I am new to using my NanoVNA V2 Plus 4 fw version 2202301. When measuring a simple 2 pole crystal filter, the display shows the primary peaks the same as my bench test equipment however as you can see in the picture attached, the waveform is not the smooth typical slopes I am used to.

Am I missing a set up parameter or is this the normal waveform I should expect from this unit? I have read on the forum that I can not test single crystals with this unit but I specifically purchased a NanoVNA to simplify testing my crystal filter prototypes.

Was the V2 Plus 4 the wrong one to buy as I find You Tube videos showing the expected filter curves when others measure crystal filters.

Any help would be appreciated.

Thanks, mark

Mark,
The frequency resolution of the V2 Plus4 is stated as being 0.01MHz (10kHz), which is too coarse for your filter.  I don't know if there is a firmware version that can ;provide smaller frequency steps in the low frequency range.
You may get better (but still not very good) results if you crank up the AVG setting.  This gives the filter more time to settle after the relatively large frequency steps.
The original NanoVNA can provide much smaller steps, but is limited to below 1.5GHz or so.  The DiSlord firmware for the original NanoVNA can do individual crystal characterization as well as filter sweeps in the frequency range you are using.
--John Gord

On Sat, Oct 29, 2022 at 09:15 PM, Mark Libner wrote:

>
> I am new to using my NanoVNA V2 Plus 4 fw version 2202301. When measuring
> a simple 2 pole crystal filter, the display shows the primary peaks the
> same as my bench test equipment however as you can see in the picture
> attached, the waveform is not the smooth typical slopes I am used to.
>
> Am I missing a set up parameter or is this the normal waveform I should
> expect from this unit? I have read on the forum that I can not test single
> crystals with this unit but I specifically purchased a NanoVNA to simplify
> testing my crystal filter prototypes.
>
> Was the V2 Plus 4 the wrong one to buy as I find You Tube videos showing
> the expected filter curves when others measure crystal filters.
>
> Any help would be appreciated.
>
> Thanks, mark

Hello Mark!

Please update firmware https://nanorfe.com/nanovna-versions.html#versions

Try increasing the AVG, 10, 20 or more. Maybe that will help. Connect a resistor of 250 Ohm...2 kOhm in series at the input and output of the filter (supposed input and output resistance of the filter) - NanoVNA has input and output resistance of 50 Ohm.

73 de Vladimir, dl7pga
P.S. The best NanoVNA for quartz surveying is NanoVNA-H4
(Translated with Google Translate)

If you do most of your analysis under 900 MHz buy a nanoVNA-H4. I love
mine and also have a Sysjoint F2 model which is junk.

On Sat, Oct 29, 2022 at 11:15 PM Mark Libner <ns9nil@gmail.com> wrote:

> I am new to using my NanoVNA V2 Plus 4 fw version 2202301. When measuring
> a simple 2 pole crystal filter, the display shows the primary peaks the
> same as my bench test equipment however as you can see in the picture
> attached, the waveform is not the smooth typical slopes I am used to.
>
> Am I missing a set up parameter or is this the normal waveform I should
> expect from this unit? I have read on the forum that I can not test single
> crystals with this unit but I specifically purchased a NanoVNA to simplify
> testing my crystal filter prototypes.
>
> Was the V2 Plus 4 the wrong one to buy as I find You Tube videos showing
> the expected filter curves when others measure crystal filters.
>
> Any help would be appreciated.
>
> Thanks, mark
>
>
>

I don't see any inductors in the matching circuit.  See this app note:
https://www.ndk.com/catalog/AN-CF_PFU_e.pdf

>From the picture it looks like you only have a series variable cap for terminations to the VNA.

Did you do sufficient points when calibrating? I don’t know how it fits the curve to the sample points.

I want to thank everyone for their inputs. Following all suggestions including updating the firmware, made an incremental improvement in the trace but clearly the course measurement steps are the issue.

Like others, I bought this VNA from the official store and it was the only option other than the 6000 at more than 2x the price. I can only hope that the developers will find the time, if it is even possible, to update the fw so we can look at narrow band filters and crystals.

Otherwise I am off buying an H4 version but fear I am back buying a clone since the official store no longer carries any of the earlier versions.

Hi, only V2 Plus4 Pro and later hardware versions have an adjustable IF filter that allows measuring crystal filters. Thanks

NanoV2Support,

Thanks for the reply. As it looks like I purchased the wrong HW, I will have to sell my Plus 4 and purchase a Plus 4 Pro.

Do you know when the Plus 4 Pro will be available on the official store? It was not listed as an option when I purchased my Plus 4 and still is not listed today.

Regards, mark

Good afternoon all,

I've got a NanoVNA V2 Plus4 bought from the official source. :) It shows version git-20210530-412578c as the firmware installed.

I've been unable to update the firmware - and checking the archives plus using Google, I have not found any discussion of my exact problem. Here's what I've done and what I'm seeing:

I downloaded and installed the USB-CDC Cypress Driver installer from the Nanorfe webpage.

I then downloaded and can run NanoVNA-QT and am able to successfully connect to and control the NanoVNA - no problems. Normally, my computer sees the NanoVNA as COM9, as I'm running Windows 10. When I look at COM9's driver details, it shows a Cypress driver from the year 2015, which I believe is the one installed by the Cypress Driver.

When I follow the instructions in the online manual:

*** Connect the device to a PC using a USB cable.

*** Put the device into BOOTLOAD mode. This can be done from the device menu by selecting CONFIG →BOOTLOAD, and selecting RESET AND ENTER. BOOTLOAD mode can also be entered by holding down the JOG LEFT button on the device while it is powered off and on.

---> no problems here, I get the white screen. COM9 will disappear, and COM10 will appear, which I believe is proper . Again, looking at the driver details, it shows a Cypress driver from 2015.

*** The device should appear under the Device menu in NanoVNA-QT.

*** Click the device under the Device menu, for example /dev/ttyACM0.

---> COM10 does show up in the Device menu. When I click COM10 from the Device menu, I get one of two messages:

"Exception: Illegal byte sequence"

or

"Exception: No error"

This is where things end - I never get asked to select a firmware raw binary file. If go to devices and refresh, or click COM10 again in devices, it will do the same thing, either saying "No error" or "Illegal byte sequence."

Changing USB cables makes no difference. Changing USB ports (either thru a hub or direct to PC) doesn't make a difference. I've rebooted several times, and reinstalled the Cypress drivers multiple times. It doesn't matter if I change the method of entering the BOOTLOAD mode, either by holding down Jog Left on by selecting it from the CONFIG menu.

Kind of scratching my head as to what to do next?

Thanks much,
ben, kd5byb

Ah, they's hidden the selection on the ordering page for the NanoVNA V2 page in the store - the selection for the version of V2 Plus4 is in a drop down box on the right side of the ordering page in the store (yes, I made exactly the same mistake!!)

I'm interested to measure the crystal filters and I'm using the following firmware version

For example, a Kenwood YK88S filter directly on 50 Ohm (if I remember well it must be
terminated on 2700 Ohm) gives the following

In the past I've performed the same measurement on 1.8 kHz wide filter for Drake TR7.
The filter must be terminated directly on 50 Ohm and it did show a perfect shape.

Fabio - I5LHY

Yes Bob, you are exactly correct. The good news is that they have agreed to exchange my Plus 4 for a Pro for the difference in cost. The bad News is that the prices have gone up, like everything else, and the shipping to return my unit to China was just under $30.

But at least I will soon have a Plus 4 Pro and be able to perform all the functions I want. As I used to tell my students, If you get nothing else, you get and education.

My variant.

Devaise.