Steve Sandler is a well known industry authority on low impedance measurements.

The 2-port shunt measurement method is akin to 4-terminal ohmmeter measurements of very low resistances.

Ray
WB6TPU

The proper driver should be downloadable from here:

Now that we’re talking about measuring low impedances, I thought I would share this nice link on the 2 port shunt through configuration.



Regards,

--
VE6WGM

Had a similar problem.

You need to install the driver for the defuse demo program so that communications can be established between the program and the nanovna.

This driver is DIFFERENT from the one used to establish communications between the nanovna and various display programs like nanovna-saver and other similar ones.

The needed driver can be downloaded from the STM website where the dfuse demo program came from.

Ray
WB6TPU

For me, this is not helpful. The device is populated correctly and without fault, in the Device Manager USB Devices folder as STM32 BOOTLOADER... the device does not appear in the Defuse Demo dropdown list; the list is blank.

Any recommendations will be warmly received.