开云体育

It might work to check crystals as well.

Check under test jigs in /g/nanovna-users/wiki/Application-Notes

with 8 mA mode NanoVNA has a little worse dynamic range for 0-300 MHz.

Here is my measurements for both cases taken on NanoVNA-Q firmware with enabled average mode.

The test case is the following:
1) enable average mode
2) calibrate
3) connect 50 ohm on both ports
4) take s2p file with enabled average mode

2mA.s2p - use 2 mA mode for 0-300 MHz (default NanoVNA mode)
8mA.s2p - use 8 mA mode for entire frequency bandwidth

If Ipad supports USB-on-the-go, you may be able to connect it using USB.

iOS supports OTG (using so-called camera adapter) for some device classes, but not serial.
My understanding is that iOS does support serial devices via BLE.

Power 1,2 and 3 using a calibration done at power 1

I see comparable differences in resistance plots on device
when not recalibrating between power changes
e.g. from ~ 27 to 30 Ohms @ 496MHz for power 3 to 1;
inductance changes from ~1000 to 650 pH

Device recalibrations mitigate that.

I redid the 25 ohm measurement on three power levels.
Power 1,2 and 3 using a calibration done at power 1
For sure there is difference where it should not. Look at the light blue line





The 25 ohm was connected without a cable and the reference plane was shifted to eliminate the electrical length so there should be a pure constant R
--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK

Bob,
I think most NanoVNA units use a type C USB connector. Some may be Micro USB. Our local 99-cent-only store often carries both types.
--John Gord

I need a replacement cable to go from the nanoVNA to the USB port. Any links, specs, or other help?

Bob

If Ipad supports USB-on-the-go, you may be able to connect it using USB.

Is there anyway to connect the NanoVNA to an IPad ?

Sam
W3OHM

I connected a piece of coax to the nano and, at the far end, connected first a resistor, then a capacitor, then an inductor. I read the nano screen in all three cases and the value indicated was within about one percent of what my lab quality gear measured. It's an amazing device, really. As I raise the frequency, the reading changes (always putting the marker at the cable end). So it's good to see, for example, how an ordinary resistor behaves at rf. I should try a resistor and reactance in series and see how it separates them. I will try a resonant circuit as well so I can read the resonant frequency and maybe Q. It might work to check crystals as well. As you know, the frequency accuracy is better than 1 ppm.

The range over which it's accurate isn't too great but for most measurements it's entirely adequate. The signal level is around -10 dBm, about 1/10 milliwatt, not enough to damage parts.

I have already measured cable length but that's a lot of trouble; cable attenuation is very easy to read. Next I will see how it measures characteristic impedance of coax. As an antenna analyzer it's very good but it has many more uses than that.

I might see if I can calibrate it as an rf voltmeter.

I have already gotten my money's worth out of it.

Hi Wolfgang and Gyula
I can just salute that, it is a very nice program.
Thank you for letting us try it
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Wolfgang Kiefer
Sendt: 25. november 2019 20:07
Til: [email protected]
Emne: Re: [nanovna-users] nanoVNA Partner #nanovna_partner

HiGyula,
a very nice and useful program!
I hope it will be freeware and open source. It was a good idea to find the minimum SWR automatically.
As an example I tested a DiskCone antenna for receiving purposes.
Best 73's, Wolfgang, DH1AKF

Neb -
Thanks so much! It works very nicely on my 'old' Windows Vista machine.
That multipurpose chart in the upper right corner is wonderful.
And the program found the right com port right away, too! You're a genius.

Doug
K8RFT

Bonjour Jean,
There have been quite a number of improvements and new functions added to the firmware since the end of September by the main devs: QRP, reald, hugen79 and edy555.?
And, as the wiki and files sections can be updated by almost any forum member and since it is trivial to flash new firmware into the nanoVNA, it would be a great help if another member (you or someone else) could take some time to play with the various releases of firmware and create a feature table.?
Now, with that said, someone could also browse the various GitHub NanoVNA repo's and compile a list of the various enhancements and changes for each Dev's release. I am currently the maintainer of the Console Command doc and that is how I started it - by browsing the source code and creating a document.?
In any case, for anyone reading this - if you have some free time, by all means create a firmware release feature table that can be exported as a PDF and upload it to the files section. If more that one is created, the best of each can always be merged into an all encompassing document.??
Several forum members have already built really good reference sections. If you'd like to help make them even better, contact myself, Oristo, Herb W, David Feldman or just ask in a new general message.?
Cheers,.??Larry

On Mon, 25 Nov 2019 at 4:51 PM, ptapon@...<ptapon@...> wrote: Hello,
we have, with this fantastic device and everyone's contribution,? a great tool for our hobby.
We see quite often a new firmware popping up.
Is there a way to understand how a new firmware will compare with another one. Additional functions, additional commands, features, more precise for a set of frequencies, what have you.
More clearly, witch one to choose when we have a specific usage for the nanovna. What will be the preferred firmware for, say, nanovna saver. What are you going to loose it you use this one instead of this other one.
As an example, we have seen these days 2 firmware proposed. One form Edy555 and one from Hugen79. After reading the readme.md form the 2 releases, I'm still undecided to use one over the other.

Can someone throw some lights?

Anyway thanks to everyone for their contributions.
I'm learning a lot with all of you and this tool is something I had in my dreams.

Jean

Hi Jean -

What will be the preferred firmware for, say, nanovna saver

Rune Broberg is the author of nanovna saver, which
I think uses a minimal subset of nanoVNA commands that work with most firmware,
particularly including originally installed by Hugen, which many never change.

If you login to [email protected] and search for any message by Rune,
one option is to list all of his messages, which can be searched.
If you do, then you will find that many refer to edy555
while few are about hugen and very few are about hugen firmware.

On the other hand, latest hugen firmware inlines some code that edy555 does not,
so may be slightly faster.
I think latest hugen firmware includes accuracy improvements from QRP.

Hello,
we have, with this fantastic device and everyone's contribution, a great tool for our hobby.
We see quite often a new firmware popping up.
Is there a way to understand how a new firmware will compare with another one. Additional functions, additional commands, features, more precise for a set of frequencies, what have you.
More clearly, witch one to choose when we have a specific usage for the nanovna. What will be the preferred firmware for, say, nanovna saver. What are you going to loose it you use this one instead of this other one.
As an example, we have seen these days 2 firmware proposed. One form Edy555 and one from Hugen79. After reading the readme.md form the 2 releases, I'm still undecided to use one over the other.

Can someone throw some lights?

Anyway thanks to everyone for their contributions.
I'm learning a lot with all of you and this tool is something I had in my dreams.

Jean

It doesn't look like hugen has any plans to update his original NanoVNA-Sharp application. Both QRP and neb40gsm@... have done an excellent job of taking hugen's reverse engineered NanoVNA-Sharp application and putting their own stamp on it. Seems the line about standing on the shoulders of others still has merit.

- Herb

The T connector is not accounted for by the calibration.....

Certainly, that can be noted in the Smith plot.

BNC 50 ohm terminators can be very poor.

Agreed; in this case one is a legit cal standard and the other is about 47.5 Ohms and 1.4nH

The T connector is not accounted for by the calibration.....

BNC 50 ohm terminators can be very poor. They are sometimes a 1/8 watt axial lead resistor in the metal extension of the BNC. R varies considerably from one to the next and effective of inductance in the resistor is very noticeable as you increase frequency.

Hi Wolfgang,
i'm glad you like it, the design and solution is Neb's merit - i just tested it and gave an opinion.
I like it too, with clever solutions.

73, Gyula

comes with 'free' shipping too !

cal adapters appear to be collectors item