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Re: The T-Check confusion

 

Hi Erik
Just one more practical comment. Whatever you do the single forward and the single reverse measurement s1p files does not carry any information about the port mismatch to take into account for the T-Check calculation.
And besides that I consider this discussion is only of pure interest how T-Check is done the right way, and my report was only to demonstrate some facts. I do not think 99% of the NanoVNA users are benefitted if such facilities was implemented in future and would not try to motivate such a initiative.
This product is great as is and a calibration is tested quite well investing in a semirigid cable of some 25cm both for frequency range up to 500MHz and 900MHz. To 1500MHz is does not show useable trace along the Smithchart circumference.
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af erik@...
Sendt: 9. december 2019 08:57
Til: [email protected]
Emne: Re: [nanovna-users] The T-Check confusion

Kurt,

It appears (in my limited understanding) the poor matching to Z0 of CH1 (port 2) is the biggest reason why the T-check is not performing well on the nanoVNA.
Would you agree that using a 10dB attenuator between DUT and CH1 (port 2) would solve most of this?
What would be the impact of the remaining non-compensated delay?
Should we add to the instructions that, for best nanoVNA 2 port DUT measurements one should seriously consider using a 10dB attenuator between DUT and CH1 (port 2) till new HW becomes available that solves the poor matching of CH1 (port2)?

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK
Re: Using the Nano as a receiver?

 

Is there a way to use it like a "scanner"?
Yes, CH1 is a receiver that looks for signals at the frequency (or harmonic) of CH0.
Keep in mind that nanoVNA steps, rather than sweeps,
so that if set for a wide span will probably miss a narrow bandwidth signal.
Re: Using the Nano as a receiver?

 

Read here:
/g/nanovna-users/topic/34079496#2165

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK
Re: The T-Check confusion

 

I've found and bought an affordable SMA transfer switch (2x2 switch) on eBay and I was hoping it would allow me to extend nanoVNA or one of my home build VNA's to full two port capability by extending the calibration routines in the TAPR VNA software
Do I understand correctly that, as you are not able to measure all errors using a transfer switch connected to port 1 and port 2, you can only do the TwoPortOnePath calibration?
What would be the impact of this in practice????
Given I can measure and ensure both ports are rather close to a real 50 ohm using a second VNA: would the inability to correct some errors have a major impact on practical measurements of filters that are sensitive to port mismatch?
Remember for me this is all hobby use and being able to measure with an error less then some/one dB is great

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK
Using the Nano as a receiver?

 

Hi,

I'm quite new to the topic. I learned a lot about the bad design of commonly available antennas and have modified quite a number since then with the help of the Nano.

From what I understand, a VNA is also a receiver (of its own signals). Is there a way to use it like a "scanner"? I do occasionally have to deal with Chinese HF transmitter setups, that only say "UHF" or "VHF" but do not specify the frequency. Normally I go to the company's testlab and have it checked for me.

Is there any practical way to use the NanonVNA for that purpose?

Thomas
Re: The T-Check confusion

 

Hi Gabriel
You are right it is a matter og software and for that matter firmware. As the NanoVNA is presently it does not have facilities embedded for neither calibration kit data and full 10/12 term error correction and none of the present software packages I know off has. That counts for NanoVNA-saver, NanoVNAsharp, NanoVNApartner or the TAPR adjusted program.
Thee link you provide is not implemented in the NanoVNA-saver but of course of interest for Rune to consider. You say it is trivial to use in NanoVNA-saver but that requires a "software developer brain" my comment are based on what is on hand for everyone.
The VNWA is actually a full two port devise as when fitted with a testset it swaps the direction so your comment is not entirely correct. It has besides a feature in the software (by pressing the F2 key) to do a full two port measurement, without having a testset attached and that is done by mechanically reverting the DUT between the forward and reverse sweep. So you study of the VNWA manual has not been complete.
Kid regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Gabriel Tenma White
Sendt: 9. december 2019 09:06
Til: [email protected]
Emne: Re: [nanovna-users] The T-Check confusion

On Mon, Dec 9, 2019 at 12:54 AM, Kurt Poulsen wrote:


Sorry these kind of measurements is only possible with a VNA having
10/12 term error correction facilities.
NanoVNA is not able to do such measurements.
This is wrong. I double checked the VNWA user guide and it is also a T/R VNA just like the Nano, not a full two port VNA. Therefore any calibration types used on the VNWA also apply to the Nano, it's just a matter of software.

What you are describing is the Two Port One Path calibration, which is nothing new and there is an implementation of it in scikit-rf:

Since scikit-rf is a Python library it is also trivial to use in nanovna-saver.
Re: errors of "error" models

 

@ Gary O'Neil, N3GO - 8 December 2019
/g/nanovna-users/message/8024

Dear Gary,

Once again, we thank you for your time.

You are right. Yes, this is indeed an endless, multidisciplinary, research
and one of its objectives is to bridge the gap between the now and the
past. Yes, we tried to see the fundamental ideas of quantities and their
ratio measurements in our sow, particularly in the two-port network case.
Well, this is not at all a simple task as it may sounds, because it has to
do with elementary concepts lying on the historical boundaries between
science and philosophy. Anyway, after many years of returning attempts,
we discovered yesterday that we had to restore the "multiplicative balance"
in the two basic, well-known, linear equations, that is instead e.g. of the
mathematical: b1=S11a1+S12a2, the "physical" one: 1.b1=S11.a1+S12.a2.
That was all.

Finally, yes, we also know that you are also absolutely right at all of the
rest matters you rise, including the badly shaped o, O, 0, 1 and l of MS
Courier New font and especially in this particular size. For that last one,
we will try to re-use the font of our choice: Liberation Mono, in an
appropriate size. of course. As of the above matters, unfortunately enough,
we have to invoke, once again, our permanent excuse : in our sow, this is
a research in progress and thus we have to find time to answer all of them.
We are terribly sorry for the inconvenience caused. Please, accept our apologies.

Best regards,

gin&pez@arg
Re: The T-Check confusion

 

Hi Eric
A 10dB att in the Ch1 path will not cure the problem as you also have a (invisible) mismatch in the Ch0 sourse impdance as well. So two attenuator might give some further improvements. But it is a fundamental problem as the 10/12 term error correction "totally" remove the tx and rx port mismatch and establish pure 50 ohm source and load impedance in the two calibration planes at the end of the two test cables. Always remember the test cables are an integral part of the VNA instrument and influence removed by the calibration. For the VNWA two custom traces with the expression SS and SL shows the source impedance (SS) and load impedance (SL) after a calibration at the two mentioned calibration planes. However the NanoVNA or for that matter any of the NanoVNA software has such facilities to do a complete S11/S21/S12/S22 measurement controlling a test switch reverting the DUT direction or any other smart tricks for passive bi-direction DUT's
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af erik@...
Sendt: 9. december 2019 08:57
Til: [email protected]
Emne: Re: [nanovna-users] The T-Check confusion

Kurt,

It appears (in my limited understanding) the poor matching to Z0 of CH1 (port 2) is the biggest reason why the T-check is not performing well on the nanoVNA.
Would you agree that using a 10dB attenuator between DUT and CH1 (port 2) would solve most of this?
What would be the impact of the remaining non-compensated delay?
Should we add to the instructions that, for best nanoVNA 2 port DUT measurements one should seriously consider using a 10dB attenuator between DUT and CH1 (port 2) till new HW becomes available that solves the poor matching of CH1 (port2)?

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK
Re: The T-Check confusion

 

I've deliberately chosen not to rely on scikit-rf in NanoVNA-Saver. Library
reliance is kept at a minimum, and figuring out the mathematics behind the
calibration was part of the fun of writing the software. :-)

I might implement 12-term calibration at some point, but it's not high on
my list. I'm still not sure it would be very useful. :-)

--
Rune / 5Q5R

On Mon, 9 Dec 2019 at 09:24, Gabriel Tenma White <OwOwOwOwO123@...>
wrote:

This might be unintuitive at first but long story short, a T/R VNA *can*
correct for a mismatched port 2 but *only if it knows the DUT's S22 and
S12*, which is why to do two port one path/enhanced response you must
either measure the DUT in both directions, or the DUT must be reciprocal,
even if you only care about S11 and S21.

More detailed explanation: When you measured the thru standard, you
already discovered the reflection coefficient of VNA port 2 (plus its
cable). You know S21 of the DUT, therefore you know how much power is
entering VNA port 2 and how much is reflected back into the DUT. However,
to know how the outgoing power from VNA port 2 affects the S11 (and other)
measurements, it is necessary to know in what way the DUT will scatter
power incident on DUT port 2 to port 1, etc. Therefore a reversed DUT
measurement is necessary. The math is pretty simple and it's just solving a
linear system of equations as usual.

TL;DR bug the nanovna-saver developer to implement two port one path using
scikit-rf, then do the SOLT calibration as usual, measure DUT forward and
reversed, and enjoy a 12-term full two port VNA ;)
Re: The T-Check confusion

 

Kurt,

It appears (in my limited understanding) the poor matching to Z0 of CH1 (port 2) is the biggest reason why the T-check is not performing well on the nanoVNA.
Would you agree that using a 10dB attenuator between DUT and CH1 (port 2) would solve most of this?
What would be the impact of the remaining non-compensated delay?
Should we add to the instructions that, for best nanoVNA 2 port DUT measurements one should seriously consider using a 10dB attenuator between DUT and CH1 (port 2) till new HW becomes available that solves the poor matching of CH1 (port2)?

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK
Re: Brand new user here

 

Stylus: Guitar pick works also

STX VHF/UHF Rover

On Dec 8, 2019, at 9:49 PM, k9wkj <k9wkjham@...> wrote:

?i use a pen cap or a tooth pick
its a resistive screen so anything pointy and non metalic will work
even a #2 pencil
Re: Brand new user here

Bob Albert
 

I find metallic works well.

On Sunday, December 8, 2019, 07:49:07 PM PST, k9wkj <k9wkjham@...> wrote:

i use a pen cap or a tooth pick
its a resistive screen so anything pointy and non metalic will work
even a #2 pencil
Re: Brand new user here

 

i use a pen cap or a tooth pick
its a resistive screen so anything pointy and non metalic will work
even a #2 pencil
Re: connector swap

 

Photos?



On Sun, 8 Dec 2019 at 1:49 PM, Nulluser00@...<Nulluser00@...> wrote: I mounted my NanoVNA on an Budd aluminim cast box and use male SMA to male SMA to a female SMA to male BNC to bulkhead female to female BNC.
I'm building a RF project gadget box with my
Elecraft XG-1 1/50uV 7.040KHz RF source
Electraft NG-1 RF white noise generator
and other stuff to be added as I go along.
Works great.
Re: 1.5 GHz ??

 

Oh that's useful information. I have some simple measurements to do at 1.2Ghz, will give it a try.

On 12/8/2019 4:34 PM, Bob Albert via Groups.Io wrote:
No configuring necessary.? Simply key in the frequency.
By default it comes up with 900 MHz but you can ask for up to 1.5 GHz and you will get it.
Bob
On Sunday, December 8, 2019, 04:09:55 PM PST, David Eckhardt <davearea51a@...> wrote:
I have read elsewhere than the NANOVNA will operate to1.5 GHz.? Is this
ture?? If so, how do I configure it to do so?
Re: Brand new user here

 

Try your local computer store. I just bought a pack of 10 from Amazon for
less that $& US.
*Clyde K. Spencer*

On Sun, Dec 8, 2019 at 3:52 PM Ray, W4BYG <w4byg@...> wrote:

Clyde,
Thank you. No I don't have a stylus. Not quite sure where to find one.
Ray, W4BYG

On 12/7/2019 10:09 PM, Clyde Spencer wrote:
Have you used a stylus? Fingers are too large for that little screen.
*Clyde K. Spencer*



On Sat, Dec 7, 2019 at 7:53 PM Ray, W4BYG <w4byg@...> wrote:

Just received my new NanoVNA and beginning to learn how to use it. I
have read the "user guide" but it is not much help with my problems:

After I set the menu settings for display, frequency, etc., and start
trying to use it, I am having trouble moving the markers to where I want
them on the trace.

As I go to touch a marker to move it where I want it, the menu comes up
automatically on the right and the marker doesn't move. I close the menu
and try again with the same result. Repeated attempts will eventually
allow me to move the marker, but it is still problematic.

What am I doing wrong or missing?

Also, is there a setting where I can tell it to boot back up to my last
screen settings, instead of the factory default out to 900 MHz? This
would allow saving the battery when I have to be make extended changes
to an antenna and not have to reprogram everything again.

Additionally: Is there software for use with a Win 7 or Win 10 PC and
for Android?

Your assistance would be appreciated.
Ray, W4BYG
Re: nanoVNAPartner v0.17

 

I have this problem also.

On 12/8/2019 8:36 AM, Shmulik Shechter wrote:
i'm not sure i am the first to alert it, but....
somehow the link is blocked by Anti Virus , which states that this site or the file contains " a risk" while the browser tries to reach it.
it might that the site is the problem and not the content , but, is there a way to place it in other location NOT in this site?
--
Cheers, Ed Humphries, KT4ED
Re: The T-Check confusion

 

Hi Herman
First of all it is not the mini-VNA it is the DG8SAQ VNWA.
Sorry these kind of measurements is only possible with a VNA having 10/12 term error correction facilities.
NanoVNA is not able to do such measurements.
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Herman De Dauw
Sendt: 9. december 2019 00:01
Til: [email protected]
Emne: Re: [nanovna-users] The T-Check confusion

Please, can you not make the PDF with plots of the NanoVNA, and not the Mini-VNA ?
Re: 1.5 GHz ??

Bob Albert
 

No configuring necessary.? Simply key in the frequency.
By default it comes up with 900 MHz but you can ask for up to 1.5 GHz and you will get it.
Bob

On Sunday, December 8, 2019, 04:09:55 PM PST, David Eckhardt <davearea51a@...> wrote:

I have read elsewhere than the NANOVNA will operate to1.5 GHz.? Is this
ture?? If so, how do I configure it to do so?

--

*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*
1.5 GHz ??

 

I have read elsewhere than the NANOVNA will operate to1.5 GHz. Is this
ture? If so, how do I configure it to do so?

--

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