Beware of cheap underperforming clones

As of 2022 there are many badly performing clones on the market. V2/3GHz NanoVNA uses parts like ADF4350 and AD8342 which are costly and clones have been cutting costs by using salvaged or reject parts.

See official store and look for V2 Plus4/V2 Plus4 Pro versions only to avoid getting a bad clone. We have stopped selling V2.2 versions since October 2020, so all V2 hardware that are not Plus or Plus4 are not made by us and we can not guarantee performance.

NanoVNA V2 Forum

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Click here to join and see most recent posts.

Calibration


Francesco 2021/11/29 03:34

I select some 50ohms load with part n: 60-601-0000-31 from the US (I suppose) and I get this calibration my question: Is it really or pure philosophy? I don't get one professional lab instrument to compare.

Francesco 2021/11/29 13:16

I calibrate on input of the trasfer relay switching test set (pseudo 2 port
calibration).





**Sent:** Monday, November 29, 2021 at 11:34 AM
**From:** "Francesco" <realfran@gmx.co.uk>
**To:** NanoVNAV2@groups.io
**Subject:** [nanovnav2] Calibration

I select some 50ohms load with part n: 60-601-0000-31 from the US (I suppose)
and I get this calibration my question: Is it really or pure philosophy? I
don't get one professional lab instrument to compare.

_._,_._,_

* * *

Joe Smith 2021/11/30 16:23

I will guess at what you are trying to show.
You are using this box with some sort of transfer relay and N to SMA adapter.  You perform a full 2-port cal with the Nano's standards attached to this box.  Then you attempt to measure a a terminator (60-601-0000-31).  You are asking if the results are correct as you have no way to verify them.

My philosophy is to keep things simple until I know something works.  I would start by ditching that box.  Perform an SOL calibration and then measure the terminator.

Looking at the part,
https://www.abex.co.uk/esales/microwave/sealectro/termination/60-601-0000-31/000/index.php

I would compare your findings with their results.   If that doesn't provide acceptable results, adding an unknown box certainly isn't going to improve things.

Calibration is not a magic fix for bad cables, adapters, and unknown boxes.  Get the basics working before making things more complex.

Francesco 2021/12/01 09:10

Thank you for the suggestion and I get this result (better), I make all this
result doing direct on the SMA NanoVNA connector.

Calibration screen shots.

Device 50 ohms LOAD DUT.

From the bach of 7 this is the best.





**Sent:** Wednesday, December 01, 2021 at 12:23 AM
**From:** "Joe Smith via groups.io" <joeqsmith49=yahoo.com@groups.io>
**To:** NanoVNAV2@groups.io
**Subject:** Re: [nanovnav2] Calibration

I will guess at what you are trying to show.
You are using this box with some sort of transfer relay and N to SMA adapter.
You perform a full 2-port cal with the Nano's standards attached to this box.
Then you attempt to measure a a terminator (60-601-0000-31). You are asking
if the results are correct as you have no way to verify them.

My philosophy is to keep things simple until I know something works. I would
start by ditching that box. Perform an SOL calibration and then measure the
terminator.

Looking at the part,
<https://www.abex.co.uk/esales/microwave/sealectro/termination/60-601-0000-31/000/index.php>

I would compare your findings with their results. If that doesn't provide
acceptable results, adding an unknown box certainly isn't going to improve
things.

Calibration is not a magic fix for bad cables, adapters, and unknown boxes.
Get the basics working before making things more complex.

_._,_._,_

* * *

Joe Smith 2021/12/01 05:24

I am not sure if you still have a question.  If you are just looking for feedback, for some reason you continue to sweep from 50kHz to 4.4GHz with the leakage term enabled.  Of course, if you had read the manual you would know this can lead to problems.  So I assume you are not really interested in optimizing the performance.

12.3 Selecting Calibration Standards

The V2+ was designed to work above 3GHz but it seems to have a fair amount of leakage (or cross coupling) between ports 1&2. Using the leakage terms can introduce noise into the reading and is normally ignored. However, it seems that without accounting for these terms with the V2+, the errors above 3GHz make the unit useless. You may manually enable these by selecting Leakage Terms. This setting is stored into the default file.

I would also stop using the software until you understand how the V2Plus4 runs standalone.  Again, simplify rather than adding more variables.  I would also remove cables, adapters, torque the standards right at port 1 of the VNA.

You also have the specs for the V2Plus4 as a reference.  I wouldn't expect better results than what's been published.  It looks like the data for your terminators was taken from an older HP VNA.  I suspect you will not get better numbers with a $200 VNA.

I did publish some data for the various low cost VNAs I have.  You can certainly repeat those tests and make sure your getting similar results.

tclupper 2021/12/06 19:49

Hello.  I recently compared S-parameter data from a couple of VNAs and included the nanoVNA V2 4GHz in the experiment.  Admittedly, I did not spent a lot of time optimizing the calibration of the nanoVNA (I just used the calibration that was built into the firmware and the standards and cable that came with it).  I am sure better data can be produced.  With that said, it yielded impressive results for a $200 VNA.  If this brief report is useful, I can update it as I continue experimenting.

Steve Cheng 2021/12/06 22:06

Thank you so much for sharing the experiment info, this is very valuable
for us to knowing its present capability… Thanks.



Steve

Gary Cobb 2021/12/07 04:10

Hi Tom,

You've taken a lot of time and trouble in your detailed analysis. However, I belive you are tying to compare apples and pears.

You measures on both the HP8720 and the Keysight E8364 are commendable and is an excellent test for both these instruments. But, I take it you have used the full 2-port, 12-term, calibration which is all well and good accept that you are comparing these results with the Nano which doesn't take account, in any meaningful way, of the Port-2 characteristics - basically, just a 3-term Port-1 cal and thru normalisation using the known poor reflection coefficient. The tests you have performed are just for the S21 parameter and a 3-term model cannot be seriously compared tp that of a 12-term model.

It might be more constructive to compare S11 measures with your lovely air-line and Beaty standards, together with the calibration load as a DUT termination, as the calibrations would be more appropriately comparable. These results would be more meaningful for those of us that have just a, so called, 2-port, single path, NanoVNA.

Regards
Gary

Joe Smith 2021/12/07 05:30

You may want to correct the model of the VNA you used (64C or 62C).

I had looked at the system dynamic range of the V2Plus and V2Plus4.  What you show with the 90dB attenuator on your NanoVNA V2 is much better.   I take it you have a way to pull the data off your V2 without interfering with the calibration.    I can't do this with the V2Plus but after seeing how well yours performed, I will try it standalone and see if I get better results.

We are waiting on the LiteVNA to arrive.

Francesco 2021/12/07 16:16

Please continue to send test on the NanoVNA 2+ and 2+4 ad moment I tray to
improve calibration standard but I don't have one professional VNA to compare
my test I need some reference (I'm lost)





**Sent:** Tuesday, December 07, 2021 at 3:49 AM
**From:** "tclupper via groups.io" <tclupper=yahoo.com@groups.io>
**To:** NanoVNAV2@groups.io
**Subject:** Re: [nanovnav2] Calibration

Hello. I recently compared S-parameter data from a couple of VNAs and
included the nanoVNA V2 4GHz in the experiment. Admittedly, I did not spent a
lot of time optimizing the calibration of the nanoVNA (I just used the
calibration that was built into the firmware and the standards and cable that
came with it). I am sure better data can be produced. With that said, it
yielded impressive results for a $200 VNA. If this brief report is useful, I
can update it as I continue experimenting.

_._,_._,_

* * *

tclupper 2021/12/07 08:31

Hi Gary,

Yes, I did realize that the nanoVNA only supports a one-path calibration technique (similar to the old HP8752A VNA).  However, I initially wanted to compare against a reference, or golden set of S-parameter files for a set of "standards" to see how well it did.  I was then planning on seeing how close I could make the S-parameters from the nanoVNA look to the reference by playing with various approaches and standards.  I am open to make whatever measurements folks suggest (So, I will include a one-path calibration in the next round).  I am looking for the best way to get the S-parameters off the nanoVNA and am looking for suggestions.  Thanks for your input.

mce66 2021/12/07 10:14

Hello Tom,

How did you collect data from NanoVNA? How did you apply the calibration? If the data was just collected from a SW outside the NanoVNA that also provide the calibration, maybe is this SW that is not calibrating the NanoVNA for S21 (enhanced calibtration).

Best Regards, Marco.

Francesco 2021/12/10 15:40

I got two screen shot for calibration load one is the best Chinese calibration
load on my possession of 6. And one of the best SMA recycled load from various
HP equipment's 14, It is one empiric mensuration

based on observation of this loads with this software and on other software,
NOT tested with one calibration standard.

I considered for one of less 200$ VNA is not to bad if is near to realistic
measure on the range +/- 3 dB is Good!

Wherever if there is some suggestion to make better mensuration is
**WELCOME.**

Not certainly with 3000$ of calibration kit
![](https://s.uicdn.com/3c-cdn/mail/client/wicket/resource/static-
res/---/mc/img/smileys/default/s_03.gif)



**Sent:** Tuesday, December 07, 2021 at 1:30 PM
**From:** "Joe Smith via groups.io" <joeqsmith49=yahoo.com@groups.io>
**To:** NanoVNAV2@groups.io
**Subject:** Re: [nanovnav2] Calibration

You may want to correct the model of the VNA you used (64C or 62C).

I had looked at the system dynamic range of the V2Plus and V2Plus4. What you
show with the 90dB attenuator on your NanoVNA V2 is much better. I take it
you have a way to pull the data off your V2 without interfering with the
calibration. I can't do this with the V2Plus but after seeing how well
yours performed, I will try it standalone and see if I get better results.

We are waiting on the LiteVNA to arrive.

_._,_._,_

* * *

W0LEV 2021/12/10 18:29

After many comparisons between the HP 8753C and the precision HP standards,
I can assure you the NANOs are far better than ±3 dB. I have several
friends who are still working who professionally use the NANOs in their
work. They are the best piece of test equipment to be released at an
affordable price since the introduction of the DMM (digital multimeter)
decades ago.

Dave - WØLEV

On Fri, Dec 10, 2021 at 2:40 PM Francesco <realfran@gmx.co.uk> wrote:

> I got two screen shot for calibration load one is the best Chinese
> calibration load on my possession of 6. And one of the best SMA recycled
> load from various HP equipment's 14, It is one empiric mensuration
> based on observation of this loads with this software and on other
> software, NOT tested with one calibration standard.
> I considered for one of less 200$ VNA is not to bad if is near to
> realistic measure on the range +/- 3 dB is Good!
> Wherever if there is some suggestion to make better mensuration is
> *WELCOME.*
> Not certainly with 3000$ of calibration kit
>
> *Sent:* Tuesday, December 07, 2021 at 1:30 PM
> *From:* "Joe Smith via groups.io" <joeqsmith49=yahoo.com@groups.io>
> *To:* NanoVNAV2@groups.io
> *Subject:* Re: [nanovnav2] Calibration
> You may want to correct the model of the VNA you used (64C or 62C).
>
> I had looked at the system dynamic range of the V2Plus and V2Plus4. What
> you show with the 90dB attenuator on your NanoVNA V2 is much better. I
> take it you have a way to pull the data off your V2 without interfering
> with the calibration. I can't do this with the V2Plus but after seeing
> how well yours performed, I will try it standalone and see if I get better
> results.
>
> We are waiting on the LiteVNA to arrive.
>
>
>

--
*Dave - WØLEV*
*Just Let Darwin Work*

Francesco 2021/12/10 20:50

Hello Dave, this make me happy thank you ad moment I stumbling around in the
dark, this is the best calibration I make, not any reference with any
professional calibration standard kit.

Possible you can give me one idea reading the screen shot? or some idea to
make better calibration, I'm NOT one professional metrologist. Only one
geriatric 76 old boy playing with the NanoVNA.

73/G7OYO

Francesco





**Sent:** Friday, December 10, 2021 at 6:29 PM
**From:** "W0LEV" <davearea51a@gmail.com>
**To:** NanoVNAV2@groups.io
**Subject:** Re: [nanovnav2] Calibration

After many comparisons between the HP 8753C and the precision HP standards, I
can assure you the NANOs are far better than ±3 dB. I have several friends
who are still working who professionally use the NANOs in their work. They
are the best piece of test equipment to be released at an affordable price
since the introduction of the DMM (digital multimeter) decades ago.



Dave - WØLEV



On Fri, Dec 10, 2021 at 2:40 PM Francesco
<[realfran@gmx.co.uk](mailto:realfran@gmx.co.uk)> wrote:

> I got two screen shot for calibration load one is the best Chinese
calibration load on my possession of 6. And one of the best SMA recycled load
from various HP equipment's 14, It is one empiric mensuration

>

> based on observation of this loads with this software and on other software,
NOT tested with one calibration standard.

>

> I considered for one of less 200$ VNA is not to bad if is near to realistic
measure on the range +/- 3 dB is Good!

>

> Wherever if there is some suggestion to make better mensuration is
**WELCOME.**

>

> Not certainly with 3000$ of calibration kit
![](https://s.uicdn.com/3c-cdn/mail/client/wicket/resource/static-
res/---/mc/img/smileys/default/s_03.gif)

>

>
>

> **Sent:** Tuesday, December 07, 2021 at 1:30 PM
> **From:** "Joe Smith via [groups.io](http://groups.io)"
<joeqsmith49=[yahoo.com@groups.io](mailto:yahoo.com@groups.io)>
> **To:** [NanoVNAV2@groups.io](mailto:NanoVNAV2@groups.io)
> **Subject:** Re: [nanovnav2] Calibration

>

> You may want to correct the model of the VNA you used (64C or 62C).
>
> I had looked at the system dynamic range of the V2Plus and V2Plus4. What
you show with the 90dB attenuator on your NanoVNA V2 is much better. I take
it you have a way to pull the data off your V2 without interfering with the
calibration. I can't do this with the V2Plus but after seeing how well
yours performed, I will try it standalone and see if I get better results.
>
> We are waiting on the LiteVNA to arrive.
>

>
>

>



\--

**Dave - W ØLEV**

_**Just Let Darwin Work**_

_._,_._,_

* * *

aleks07111971 2021/12/10 14:29

Hi all!
Please tell me how to determine the delay, when carrying out calibration, knowing the geometry of the load?
Are there any formulas?

W0LEV 2021/12/10 23:46

If you are making only reflection or SWR measurements, all that is required
for cal. is an OSL (Open, Short, Load). If you are making transmission
measurements like measuring the response of a bandpass filter or
attenuator, the full OSLT (Open, Short, Load, Through) will be necessary.
Since you are not experienced, I would hold off on measuring active devices
like amplifiers or LNAs for the time being.

Don't feel anything regarding your 76 years of age. I'm 75 (recently) but
have worked in the field for years.

I would strongly advise you to use the cal. procedure embedded in SAVER or
the other dedicated apps for the NANOs. These are supported on an external
PC or laptop via the USB interconnection. They will guide you through the
complete cal. procedure. Once you learn the procedures using those canned
apps, then graduate to the cals. directly with the stand-alone NANOs. Once
you believe you have a good cal, go back in measurement mode and check the
OSL on the output port (source port or S11). The Smith Chart is the best
display to verify a good OSL cal. Open should be on the horizontal line at
the extreme right of the chart, short should be on the horizontal line at
the extreme left of the chart, and load should be "bullseye" on the
horizontal line in the center of the chart. For more information, also
consult the WIKI associated with this site. There is much excellent
information there.

Dave - WØLEV

On Fri, Dec 10, 2021 at 7:50 PM Francesco <realfran@gmx.co.uk> wrote:

> Hello Dave, this make me happy thank you ad moment I stumbling around in
> the dark, this is the best calibration I make, not any reference with any
> professional calibration standard kit.
> Possible you can give me one idea reading the screen shot? or some idea to
> make better calibration, I'm NOT one professional metrologist. Only one
> geriatric 76 old boy playing with the NanoVNA.
> 73/G7OYO
> Francesco
>
>
> *Sent:* Friday, December 10, 2021 at 6:29 PM
> *From:* "W0LEV" <davearea51a@gmail.com>
> *To:* NanoVNAV2@groups.io
> *Subject:* Re: [nanovnav2] Calibration
> After many comparisons between the HP 8753C and the precision HP
> standards, I can assure you the NANOs are far better than ±3 dB. I have
> several friends who are still working who professionally use the NANOs in
> their work. They are the best piece of test equipment to be released at an
> affordable price since the introduction of the DMM (digital multimeter)
> decades ago.
>
> Dave - WØLEV
>
> On Fri, Dec 10, 2021 at 2:40 PM Francesco <realfran@gmx.co.uk> wrote:
>
>> I got two screen shot for calibration load one is the best Chinese
>> calibration load on my possession of 6. And one of the best SMA recycled
>> load from various HP equipment's 14, It is one empiric mensuration
>> based on observation of this loads with this software and on other
>> software, NOT tested with one calibration standard.
>> I considered for one of less 200$ VNA is not to bad if is near to
>> realistic measure on the range +/- 3 dB is Good!
>> Wherever if there is some suggestion to make better mensuration is
>> *WELCOME.*
>> Not certainly with 3000$ of calibration kit
>>
>> *Sent:* Tuesday, December 07, 2021 at 1:30 PM
>> *From:* "Joe Smith via groups.io" <joeqsmith49=yahoo.com@groups.io>
>> *To:* NanoVNAV2@groups.io
>> *Subject:* Re: [nanovnav2] Calibration
>> You may want to correct the model of the VNA you used (64C or 62C).
>>
>> I had looked at the system dynamic range of the V2Plus and V2Plus4. What
>> you show with the 90dB attenuator on your NanoVNA V2 is much better. I
>> take it you have a way to pull the data off your V2 without interfering
>> with the calibration. I can't do this with the V2Plus but after seeing
>> how well yours performed, I will try it standalone and see if I get better
>> results.
>>
>> We are waiting on the LiteVNA to arrive.
>>
>>
>>
>>
>>
>
>
> --
> *Dave - WØLEV*
> *Just Let Darwin Work*
>
>
>

--
*Dave - WØLEV*
*Just Let Darwin Work*

aleks07111971 2021/12/10 15:54

All this is not interesting to me!
I wonder how to set the delay based on the geometry of the loads.

W0LEV 2021/12/10 23:59

I was not responding to your specific question, but, rather, the original
post.

But,........what is the geometry of your load? Without that, I can't help.

Dave - WØLEV

On Fri, Dec 10, 2021 at 11:54 PM <aleks07111971@yandex.ru> wrote:

> All this is not interesting to me!
> I wonder how to set the delay based on the geometry of the loads.
>
>
>
>

--
*Dave - WØLEV*
*Just Let Darwin Work*

aleks07111971 2021/12/10 16:09

Open 10mm, Short 15mm, Load 40mm.

W0LEV 2021/12/11 00:29

Why must these be so different? What is the system you are attempting to
measure.

On Sat, Dec 11, 2021 at 12:09 AM <aleks07111971@yandex.ru> wrote:

> Open 10mm, Short 15mm, Load 40mm.
>
>
>

--
*Dave - WØLEV*
*Just Let Darwin Work*

aleks07111971 2021/12/10 16:58

The dimensions are relative, I want to understand the principle.
I need to convert mm to nc

Francesco 2021/12/11 11:45

Thank you for your courtesy and time, my not express my question properly:

1\. If I make the SOLT calibration with the original NanoVNA calibration kit,
all my SMA 50ohm load US made with military specs hare not good.

2\. If I make the SOLT calibration on the NanoVNA with SMA 50ohm load US made
with military specs, the Chinese load is bad.

May question: The result of the measured is determined from the calibration
load I use?

On this case there no way to distinguish the bad and the good? The only
solution is one tested calibration kit for reference.

I stumbling around in the dark, asking myself **; which is true?**

**73/G7OYO**

**Francesco.**

**Sent:** Friday, December 10, 2021 at 11:46 PM
**From:** "W0LEV" <davearea51a@gmail.com>
**To:** NanoVNAV2@groups.io
**Subject:** Re: [nanovnav2] Calibration

If you are making only reflection or SWR measurements, all that is required
for cal. is an OSL (Open, Short, Load). If you are making transmission
measurements like measuring the response of a bandpass filter or attenuator,
the full OSLT (Open, Short, Load, Through) will be necessary. Since you are
not experienced, I would hold off on measuring active devices like amplifiers
or LNAs for the time being.



Don't feel anything regarding your 76 years of age. I'm 75 (recently) but
have worked in the field for years.



I would strongly advise you to use the cal. procedure embedded in SAVER or the
other dedicated apps for the NANOs. These are supported on an external PC or
laptop via the USB interconnection. They will guide you through the complete
cal. procedure. Once you learn the procedures using those canned apps, then
graduate to the cals. directly with the stand-alone NANOs. Once you believe
you have a good cal, go back in measurement mode and check the OSL on the
output port (source port or S11). The Smith Chart is the best display to
verify a good OSL cal. Open should be on the horizontal line at the extreme
right of the chart, short should be on the horizontal line at the extreme left
of the chart, and load should be "bullseye" on the horizontal line in the
center of the chart. For more information, also consult the WIKI associated
with this site. There is much excellent information there.



Dave - WØLEV



On Fri, Dec 10, 2021 at 7:50 PM Francesco
<[realfran@gmx.co.uk](mailto:realfran@gmx.co.uk)> wrote:

> Hello Dave, this make me happy thank you ad moment I stumbling around in the
dark, this is the best calibration I make, not any reference with any
professional calibration standard kit.

>

> Possible you can give me one idea reading the screen shot? or some idea to
make better calibration, I'm NOT one professional metrologist. Only one
geriatric 76 old boy playing with the NanoVNA.

>

> 73/G7OYO

>

> Francesco

>

>
>

>
>

> **Sent:** Friday, December 10, 2021 at 6:29 PM
> **From:** "W0LEV" <[davearea51a@gmail.com](mailto:davearea51a@gmail.com)>
> **To:** [NanoVNAV2@groups.io](mailto:NanoVNAV2@groups.io)
> **Subject:** Re: [nanovnav2] Calibration

>

> After many comparisons between the HP 8753C and the precision HP standards,
I can assure you the NANOs are far better than ±3 dB. I have several friends
who are still working who professionally use the NANOs in their work. They
are the best piece of test equipment to be released at an affordable price
since the introduction of the DMM (digital multimeter) decades ago.

>

>
>

> Dave - WØLEV

>

>
>

> On Fri, Dec 10, 2021 at 2:40 PM Francesco
<[realfran@gmx.co.uk](mailto:realfran@gmx.co.uk)> wrote:

>

>> I got two screen shot for calibration load one is the best Chinese
calibration load on my possession of 6. And one of the best SMA recycled load
from various HP equipment's 14, It is one empiric mensuration

>>

>> based on observation of this loads with this software and on other
software, NOT tested with one calibration standard.

>>

>> I considered for one of less 200$ VNA is not to bad if is near to realistic
measure on the range +/- 3 dB is Good!

>>

>> Wherever if there is some suggestion to make better mensuration is
**WELCOME.**

>>

>> Not certainly with 3000$ of calibration kit
![](https://s.uicdn.com/3c-cdn/mail/client/wicket/resource/static-
res/---/mc/img/smileys/default/s_03.gif)

>>

>>
>>

>> **Sent:** Tuesday, December 07, 2021 at 1:30 PM
> **From:** "Joe Smith via [groups.io](http://groups.io)"
<joeqsmith49=[yahoo.com@groups.io](mailto:yahoo.com@groups.io)>
> **To:** [NanoVNAV2@groups.io](mailto:NanoVNAV2@groups.io)
> **Subject:** Re: [nanovnav2] Calibration

>>

>> You may want to correct the model of the VNA you used (64C or 62C).
>
> I had looked at the system dynamic range of the V2Plus and V2Plus4. What
you show with the 90dB attenuator on your NanoVNA V2 is much better. I take
it you have a way to pull the data off your V2 without interfering with the
calibration. I can't do this with the V2Plus but after seeing how well
yours performed, I will try it standalone and see if I get better results.
>
> We are waiting on the LiteVNA to arrive.
>>

>>
>>

>>
>

>
>
> \--

>

> **Dave - W ØLEV**

>

> _**Just Let Darwin Work**_

>

>
>

>



\--

**Dave - W ØLEV**

_**Just Let Darwin Work**_

_._,_._,_

* * *

Steve Cheng 2021/12/11 03:33

Please note that during the cal procedure the system simply treat whatever
open/shot/load/through you connected to the system as a perfect 50 ohm
OSLT, and train the system what a perfect 50 OSLT response should look
like. After cal it will report perfect 50 ohm OSLT connected only if you
connected the one you use during the cal procedure (or very close device)
as a good 50 ohm device. So you can tell which one is good only if you have
a know good set of OSLT cal kit.



Steve

W0LEV 2021/12/11 17:28

How different are the cal. standards between sets?

1) If you cal. with the US standards, how different are those compared to
the Chinese standards.

2) And the opposite of (1)?

3) Measure the 50-ohm load from each set with a DMM. Do they all measure
50-ohms DC? If not, how different are they from each other?

4) If you have a 50-ohm (47 or 51 ohms are standard values) "reasonable"
resistor, after cal., how does that measure against your cal. standard(s).
Use a frequency sweep of only 1 through 30 MHz for this comparison.

5) For anything of this sort, use only a frequency sweep of 1 through 30
MHz. Above this, parasitic inductance may be more of the measurement than
the actual standard.

Dave - WØLEV

On Sat, Dec 11, 2021 at 10:45 AM Francesco <realfran@gmx.co.uk> wrote:

> Thank you for your courtesy and time, my not express my question properly:
> 1. If I make the SOLT calibration with the original NanoVNA calibration
> kit, all my SMA 50ohm load US made with military specs hare not good.
> 2. If I make the SOLT calibration on the NanoVNA with SMA 50ohm load US
> made with military specs, the Chinese load is bad.
> May question: The result of the measured is determined from the
> calibration load I use?
> On this case there no way to distinguish the bad and the good? The only
> solution is one tested calibration kit for reference.
> I stumbling around in the dark, asking myself*; which is true?*
> *73/G7OYO*
> *Francesco.*
> *Sent:* Friday, December 10, 2021 at 11:46 PM
> *From:* "W0LEV" <davearea51a@gmail.com>
> *To:* NanoVNAV2@groups.io
> *Subject:* Re: [nanovnav2] Calibration
> If you are making only reflection or SWR measurements, all that is
> required for cal. is an OSL (Open, Short, Load). If you are making
> transmission measurements like measuring the response of a bandpass filter
> or attenuator, the full OSLT (Open, Short, Load, Through) will be
> necessary. Since you are not experienced, I would hold off on measuring
> active devices like amplifiers or LNAs for the time being.
>
> Don't feel anything regarding your 76 years of age. I'm 75 (recently) but
> have worked in the field for years.
>
> I would strongly advise you to use the cal. procedure embedded in SAVER or
> the other dedicated apps for the NANOs. These are supported on an external
> PC or laptop via the USB interconnection. They will guide you through the
> complete cal. procedure. Once you learn the procedures using those canned
> apps, then graduate to the cals. directly with the stand-alone NANOs. Once
> you believe you have a good cal, go back in measurement mode and check the
> OSL on the output port (source port or S11). The Smith Chart is the best
> display to verify a good OSL cal. Open should be on the horizontal line at
> the extreme right of the chart, short should be on the horizontal line at
> the extreme left of the chart, and load should be "bullseye" on the
> horizontal line in the center of the chart. For more information, also
> consult the WIKI associated with this site. There is much excellent
> information there.
>
> Dave - WØLEV
>
> On Fri, Dec 10, 2021 at 7:50 PM Francesco <realfran@gmx.co.uk> wrote:
>
>> Hello Dave, this make me happy thank you ad moment I stumbling around in
>> the dark, this is the best calibration I make, not any reference with any
>> professional calibration standard kit.
>> Possible you can give me one idea reading the screen shot? or some idea
>> to make better calibration, I'm NOT one professional metrologist. Only one
>> geriatric 76 old boy playing with the NanoVNA.
>> 73/G7OYO
>> Francesco
>>
>>
>> *Sent:* Friday, December 10, 2021 at 6:29 PM
>> *From:* "W0LEV" <davearea51a@gmail.com>
>> *To:* NanoVNAV2@groups.io
>> *Subject:* Re: [nanovnav2] Calibration
>> After many comparisons between the HP 8753C and the precision HP
>> standards, I can assure you the NANOs are far better than ±3 dB. I have
>> several friends who are still working who professionally use the NANOs in
>> their work. They are the best piece of test equipment to be released at an
>> affordable price since the introduction of the DMM (digital multimeter)
>> decades ago.
>>
>> Dave - WØLEV
>>
>> On Fri, Dec 10, 2021 at 2:40 PM Francesco <realfran@gmx.co.uk> wrote:
>>
>>> I got two screen shot for calibration load one is the best Chinese
>>> calibration load on my possession of 6. And one of the best SMA recycled
>>> load from various HP equipment's 14, It is one empiric mensuration
>>> based on observation of this loads with this software and on other
>>> software, NOT tested with one calibration standard.
>>> I considered for one of less 200$ VNA is not to bad if is near to
>>> realistic measure on the range +/- 3 dB is Good!
>>> Wherever if there is some suggestion to make better mensuration is
>>> *WELCOME.*
>>> Not certainly with 3000$ of calibration kit
>>>
>>> *Sent:* Tuesday, December 07, 2021 at 1:30 PM
>>> *From:* "Joe Smith via groups.io" <joeqsmith49=yahoo.com@groups.io>
>>> *To:* NanoVNAV2@groups.io
>>> *Subject:* Re: [nanovnav2] Calibration
>>> You may want to correct the model of the VNA you used (64C or 62C).
>>>
>>> I had looked at the system dynamic range of the V2Plus and V2Plus4.
>>> What you show with the 90dB attenuator on your NanoVNA V2 is much better.
>>> I take it you have a way to pull the data off your V2 without interfering
>>> with the calibration. I can't do this with the V2Plus but after seeing
>>> how well yours performed, I will try it standalone and see if I get better
>>> results.
>>>
>>> We are waiting on the LiteVNA to arrive.
>>>
>>>
>>>
>>>
>>>
>>
>>
>> --
>> *Dave - WØLEV*
>> *Just Let Darwin Work*
>>
>>
>>
>>
>>
>
>
> --
> *Dave - WØLEV*
> *Just Let Darwin Work*
>
>
>

--
*Dave - WØLEV*
*Just Let Darwin Work*

Joe Smith 2021/12/11 10:35

On Sat, Dec 11, 2021 at 06:45 PM, Francesco wrote:

>
> Thank you for your courtesy and time, my not express my question properly:
>
> 1. If I make the SOLT calibration with the original NanoVNA calibration
> kit, all my SMA 50ohm load US made with military specs hare not good.
> 2. If I make the SOLT calibration on the NanoVNA with SMA 50ohm load US
> made with military specs, the Chinese load is bad.
> May question: The result of the measured is determined from the
> calibration load I use?
> On this case there no way to distinguish the bad and the good? The only
> solution is one tested calibration kit for reference.
> I stumbling around in the dark, asking myself *; which is true?*
> *73/G7OYO*
> *Francesco.*
>

I suggest neither are true!!  One may be closer to true in some areas than others but both are certainly not perfect.  Adding your box is certainly not going to help but you seem to like it.  Maybe in the future I can provide you with software that will help remove some of the errors you are introducing but don't look for it anytime soon.

If you look at my document, figure 25, I show six different loads.  Note that everyone of them gives a different answer.  Two of the parts shown are a Mini-Circuits ANNE-50+.  I bought seven of them and then sorted the parts.  The two shown in figure 25 were the best of the group.  These two are what I currently use which is good enough in my case but still not true!   Attached you can see where I have the V2Plus4 powered on with no calibration at all, then attaching a home made load on FR4 (Yellow trace).   Not too bad.  I then run a 1-port SOL cal and measure the same load (purple).  Looks really good out to 3.5GHz or so (of course, we know that answer is not even close to true).    Last, I insert the Mini-circuits ANNE that I had sorted and use for a standard (red).  Of course, the calibration is obviously not very good.

What are your requirements?  Think about it.   Do you really need to measure VSWR three places beyond the decimal (someone actually posted that!)?   You can certainly buy your way into a very good class of standards and equipment if that's what you need.  On the low end side there may be new standards that fit your needs under $1000 USD.   I think the two sets shown in the document that I had on loan were closer to $10,000 ea.   They still won't provide true answers.

Jim Lux 2021/12/11 11:21

Re 1,2

There are both good and bad quality standards made all over the world. Perhaps the really cheap ones imported from China might be worse, in general.  But ultimately, it's a matter of manufacturing tolerances (there's no "secret design" in a SMA short or open, or even  load), and unless you're in a metrology lab, the machining tolerances are much the same, if they're built from "off the shelf" SMA connectors.  A metrology lab, buying calibration standards, might impose and expect tighter tolerances on things like the flatness of the mating surfaces, the dimensions of the center pin, where the dielectric starts and ends, etc. They'll have a bunch of mechanical gauges to check.  And, of course, they won't usually use SMA for precision work - APC-7, APC-3.5, 2.92mm, etc. would be more typical.

re 3,4,5

Yes, measuring a 51 ohm, or a 27 ohm, or a 82 ohm, or 100 ohms is a good cross check.

W0LEV 2021/12/11 20:07

I have found the cal standards supplied with the NANOs are pretty good
against HP precision cal. standards (both the SMA and N-types). I haven't
tested those of recent issue, but nearly all the original through the H4
were excellent as compared against the HP standards.

Yes, test other resistors, if you have them as Jim suggested. However, and
again, set the sweep from 1 through 30 MHz. Stay out of the VHF/UHF/µwave
range for initial confirmations of your standards. As the frequency
increases, parasitic components inherent with the resistors and other
lumped elements may come into play and confuse the real issue(s).

Again, rather than an S21 or throughput measurement, the Smith Chart S11
shows variables in what you are attempting to measure a bit more
intuitively.

On Sat, Dec 11, 2021 at 7:21 PM Jim Lux <jim@luxfamily.com> wrote:

> Re 1,2
>
> There are both good and bad quality standards made all over the world.
> Perhaps the really cheap ones imported from China might be worse, in
> general. But ultimately, it's a matter of manufacturing tolerances
> (there's no "secret design" in a SMA short or open, or even load), and
> unless you're in a metrology lab, the machining tolerances are much the
> same, if they're built from "off the shelf" SMA connectors. A metrology
> lab, buying calibration standards, might impose and expect tighter
> tolerances on things like the flatness of the mating surfaces, the
> dimensions of the center pin, where the dielectric starts and ends, etc.
> They'll have a bunch of mechanical gauges to check. And, of course, they
> won't usually use SMA for precision work - APC-7, APC-3.5, 2.92mm, etc.
> would be more typical.
>
>
>
> re 3,4,5
>
> Yes, measuring a 51 ohm, or a 27 ohm, or a 82 ohm, or 100 ohms is a good
> cross check.
>
>
>

--
*Dave - WØLEV*
*Just Let Darwin Work*

Francesco 2021/12/11 22:55

Yes, make sense ("neither are true!!) The absolute measure even on $10.000
instrument is not possible. I learn a lot on this and I'm gratefully to you
for take me on the right track I read the manual, my question is possible to
select the best reliable load for the NanoVNA without one reference load?



I don't ask for metrology grade stuff but some decent relatable for the
NanoVNA possibility, with your software make one gadget to one relatable
instrument for small home lab. This is my ambition.



For the BOX; I tested with and without the box and I don't notate big
difference "The box is one HP 8711A Switching test set the 2 Tranfer Relay
inside 100dB/4Ghz isolation I change only the

board for power the transfer relay all the RF part still the same from
original, the same connectors the rigid cable still the same, only on one end
there is connected the NanoVNA directly on the T/R torqued, on the RF part I
lived all connection on the original status for not alterate the RF circuit. I
got two NanoVNA V2 plus I test both and I waiting for the LiteVNA (probably
arrive before the end of December).

I hope sun get the V3 of you software when is published.

Thank you again for your suggestion.

Francesco.





**Sent:** Saturday, December 11, 2021 at 6:35 PM
**From:** "Joe Smith via groups.io" <joeqsmith49=yahoo.com@groups.io>
**To:** NanoVNAV2@groups.io
**Subject:** Re: [nanovnav2] Calibration

On Sat, Dec 11, 2021 at 06:45 PM, Francesco wrote:

> Thank you for your courtesy and time, my not express my question properly:

>

> 1\. If I make the SOLT calibration with the original NanoVNA calibration
kit, all my SMA 50ohm load US made with military specs hare not good.

>

> 2\. If I make the SOLT calibration on the NanoVNA with SMA 50ohm load US
made with military specs, the Chinese load is bad.

>

> May question: The result of the measured is determined from the calibration
load I use?

>

> On this case there no way to distinguish the bad and the good? The only
solution is one tested calibration kit for reference.

>

> I stumbling around in the dark, asking myself **; which is true?**

>

> **73/G7OYO**

>

> **Francesco.**

I suggest neither are true!! One may be closer to true in some areas than
others but both are certainly not perfect. Adding your box is certainly not
going to help but you seem to like it. Maybe in the future I can provide you
with software that will help remove some of the errors you are introducing but
don't look for it anytime soon.

If you look at my document, figure 25, I show six different loads. Note that
everyone of them gives a different answer. Two of the parts shown are a Mini-
Circuits ANNE-50+. I bought seven of them and then sorted the parts. The two
shown in figure 25 were the best of the group. These two are what I currently
use which is good enough in my case but still not true! Attached you can see
where I have the V2Plus4 powered on with no calibration at all, then attaching
a home made load on FR4 (Yellow trace). Not too bad. I then run a 1-port
SOL cal and measure the same load (purple). Looks really good out to 3.5GHz
or so (of course, we know that answer is not even close to true). Last, I
insert the Mini-circuits ANNE that I had sorted and use for a standard (red).
Of course, the calibration is obviously not very good.

What are your requirements? Think about it. Do you really need to measure
VSWR three places beyond the decimal (someone actually posted that!)? You
can certainly buy your way into a very good class of standards and equipment
if that's what you need. On the low end side there may be new standards that
fit your needs under $1000 USD. I think the two sets shown in the document
that I had on loan were closer to $10,000 ea. They still won't provide true
answers.

_._,_._,_

* * *

Joe Smith 2021/12/11 17:21

On Sun, Dec 12, 2021 at 05:55 AM, Francesco wrote:

>
> my question is possible to select the best reliable load for the NanoVNA
> without one reference load?
>
> I don't ask for metrology grade stuff but some decent relatable for the
> NanoVNA possibility, with your software make one gadget to one relatable
> instrument for small home lab. This is my ambition.
>
> For the BOX; I tested with and without the box and I don't notate big
> difference "The box is one HP 8711A Switching test set the 2 Tranfer Relay
> inside 100dB/4Ghz isolation I change only the
> board for power the transfer relay all the RF part still the same from
> original, the same connectors the rigid cable still the same, only on one
> end there is connected the NanoVNA directly on the T/R torqued, on the RF
> part I lived all connection on the original status for not alterate the RF
> circuit. I got two NanoVNA V2 plus I test both and I waiting for the
> LiteVNA (probably arrive before the end of December).
> I hope sun get the V3 of you software when is published.
> Thank you again for your suggestion.
> Francesco.
>

I've only ever looked at my own software and currently it is not possible to calibrate the VNA without a load.  Other software could very well support more advanced methods.   As you can see in Figure 25, the return loss for the supplied loads is not very good compared with an actual standard.  The original part supplied with my first NanoVNA was by far the worse but that VNA isn't much good above 290MHz anyway.  It's fine for that application.   Even if TRL was supported, you would still need a set of standards (Figure 27).

Again, be aware that the latest available software on Github doesn't account for the switch errors.  The fact you are happy with what you have, says a little bit about your needs.  When I bought my vintage VNA, I was looking for a 4Xreceiver.  I use SOLR a fair bit and am attempting to learn more about it.  That's really the reason for V3.   It won't help you measure your antenna SWR but I certainly have other uses for it.  With you playing around with the transfer relay, you may also find a use for it.  Join up on EEVBLOG and post some of your projects.   I'm interested in seeing what you are doing.

Joe Smith 2021/12/12 09:48

On Mon, Dec 13, 2021 at 12:54 AM, Steve Cheng wrote:

>
> Please note that during the cal procedure the system simply treat whatever
> open/shot/load/through you connected to the system as a perfect 50 ohm
> OSLT, and train the system what a perfect 50 OSLT response should look
> like. After cal it will report perfect 50 ohm OSLT connected only if you
> connected the one you use during the cal procedure (or very close device)
> as a good 50 ohm device. So you can tell which one is good only if you
> have a know good set of OSLT cal kit.

Sort of but if you perform a one port SOL and leave the load attached and measure it, it will still not be perfect.  We can use this to get some idea what the noise floor looks like.  With the SOLT, we can also look at S21 to get some idea what the system dynamic range is.   With OP using a transfer relay and my software not accounting for the switch errors, we could certainly improve it by introducing the common 12 term error model.  Again, I do not do this today but it is certainly something easy enough to add.   The problem is the thru is not going to be characterized which is where I would like to include SOLR.  TRL would be next.  Problem is finding reference materials.

Dragan Milivojevic 2021/12/12 20:01

It seems that this is the accepted reference material for 12 and 16 term
calibration:
http://emlab.uiuc.edu/ece451/appnotes/Rytting_NAModels.pdf


On Sun, 12 Dec 2021 at 18:48, Joe Smith via groups.io <joeqsmith49=
yahoo.com@groups.io> wrote:

Joe Smith 2021/12/14 06:10

On Tue, Dec 7, 2021 at 12:17 PM, <tclupper@yahoo.com> wrote:

>
> Hello.  I recently compared S-parameter data from a couple of VNAs and
> included the nanoVNA V2 4GHz in the experiment.  Admittedly, I did not
> spent a lot of time optimizing the calibration of the nanoVNA (I just used
> the calibration that was built into the firmware and the standards and
> cable that came with it).  I am sure better data can be produced.  With
> that said, it yielded impressive results for a $200 VNA.  If this brief
> report is useful, I can update it as I continue experimenting.

I finally got around to repeating the test using my V2Plus4.  I ran a sweep from 3 - 4.4GHz, no cal, no USB connection, both ports terminated.  Next I tethered the VNA to the PC but did not start my software.  Noise goes up 15-20dB in this range.  I then cut a USB cable in half, routing the shield, data+/- and ground (no power).  I used this cable to tether the VNA to the PC and there was no difference between tethering the VNA or running it standalone.    Next I routed out a separate ground and power, allowing me to power the VNA from an isolated linear supply.  With the powered, the noise was roughly the same level as with it powered from the PC.    I tried a few other tests and it appears that any time the V2Plus4 is running from an external power source, the noise in the upper range increases dramatically.   I can run the VNA off the internal battery and the modified cable if I need the lower noise.

I am sure a few of you were aware of this.  It explains why the spec'ed numbers were on the edge.  Doubt I will dig into it or attempt to modify the original design.

Dave (G1OGY) 2021/12/14 15:38

This is mighty helpful, Joe.
Thanks.

Dave, G1OGY

On Tue, 14 Dec 2021 at 14:10, Joe Smith via groups.io
<joeqsmith49=yahoo.com@groups.io> wrote:

Dave Johnson 2021/12/15 06:25

The charge controller is likely the culprit although I haven’t taken my V2+4 apart to inspect the what chip is in there but they almost all have the typical noisy switching buck setup. Probably much easier to just break out the battery leads and run it from either a quality regulated bench supply, or a much larger 1S battery config.

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