Version 1.1; Build Dec 21 2021.
Verbatim 16 GB micro SD card.
First formated Fat 32 via Windows 10 system. Wouldn't write from NANO.
Next installed "SD Card Formater" on my desktop. Did a full Fat 32 format. Wouldn't write from NANO.
Made sure to have NANO "off", then installed card, then turned NANO "on." No joy.
Suggestions?
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Is the MFJ running on batteries?? Or a wall wart?
Personally seen erroneous readings MFJ on wall wart, batteries are better.
Then check adapter/cable for NanoVNA.
Something is different in the RF path.? Search, Grasshopper. WA0VYU
Sent from the all new AOL app for Android
On Mon, Jun 6, 2022 at 5:29 PM, Stefan<spommere@...> wrote: Thanks.
How do you explain this:
MFJ: 1.8
NanoVNA not connected to laptop via USB-C: 2.7
Forget about the laptop, the USB-C cable, the NanoVNA Saver app .. but just unplugging/plugging the coax among MFJ/NanaoVNA.
The MFJ is correct; I used it at another site last weekend, and compared the reading to a $10k spectrum analyzer someone used there.
I went through several cycles of calibrating the NanoVNA, all with the same result.
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1. I cannot get "VSWR" to start / display anything reasonable , BUT "return loss" works as expected
2. How do I delete "marker" - say delete all markers? (I hate clutter)
3. moving mouse wheel zooms "vertical display " , how do I "unzoom "? "
4. is the app missing "save" buttons ( any change ) intentionally ?
5. Can the "sweep " be sped-up ? (serial port baud rate ?)
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On Mon, Jun 6, 2022 at 02:56 AM, Victor Reijs wrote: I have also checked my NanoVNA.
If I measure the Zload of port 2 (using Port 1, so using a calibration
Through connection and measuring port2's S11). I get the following |Zload|
of port 2:
[image: afbeelding.png]
This is ok-ish IMHO (variation some 0.1ohm (less than 0.2%). There is a
deviation from 50ohm (around 05%), but this could be partly due to
inaccuracy calibration Load (measured with DVM: 49.7ohm).
I don't think the Zload (|Z| of port2/load) is problematic. The calculations for S21 series method are based on the Port1 (Ch0) and Port2 (CH1) impedances Zref being 50+j0 (not |Z| = 50). See attached equations. I used the 15 cm Cable that came with my -H4 and calibrated it using SMA loads. The DC resistance of the 50 ohm load was 49.87 ohms. I then calibrated at the end of this cable to establish the reference plane (photo attached). Next I attached the cable to Port2 (CH1) and measured the complex impedance R +/-jX fro 10 kHz to 250 MHz. The attached plots show that there is a considerable change in resistance over this range and an unwanted capacitive reactance. One "trick" that works is to use a quality SMA attenuator and attach it to Port2 (CH1) and this will give a better impedance match. I have a good 6 dB one and you can see the improved performance with it attached. When calibrating for S21 with it attached you get a better impedance match but reduce the S21 dynamic range by 6 dB. What I have not tested is how the impedance of Port1 (Ch0) varies with frequency. This is not as easy a measurement and I have not done it. The attenuator "trick" could be used here as well but needs further investigation. If I measure metal resistors (averaged between 300 and 1800kHz) using
Reflection and Series S21 I method, I get the below |Z| values. I also give
the R values measured with DVM
So indeed |Zrefl| does not deviate much from the DVM value (<2%). The
|ZseriesS21| though differs quite a lot (~9%) from DVM value and looks to
be proportional to the resistor value Yes the S11 reflection method gives good results at resistances in the thousands of ohms. What happens with the S21 series method is that as you increase the DUT resistance you get more error in the S21 gain AND S21 phase. This translates to larger differences in the expected complex impedance of the DUT.
Where is this 9% error coming from? A 9% error is large! I don't think the
deviation of the port2 load (Zload) from 50ohm is problematic (only some
0.2%). Looking at the Zsourse (the impedance of port 1): would that not be
close to Zload (impedance of port2, I hope/assume...). But that one is
compensated using the SOLTI method, or not?
I believe there are many sources of error such as the following: - Port1 and Port 2 impedance is not 50 +j0 as pointed out above - Stray inductance and capacitance of the test jig have a considerable effect on the magnitude and phase of the S21 measurement. I have tried several different test jigs and keep trying to improve. The attached photo shows one I use but still needs work because the S11 reference plane is too far from the DUT and I get an unwanted phase shift - To calculate S21 the NanoVNA needs to know the power level generated on Port 1. I have a hunch that this power level fluctuates as the Return Loss decreases due to a higher DUT impedance. I understand the missing of 12-term correction is the other problem (as
stated by Owen Duffy: ). Who has a
procedure for this? I could not find this on the web (Owen Duffy refers to
it, but I don't see a procedure). For more discussion on this topic here are some old post links... /g/nanovna-users/topic/67738316#7993/g/nanovna-users/topic/hardware_deficiencies_when/80639862?p= With care it is possible to get S21 results that compare well with S11 measurements. Here is a post I made earlier on the subject. /g/nanovna-users/message/24390. But I just use S11 method most of the time for ease of use. Roger
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Another case which will result in varying readings is a vertical antenna (e.g for a handheld) which is lacking a ground/counterpoise/ground plane/feedpoint choke; then the measurement system becomes part of the antenna's ground. End fed antennas often have considerable feedline currents which will affect the readings.
Use the VNA in the state it was calibrated in, for antenna work probably best to use the battery and leave the charger disconnected, or add chokes/ferrites etc. You may need ferrites on both feedline and charger cord, it is hard to predict.
You might want to set the VNA down on a nonconductive stool or table for use, to avoid body effects on antenna measurements.
73, Don N2VGU
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Re: NanoVNA - Signal Generator
In some applications a square wave can be beneficial. Many mixers will perform better with a square wave LO than with a sinusoidal one.
73, Don N2VGU
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Thanks.
How do you explain this:
MFJ: 1.8
NanoVNA not connected to laptop via USB-C: 2.7
Forget about the laptop, the USB-C cable, the NanoVNA Saver app .. but just unplugging/plugging the coax among MFJ/NanaoVNA.
The MFJ is correct; I used it at another site last weekend, and compared the reading to a $10k spectrum analyzer someone used there.
I went through several cycles of calibrating the NanoVNA, all with the same result.
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When I have this problem it¡¯s usually because I¡¯m getting RF coming back on the shield, I put a couple of clamp on fairite chokes on or coil the coax and I get good readings again. Just an idea.
73 Bill N7OQ
toggle quoted message
Show quoted text
On Jun 6, 2022, at 14:45, W0LEV <davearea51a@...> wrote:
?This has been addressed a number of times in this group. If you cal
without the USB cable connected and then connect it for a measurement of
your unknown, this is quite expected. The case of the VNA is "extended" by
the presence of the USB cable and interacts with the unknown, especially if
it is a radiating structure.
Dave - W0LEV
On Mon, Jun 6, 2022 at 12:19 PM Stefan <spommere@...> wrote:
Hi,
I have a MFJ-259B antenna analyzer and now also a NanoVNA-H, along with
the NanoSaver App.
I get inconsistent VSWR readings with both devices:
MFJ: 1.8
NanoVNA not connected to laptop via USB-C: 2.7
NanoVNA connected to laptop via USB-C: 1.1
The VSWR reading on the NanoVNA literally goes from 1.1 to 2.7 when I
unplug the USB-C cable from the NanoVNA.
I went through call calibration steps at least a half dozen times on the
NanoVNA for 50kHz to 900MHz, and for the 40m band (7.0 MHZ - 7.3 MHZ).
Any suggestions as to what value I should actually trust ?
I wonder if I need to calibrate the NanoVNA through the Saver app
separately; based on what I've gathered, it should not be necessary.
Thanks for any advice.
--
*Dave - W?LEV*
*Just Let Darwin Work*
--
Dave - W?LEV
|
This has been addressed a number of times in this group. If you cal
without the USB cable connected and then connect it for a measurement of
your unknown, this is quite expected. The case of the VNA is "extended" by
the presence of the USB cable and interacts with the unknown, especially if
it is a radiating structure.
Dave - W0LEV
toggle quoted message
Show quoted text
On Mon, Jun 6, 2022 at 12:19 PM Stefan <spommere@...> wrote: Hi,
I have a MFJ-259B antenna analyzer and now also a NanoVNA-H, along with
the NanoSaver App.
I get inconsistent VSWR readings with both devices:
MFJ: 1.8
NanoVNA not connected to laptop via USB-C: 2.7
NanoVNA connected to laptop via USB-C: 1.1
The VSWR reading on the NanoVNA literally goes from 1.1 to 2.7 when I
unplug the USB-C cable from the NanoVNA.
I went through call calibration steps at least a half dozen times on the
NanoVNA for 50kHz to 900MHz, and for the 40m band (7.0 MHZ - 7.3 MHZ).
Any suggestions as to what value I should actually trust ?
I wonder if I need to calibrate the NanoVNA through the Saver app
separately; based on what I've gathered, it should not be necessary.
Thanks for any advice.
-- *Dave - W?LEV* *Just Let Darwin Work*
--
Dave - W?LEV
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Re: Firmware Upgrade What Am I Doing Wrong?
Very happy you were able to resolve your issue73's
toggle quoted message
Show quoted text
On Monday, June 6, 2022, 01:44:02 PM EDT, A DeCarmo via groups.io <wce4@...> wrote:
Thanks Chris, finally figure it out it was the driver all the time.
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Possibly a ground loop thru the USB-C. Try running the laptop from its battery, no recharging PS.
WA0VYU
Sent from the all new AOL app for Android
On Mon, Jun 6, 2022 at 1:19 PM, Stefan<spommere@...> wrote: Hi,
I have a MFJ-259B antenna analyzer and now also a NanoVNA-H, along with the NanoSaver App.
I get inconsistent VSWR readings with both devices:
MFJ: 1.8
NanoVNA not connected to laptop via USB-C: 2.7
NanoVNA connected to laptop via USB-C: 1.1
The VSWR reading on the NanoVNA literally goes from 1.1 to 2.7 when I unplug the USB-C cable from the NanoVNA.?
I went through call calibration steps at least a half dozen times on the NanoVNA for 50kHz to 900MHz, and for the 40m band (7.0 MHZ - 7.3 MHZ).
Any suggestions as to what value I should actually trust ?
I wonder if I need to calibrate the NanoVNA through the Saver app separately; based on what I've gathered, it should not be necessary.
Thanks for any advice.
|
Hi,
I have a MFJ-259B antenna analyzer and now also a NanoVNA-H, along with the NanoSaver App.
I get inconsistent VSWR readings with both devices:
MFJ: 1.8
NanoVNA not connected to laptop via USB-C: 2.7
NanoVNA connected to laptop via USB-C: 1.1
The VSWR reading on the NanoVNA literally goes from 1.1 to 2.7 when I unplug the USB-C cable from the NanoVNA.
I went through call calibration steps at least a half dozen times on the NanoVNA for 50kHz to 900MHz, and for the 40m band (7.0 MHZ - 7.3 MHZ).
Any suggestions as to what value I should actually trust ?
I wonder if I need to calibrate the NanoVNA through the Saver app separately; based on what I've gathered, it should not be necessary.
Thanks for any advice.
|
Re: Firmware Upgrade What Am I Doing Wrong?
Thanks Chris, finally figure it out it was the driver all the time.
|
Re: Firmware Upgrade What Am I Doing Wrong?
Thanks for Replying Fred I am using a NanoVNA-H Finally figure it out it was the driver all the time.
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Thanks Roger, I will digest your report. THANKS. I am glad that Brian's paper (which I also found some time ago) is valid, accept it looks that the NanoVNA is more accurate than the system he describes in his paper. That is good news (so the theory is corret, but the system accuracy makes the difference). So the Series S21 should perhaps also be better (over larger range) than mentioned in the article... I might look at Brian's and your paper and see if I can derive the Series/Shunt S21 error curves... I though find my |ZseriesS21| results (using NanoVNA-D, version 1.0.64, kernel 4.0.0) worrying... Thanks again for informing me about your paper. All the best, Victor Op ma 6 jun. 2022 om 18:30 schreef Roger Need via groups.io <sailtamarack= [email protected]>:
On Tue, May 31, 2022 at 02:07 PM, Victor Reijs wrote:
It is not me but
or
who derives the accuracy.
Can you provide where they go wrong? The accuracy of any measurement is important and an excellent paper on
this subject was
written by Brian Walker of Copper Mountain Technologies (a VNA
manufacturer).
"Make Accurate Impedance Measurements Using a VNA" available from
This paper has been discussed on groups.io before and has been subject to
misinterpretation
by myself and others. So I contacted the author and he was kind enough to
answer my
questions and send me his spreadsheet for error analysis. The paper goes
into considerable depth on how to calculate the impedance measurement and
an error equation is derived to calculate ¦¤S11(max).
The author then goes on to derive ¦¤S11 for a Copper Mountain Technologies
S5065 VNA which can measure from 9 kHz to 6.5 GHz with a reflection
accuracy (S11) specified to be ¡À0.4 dB for measurements from ?15 to 0 dB.
The curves and charts in his article are all based on THIS specification.
They are NOT applicable to the NanoVNA which has better performance when
used over a much narrower frequency range.
I wrote a technical note that provides more detail on his paper and how it
can be applied to the NanoVNA. I hope you find it informative. It can be
downloaded from my Box account at the link below"
Roger
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On Tue, May 31, 2022 at 02:07 PM, Victor Reijs wrote: It is not me but
or
who derives the accuracy.
Can you provide where they go wrong? The accuracy of any measurement is important and an excellent paper on this subject was written by Brian Walker of Copper Mountain Technologies (a VNA manufacturer). "Make Accurate Impedance Measurements Using a VNA" available from This paper has been discussed on groups.io before and has been subject to misinterpretation by myself and others. So I contacted the author and he was kind enough to answer my questions and send me his spreadsheet for error analysis. The paper goes into considerable depth on how to calculate the impedance measurement and an error equation is derived to calculate ¦¤S11(max). The author then goes on to derive ¦¤S11 for a Copper Mountain Technologies S5065 VNA which can measure from 9 kHz to 6.5 GHz with a reflection accuracy (S11) specified to be ¡À0.4 dB for measurements from ?15 to 0 dB. The curves and charts in his article are all based on THIS specification. They are NOT applicable to the NanoVNA which has better performance when used over a much narrower frequency range. I wrote a technical note that provides more detail on his paper and how it can be applied to the NanoVNA. I hope you find it informative. It can be downloaded from my Box account at the link below" Roger
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On 6/6/22 9:15 AM, Costin R wrote: Hi all!
In the following link you can find an interesting use for NanoVNA.
I know there were discussions about using it as a signal generator.
Everyone was referring to the rectangular shape of the signal and the
problems of using this signal.
Adam Rong (BD6CR) successfully tested the device as a local oscillator
using the STIMULUS-CW FREQ function.
I think the article below may be the beginning of many experiments.
If Adam's language is a problem (;-) it is for me too), use Google
Translate.
73!
YO8RCD <> As a LO, the square-wave isn't a problem, since for most mixers, the LO should be driving the mixer into saturation. (that is, the mixer acts as a switch).? It's no different than what's inside the NanoVNA driving the SA612 LO ports. Depending on the mixer, one might need some gain, but if you can get +10dBm out, then driving a +7dBm mixer should be no problem.
|
Hi all!
In the following link you can find an interesting use for NanoVNA.
I know there were discussions about using it as a signal generator.
Everyone was referring to the rectangular shape of the signal and the
problems of using this signal.
Adam Rong (BD6CR) successfully tested the device as a local oscillator
using the STIMULUS-CW FREQ function.
I think the article below may be the beginning of many experiments.
If Adam's language is a problem (;-) it is for me too), use Google
Translate.
73!
YO8RCD <>
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Re: spreadsheet for importing snp files, Excel 2010
Hi Ed, Well...new day! Raised in the woods...literally...in N Maine. 2-room school. No electricity until I was 10. Traveled quite a bit after 18. Spent a lot of time in Ca, including visiting Sausalito. Lived in SF, N of SF later, then San Clemente, and Oceanside. Now back in New England. Not often to hear of someone from the area, though there are a lot of active hams in New England. We test 5-10 per month, new and upgrades. Your cell ¡°M4¡± states value of RLdB = 35.9176dB I see you are one of those folks who like "smart" quotes...apparently, my email is too dumb to understand them. Sigh. Like me, like my email ;-) Actually L4 in my copy... Small fix. Not necessary...as I posted in the thread, the point of the spreadsheet is just to give folks the tools do as they like. No warranty expressed or implied. Feel free to use it as ye will. ~R~ 72/73 de Rich NE1EE The Dusty Key On the banks of the Piscataqua
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Thanks Roger for pointing this out. Knowing one's measurement tools is the basic rule here. Thanks for pointing out. I have also checked my NanoVNA. If I measure the Zload of port 2 (using Port 1, so using a calibration Through connection and measuring port2's S11). I get the following |Zload| of port 2: [image: afbeelding.png] This is ok-ish IMHO (variation some 0.1ohm (less than 0.2%). There is a deviation from 50ohm (around 05%), but this could be partly due to inaccuracy calibration Load (measured with DVM: 49.7ohm). I don't think the Zload (|Z| of port2/load) is problematic. If I measure metal resistors (averaged between 300 and 1800kHz) using Reflection and Series S21 I method, I get the below |Z| values. I also give the R values measured with DVM [image: afbeelding.png] [image: afbeelding.png] So indeed |Zrefl| does not deviate much from the DVM value (<2%). The |ZseriesS21| though differs quite a lot (~9%) from DVM value and looks to be proportional to the resistor value. Where is this 9% error coming from? A 9% error is large! I don't think the deviation of the port2 load (Zload) from 50ohm is problematic (only some 0.2%). Looking at the Zsourse (the impedance of port 1): would that not be close to Zload (impedance of port2, I hope/assume...). But that one is compensated using the SOLTI method, or not? I understand the missing of 12-term correction is the other problem (as stated by Owen Duffy: ). Who has a procedure for this? I could not find this on the web (Owen Duffy refers to it, but I don't see a procedure). Something must deviate some 9% from the 'my norm', but what? I tried to simulate this by varying Zo, Zload, Zsource; but I can't find really realistic values to cater for the variation see in ZseriesS21 (I need to bring Zload back to some 40ohm to cater for this 9%, but then some other Z values (|ZseriesS11|) don't match properly [and it is not measured, see above!];-). Any help to understand this is appreciated. Thanks. So at this moment I agree that 2port Series method does not produce good values. All the best, Victor Op di 31 mei 2022 om 23:07 schreef Victor Reijs via groups.io <pe1atn.victor.reijs@...>:
Hello Roger,
Op di 31 mei 2022 om 19:40 schreef Roger Need via groups.io <sailtamarack=
[email protected]>:
The intent of my post was to reply to comments by Victor Reijs and G3TXQ
(sk) that the S11 mode was not suitable for measuring high impedances.
When it comes to the NanoVNA this is not true and actual measurements
like
the one I posted can be used to prove my point.
It is not me but
or
who derives the accuracy.
Can you provide where they go wrong? That would be very helpful. For me.
Thanks.
All the best,
Victor
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gfmucci
Roger Need
Donald S Brant Jr
Rich NE1EE
