Re: nanovna Battery Specifications
No battery needed for saving calibration data, It is stored in flash memory
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Re: nanovna Battery Specifications
@ warren
Your nanovna is ver 3.1 printed on pcb with shields for three sections.
Is it the latest PCB Version.
Is internal battery necessary for saving Calibration data.
73
de VU2PGB
VEEN
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On Fri, Sep 27, 2019, 11:59 PM 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
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Re: Step attenuator testing versus dynamic range
Bruce
What you are seeing is leakage through your attenuator. Attenuators intended for HF work and below, especially those with a network of mechanical switches and resistors, often display this behavior. The higher the frequency the more the leakage around the attenuator.
Measurement of the Nanovna dynamic range is simply a matter of reading from the screen. It is defined as the difference between the level shown on the screen when port 0 is connected directly to port 1, and the level of noise shown in the screen with nothing connected to port 1. This would be measured using Logmag format and looking at CH1.
The dyhamic range decreases with frequency due to the output level from port 0 decreasing as well.
WA8TOD
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Re: Step attenuator testing versus dynamic range
I just did the experiment here with my hp 355D 100 dB attenuator/ 10 dB steps.
Attenuation is spot on and the VNA follows it just fine all the way down to 80 dB.
No surprises at HF.
If you have a COM receiver, certainly with sensitivity of better than -80 dBm and a sig gen,
try that combo and see if you have a defective step attenuator.
QSL. Alan
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Re: Step attenuator testing versus dynamic range
Hi Bruce.
Interesting. Well, I have measured HF filters whose center frequency is less than 30 MHz and readily saw skirt responses that were 80 dB below the pass band response. Now I made sure I took the 0 dB reference line to the very top of the display range. So with 8 divisions at 10 dB/division I would see the 80 dB attenuation point plus some noise.
Now the attenuator certainly could be limited in its true attenuation range if not properly constructed. Not easy to build 100 dB attenuators! Take a decent HP step attenuator, there not cheap when new! Could be leakage.
As a check, I'll try the same simple experiment at my end.
Alan
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Re: errors of "error" models
Hello yin&pez,
The software documentation mentions that there was a Mathematica version of
the software tools, even though the Matematica version may not be uptodate,
I am better at reading Mathematica code than fortran + maxima, I would like
if possible to have a look at the Mathematica code, could you upload it ?
Regards
Jose
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On Sun, Sep 22, 2019 at 10:23 PM yza <yzaVNA@...> wrote: 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
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Step attenuator testing versus dynamic range
I have a step attenuator with a series of switches (1-20 dB assorted values) that can be combined for (in theory) up to 80 dB total attenuation. Measuring the S21 individually, the 1,2,3,6,10,and 20dB switches yield S21 results on the nanoVNA that are very close to the stated values, testing over a 3-30 MHz frequency range. However, when I combine assorted switch values that sum to greater than 40 dB, the S21 results more or less max out at about -43 dB. On the other hand, the nanoVNA does displays S21 values in the -80 dB range with the step attenuator disconnected.
This makes we wonder whether the -43 dB maximum S21 result is a property of the step attenuator itself (internal leakage?), or is it simply the true dynamic range with my specific calibration, cables, connectors etc? Even 40 dB of dynamic range is plenty for my uses, and it seems like I find a new way to use this amazing device every day, but I am curious to learn more about what the dynamic range is.
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Re: Experimental 256 point FFT Firmware
On Sat, Sep 28, 2019 at 02:19 AM, Reginald Beardsley wrote:
Solving d = a*exp(j*2*pi*f*t) with 256 measurements will give better accuracy
Reginald could you please explain what means this equation? What means "d" and "a" variables? It seems that "f" is frequency and "t" is time, but I'm not sure what frequency and time exactly? If "f" is frequency of S11 point in frequency domain, then what means "t"?
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Re: Experimental 256 point FFT Firmware
Purchasing used cable is a very iffy business because hams tend to
leave cable in place for two decades and more. It should be changed out regularly, of course. A suggestion I would offer is to make Herb's observation below, of
course, for irregularities but also to measure the length physically and then relate that result to what appears in the t.d.r. reflectometry. The reason is dielectric contaminated by old formulation jackets and by moisture and even overt water ingress. The author was called out to investigate the station of a chap who was in a wheel chair because of spina bifida. Disconnecting his coaxial cable at his transceiver produced dribbling water! Presumably the installation up the tower at his Yagi-Uda had been done incompetently or something had come adrift up there. Anyway, the local ham club was called and the fellows came out and ran in new cable for him and this time installed it properly up his tower at the antenna. Especially with all the estate sales we see these days, we should be
very suspicious of used coax for sale. It may be antique and in deplorable condition. Physical length and velocity factor determined length must agree. Meggering the cable would be a fine idea, too. See if you can can beg, borrow or steal a megger for the day of the flea market. If the seller won't let you megger the cable, then you know all that you have to know about that piece of cable! The cable is a capacitor, short it before connecting your analyzer.
John
at radio station VE7AOV
+++++ On 2019-09-27 2:38 p.m., hwalker wrote: 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: Another modified nanoVNA software
Neat antenna response with the double frequency match.
They did a nice job.
Would be interesting to see how the radiation efficiency holds up.
Alan
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Re: errors of "error" models
20 : Measurements with Core Uncertainty
Hello,
Allow us, please, to inform you that in the course of preparation
for the final comparison between VNA and NanoVNA, which we
planned to base it on Results with Core Uncertainties regarding
the Zinp of the "ref2007box" shown here:
(1) externally :
(2) internally :
we applied yesterday the current versions of our [REGION] &
[DERDEI] combined /F/L/O/S/S/ on the "raw" (S, L, O) + DUT
measurements, sometime taken with a HP8505A system in
CW mode under HP-IB control, from which we finally got for
the Z-inp in the the frequency range of [2,1289] MHz with step
of 13 MHz, the following graphics:
(3) R ~ f :
(4) X ~ f :
(5) Magnitude ~ f :
(6) Argument ~ f :
(7) R and X ~ f :
where, the sine qua non Core Uncertainty is due both to:
(a) the 5 = 2 + 1 + 2 uncertainties of the S, L, and O standards,
which are known from their manufacturers' data, as well as
(b) the 8 = 2 x 4 inaccuracies of the four VNA readings,
that is the Core Uncertainty is due to a combination of
26 = 13 x 2 error bounds, in total.
Sincerely,
pez&yin@arg
20
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Another modified nanoVNA software
Testing a U/V Baofeng HT antenna with my modified nanoVNA software.
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Re: Calibration bug in newer firmwares?
Last edy555 firmware DFU. 27-09-2019.
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Re: Calibration bug in newer firmwares?
Larry,
I deleted the un-edited user guide I uploaded in favor of your version. We appreciate the effort you spent cleaning the user guide up. Props to ch045 for authoring the original guide.
Herb
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Hi Rune Measuring phase is much used by me. It you e.g. want to measure using the port extension (in ps) to the end of an adaptor to which you solder leaded components then you check the S11 phase being 0 with e.g. 1 degree / division. That can of course be done with the native NanoVNA and then further measure with the NanoVNA-saver. A continuous trca facility woul not be bad either Kind regards Kurt -----Oprindelig meddelelse----- Fra: [email protected] < [email protected]> P? vegne af Rune Broberg Sendt: 27. september 2019 21:43 Til: [email protected]Emne: Re: [nanovna-users] NanoVNA-Saver 0.0.12 Hi Kurt, 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
Version 0.0.12 great news.
I have tested your calibration using the Delay and L/C coefficients
together with my HP83033C female calibration standards and tested the
calculated data for equivalent L and C and at 100MHz they are OK.
The scaling of the Data Axis is super but some problem still exist.
The
R+jx is if setting to + - 11 is showing 10. I suppose it will come but
R+the
Dara Axis for any of the phase displays are greyed out. That was what
I stumbled over.
I did a T-Check manipulation where I copied the S11 to S22 and S21 to
S12 after I subtracted the Thru adaptor delay (42ps) from S21/S11.
Result attached but is not nice simply because there is no 12term
error correction performed. Adding a 10 or 20dB attenuator in front of
Port1 would help as linearizing the port1 input impedance to be closer
to 50ohm Keep up the good work very much appreciated.
Kind regards
Kurt
-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af
Rune Broberg
Sendt: 27. september 2019 13:05
Til: [email protected]
Emne: [nanovna-users] NanoVNA-Saver 0.0.12
I just released 0.0.12:
This release of NanoVNA-Saver offers a number of new features, all of
which have been widely requested.
First of all, there's now the option of scaling the plots: right click
them for a menu, where it's possible to set the maximum and minimum
values for the frequency and data axes. Sadly not yet ready for the
polar plots, and mouse control of zoom is also pushed to a future release.
Second, it's not possible to have "bands" displayed in the frequency
based
plots: Select "Display setup" to find the option for this. The default
data is for amateur radio bands - or you can put in your own.
Thirdly, the calibration procedure has received a new "calibration
assistant": A series of popup messages prompting you to switch between
calibration standards, and code to automatically sweep them for you
and store the results.
Finally, there's as always a number of bugfixes and stability improvements.
With more than 800 downloads of the 0.0.11 version, I can't wait to
hear what you all think of it this time - and I can't thank this
community and mailing list enough for the support, encouragement,
suggestions and testing you have provided!
I am interested in knowing what platforms you are getting this
software running on, *particularly* if you had had to jump through
hoops or do anything unexpected to get it to run: Do email me at
mihtjel@... if you can tell me what you had to do to make it
work, so that I may update the documentation, or make things easier to install in the future.
Thank you!
--
Rune / 5Q5R
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Re: Calibration bug in newer firmwares?
Paul, I uploaded a manual in the files section that has the answer to that. It is authored by cho45. My version has live links.
Hope this helps
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Re: Experimental 256 point FFT Firmware
Solving d = a*exp(j*2*pi*f*t) with 256 measurements will give better accuracy than the 32k point FFT with far less computation. The sole limitation to the accuracy from computing a linear fit to the phase is the accuracy of the velocity factor and the angular accuracy of the phase measurements. A nanoVNA should be able to measure the length of an airline to 4.4 mm or less using 101 frequency magnitude and phase measurements. That's assuming a 3.6 degree phase accuracy based on a 40 dB SNR at 900 MHz.
One can do better than that by restricting the sweep to a range with higher SNR.
In summary, the number of points in the FFT is a red herring. The error cited is only an issue if the calculation is done incorrectly. One could also interpolate the sinc(t) in the time domain using 8 points to any desired sampling from a 256 point FFT. However, that would still be the wrong way to determine the delay time. Solving the equation in the first sentence is how it is properly done.
Have Fun!
Reg
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On Fri, Sep 27, 2019 at 04:13 PM, Rune Broberg wrote:
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... ;-)
--
No such thing as bugs... they're all undocumented features.?
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Hello Rune,
I have just uploaded V0.0.12, and it works superbly on my Win10 64Bit machine! I did have it shut down inexplicably shortly after I had first started the program, however I powered down the nanoVNA, restarted 'nanoVNA-Saver, then repowered the VNA and everything has worked normally since doing that. I also noted that your software immediately recognised com4 from the nanoVNA immediately!
I haven¡¯t done a remote Calibrate yet, but I will do that later in the day. Thank you so much for your continuing efforts with nanoVNA-Saver! We all very much appreciate your expertise!
Regards & 73's
Pete
ZL2iK
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Rune Broberg Sent: Friday, 27 September 2019 23:05 To: [email protected]Subject: [nanovna-users] NanoVNA-Saver 0.0.12 I just released 0.0.12: This release of NanoVNA-Saver offers a number of new features, all of which have been widely requested. First of all, there's now the option of scaling the plots: right click them for a menu, where it's possible to set the maximum and minimum values for the frequency and data axes. Sadly not yet ready for the polar plots, and mouse control of zoom is also pushed to a future release. Second, it's not possible to have "bands" displayed in the frequency based plots: Select "Display setup" to find the option for this. The default data is for amateur radio bands - or you can put in your own. Thirdly, the calibration procedure has received a new "calibration assistant": A series of popup messages prompting you to switch between calibration standards, and code to automatically sweep them for you and store the results. Finally, there's as always a number of bugfixes and stability improvements. With more than 800 downloads of the 0.0.11 version, I can't wait to hear what you all think of it this time - and I can't thank this community and mailing list enough for the support, encouragement, suggestions and testing you have provided! I am interested in knowing what platforms you are getting this software running on, *particularly* if you had had to jump through hoops or do anything unexpected to get it to run: Do email me at mihtjel@... if you can tell me what you had to do to make it work, so that I may update the documentation, or make things easier to install in the future. Thank you! -- Rune / 5Q5R
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Re: Experimental 256 point FFT Firmware
I'm talking about polyethylene dielectric cable. It has velocity
coefficient of 0.659. Its temperature coefficient is negligible.
If you cant identify polyethylene in the cable you are purchasing, then
that's not my problem.
A
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On Fri, 27 Sep 2019, 23:01 , <qrp.ddc@...> wrote: 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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Warren Allgyer
Jose Luu
gin&pez@arg
Kurt Poulsen
Peter Mulhare