Re: errors of "error" models

 

Hello,

Allow us, please, to insist staying on the subject by transferring
and repeating here the contents of the following messages,
in order to somehow protect -if not save- them [*]

- - - - -

4 : on the comparison - https://groups.io/g/nanovna-users/message/2913
Hello,

Allow us, please, to point out that to be possible to the slightest a comparison
between measurements regarding nanovna and/or vna, these measurements
should be accompanied by an estimation of their uncertainty, as well as by a
clearly stated way of its calculation.

Sincerely,

yin@pez@arg

- - - - -

5 : Re: on the comparison - https://groups.io/g/nanovna-users/message/2943
Hello,

We both thank you very much all of you for your most valuable comments !
We gladly feel that we find a sound ground for a fruitful discussion, as we hope.

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, so, we don't
believe at all that this matter is due to any lack of knowledge or of ability among
Radio Amateurs, while, in direct contrast to that, the pioneered Work of whom is
usually exploited by patentees.

Anyway, we just ask you now to be patient enough and give us the chance to present
you:

(1) the fortran code by which we estimate the errors of the aforementioned "errors",
in full one-port vna measurements (see, please, the related "discussion" [1]), as well as

(2) sometime later, the way in which we calculate the errors of the corresponding
"errors" in full two-port vna measurements.

Finally, we just mention that in the case of nanovna we just took a look at the mathematical expressions included there and we have a feeling -but notice, please, NOT a proof yet-
that the "error" model(s) used in the original nanovna code are missing some terms which
are present in the original "error" model(s). And this is the reason that we already asked:

"if is there any certain knowledge available regarding the specific error model(s) that
NanoVNA uses" [2]

--but unfortunately without any response yet--so, we did not be able to comment our
vna-nanovna comparison results [3],

and by the way: after we followed, almost fully, the suggestions given in the Excellent
Work of Larry Rothman [4].

Sincerely,

yin&pez@arg

[1] errors of "error" models
https://groups.io/g/nanovna-users/message/2770
Saturday, September 21, 2019 04:10

[2] error model(s)
https://groups.io/g/nanovna-users/message/2553
Wednesday, September 18, 2019 00:24

[3] vna ~ nanovna : (r,x) comparative results but no comments
https://groups.io/g/nanovna-users/message/2521
Tuesday, September 17, 2019 02:31

[4] Re: List of NanoVNA Console Commands
https://groups.io/g/nanovna-users/message/2457
Sunday, September 15, 2019 15:23

- - - - -

6 : Re: on the comparison - https://groups.io/g/nanovna-users/message/2968
Hello,

Allow us, please, to summarize briefly:

(0) The measurement uncertainty is error-bounds of the
measurement.

(1) If a measurement does not involve mathematical expressions
then someone can choose the statistical way he likes to
mathematically estimate|compute a subjective uncertainty .

(2) If a measurement involves known mathematical expressions
then either there is or there is not -up to now- a known, unique,
mathematical way, that is a way solely based on these
mathematical expressions alone, to estimate|compute an
objective uncertainty.

(3) A vna measurement involves known mathematical expressions
and after more than ten 10 years there are now five 5 known
mathematical ways to estimate|compute a unique objective
uncertainty, each one for each of the five 5 "error" models considered
(by intermediately estimate|compute the errors of these "errors"),
as well as new one(s), the sixth 6th (or more), shall be added
as soon as the "error" model(s) of the NanoVNA will be revealed.

(4) These "errors" of "error" models are just historical names of
parameters mathematically expressed in terms to what is widely
known today collectively as "S-parameters" and thus these are
not error bounds - they are not uncertainties of the measurement.

Sincerely,

yin&pez@arg

[ *
[ which -unfortunately enough, but not unexpectedly in almost any
[ suffering public discussion- were interfered elsewhere, as usually,
[ that is using the well-known technique of the coordinated barrage
[ of disorienting, non-answering, non-participating, non-discussing
[ cries - that is, once more : business, as usual

Sincerely,

yin&pez@arg

8

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