开云体育

ps...

For the record, I value Dave K's content.
He seems a decent chap and I'd buy him a drink anytime.
I just don't quite like the presentation of the messages in a hobbyist forum.

I don't go bragging about my titles, (I officially have a Lord's title, I don't brag about my qualifications, or the numerous
world first patents that some you may even be using right now ;-)

I'm just plain old Mister Andy, in a hobbyist on a forum having fun with other hobbyists.

Damn me if you want, but I'll still be holding my head up high.

73 de Andy

Hello Yza;

I admire and appreciate your persistence, as well your desire to stay on topic. I suspect this discussion is far above most on this list... myself included. There may be a few whose attention you have not yet captured, but whose support and insight may prove worthwhile when they realize the extent and focus of your work.

Your posts have been difficult to follow, but not impossible, and I’ve tried to dig a bit into your questions to see if there are any I can answer.

Some questions first:

1) Are you proposing your DERDEI software (algorithms) with “uncharacterized” standards as an alternative to using error coefficient polynomials that rely on “characterized” standards?

or

2) Are you proposing your DERDEI software (algorithms) with “characterized” standards as an enhancement to existing calibration processes as a means to establish boundaries on residual post calibration uncertainties?

or

3) Are you proposing a tertiary algorithm to be used as a means of fairly comparing the hardware performance of two independent VNA platforms; such as when making like measurements of an identical device on two completely independent VNA’s but under otherwise exacting conditions?

3) Are you in search of Beta testers of your DERDEI program using NanoVNA raw data, corrected post calibration data using uncharacterized standards, or corrected post calibration data using traceable characterized standards?

4) In your example INPUT.TXT file, the fourth input (AUT) is assumed to be Antenna Under Test. Are these the measurements of the UHF ground plane antenna in the described anechoic chamber environment described?

5) Is the purpose of the INPUT.TXT file intended for our evaluation and comments, or as a test file to verify your software is correctly installed and functional?

6) What do you want/need from users on this list in our response to you on this software? Most on this list lack VNA experience, and most DO NOT have characterized SOL or SOLT standards.

To answer your early question as to what is used in the NanoVNA, my “guess” would confirm your suspicion of missing terms in the calibration routine. There are no provisions for the input of calibration error coefficients of a user’s unique set of standards. Therefore; calibration terms embedded in the firmware of the NanoVNA would at best have no meaning, and at worst introduce error uncertainties of their own. I do not however have any knowledge of how calibration is achieved, or uncertainties defined... other than to say they are declared to be zero as this is generally acceptable to most amateur enthusiasts.

There are however two sources you may want to review if you haven’t done so already.

The hardware and software is open source, and derived from the efforts of edy555 in Japan. The NanoVNA is feature rich, but the product is restricted to the processors on chip resources, and thus memory limited...likely insufficient to accommodate supporting more sophisticated error correction algorithms.



NanoVNA Saver is an Open Source GUI supporting a PC connected NanoVNA that has made provisions for incorporating calibration coefficients for the standards in use in the calibration routine employed by that program, presumably using the NanoVNA’s raw data. It is written in Python and should be straight forward to analyze. It’s author Rune Broberg would the source to question the algorithms he employs.

/g/nanovna-users/files/NanoVNA%20PC%20Software/NanoVNA-Saver

You commented: “Well, we don't mean to offend you but, in our humble opinion, the whole story of
hp "error" models is just a myth serving the powerful advertisement.” While not intended to sound offensive, this likely did raise a few hackles. :-) Your use of the term myth suggests you may be slightly mis-informed.

HP, R & S, and others have a competing interest in growing the RF industry. There is no question that marketing among them is highly competitive as well. To their market however; capability, repeatability, stability, and accuracy are unquenchable demands, and the key parameters used to differentiate one vendor from another. Mythical error models would yield failed products by their customer base, and as such their business wouldn’t thrive. That said; the quest for absolute accuracy will continue until everybody is certain, and in unanimous agreement, that absolute accuracy has been achieved. :-)

I wish I could help you more, but this is likely my best effort toward your cause. Perhaps it will seed further discussion of your proposal, or the comments of others; as it appears to have merit for consideration.

You stated your efforts are Open Source, and have provided good resource links to launch and evaluate your software. Is there an online forum corroborating your efforts?

--
73

Gary, N3GO

Hello,

Allow us, please, to inform the interested reader
and/or contributor that we shall copy -"just in
case"- sometime later, all of our messages from
here to out there:



Sincerely,

yin&pez@arg

9

One other note Rune. And others can comment in if I am off base. After thinking about this a bit more, there may be an issue in obtaining GD and what is known as differential group delay accurately particularly for NARROW band networks. The Nanovna is currently limited to 101 data points. No issue for wide band networks but for narrow band there may be a problem with just 101 points to obtain a sufficiently small aperture. As a rule of thumb, to get GD proper, the frequency step size must be a fraction of the network band width. Taking that into consideration, 101 data points may fall short of the desired resolution to obtain GD. Maybe not, have to run a simulation for grins on say a crystal filter or a very high Q LC filter and see if this is an issue. FUN!

Alan

On Tue, Sep 24, 2019 at 11:54 PM, peter_pc2a wrote:

Hi

I have a problem to get Saver working together with Win7
The program starts, but as soon I connect the VNA the program top working

Did try on Win7 32, 64 and different pc's, but same result
Swap HD op the pc and run Win10,? it works

Any idea?

Peter

We had the same problem here... works with Win10 but not Win7. Not sure if this is the cause of your problem.
We found that Win7 did not have latest Framework 4.0.
Many software developers assume that we all have the latest versions.
We finally gave up trying to get it to work with Win7 on all of the laptops here.

On Tue, Sep 24, 2019 at 11:35 PM, Dave Daniel wrote:

A second violation gets you put under moderation. A third violation gets you
removed from the list.

Others here agree with Michael.
That includes myself, others who have posted on this forum as well as personal feedback that I have personally received.

The ridiculous self aggrandizement takes the piss, and is not suited to a hobbyist group.
You wanna put Michael on a watch list, or ban him, then please add me to your list.

73 de Andy

Folks,
I have just uploaded an updated Console Command document to the Files section.
It now references Erik's last build 0.1.1 with TDR and battery.

However, there are a few items that I am not sure of at this point:
Markers: outputs: marker#, index#, frequency. What is the 'index' number referencing? It changes as I move the marker along the trace.
Capture: this is a new command. What does it do? If you run it in the console, the Nano locks-up.
Sample: samples gamma, ampl or ref - how is it used?
Time: is still there and increments the counter - but how can it be set to current time?
DAC: does the dac variable control the DSP gain?
Test: is still there but what does it do?

As always, a Thank You to all that have helped with this document previously!

Regards,
Larry

08:06 Wed 25 Sep 19 , Steve London wrote:

I will apologize if this has already been covered. I didn't find it in a search.

I see that, by default, NanoVNA reports R + L/C . Is there a way to change that to R +- X ?

Yes, I know the PC software can display it both ways, but my primary use for the NanoVNA is up on the tower, to make measurements at the feedpoint. The NanoVNA is a lot more convenient than carrying up a bulky and expensive antenna analyzer.

I faced the same problem and I've modified a bit smith chart presentation
to show R+jX. I think my patch will not apply to current fw but if you want to
try to adapt it to newr fw I'll attach below.

When I'll find a bit of time I'll try to integrate in actual fw.

Lapo, IK5NAX

diff --git a/plot.c b/plot.c
index 10074c3..c5c92e5 100644
--- a/plot.c
+++ b/plot.c
@@ -576,16 +576,22 @@ gamma2imp(char *buf, int len, const float coeff[2], uint32_t frequency)
// float z = sqrtf(zr*zr + zi*zi);
int n;

- n = string_value_with_prefix(buf, len, zr, S_OHM[0]);
- buf[n++] = ' ';
+ n = string_value_with_prefix(buf, len, zr, '\0');
+ if(zi<0)
+ buf[n++]='-';
+ else
+ buf[n++]='+';
+ buf[n++]='j';
+ string_value_with_prefix(buf+n, len-n, fabs(zi), S_OHM[0]);

- if (zi < 0) {
- float c = -1 / (PI2 * frequency * zi);
- string_value_with_prefix(buf+n, len-n, c, 'F');
- } else {
- float l = zi / (PI2 * frequency);
- string_value_with_prefix(buf+n, len-n, l, 'H');
- }
+
+ /* if (zi < 0) { */
+ /* float c = -1 / (PI2 * frequency * zi); */
+ /* string_value_with_prefix(buf+n, len-n, c, 'F'); */
+ /* } else { */
+ /* float l = zi / (PI2 * frequency); */
+ /* string_value_with_prefix(buf+n, len-n, l, 'H'); */
+ /* } */
}

void

Hello,

Allow us, please, to inform the interested reader and/or contributor that in order to we
stay on- and continue on this subject, we had to copy our messages from this topic
to that one:

[errors of "error" models]:
/g/nanovna-users/message/3004

as well as that we shall also copy -"just in case"- sometime later, all of our messages
to out there:



Thank you for your attention.

Farewell !

Sincerely,

yin&pez@arg

9

With totally different software (National Fire Information Reporting System),
installing on Windows 7 you need to ignore the default install location and go direct to the C: drive.
With the default location you're in permissions hell.

I don't know if this is relevant but it might be.

Bear W5VZB

On Wed, 25 Sep 2019 at 18:47, Dr. David Kirkby <
drkirkby@...> wrote:

On Wed, 25 Sep 2019 at 15:53, <erik@...> wrote:

Using a not too good BNC Tee I performed a T-Check

The T-check theory assumes that the T is lossless.

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

On Wed, 25 Sep 2019 at 15:53, <erik@...> wrote:

Using a not too good BNC Tee I performed a T-Check
Attached the measurement (.s2p) and the excel file (.xlsx) in which the
T-Check is calculated.
Next to the T-Check calculation the excel also calculates the
abs(Zin-Zout)/Z0 (the percentage absolute distance of the two impedances as
another estimate of error)
The frequency is denoted in MHz
Do ignore anything above say 500MHz

The T-Check suggests the error quickly increases to substantial levels but
the abs(Zin-Zout)/Z0 suggests there is a very systematic error in my
measurement where the absolute distance of the two rotating impedances
grows very linear with frequency.

What do you connect on the the third port of the T? Most people connect 50
ohm loads, but personally I am skeptical of the logic of that, as it means
both ports see a constant 25 ohms.

BNC calibration kits are as rare as rocking horse dung, so I doubt that the
calibration kit is working correctly.

What am I doing wrong?

Dave.

--

Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

Could someone repeat my tests? I have described the issue here:


Carlos

XENOMORPH, who I believe first introduced the 1500 MHz, tdr, and battery icon firmware mod, has just released a firmware mod that adds additional 256 point FFT capabilities versus the current 128 point FFT. He posted a photo showing the new firmware being used to perform a tdr measurement on a 65 meter length of RG-6U (0.89) see attachment. The measurement was accurate to 0.07 meters. I have also attached his DFU file in-case someone wants to play with it. I am going to order another nanoVNA to experiment with all the new firmware mods that have started to appear. My current firmware works so well that I hesitate to muck with it.

Yeah, I thought that would do it as well, BUT it gives reflection coefficient.

Alan

Hi Steve,

Others have asked for this as well. And I think as far as I know, the short answer is NO.

Unless there is a plan to update the firmware to do that calculation and provide a touch key to bring up that format.

May I ask... when up on the tower, so you know in advance what range of X your supposed to see. Pre- calculate the expected value and go with that? Not the ideal answer, but that's sort of what I have done with my simple wire antenna.

Alan

Did you try polar output?

Bruce
Have a look here
Cheers
Al

I will apologize if this has already been covered. I didn't find it in a search.

I see that, by default, NanoVNA reports R + L/C . Is there a way to change that to R +- X ?

Yes, I know the PC software can display it both ways, but my primary use for the NanoVNA is up on the tower, to make measurements at the feedpoint. The NanoVNA is a lot more convenient than carrying up a bulky and expensive antenna analyzer.

Thanks,
Steve, N2IC

I have seen a technique where the font is "enlarged" simply by outputting each scan of the character font twice. This makes the character appear taller. It can make the text surprisingly more legible with no more font RAM and just a small hit on the code space. Of course you still will need screen space. Because the characters, while more legible, are a bit ill formed, this might be available as an selectable "ZOOM" mode unneeded by those who purchase the reading glass option.