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errors of "error" models
Hello,
Allow us, please, to we report that in order to be adequately prepared to estimate the uncertainty in NanoVNA measurements using complex differential error regions and real differential error intervals, that is to attempt for the first time scientific measurements using NanoVNA with the only available method we know and with the currently available software tools, we need, in addition to a correctly working version of the interpreted foss [maxima-cas] to run the /f/l/o/s/s/ [derdei.mc], a foss compiled language to we be able to independently cross-verify the computation results, and as a such one we intend to use for now the [openwatcom][fortran]. Also, allow us, please, to we report that in a correctly working operating system [wxp64p&sp2] we know that the following versions of these two languages are respectively the last ones which are correctly working under the 32-bit emulation mode of an AMD x86-64 cpu: [maxima-cas][5.38.1]: [openwatcom-fortran][1.9]: ftp://ftp.openwatcom.org/install/open-watcom-f77-win32-1.9.exe Sincerely, yin&pez@arg 2 |
Hello,
We just uploaded the currently available version of /F/L/O/S/S/ Maxima code: as well as, the currently available version of its documentation: for the Uncertainty Estimation of Full One-Port VNA Measurements. Next to come : the currently available version of /F/L/O/S/S/ FORTRAN code. Sincerely, yin@pez@arg 3 |
Hello,
We just uploaded the currently available version of /F/L/O/S/S/ FORTRAN code: Check the functionality of the program, please, by using the included text files : [INPUT.TXT] : 101 Frequencies etc, and: [SH.SC] : Short, [LD.LD] : Load, [OP.OC] : Open, and [ME.ME] : AUT which are the real raw measurements, collected by using an HP 8505A VNA Automatic Network Analyzer System in CW mode under HP-IB control, from a deliberately roughly constructed UHF Ground-Plane Antenna, which was also deliberately roughly installed just outside and in the immediate vicinity of the metal walls of the Anechoic Chamber in our past Antennas Laboratory, in order to produce as much as possible anomalies in the results of Rho and Zeta, as well as of their computed uncertainties both of complex and real value, in terms of 101 frequency steps. Next to come : numerous related references Sincerely, yin&pez@arg PS Also, take a look, please, at the related discussion "on the comparisons": /g/nanovna-users/message/2913 5 |
Hello,
Here are the references - for a few wrongly shaped pdfs you may use, please, a "secure" removal tool - e.g. the freeware : [1] Total Differential Errors in One-Port Network Analyzer Measurements with Application to Antenna Impedance: [2] Measurement Uncertainty in Network Analyzers: Differential Error Analysis of Error Models Part 1: Full One-Port Calibration: [3] Measurement Uncertainty in Network Analyzers: Differential Error Analysis of Error Models Part 2: Full Two-Port Calibration: [4] S-Parameter Uncertainties in Network Analyzer Measurements with Application to Antenna Patterns: [5] Measurement Uncertainty in Network Analyzers: Differential Error Analysis of Error Models Part 3: Short One-Port Calibration - Comparison: [6] Measurement Uncertainty in Network Analyzers: Differential Error Analysis of Error Models Part 4: Non-Zero Length Through in Full Two-Port SLOT Calibration: [7] Measurement Uncertainty in Network Analyzers: Differential Error DE Analysis of Error Models Part 5: Step-by-Step Graphical Construction of Complex DE Regions and Real DE Intervals: Sincerely, yin&pez@arg 7 |
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 - /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 - /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 /g/nanovna-users/message/2770 Saturday, September 21, 2019 04:10 [2] error model(s) /g/nanovna-users/message/2553 Wednesday, September 18, 2019 00:24 [3] vna ~ nanovna : (r,x) comparative results but no comments /g/nanovna-users/message/2521 Tuesday, September 17, 2019 02:31 [4] Re: List of NanoVNA Console Commands /g/nanovna-users/message/2457 Sunday, September 15, 2019 15:23 - - - - - 6 : Re: on the comparison - /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 |
@yza
As I am not scientifically trained I have great difficulty to follow your posts and to understand what it is you ask. - Are you merely sharing knowledge on error models applicable to VNA? Great, need some help on how we can use your knowledge to understand the limitations of our own measurements - Do you invite only those with a solid scientific background to participate in an performance evaluation of the nanoVNA? Excellent, let the experts join and deliver a solid foundation to understand the limitations of nanoVNA performance - Do you want the wider group to participate? If so, in what way? How to contribute? Please help me to understand. |
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 point out that: The notion of error bounds (in the plural, since they are two -implicitly, but definitely real numbers, which are the two estimated| |computed real numbers, which are lower than- and greater than- the real number that expresses the (unavoidably real) measurement of any (unavoidably real) quantity, looses its meaning in the case of any "complex" ("existing" by agreement) quantity, that is one which is expressed by complex numbers, because the notion of the ordering : lower| |greater than- does not make any sense between complex numbers. Therefore, we need to somehow extend this bound notion in the case of (once again : by agreement) "complex" quantities. Sincerely, yin&pez@arg 10 |
@Gary O'Neil
Hello, Thank you very much for your kind interest on our Work! We much appreciate that. Especially, the most encouraging guess also made by you about "missing terms". Very interesting indeed! Thank you, once more. Now, regarding your questions included at: /g/nanovna-users/message/3041 we would like to ask you first to tell us, please, if you tried our software, that is if you already compiled and run the FORTRAN REGION and then the MAXIMA DERDEI, to see its rich, multiple-output graphics. Sincerely, yin&pez@arg 11 |
Hello again YZA;
I have not yet attempted to install the relevant software and math engine required to compile and run your Fortran code, and it would take some effort on my part (or any evaluator not programatically versed or equipped) to work through that process. Before investing the effort to do so, I am attempting to understand the goals and objectives of your work, and if or how it might benefit users of the NanoVNA, and the VNA community overall. The principal utility and benefit of the NanoVNA is it's size and portability. To that end, it is limited in its available reserve of stand alone computational resources. Additionally; most users on this forum are not motivated to invest in high quality (accurately characterized) calibration standards that cost many times the price of the device itself. System requirements of the evaluator(s) need to be clearly defined. The software you describe would, by necessity, require PC connectivity, and operates on data files collected by the NanoVNA and ported to your software for statistical analysis in order to derive the error bounded plots shown in your documentation. There are sophisticated VNA users in this group that might find great interest in your work if the goals, objectives, system requirements, output results, and the utility and benefit of those results were clearly presented such that they could be easily and clearly understood in the context of how they might enhance the quality of the NanoVNA measurements. Those users are likely a minority. There may be an even smaller subset of this group that may simply have an academic interest in your work. I think your documentation may be sufficient for those motivated to dig into the details of your algorithms; given that there is a clear benefit for investing in that effort. What type of support are you requesting from this group? What dictates the need to distribute Fortran code? Can it not be compiled and distributed as a stand alone executable, and a readme.txt file outlining the detailed feedback content you desire? 73 Gary, N3GO -- 73 Gary, N3GO |
@Gary O'Neil :
/g/nanovna-users/message/3070 Hello, And thank you, once more, for your most valuable contributions ! Well, (1) regarding the objective requirement for a distribution of the REGION executable, allow us, please, to notice the useless result of such an action, because, once again, this file is not a standalone program but it constitutes just the one part of this two-part /F/L/O/S/S/, and (2) regarding the subjective concerns you most reasonably expressed about your time, also allow us, please, to notice that since the personal taste is the decisive criterion that governs humans' choices, and since the expediencies of any kind were never dictated our acts, we are not be able to the slightest to suggest you what to do in order to meditate these worries of you. Finally, since we mostly respect your efforts and your time you spent to take a look at our humble work, allow us, please, to conclude our communication by thanking you, once again, very much! Sincerely, yin&pez@arg |
@erik@...:
/g/nanovna-users/message/3008 Hello, First of all, allow us, please, to express, on the occasion, our deep respect for your impressive Work with NanoVna. Next, allow us, please, to inform you that just after the message including the preliminaries of the uncertainty: [6] : /g/nanovna-users/message/2968 we took into account your clear call for understanding and thus we started a sequence of very short messages on this subject, beginning with: [10] : /g/nanovna-users/message/3043 Finally, allow us, please, to comment that, in our humble opinion, regarding 'Understanding', there are the following types of human beings, according their personal tastes: (1) Those who don't want to understand, and those who want to understand, but when they don't understand then, according to their judging abilities, they put constantly the blame: (2) on the others, (3) on themselves, and (4) either on the others or on themselves, according to the state of their progress in the Knowledge Keep up the Good Work ! Sincerely, pez&yin@arg 13 |
@Reginald Beardsley via Groups.Io :
/g/nanovna-users/message/2927 /g/nanovna-users/message/2948 Hello, Allow us, please, to point out that frankly we are not sure if the messages on this very topic, as well as, the references especially included at: [7] : /g/nanovna-users/message/2984 cover to the slightest your expressed interests, so, let us know, please, accordingly, taking into account that this is the current state of published research on this subject, excluding some papers under preparation in order to be published in our small journal: Once again, thank you very much for your interest in our work ! Sincerely, pez&yin@arg 14 |
Hello,
Allow us, please, to inform you that we just uploaded the following two, very rare, references: [1] Richard H. Hackborn, "An Automatic Network Analyzer System", Microwave Journal, May 1968, p.47 : [2] Paul Schmitz, "Vector Measurements of High Frequency Networks", HP 5958-0387, 5481, 1989, p.3-9 : which, unfortunately enough, justify fully the writings at [7][3]: /g/nanovna-users/message/3004 although, some honorable members of this forum considered them as outrageous allegations of the insulting kind. Sincerely, yin&pez@arg 15 |
Hello,
Allow us, please, to inform you that, after: [15] : /g/nanovna-users/message/3147 we just uploaded our well-formed mathematical expressions of full-one port vna measurements [*] : which--due to their apparent symmetries, as well as to their arrangement--we consider them as the most economical and appropriate ones for programming them in any computer language - either having the complex data type internally or not. Sincerely, yin@pez@arg [*] 16 |
17 : From A Common User's Point Of View
Hello, Allow us, please, for the sake of completeness of an appropriate preparation of a presentation for the Estimation of the -sine qua non- Core of the Measurement Uncertainty that Exists in *A N Y * VNA System, regardless of what it really is, a VNA or a NanoVNA, facupov : that is like that very one of ours, to also include here the initial findings by us: = | Subject: vna ~ nanovna : (r,x) comparative results but no comments | Sent: Tuesday, September 17, 2019 02:31 | To: [email protected] | From: yin.oe3zgn.sv7dmc-pez.oe3zzp.sv7bax-arg yza@... = | Hello, | | 1 one-port box + adapter - initial version: | | | 2 one-port box + adapter - modified version: | | | 3 one-port box + adapter - modified version: | | black : vna system | red : nanovna + 31 mm adapter | blue : nanovna - 31 mm adapter mathematically | | r : | | x : | | Sincerely, | | yin&pez@arg = 0 : /g/nanovna-users/message/2521 Sincerely, yin&pez@arg 17 |
Dr. David Kirkby from Kirkby Microwave Ltd
On Fri, 27 Sep 2019 at 12:33, yza <yzaVNA@...> wrote:
17 : From A Common User's Point Of View Maybe if you wrote a document on this, including adequate references, much like a scientific paper, we could follow you. But you have made endless posts, at least one of which has incomplete definitions of the equations, it is almost impossible for anyone to follow you. I am sure what you have is interesting, and some will be able to follow you - perhaps not myself as my mathematics is not very good. But the way the information is presented makes it impossible to follow. One of things that is important is the phase difference between the offset male and offset short standards. This will obviously be 180 degrees at low frequency, but will depart from this as frequency is increased. I have seen calibration kits assembled from inappropriate parts where the phases difference drops to zero at one frequency. It¡¯s obviously impossible to calibrate then. But if one standard has a phase able of 0 degrees, and the other 10 degrees, the calibration will be poor. The whole issue is far from simple, but the way you are presenting the information makes it difficult for anybody to follow you. G8WRB -- 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 |
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