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Raoul,

If you are interested in more info on measuring crystals with your NanoVNA I suggest the video by W2AEW on this subject. He carefully explains the terms and definitions and compares various testing methods. He has an extensive collection of videos and is well respected for the clarity and technical accuracy of what he presents. Quite a few recent ones deal with NanoVNA subjects.



Roger

I received this same six-connector "NanoVNA Testboard Kit" with my VNA. Where can I find documentation for this kit? The documentation link in this thread is for a different two-connector test board.

Great video, Gregg. Thanks very much.

73 de Raoul, CE3RY

This just became a bit more interesting.
It seems that there is a discrepancy in how
SimSmith calculates the angle depending on
the circuit block used. For an S block it shows
the same curve as in NanoVNA Saver and also
in Rogers graph (green trace).
But for a impedance block angle is different (red trace)
and much closer to the modeled resistor (blue trace).

[image: image.png]



On Wed, 17 Feb 2021 at 03:52, Dragan Milivojevic via groups.io
<d.milivojevic@...> wrote:

I guess that depends on what you consider as minimal
and if you are modeling an ideal resistor or a more
realistic one.

I guess that depends on what you consider as minimal
and if you are modeling an ideal resistor or a more
realistic one.

For example: on the first image is the plot of voltage
angle at the load (port 2 in this case), calculated from the
S21 file if the load is an ideal 50Ω.
The black trace is for a model of a 10K resistor with 50fF
of capacitance (reasonable value, according to Vishay for a
0805 capacitor) also into an ideal 50Ω.

[image: image.png]

The second image shows the same plot but this
time instead of an ideal 50Ω termination at port2,
I used the measured values for port2.
Not much of a change.

[image: image.png]

Last image is the port2 as measured, on a Smith chart (zoomed in quite a
bit).

[image: image.png]


Keep in mind that the calibration was done with
DIY "standards" and jig all made from cheap SMA
connectors from AliExpress, where the center
pin moves if you tighten the connectors enough.
DYT also from China with unknown properties.
Quite a sloopy setup.








On Tue, 16 Feb 2021 at 20:47, Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

Dragan,

Thank you for clarifying what you did on your tests. I took a look at the
.s2p file that you posted and see that you get the same large S21 phase
shift that I got in my tests. I posted my plot of your S21 data below.
For a tiny SMD resistor like the one you used the phase shift should be
minimal (at least on the lower frequencies.). The S21 magnitude loss is
very close to what it should be for a 10K resistor but that phase shift
will give a lower R value and indicate reactance that isn't there if I
understand this correctly. Do you agree?

I also did a conversion from serial to parallel impedance and your S11
measurement was surprising close to 10K ohms. For a VNA designed for 50
ohm system impedance this was very good. Plot attached.

Roger

I would presume type 43 material is used?

For 160 and 80-meters your setup is quite reasonable. If you scanned to 30
MHz, likely a clean-up would be required, but you are aware of that.

Good work!

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*

Here’s what I did to measure the common mode attenuation of a current balun that I recently constructed.
--
VE6WGM

Dragan,

Thank you for clarifying what you did on your tests. I took a look at the .s2p file that you posted and see that you get the same large S21 phase shift that I got in my tests. I posted my plot of your S21 data below. For a tiny SMD resistor like the one you used the phase shift should be minimal (at least on the lower frequencies.). The S21 magnitude loss is very close to what it should be for a 10K resistor but that phase shift will give a lower R value and indicate reactance that isn't there if I understand this correctly. Do you agree?

I also did a conversion from serial to parallel impedance and your S11 measurement was surprising close to 10K ohms. For a VNA designed for 50 ohm system impedance this was very good. Plot attached.

Roger

Hi all!
I don't know if I have problem, a faulty display or a firmware bug. I'm testing the function L/C Match. I enable the function by clicking "MARKER/SMITH VALUE/L/C MATCH" in the menu system, but I get no visible text on my screen! I also have a nanoVNA SAA-2N, and it's working nice in this model, but not in the NanoVNA H4.....
By studying the screen very close, I can see parts of letters. I can see the lines are interferred with black pixels! I can se the pattern changes when moving the marker and it seems to mee that the letters are written in black, and therefor they are not shown. Anyone out there seen this, or is it only me/my system?

I compared the SAA2N and the H4, and there is something odd with the SAA2N too, not really a problem, just a bit odd. When using the function on the SAA2N, some of the results fro the L/C Match calculation is not removed from the screen. This only happens when using a stylus to move the marker, and not when moving the push buttons!

I almost forgot to mention the firmware version information :-)
NanoVNA-H 4 have got the 1.0.45 from Dec 15 2020 - 20-03:40
The NanoVNA SAA 2N have got version: git-202001226-7b1abc9 Built Time: Dec 27 2020 - 00:35:52

Anyone else seen this problems?

Karl Jan - LA3FY

Your setup is far from ideal, the breadboard is rarely
a proper choice for VNA measurements.
If you want to go via that route use something like this:

Most of it is in the initial post, except for software (SimSmith).
Plot commands for SimSmith were:

Plot("R1", S1.z.R, "Ω", "y1");
Plot("X1", S1.z.X, "Ω", "y2");
Plot("Z1", S1.z.M, "Ω", "y1");

I have attached the simsmith circuit and the s2p file if someone wants to
play with it.
The second set of measurements were done with the test jig directly at
port2, in the first
test the jig was connected via 30cm of RG405. I was lazy, could not be
bothered to
solder a jumper on the jig so I did not calibrate out the test jig, just
used a -2ps offset.


On Tue, 16 Feb 2021 at 18:16, Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

On Mon, Feb 15, 2021 at 06:43 PM, Dragan Milivojevic wrote:

Calibrated with "0 length through", test jig connected to port2 directly:

You did not provide any detail in your post about your test setup or how
you derived R, X and Z from the S21 measurement. I do not recognize the
plot formats that you are using. Also you did not describe what component
you are measuring.

For those that are not familiar with the S21 series method here is an
introductory paper.


Keysight gives a derivation of the conversion formula. (note S21 is a
complex number)



If we are to have a discussion on this topic please let the group know a
bit about what you are doing...
- What VNA is being used
- A description of the test jig
- What software program or method you are using to convert S21 to complex
impedance (R,X)
- What component you are measuring. I suggest a 1K SMD resistor of around
1000 ohms because it is easy to see measurement errors and compare
results. Another is a 10 pF SMD capacitor or very short lead ceramic type.

- When I measure (with a NanoVNA-H4) a 1K resistor on a microstrip with 50
ohm impedance my S21 phase starts at 0 but goes to 17 degrees by 100 MHz.
. It should stay close to 0 degrees for a component that has minimal
inductance.

Roger

This user group is for both versions (I believe) but a new topic would
be appreciated.

Firmware clone, especially when it is an open source project
is a meaningless term. Hope that clears things up.

On Mon, Feb 15, 2021 at 06:43 PM, Dragan Milivojevic wrote:

Calibrated with "0 length through", test jig connected to port2 directly:

You did not provide any detail in your post about your test setup or how you derived R, X and Z from the S21 measurement. I do not recognize the plot formats that you are using. Also you did not describe what component you are measuring.

For those that are not familiar with the S21 series method here is an introductory paper.


Keysight gives a derivation of the conversion formula. (note S21 is a complex number)


If we are to have a discussion on this topic please let the group know a bit about what you are doing...
- What VNA is being used
- A description of the test jig
- What software program or method you are using to convert S21 to complex impedance (R,X)
- What component you are measuring. I suggest a 1K SMD resistor of around 1000 ohms because it is easy to see measurement errors and compare results. Another is a 10 pF SMD capacitor or very short lead ceramic type.

- When I measure (with a NanoVNA-H4) a 1K resistor on a microstrip with 50 ohm impedance my S21 phase starts at 0 but goes to 17 degrees by 100 MHz. . It should stay close to 0 degrees for a component that has minimal inductance.

Roger

It's a cool firmware. But I think we have to discuss this in an other group. It's not for V1.

--
Klaus, DL5KV

I'm not sure, but I think there are clones for H4 firmware, too. This ist only a notice of me. Maybe this problem doesn't exist on the V1. I haven't updated the firmware on V1 for a long time.

--
Klaus, DL5KV

This has been discussed before:
/g/nanovna-users/message/2726
45 messages in thread.

a number of thread of similar problems on different units. So I don't think a dif mfg is going to solve the problem. One solution in a thread was to add ESD diodes which may be the best solution. Not sure what the best type are, but the ones specified were listed as "not for new design" and there were a couple opinions as to operating and clamping voltage. So if anyone has a good suggestion RE ESD diodes???

Wow! Your calculator is great Lex.

Thank you for making it available to the rest of us.

John
AA7US

TU sir. Yes tried cal right at the terminal no cables. Checked the short and it is. The load is 50 ohms
I am too unsure of loading firmware but a Buddy ham offered Thought might hv been a static discharge as I was measuring the character of an antenna. So who knows. Perhaps he can un mess it up Hihi
Good excuse to buy the H4 from another Chinese company.
73 my friends
Paulk


Paul Kobetz
SKCC 19615C
CWOPS 2589
Rubicon Observatory