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Re: BNC
For those on this list first venturing into the v.h.f. and u.h.f. regionsFWIW, 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.. |
Re: NanoVNA-Saver 0.0.12
Hi Bo,
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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 On Fri, 27 Sep 2019 at 18:47, Bo, OZ2M <groups.io@...> wrote:
Hi |
Re: nanovna Battery Specifications
Thanks Warren.? Mine has those shields.? I have heard that the shields increase the dynamic range above 300 MHz and especially above 600 MHz.? Is that not true?
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Mike WY6K On Friday, September 27, 2019, 01:29:24 PM CDT, Warren Allgyer <allgyer@...> wrote:
This is the bottom side of the shielded version.? The shields are on the right and cover the RF portions. Many..... most maybe.... do not have these shields. If yours does not, do not fret. They make no significant difference in practical use. The space on the lower left is where the battery goes, secured by a piece of double sided tape or a dab of contact cement. Battery solder tabs are in the upper left corner. WA8TOD |
Re: NanoVNA V2
Bo,?
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HOw thick is that FR4 board?? Thinner material would improve the isolation, right? Mike WY6K On Friday, September 27, 2019, 02:48:03 PM CDT, Bo, OZ2M <groups.io@...> wrote:
Hi From a market volume point of view it might be an idea to divide the RF boards into: 1) Si5351A, as now. This is more than fine for the vast majority of radio amateurs 2) Si5351A + ADF4351, lower volume. Covers my frequencies of interest 3) Si5351A + e.g. ADF5355, very low volume and very high cost They may all share the same digital processor and display boards. Could the digital processor board be a RPi? If so, then this may have a huge impact on the price, and there is a much higher volume to drive the development of this platform. It might be a bit more clunky though. 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 |
Re: Si5351A max fundamental frequency
On Fri, Sep 27, 2019 at 10:04 PM, Bo, OZ2M wrote:
Should it be an option, in the S/W, to set the max fundamental frequency? I amThere is no such option. You can modify firmware but the logic for frequency boundaries is not easy, needs to deal with this. By the way, edy555 firmware uses different frequency segments boundaries. You can try edy555 firmware, may it will help to solve your issue with no need to change firmware code. |
Re: NanoVNA-Saver 0.0.12
Hi John,
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if you experience crashes, please try: - Running the program for a command prompt, which preserved the crash message, - Running using "-D logfile.txt" as a parameter, which saves debug data to a file, which you can then pass to me for further analysis. It *may* happen if you have not calibrated the NanoVNA itself, and it sends values that are so unrealistic, the program doesn't know how to parse it. Generally, measurements indicating severely positive gain (more than 30dB maybe?) are rejected as corrupted. If the same measurement shows bad values more than 20 times in a row, the program stops (and reports an error on the console). It's not supposed to *crash* when it does this, but ... I think sometimes it does. :-( -- Rune / 5Q5R On Fri, 27 Sep 2019 at 21:47, John AE5X <ae5x@...> wrote:
Tried it on two different Windows 10 machines - it seems some combinations |
Re: Experimental 256 point FFT Firmware
qrp.ddc,
I purchase cables of unknown quality at hamfests and the nanoVNA has paid for itself in helping me avoid selecting cables that physically looked fine, but from both cable ends looked like virtual shorts using the nanoVNA TDR function. 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. 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. Carrying a laptop with me to do the same TDR measurements is in-convenient, although at home I do use NanoVNA Saver to perform TDR measurements. With the multiple firmware versions that have appeared on the scene, maybe one of the developers will branch off a version that removes the TDR function and implements the features you would rather have. That's the great thing about open source projects, the source code is open to modification however it suits each of our individual needs. Herb. |
Re: Experimental 256 point FFT Firmware
In my previous post, I was referring to coax from my hamshack to the antenna - not a piece of transmission line a foot or 2 long.
Please remember that from a practical viewpoint, LOW resolution in a handheld device is much better that NO resolution (ie: no TDR function). ...Larry |
Re: NanoVNA V2
Hi
From a market volume point of view it might be an idea to divide the RF boards into: 1) Si5351A, as now. This is more than fine for the vast majority of radio amateurs 2) Si5351A + ADF4351, lower volume. Covers my frequencies of interest 3) Si5351A + e.g. ADF5355, very low volume and very high cost They may all share the same digital processor and display boards. Could the digital processor board be a RPi? If so, then this may have a huge impact on the price, and there is a much higher volume to drive the development of this platform. It might be a bit more clunky though. 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 |
Re: nanovna Battery Specifications
on this list.Don't sell yourself short, Frank: we hams can sometimes contribute that he has nothing to learn from a genuine ham of long and diverseIt's a fuzzy faced young engineer or academic who remains confident experience. Not all of us are simply warmed over chicken banders. Some of us have ended up embarrassing engineers. Please continue to contribute. John at radio station VE7AOV. On 2019-09-27 5:00 a.m., Frank Dinger , EI7KS wrote: Yes ,indeed a 5V USB powerpack ,readily available ,even from supermarkets , will do fine.-- |
Re: NanoVNA-Saver 0.0.12
Hi Mike,
I've heard a number of users mention antivirus problems. I have tried submitting it to VirusTotal, and it seems the "only" things it reports is a set of a few antivirus programs worried about Python programs being trojans. I think maybe it's a case of ophidiophobia. ;-) Thanks for your report! -- Rune / 5Q5R On Fri, 27 Sep 2019 at 18:13, mike watts via Groups.Io <wy6k= [email protected]> wrote: Rune, |
Re: Experimental 256 point FFT Firmware
On Fri, Sep 27, 2019 at 10:23 PM, Larry Rothman wrote:
If I'm looking for discontinuities in the circuit, which total length is 1 foot total and TDR can show it one or two foot away from real point, I think it will be useless. To be more clear what I'm talking about, here is pictures of TDR measurement for the same S1P file captured with NanoVNA, with different FFT size. This TDR implemented on PC side, so it doesn't limited with memory and don't requires TDR support in the firmware and allows to use any size FFT for tests. Actually I capture this S1P with old firmware which doesn't have TDR in the firmware at all. |
Re: NanoVNA-Saver 0.0.12
Hi Kurt,
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thanks for all your help with the calibration! I'm still working on it, and as you say, I need some better functions for saving the resulting calibration, that it may be used later. You are right that I haven't implemented scaling for the Y-axis of the phase display: I'm not entirely sure if it makes sense, so I disabled it for now. If it's requested and wanted, I'll add it in. :-) The R+jX scaling is getting another look, as it's clearly not entirely functional at the moment. There's also some rounding taking place in some of the charts where the software attempts to show "nice" values for the tick marks. This might be interfering with the user settings. The scaling is, clearly, a first attempt. :-) Thanks again for your help, and for your feedback on the software! I hope it proves useful for you! -- Rune / 5Q5R On Fri, 27 Sep 2019 at 17:33, Kurt Poulsen <kurt@...> wrote:
Hi Rune |
Re: Experimental 256 point FFT Firmware
OK, no problem then.
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However, please remember - considering the cost of the NanoVNA - it puts more capability in your shirt pocket than most of its predecessors used by Amateurs. As I mentioned, it takes no effort to flash different versions of firmware onto the device. We aren't doing microwave design were pico-seconds matter. And you can take it up an antenna tower - without a PC. If I need to check out a length of cable from my Tx to the antenna, it is more than adequate to show the approximate location of any issues - and that includes connectors. If the Nano TDR shows shows me a reflection a foot or two away from a connector, don't you think I will look at the connector before anything else? It is good enough to play with and get a feel for how it works and that in my opinion is not a waste of time. Others are using the Nano to learn from - from both a programming and an RF point of view. There has been some great dialogue in the forum regarding TDR and RF theory in general. You are sharing your TDR knowledge as well - that's great! I've worked in the RF field (no pun intended) for 40 years and I'm still learning. All I am saying here is that the various diagnostic functions that are being graciously developed for the Nano by very talented individuals, may not be for everyone but, they are NOT a waste of time for everyone. Cheers, Larry On Fri, Sep 27, 2019 at 02:21 PM, <qrp.ddc@...> wrote:
There is no question if TDR needed or not. It is definitely must have. The |
Re: NanoVNA-Saver 0.0.12
Hej Bo,
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I'll address the port numbering first: Port 0 and Port 1 should probably be "Ch0" and "Ch1", and are taken from the port numbering on the physical device: While it's quite confusing to have S11 be reflection on port 0, and S22 be reflection on port 1, that's a physical decision design ... ;-) I'll address your other comments (thank you for them!) as I go through the thread. -- Rune / 5Q5R On Fri, 27 Sep 2019 at 20:34, Bo, OZ2M <groups.io@...> wrote:
One more thing. |
Re: NanoVNA-Saver 0.0.12
Dr. David Kirkby from Kirkby Microwave Ltd
LOn Fri, 27 Sep 2019 at 19:34, Bo, OZ2M <groups.io@...> wrote:
One more thing.
I acknowledge that in programming the starting point if often zero (0) andI agree 100% with you. 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 |
Si5351A max fundamental frequency
Hi group
I have measured a low pass filter, but experience some, for me expected, oddities around the maximum usable fundamental frequency of the Si5351A. Please see the attached picture that clearly shows an abrupt change in the attenuation between ~300 MHz and ~303 MHz. The NanoVNA should be able to run in 3 x 300 MHz segments, i.e. fundamental plus second and third harmonic. So far so good. However, my experience in working with the Si5351A, and the RFzero project in particular, is that the fundamental frequency from the Si5351A can be used up 280 MHz with 100% certainty, and up to somewhere below 300 MHz depending on the actual device. But once the frequency increases, then the PLL will suddenly not lock, the frequency is of course unstable and the S/N is VERY poor. The PLL in the Si5351A I have on my RFzero right now can lock at 299,6 MHz, but not at 299,7 MHz. But I have seen Si5351As that cannot lock above ~287 MHz. I don't think it is possible to bet on the max freq. even vs batch. So why can the NanoVNA say it has 900 MHz, 3 x 300 MHz, usable bandwidth and not e.g. 840 MHz, 3 x 280 MHz, or use the fourth/fifth harmonics? I am a bit troubled with measurements in the 280 MHz - 300 MHz, 560 MHz - 600 MHz and 840 MHz - 900 MHz segments. Should it be an option, in the S/W, to set the max fundamental frequency? I am not thinking of the 1,5 GHz possibilities as such. Bo |
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