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Hi Kurt,
thanks for your reply!
The picture shows the calibration settings, that I copied from your document "Male and female calibration of NanoVNA-H".
I used the same standards as you did except the load, which I measured precisely.

Best regards
Norbert, DG1KPN

...and don't forget that male N connectors fit female BNC & TNC as well - just don't push them in too far or you'll damage the centre pin on the BNC/TNC.

Interesting. It looks like they replaced the guts of their old METROVNA DELUXE 250 (up to 250 MHz) with some form of nanoVNA. Case, screen and connectors all look the same. No mention of the nanoVNA on their web pages. There are reviews of the older model posted, including a favorable one in English from the August, 2016 issue of RADCOM.

Well, I tried several brand name connectors like Amphenol. I needed a right angle pcb mount BNC. They seems to come in just two flavors: cheap or very expensive (> 10-25 euro). My application does not justify the expensive parts. Have a look at (specs say 1 GHz) You see two wires coming out of the housing. This is not a nice 50 Ohm transmission line: I had to tune out the lead inductance to get a good matching to 50 Ohm. For a broadband application this would be impossible.
Apart from that, connections are never 100% the same. I see the s11 curve jumping over the smith chart when wiggling the cable connector.
For cheap BNC connectors (yes Asian imports), this is always an issue whereas SMA is never a problem.
So you are right, there are absolutely good versions available, but the average BNC connector is a piece of junk.

Op 24-1-2020 om 11:58 schreef hwalker:

Thanks for feedback

"There are 3 possible drivers that may appear in Device Manager:

Another possible driver "ChiBios/RT Virtual COM Port"

Why? Someone with this problem needs to test why and post repeatable results here.

Presumably because, sometime in the past, another device (e.g. ST-Link)
or application provoked installation of those drivers
along with a .inf file that associates nanoVNA USB device ID with those drivers.

"Connect your device in bootloader mode." I think you mean "... DFU mode."

Oops, my bad for copying from another suggestion without proofreading.

From STM's driver page:
"Starting from Windows? 10, the STSW-STM32102 driver is no more adequate
and the usage of the native inbox driver is recommended."


I have taken another whack:
/g/nanovna-users/wiki/drivers

On Fri, Jan 24, 2020 at 02:16 AM, Reinier Gerritsen wrote:

" BNC on 900 MHz is just so so, on a measurement device it is an absolute no no! ''
========================================================================

Not true. BNC connectors are rated up to 4 GHz, although most professional test equipment in my company's laboratory only use it to about 1.5 GHz. Agilent, Rhode-Schwartz, Fluke etc. all commonly use BNC connectors on their test instruments.

Quality measurement equipment use BNC connectors manufactured by companies such as Amphenol, Pasternak, etc. If you are talking about a bad experience with cheap Asian imports then you should say that and not disparage all BNC connectors.

- Herb

Hi Norbert
On the contrary I see better results. It is all about the calibration so show us a picture of calibration settings and give information about what you are using for calibration
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Norbert Kohns
Sendt: 24. januar 2020 09:27
Til: [email protected]
Emne: [nanovna-users] Full reflection runs over the perimeter of the smith chart

Hi Rune,

after calibration with the nanovna saver software, I connected a 35cm long semi rigid coax to CH0. I am wondering, that at full reflection the response moves over the perimeter of the smith chart.
On the NanoVNA display it doesn't go over the perimeter but with increasing frequency it should spiral more inwards.
The calibration procedure I repeated twice with the same result.

Maybe I am doing something wrong!?

Does anyone else see the same symptom?

Best regards
Norbert, DG1KPN

Hi Gabriel
Nice to hear you about experiments with the tuning of cal kit parameters which my great hobby. You may find interst in finding the fringe C for the open using the program FEMM which does that with great accuracy. When using a stub for sweep and adjust for (not minimum) then use a rigid cable e.g. UT141A and use SimSmith to figure out the k0, k1 and k2 and the also create a s1p file for the given length e.g. 25cm to have as a background trace and tune for same ripple. For the stub use both a shorted and an open one where the open has a fringe C of 146.4fF (offset 7.32ps) which I have calculated with FEMM. The UT141 has the following k values k0=1.85 k1=0.327 k2=0.00095 so SimSmith does the rest creating a s1p file by either a short as termination or 10Mohm as termination for open.
The only missing detail is the delay in the adaptor from rear to calibration reference plane which I do measure by a caliper and use VF 0.695 for Teflon. Then delay is distance multiplied by 0.3 and divided by VF
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Gabriel Tenma White
Sendt: 24. januar 2020 04:48
Til: [email protected]
Emne: Re: [nanovna-users] First PCB pictures of the V2

I heard from the customer that they've finished testing half of the first batch. I think it will become available right after the holidays, so in just over a week.

"On some of her other projects she had to find a client before the finished product could be manufactured. "
Actually it's the other way around :) the client comes to us for a R&D job, we do the design work and build prototypes. So my job is done :) However I'll continue work on the firmware and software on an independent basis, that way we aren't relying on a single manufacturer for software updates (you know how well that usually works out). When in between contracts we (OwOComm) also work on core projects like the software defined radio for OwONet and other fun projects. See

The passives parasitics on the board aren't usually a bottleneck and we've used techniques to tune out e.g. resistor inductance. On the cal kit though we found that soldering resistors upside down improved performance. For example this type of cal kit:
I've just implemented calibration kit parameter fine tuning in the PC software so you can adjust cal kit parasitics and see the results in realtime, so you can e.g. connect a coax stub and adjust cal kit parasitics until the S11 ripple is minimized for a "best guess" of the kit parameters.

There is already a switch on port 2 and in theory can be used to implement ecal. The issue is just that the ecal parameters have to be individually characterized for each board (because the SMA connector soldering introduces variations), which is too expensive to do at manufacturing so would have to be done by the user, which means you need a traditional cal kit anyway. I'll think about introducing this in a later revision.

Yes the output is a square wave under 2.2GHz. The harmonics of the LO and RF mix to produce 2*IF, 3*IF, etc which is how harmonics mode works in the original Nano. When not in harmonics mode these are filtered out digitally and has few impacts on performance (assuming good receiver linearity) unless they get aliased by the ADC, which is why there is also an analog LPF after the mixer.

BNC on 900 MHz is just so so, on a measurement device it is an absolute no no!
I will happily stay with SMA for most of my RF work, and u.fl if it needs to be small.

Op 24-1-2020 om 00:38 schreef Kleibe PP2KR:

On Wed, Jan 22, 2020 at 11:22 AM, Bob Albert wrote:

I just don't have the visual acuity, steady hand, and tiny soldering tool needed.

Howdy Bob,
I don't know if it would be worth the cost, but cell-phone repair techs are always fixing those tiny connectors. There's some youtube videos.
Most don't use a tiny-point iron for fine-pitch devices; they clean the pads, smear solder paste (with flux) across them, set the device in place, then hit it with the hot-air gun. The solder paste melts and surface tension pulls it apart and under the pins, all at once. If done right, no bridges. They also have a microscope!
I have your same afflictions. Last year I got a cheap imported hot-air & soldering iron rework station ($50), a USB microscope on a stand ($45), and a practice board with some SMT chips. It works! The hot air gun takes practice; smallest nozzle, very low air flow, and right temp for the paste used. The hard part is not blowing away the part... :)
73, --KV5R

Hi Rune,

after calibration with the nanovna saver software, I connected a 35cm long semi rigid coax to CH0. I am wondering, that at full reflection the response moves over the perimeter of the smith chart.
On the NanoVNA display it doesn't go over the perimeter but with increasing frequency it should spiral more inwards.
The calibration procedure I repeated twice with the same result.

Maybe I am doing something wrong!?

Does anyone else see the same symptom?

Best regards
Norbert, DG1KPN

Thanks Bob,you are right it was bought with no battery. Not up to working with SMD size components and soldering so have bought a 5V power bank and will run it from that when in the field.
Regards & 73
Chris G0EYO

Hi Oristo,
Good work on the driver wiki page. For better new-user understanding, you might consider adding something like:

"There are 3 possible drivers that may appear in Device Manager:
1 - STMicroelectronics Virtual COM port (for normal communication, as with nanovna-saver, terminal, etc)
2 - STM Device in DFU Mode (for DfuSE Demo software)
3 - STM32 Bootloader (for the ST-Link dongle)
User needs #1 & #2, not #3 (unless they are using the ST-Link dongle).
Sometimes #2 gets replaced by #3."

Why? Someone with this problem needs to test why and post repeatable results here. I thought maybe Windows is grabbing the bootloader driver because of user doing some wrong sequence, so just spent an hour plugging, powering, switching to DFU, and starting software, in many sequences. It didn't matter. If nano is in normal mode, Windows always started the COM driver. If it's in DFU mode, windows always switches to the DFU Mode driver. So now I think some users are searching for a driver online and finding the ST-Link bootloader driver (or some package that installs it) because it's confusing. There are too many (old) instructions for drivers and ways to install them; all Windows' users need is DfuSE Demo, it will bring the right drivers.

"Next, disconnect the nano and place it into DFU mode and connect to the computer again." On mine, when I switch to DFU mode (by nano menu), Windows makes noises; Device Manager shows the COM port driver disappear, and the DFU mode driver appears, without disconnecting or powering off/on. Of course, power off/on is needed to exit DFU mode, but not to enter it (unless using boot jumper, or new press button & power-on method.)

"Connect your device in bootloader mode." I think you mean "... DFU mode." A new user will say "what's bootloader mode?" (The phrase from the site Brian found is not specific to the nanovna; to me, the "bootloader" phrase implies using the ST-link dongle, since DFU via DfuSE does not access the bootloader.)

Hope this is helpful, and not too noisy :)
--KV5R

I heard from the customer that they've finished testing half of the first batch. I think it will become available right after the holidays, so in just over a week.

"On some of her other projects she had to find a client before the finished product could be manufactured. "
Actually it's the other way around :) the client comes to us for a R&D job, we do the design work and build prototypes. So my job is done :) However I'll continue work on the firmware and software on an independent basis, that way we aren't relying on a single manufacturer for software updates (you know how well that usually works out). When in between contracts we (OwOComm) also work on core projects like the software defined radio for OwONet and other fun projects. See

The passives parasitics on the board aren't usually a bottleneck and we've used techniques to tune out e.g. resistor inductance. On the cal kit though we found that soldering resistors upside down improved performance. For example this type of cal kit:
I've just implemented calibration kit parameter fine tuning in the PC software so you can adjust cal kit parasitics and see the results in realtime, so you can e.g. connect a coax stub and adjust cal kit parasitics until the S11 ripple is minimized for a "best guess" of the kit parameters.

There is already a switch on port 2 and in theory can be used to implement ecal. The issue is just that the ecal parameters have to be individually characterized for each board (because the SMA connector soldering introduces variations), which is too expensive to do at manufacturing so would have to be done by the user, which means you need a traditional cal kit anyway. I'll think about introducing this in a later revision.

Yes the output is a square wave under 2.2GHz. The harmonics of the LO and RF mix to produce 2*IF, 3*IF, etc which is how harmonics mode works in the original Nano. When not in harmonics mode these are filtered out digitally and has few impacts on performance (assuming good receiver linearity) unless they get aliased by the ADC, which is why there is also an analog LPF after the mixer.

Just seen on Twitter a version with BNC connectors.



Kleibe
PP2KR

Greetings to everyone,

Good work on the new boards, I will surely get one when they reach market.
Have you checked if mounting passives upside down makes any difference in this design or does that only help at much higher frequencies, just curious. Check this short PDF for example:


I would like to suggest an ECAL expansion board (for SOLT calibration or some other calibration scheme) that could replace the display, that would be a neat accessory to these devices

From the PDF of the schematic I see that the ADF4350 is used. The fundamental VCO of those is 2.2 - 4.4 GHz if memory serves, which means the synthesizers will have higher harmonics from the digital dividers in the synthesizers at significant amplitudes which I assume means that signal will be downconverted at those frequencies also? Anybody RF wizard willing to chip in on this ?

Keep up the good work
Kalle

On Thu, Jan 23, 2020 at 09:24 AM, dwabbit wrote:

" any update on a release yet. im holding off on a few 2.4ghz projects as I will be needing the use of a vna @2.4ghz to do some antenna testing "

dwabbit,
Gabriel hasn't announced an anticipated release date. On some of her other projects she had to find a client before the finished product could be manufactured. It would also be nice to know what the expected performance specifications are so you could determine if they will meet your project requirements.

I did notice the first public release of her V2 software application, VNA View, is available for down load at . It has a mock device selection if you want to kick the tires and take it for a spin.

- Herb

Larry,

Thanks for posting this. I bookmarked that "Engineer's Garage" site. Lots of interesting stuff to read...

Roger

That display looks like the one that hugen is using on his new H4 version of the nanovna.
Is the LCD and touch surface broken or just the touch surface? It looks like it's a 3.9inch diagonal.Remove the display assembly and check the part number on the backside of it.

any update on a release yet. im holding off on a few 2.4ghz projects as I will be needing the use of a vna @2.4ghz to do some antenna testing
cheers