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On 19/08/2023 13:34, Nuno Lopes - CT2IRY via groups.io wrote:

Hi guys, this is my first post here, I would like an advice to buy a new VNA, my main operation is till 50MHz, but eventually I can operate till 1.2GHz, what would be a good VNA to buy, H4; F; SAA.
Can anyone recommend one.

Thanks
Nuno
CT2IRY

Welcome to the group, Nuno.

Do take a look at the Wiki:

/g/nanovna-users/wiki

Whatever you get, buy from the original manufacturer if at all possible. Avoid
clones! I have several NanoVNA models and am happy with the H4 and its SMA
connectors (the H4 is reputed to need regular charging every few months as the
physical on-off switch still leaves some slight drain).

Consider whether you want to use it outdoors, and whether SMA or N-type
connectors are better for you. Do you need to measure crystal filters?

Others will doubtless chip in with their own choice!

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

Hi guys, this is my first post here, I would like an advice to buy a new VNA, my main operation is till 50MHz, but eventually I can operate till 1.2GHz, what would be a good VNA to buy, H4; F; SAA.
Can anyone recommend one.

Thanks
Nuno
CT2IRY

I have.
Luckily it was still within the return period on ebay

So far I haven't seen any incompatible clones of the Nano H or H4.
Maybe I missed some ...

On 8/18/23 8:15 AM, Brian Beezley wrote:

On Tue, Aug 15, 2023 at 09:25 PM, Jim Lux wrote:

Sometimes, I find the derivative of unwrapped phase (group delay) more useful,
too.

Jim, your comment inspired me to add group delay to my program. I don't see its relevance for ground probe data, but it provides a powerful diagnostic tool that can reveal anomalies otherwise invisible. The first two plots show an ordinary-looking phase plot and the corresponding group delay plot. The big group delay spike corresponds to a barely perceptible flat spot in the phase curve. It's easier to see in the third plot with a narrower frequency span. I think it's due to a VNA frequency stepping issue.

Yeah, derivatives do accentuate noise - but sometimes that's actually useful to spot a discontinuity in a system that should otherwise be "smooth" And when you have multiple resonances, is makes them obvious.

Make sure you are taking frequency steps that are small wrt to the DUT bandwidth. GD on a xtal filter is one example.

. . . and far, far, less portable (IE not an option for all, unlike Cube) . . .

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

On Tue, Aug 15, 2023 at 09:25 PM, Jim Lux wrote:

Sometimes, I find the derivative of unwrapped phase (group delay) more useful,
too.

Jim, your comment inspired me to add group delay to my program. I don't see its relevance for ground probe data, but it provides a powerful diagnostic tool that can reveal anomalies otherwise invisible. The first two plots show an ordinary-looking phase plot and the corresponding group delay plot. The big group delay spike corresponds to a barely perceptible flat spot in the phase curve. It's easier to see in the third plot with a narrower frequency span. I think it's due to a VNA frequency stepping issue.

Brian

The STM32CubeProgrammer is good, I like it but, the app is more problem free...

did You saw this topics?


/g/nanovna-users/topic/100723284

/g/nanovna-users/topic/99570191

/g/nanovna-users/topic/100725961

Istvaan

While that is technically true, its only possible if you either made a backup of the firmware on the unit prior to flashing the new firmware or were able to find the firmware originally on the unit.

These things can't be bricked, in the worst case scenario you would
need a $2 ST Link clone to
flash the firmware.

Me as well.
I have 2 desktops
Both running windows 11
One is a custom built amd gaming system and the driver did not work.
The other is a customer built intel system functioning as a file server.
Drivers worked just fine.
both were done with the same downloads and exact same process was followed.
Same windows 11 build as well.

I've just been down this road, encountering many problems. My environment is MacOS Ventura 13.5 on a Macbook Air M1. I also run Windows 11 in a virtual machine with VMware Fusion. I could never get the drivers installed on Windows 11 for the VanoVNA software. In my case, there were too many variables: Windows 11, W11 running in a VM, and USB support with a thunderbolt dock. I finally am using STM32CubeProgrammer (which runs on windows, linux, and MacOS). I extracted my existing VanoVNA-H FW from the device. I couldn't reconcile the extracted FW's size, so I looked for another means of extraction, dbutil. It also runs on windows, linux, and MacOS. I installed on MacOS (easy install with homebrew). I then extracted my VanoVNA-H FW from device for safe keeping. I happen to have a spare VanoVNA-H, I have to return by early Sept. This turned out to be a good test device, although I have read in many threads that the NanoVNA-H is nearly impossible to permanently brick. I have flashed several different FWs and then returned to original. If you can get past the driver issue on windows, the rest is a breeze. I would still recommend STM32CubeProgrammer.

Peter

Hi,
Follow this guide:

If your not sure if your Nanovna is an official one or not, do not upgrade or risk bricking your unit.


Tim.
KD2YYI

Hello
Can someone please point me in the direction of instructions of how I can update the firmware of my nano VNA. The firmware is currently 1.0.45. I am new to the group and have searched the topic and there are many answers but no specific step by step instructions I can see. Can someone please point me in the right direction.
Thanks

Makes sense. I setup LTSpice for 0 dBm out of CH0 with 50 Ohm load. Then inserted 1k Ohm and got 20.7 dBm at CH1. Thanks for the explanation.

When you put a 1000 ohm resistor between CH0 (port1) and CH1 (port 2) of the NanoVNA you should measure an "Insertion Loss" of -20.8 dB if the NanoVNA was a perfect device. It is not for several reasons including impedance of CH0 and CH1 are not exactly 50 ohms and the way calibration is done. So your measurement of 20 db is pretty close.

Your LTSpice and Sig Gen experiment is off by 6 dB because you did not calculate correctly. Try calculating the power in dBm of the 50 ohm load resistor without the 1K resistor and with the 1K resistor. Subtract the two and you get a 20.8 dB difference.

Roger

Why for the same circuit is the NanoVNA (-20 dB), LTSpice (-27 dB), and Scope/Sig Gen (-27 dB) result in different answers. The circuit is a 1,000 Ohm resistor tied from CH0 to CH1. Based on some experiments the input impedance to CH1 is 50 Ohms so the circuit is a voltage divider (see attached Fig. 1 NanoVNA Circuit Setup).

The scope and signal generator were setup to mimic the NanoVNA circuit by using the signal generator to apply potential to a series 1,000 Ohm and 50 Ohm resistor network (see attached Fig. 2 Scope/ Signal Generator Circut Setup). The scope was used to measure the voltage of the applied signal (Vin) and the output across the 50 Ohm resistor (Vout).

The results:
NanoVNA LogMAg = -20 dB @ 1 MHz, Smith 982 Ohms @ 1 MHz,
Scope/Sig Gen @ 1MHz, Vin = 722 mVrms, Vout = 34 mVrms, -27 dB,
LTSpice @ 1MHz, Vin = 452 mVrms, Vout = 21 mVrms, -27 dB.

The Scope/Sig Gen and LTSpice are a good correlation. The NanoVNA is different, why?

Any thoughts?

Wes
W4JYK

On Wed, Aug 16, 2023 at 07:26 PM, Peter (WB3IZU) wrote:

The extracted file is 130K and most of the FWs I see online are under 100K.
That concerns me?

That is OK, because the upload to the PC reads the complete 128KByte from the flash including the unused bytes after the program at the memory end while the FW files of about 100K contain only the program bytes.

I have made some progress. I wanted to be able to extract the FW from my device for backup. I can't seem to find FW that matches mine online. This () seems to be the closest. However, if I download the DFU, convert it to BIN and compare using STM32CubeProgrammer, they do not match. I extracted the firmware using "dfu-util -d 0483:df11 -a 0 -s 0x08000000:leave -U /Users/USERID/DELETE/test.bin". The log is attached. The extracted file is 130K and most of the FWs I see online are under 100K. That concerns me? If I compare using STM32CubeProgrammer, they do match. I then flashed this back to my NanoVNA using STM32CubeProgrammer. The log is attached. If I compare the versions from the VanoVNA (config | version) pre and post, they are identical. I guess next I will flash an updated FW, maybe the one that removes SDcard support and allows for 8 saved calibrations. My only concern at this point is the discrepancy in file sizes. If anyone can explain, I would appreciate it?

73
Peter