Re: Experimental 256 point FFT Firmware
On Sat, Sep 28, 2019 at 12:09 AM, Alan Lloyd wrote:
I think polyethylene dielectric coax has a pretty reliable velocity
factor of
0. 66.
No, it depends on environment temperature and used frequency. Also, different cables uses different dielectric and VF may be significantly different. For example: - PE: solid polyethylene, VF=0.659 - PTFE: solid polytetrafluoroethylene, VF=0.695 - ST: solid teflon, VF=0.694 - FE: foam polyethylene, VF=0.79 - 0.88 - FS: foam polystyrene, VF=0.91, - etc. I got several cables from aliexpress, some of them doesn't have marking, but these which have marking has different VF than claimed in specification. Some RG58 cable from aliexpress have large deviation for VF and Z. So, there is no way to identify dielectric with no special equipment. And there is no way to 100% know exact VF of the cable, even if it has marking.
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Re: Experimental 256 point FFT Firmware
qrp.ddc,
Thanks for taking the time to reply. Ham's such as myself are generally looking to purchase specific types of 50 ohm cable such as RG-58, RG-223, RG-6 etc. The cables are all marked by the manufacturer according to type and we pretty much know the velocity factors by heart, so entering that info into the nanoVNA is a no-brainer. I don't really use the nanoVNA's TDR function for purchasing specific lengths, but rather to ensure for instance that a 10 meter length of cable being offered for sell doesn't have damage at say 4 meters to its inner conductor. One cable I measured before purchasing had very strange peaks and valleys on the nanoVNA's TDR function (wish I could have saved the screenshot), when I examined it more closely I could see slight equally spaced pits on its outer insulation. I'm guessing the cable was used in a mismatched power transmitting application and the spacing of the insulation pit marks was associated with the transmit frequency. So I use the TDR function as more of a sanity check to help sort the chaff from the wheat.
Sorry, I mistakenly assumed you had access to a professional level TDR to not appreciate how, even with its limits, the TDR function on the nanoVNA is a godsend to hobbyists, students, and radio amateurs as essentially a throw-in to its vector network analyzer capabilities. Let's hope in nanoVNA V2 that Hugen increases the number of measurement points and gives you some of the other things on your wish list.
Herb
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Re: Calibration bug in newer firmwares?
Where can I find the later, bug free firmware? Paul
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Re: nanovna Battery Specifications
On Thu, Sep 26, 2019 at 06:59 PM, Dr. David Kirkby from Kirkby Microwave Ltd wrote:
When I buy very small lithium batteries from Farnell, it will come in a box
with hazardous labels on the outside, and say it should not be shipped if
damaged.
Probably this is the reason why NanoVNA shipped within plastic box. When I buy Li-Ion batteries on aliexpress, they are also shipped in plastic box. It seems that shipping Li-Ion battery requires plastic box.
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Re: errors of "error" models
Respectfully Dr¡¯s Yin and Pez;
Perhaps much of the frustration you must share with Dr. Kirby and myself, and perhaps a few others who might be following for want of discovery of what these exchanges are all about; results from distorted translation.
To wit...
Early in your entry into this forum, and repeatedly in your responses to those who have reached out to engage technically with you; your posts translate with many judgmental and condescending overtones. In the English speaking world, such overtones can be interpreted as unwelcoming and an invitation to terminate ones gesture of willingness to support.
By example...
I did not anticipate a reprimand as a result of my request for executable code. While the technical content in your response answered my query clearly by identifying a need to compile multiple modules locally, and thus moved my understanding in a progressive direction; it was immediately followed by an invitation to terminate our discussion, based upon your judgement of the time I might feel obliged to bear focus on your efforts.
Those of us who may or may not be attempting to understand you lack neither intellect, nor motivation. We also participate in this forum as equals, and maintain decorum by agreeing to disagree, and occasionally sparring with one another philosophically, when our differences are slight or of limited consequence.
On occasion, I disagree with Dr. Kirby philosophically, but almost always agree with him technically; and I acknowledge with respect his sometimes short fused and quirky... slightly mean spirited... personality. In my own humble opinion, I find his response to you overwhelmingly supportive, and generous in his patience toward attempting to communicate with you in a civil and respectful manner. I also echo his comments and requests of you to provide enablement to the members of this forum who are indeed able, intellectually capable, and willing to invest their own and personal resources of time, knowledge, and skill without desire for remuneration in any form beyond advancing their own knowledge and insight. This is our hobby.
I also agree entirely with Dr. Kirby¡¯s assessment of the level of insight and understanding by the absolute beginners here who are seeking understanding and motivated by their own passions. The information you have provided thus far is nowhere near the level required to understand relevance or significance of anything that you have posted to date in the minds of anyone not skilled in the art.
It is difficult to read Dr. Kirby¡¯s closing and overtly encouraging comment: ¡°Please understand that I am trying to help you and others by bringing to your attention the fact that few, if anyone on this group is following you.¡±, has elicited such a condescending response. His ¡°subjective¡± comments were sincere recommendations on how best to get this community engaged and behind you, and knowledgeable of what you are attempting to achieve. You also appear to have cast off his technical comments by suggesting he has a closed mind. This is neither respectful, now will it gain you the respect that, you, your colleagues and you work may well deserve.
I will continue in my attempts to follow this thread until such time I experience an epiphany, or reach a conclusion that there is likely nothing of merit that will advance my understanding or the enjoyment of my hobby. Your posts thus far have not made this an easy journey.
In the meantime; I will consider the negative overtones to be artifacts of translation and not take them as personal attacks on my intellect, abilities, or my integrity. I will make no attempt to influence the decision of my colleagues on their assessment of your work, short of the aforementioned epiphany.
With my sincere respect and good wishes for success in your work. I wish you well my friends.
--
73
Gary, N3GO
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Re: Experimental 256 point FFT Firmware
Hmm. I think polyethylene dielectric coax has a pretty reliable velocity
factor of
0. 66. So identify the dielectric before applying the vna to measure its
length?
A
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On Fri, 27 Sep 2019, 21:39 , <qrp.ddc@...> wrote: On Fri, Sep 27, 2019 at 10:52 PM, hwalker wrote:
With your access to better equipment, the nanoVNA's TDR function probably does
seem like a toy, but if the user realizes its limitations and doesn't expect
laboratory quality from a $50 device, the function is still a worthwhile tool
and learning feature. Unfortunately I don't have access to better equipment. The only VNA that I
have is NanoVNA and EU1KY single port VNA.
If the TDR function tells me that a reel of cable marked
25 meters is 24.5 meters that's close enough for me to feel confident
purchasing it. Such cipher 25 "meters" or 24.5 "meters" is completely useless, because
you're just don't know the real cable velocity factor. You will not be able
to measure velocity factor of the cable at hamfests selling. When you don't
know velocity factor of the cables, you cannot compare two cables and
cannot measure it.
For example, you're want to buy the cable with specific length and needs
to select proper length from two pieces of cables A and B:
- cable A has 11 meters length (physical length), velocity factor 0.60,
but you're don't know that
- cable B has 7.4 meters length (physical length), velocity factor 0.90,
but you're don't know that
You're trying to measure cable length with NanoVNA TDR. Since you're don't
know the real velocity factor (which actually depends on manufacturer,
environment temperature and frequency) of these cables, you're using
default setup for velocity factor 0.66.
NanoVNA shows you:
- 9.1 "meters" for cable A
- 10.1 "meters" for cable B
You're needs to select 10 meters (physical length) piece.
Which one you will select, based on NanoVNA TDR readings? :)
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Re: nanovna Battery Specifications
Thanks!??
Mike WY6K
"... somewhere in the distance, there's a tower and a light, broadcastin' the resistance, through the rain and through the night..."
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On Friday, September 27, 2019, 03:42:37 PM CDT, Warren Allgyer <allgyer@...> wrote:
Mike,
The do indeed increase the dynamic range somewhat. The dynamic range at 600 MHz and above is rated at 40 dB and all of the units I tested , even the worst ones, met this spec. I have no uses for which I need dynamic range greater than 30 dB. For example, a return loss of 30 dB equates to a VSWR of 1.07 to 1. Trust me..... if I can achieve 1.07 to 1, even for my broadcast clients, I have no need to go further. And 30 dB return loss is easily seen with a dynamic range of 40 dB. I have never, in my broadcast or in my hobby career spanning 50 years, had the need to measure return loss greater than that number.
Some may say they want to see filter skirts down to 60 dB or below. There are such needs but I don't have them. If I can see the -3 dB point and the -40 dB point..... I have no need to know the exact frequency where the attenuation is more. And, if I did, I would use and amplifier on Port0 to expand the dynamic range as was illustrated here in an earlier post.
You have a better unit. But I would be stunned if you do anything with it that could not be done with the least of the Nanovna versions.
WA8TOD
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Re: nanovna Battery Specifications
Mike,
The do indeed increase the dynamic range somewhat. The dynamic range at 600 MHz and above is rated at 40 dB and all of the units I tested , even the worst ones, met this spec. I have no uses for which I need dynamic range greater than 30 dB. For example, a return loss of 30 dB equates to a VSWR of 1.07 to 1. Trust me..... if I can achieve 1.07 to 1, even for my broadcast clients, I have no need to go further. And 30 dB return loss is easily seen with a dynamic range of 40 dB. I have never, in my broadcast or in my hobby career spanning 50 years, had the need to measure return loss greater than that number.
Some may say they want to see filter skirts down to 60 dB or below. There are such needs but I don't have them. If I can see the -3 dB point and the -40 dB point..... I have no need to know the exact frequency where the attenuation is more. And, if I did, I would use and amplifier on Port0 to expand the dynamic range as was illustrated here in an earlier post.
You have a better unit. But I would be stunned if you do anything with it that could not be done with the least of the Nanovna versions.
WA8TOD
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Re: Experimental 256 point FFT Firmware
On Fri, Sep 27, 2019 at 10:52 PM, hwalker wrote: With your access to better equipment, the nanoVNA's TDR function probably does
seem like a toy, but if the user realizes its limitations and doesn't expect
laboratory quality from a $50 device, the function is still a worthwhile tool
and learning feature. Unfortunately I don't have access to better equipment. The only VNA that I have is NanoVNA and EU1KY single port VNA. If the TDR function tells me that a reel of cable marked
25 meters is 24.5 meters that's close enough for me to feel confident
purchasing it. Such cipher 25 "meters" or 24.5 "meters" is completely useless, because you're just don't know the real cable velocity factor. You will not be able to measure velocity factor of the cable at hamfests selling. When you don't know velocity factor of the cables, you cannot compare two cables and cannot measure it. For example, you're want to buy the cable with specific length and needs to select proper length from two pieces of cables A and B: - cable A has 11 meters length (physical length), velocity factor 0.60, but you're don't know that - cable B has 7.4 meters length (physical length), velocity factor 0.90, but you're don't know that You're trying to measure cable length with NanoVNA TDR. Since you're don't know the real velocity factor (which actually depends on manufacturer, environment temperature and frequency) of these cables, you're using default setup for velocity factor 0.66. NanoVNA shows you: - 9.1 "meters" for cable A - 10.1 "meters" for cable B You're needs to select 10 meters (physical length) piece. Which one you will select, based on NanoVNA TDR readings? :)
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Re: Si5351A max fundamental frequency
Hi
Thanks! I think I will change the firmware since "sounds" numbers are more important to me than the last 100 MHz.
Bo
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Hi
The way I see the "marker points" is semi-automatic. The user will have to press e.g. the LPF button, if the DUT is a LPF. The S/W then looks from low to high frequency for the selected "marker points". They may be way off if viewing a filter in the stop band. It is at the user's discretion to understand the functionality. Otherwise the user can place the markers manually. I don't expect any AI in this matter.
Bo
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So it is already thin.? No help there...
Mike WY6K
"... somewhere in the distance, there's a tower and a light, broadcastin' the resistance, through the rain and through the night..."
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On Friday, September 27, 2019, 03:13:09 PM CDT, Bo, OZ2M <groups.io@...> wrote:
0,8 mm.
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Dr. David Kirkby from Kirkby Microwave Ltd
On Fri, 27 Sep 2019 at 20:48, Bo, OZ2M <groups.io@...> wrote: Hi
One thing is loss, but also isolation is an issue. I have a circuit on FR4
on my desk right now, where the isolation above 1,7 GHz cannot go higher
than around 55 dB. Heavy shielding may help, but shielding and tooling are
cumbersome and expensive.
Bo How thick is your FR4? Thinner board will keep the RF more concentrated in the dielectric below the traces. 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
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Oristo,
thank you! Exactly what I need!
Now, to find time to implement all the things I want to do .. oh, and fix
all the bugs... ;-)
--
Rune / 5Q5R
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On Fri, 27 Sep 2019 at 22:12, Oristo <ormpoa@...> wrote: Screenshot/image saving is definitely interesting! Currently, the
graphs/plots are all painted directly on a Qt widget,
so I would have to find something that could save those. Does this help?
"Here is the simplest way to save a widget as an image. This approach
works on Qt 5:"
ui->myWidget->grab().save("image.png");
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Hi Maurizio,
good to hear that the antivirus cleared it - phew!
I don't know if I can do anything to make that go easier, other than put
fewer viruses in? ;-) I guess fewer than none is difficult.
I hope you enjoy using it!
--
Rune / 5Q5R
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On Fri, 27 Sep 2019 at 20:24, Maurizio IZ1MDJ <redifon500@...> wrote: Avast antivirus cheched the nanovna-saver executable , and now the program
can be execute in normal way.
Regards
Maurizio IZ1MDJ
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Screenshot/image saving is definitely interesting! Currently, the
graphs/plots are all painted directly on a Qt widget,
so I would have to find something that could save those. Does this help? "Here is the simplest way to save a widget as an image. This approach works on Qt 5:" ui->myWidget->grab().save("image.png");
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Hi Bryan, great to hear that the software just runs, and I'm also happy that the calibration assistant worked out. It was really a last-minute addition, so I'm happy it works! ;-) The plot scaling for the dB-based plots needs some work, I agree. User settable is a good option, but I think I want to make the default scaling that it attempts to have ~6-8 horizontal "segments" on the screen by default - and picks a reasonable scale for that. 1dB might be a bit much for 10dB total span, but maybe 2dB instead? I hear what you're saying on phase plots, and I'll put user settable scaling in there as well. Very good to hear that the averaging works! And thank you very much for the encouragement :-) -- Rune / 5Q5R On Fri, 27 Sep 2019 at 18:53, bryburns via Groups.Io <bryburns= [email protected]> wrote: Rune,
Thanks for your continued outstanding work! :>).
I am running 0.0.12 on Windows 7. All I am doing is downloading the file,
creating a shortcut to it , and clicking on the shortcut. No issues
observed.
Calibration assistant works fine for me. This is a nice addition. Saving
calibration is important after creating a new calibration.
S21 Marker phase is now the same as the plot and I think both are correct
:>).
I really like the new plot scaling capability because that allows one to
"zoom-in" on features of interest in the data without changing the
frequencies of interest and running another sweep. This is very useful for
careful looks at the information we have available.
I have one suggestion for scaling in a future release: When a max to min
range of 10 dB in amplitude (S11 amplitude dB or S21 amplitude in dB) could
you include 1 dB horizontal lines on the plots? Perhaps an equally useful
solution would be to let the user specify the dB per division for the
y-axis This would help interpretation when looking at things like
pass-band ripple, S21 attenuation of a cable, or .... This idea is
relevant to phase plots as well.
I have been using the averaging capability and think I am reliably
measuring S21 stop-band filter rejection down 50-60 dB from pass-band
attenuation values. The filter I am measuring is a stop-band filter for
the 88 to 108 MHz FM broadcast band here in the US. The averaging does
help in this situation to reduce the noise that is present in the nanoVNA
at those amplitude levels. I see plot-to-plot variations of less than 0.5
dB pk-to-pk. I consider this quite impressive for such an inexpensive
device and free software.
Again, great work on this software. Very helpful!
--
Bryan, WA5VAH
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For those on this list first venturing into the v.h.f. and u.h.f. regions
and who would look for repeatable results down around minus
50dBm and quibble over a tenth of a dB, BNC is not the way to go. FWIW, calibrating 50kHz to 100MHz with these 34cm SMA-to-BNC pigtails: .. and a generic BNC terminator and female coupler yields lower CH0 LOGMAG when subsequently remeasured (-68 to -81dB) than do included SMA cable and terminator (~ - 63dB) For 500-900MHz CH0 LOGMAG with BNC pigtail remeasured after cal yields -47 to -51 dB while remeasuring SMA pigtail after calibration yields -68 to -73 dB For frequencies of interest >>to me<<, BNC appears better..
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Hi Bo,
now I've gotten to your long list of ideas! Thanks for providing them!
Screenshot/image saving is definitely interesting! Currently, the
graphs/plots are all painted directly on a Qt widget, so I would have to
find something that could save those. I think it should be possible, though.
Exporting a general frequency/amplitude (or even amplitude/frequency) file
shouldn't be much of an issue. But, maybe it relates to your next
suggestion: The auto markers for filters. I'd *love* to do that! My biggest
issue is finding a way to 1) identify the filter, 2) find out what the
passband is, and what the passband level/ripple is, and then identify the
3dB/10dB etc. points. The latter part, finding the points, is "easy". What
worries me is the first part :-)
The marker architecture is fully set up to allow for more than 3 markers -
but to fit in 1366x768, it's currently limited to 3. I think I'll add it as
a setting so you can have more. :-)
Thicker trace lines should be an easy setting to make.
The cosmetic points are all sensible, and I'll endeavour to have them
included soon! The only exception is the COM port bit: The current
functionality already finds the correct device if possible, so a dropdown
menu would only really be required if you have more than 1 NanoVNA
connected... I don't think I'll present the users with devices that the
software can't identify as compatible, for now at least, but maybe the
connection functionality needs an overhaul at some point.
Segments: This was previously called sweep count, and is really the base
functionality of the software, the sole reason I wrote it: It refers to how
many segments the sweep span is broken into, each of 101 sample points, in
order to increase resolution over the default the NanoVNA provides. So
putting in 10 provides 1010 points, 50 gives 5050 points, etc. The label
next to it presents the distance between each data point, as that's proven
useful for me, at least. Hz/step is my term for the number of Hz between
two data points .. maybe that's just my own terminology bleeding through, I
don't know. I'm open to suggestions :-)
Thanks again for taking the time to write out all these suggestions!
--
Rune / 5Q5R
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On Fri, 27 Sep 2019 at 18:47, Bo, OZ2M <groups.io@...> wrote: Hi
I am relatively new to the NanoVNA thus the NanoVNA-Saver but I have spent
a number of hours in front of an 8753C :-) I really like the NanoVNA-Saver
and therefore have some ideas for further improvements. If I didn't like it
I wouldn't even bother to make suggestions :-D
Ideas rel. to 0.0.12
- make it possible to save the full NanoVNA-Saver window and/or each plot
without having to do a screen dump via another tool
- It would be ideal if there is a save dialog with an input field that is
used as preamble in the file name(s) and/or also for caption in the
pictures. In the file name please use underscore instead of spaces
- the dialog box could have check boxes for which pictures to save,
perhaps even a check box for adding a time stamp YYYYMMDD_HHMM to the file
name(s)
- in addition to the S-parameter files also to have a set of files for
plain amplitude/attenuation vs. frequency
- x dB auto markers, e.g. 1 dB, 3 dB, 6 dB, 30 dB, 60 dB is difficult in
general on the NanoVNA, and buttons for finding these points on LPF, HPF,
BPF and Notch fillters
- more than three markers in general
Cosmetics
- the lines on my monitor are rather thin. It might be related to my
screen resolution being 2560 x 1440 pixels on a 32" monitor. But it might
be an idea to allow for thicker traces lines
- reduce the number of decimals, e.g. fF and pH resolutions are not
important
- there is a missing space between the impedance value and the Ohm-symbol,
1234.5ohm-symbol -> 1234.5 ohm-symbol (ISO 80000)
- there is a missing space between the band value and the meter, 2200m ->
2200 m (ISO 80000)
- show the marker color in the caption of the marker value panes
- auto 1000 separators on frequency input boxes
- COM port dropdown box listing COM-ports and the logical names if
available. It will make it easier to find the device. Perhaps even auto
connect if logical name is found
Segments
- I am not sure I understand "segments", however, I do understand points
which might be an old habit. The Hz/step unit of the segments is confusing
to me
Bo
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WY6K Mike Watts
Warren Allgyer
Bo, OZ2M
Oristo