Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
I have a question: the numerical displays for changing (for instance) the 'reference position' do not have the 'minus' sign.... (and it's in the last version even on the V2) If i correct remember this not awaible in all fw But now possible quick change refrence and scale position for curent selected trace see attached image
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Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
Hello Dislord.
Thank you very much for the continuing excellent support of the VNAs.
I have a question: the numerical displays for changing (for instance) the 'reference position' do not have the 'minus' sign....
(and it's in the last version even on the V2)
How do you use it to change values?
TIA Joe
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Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
Not that you were, but in case you were wondering, you are amazing! Thank you from all the users for your tireless work in making this happen!
73, Willie N1JBJ
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Re: NanoVNA H / H4 / V2 / V2Plus / V2Plus4 firmware v1.0.69
#firmware
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Re: RTC NanoVNA-H4 too fast and out of date on restart
I add xtal autodetect (for more easy support vs xtal and no), but in some rare cases LSE mode enabled if no xtal on device. Need remove battery and reset this state.
But better instal it for more stable work.
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Re: Measuring a 1/4 wave balanced line
#cables
This may be of interest for those testing balanced lines with a VNA for HF applications. From the 2019 ARRL Handbook
Roger
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Re: Measuring a 1/4 wave balanced line
#cables
On Fri, Jul 30, 2021 at 02:38 PM, ward harriman wrote:
It occurs to me that it might be easier to characterize a longer piece of line
(which allows one to work at lower frequencies and have fewer capacitance
problems) and then cut the desired length¡¡.
Just thinking¡¯ outloud¡¡
I agree with you. I have been doing some tests on a 38.75 foot piece of 300 ohm twin lead with the intent of creating a 1/4 wavelength stub. I used a signal generator with a fast pulse and a digital scope to perform TDR. The round trip delay was 103.2 nanoseconds. This works out to a velocity factor of .763. Next I used the Transform mode on a NanoVNA-H4 and got 102.0 nanoseconds which is a VF of .772 which is pretty close considering the NanVNA is using a IFFT method and not an actual pulse. Once we know the VF to some degree of precision a 1/4 wavelength piece can be cut . A 20 inch piece with a VF of .763 is 1/4 wavelength at 112.49 MHz. With the NanoVNA calculated VF of .772 that same 20 inch piece is 1/4 wavelength at 113.81 MHz. So a difference of 1.32 MHz. Next step was to cut a 20 inch piece and see what the NanoVNA measures on the Smith Chart using a short or an open on the end. A photo of the test setup showing the jig and the ferrites on the short coax cable is attached. Without the ferrites the common mode was really affecting the measurements as shown in the attached screenshots. This was particularly the case when the termination was shorted and high impedance was being measured by the NanoVNA. 1/4 wavelength frequency was measured with reactance as close to zero as possible. A comparison of the results (20" 300 ohm twinlead) 1/4 wavelength frequency.. Using TDR method (calculated) 112.49 MHz. Using NanoVNA Transform method (calculated) 113.81 MHz. Open termination - NanoVNA - without ferrites 112.02 MHz. Open termination - NanoVNA - with ferrites 112.02 MHz. Short termination - NanoVNA - without ferrites 80.529 MHz. ** see screenshot Short termination - NanoVNA - with ferrites 108.02 MHz. Conclusions ----------------- 1. Common mode is an issue and adding ferrites gave better results. I used 3 mix 31 after trying 1 and 2 with poorer results. Mix 43 have higher permeability and would be better but I didn't have any snap-on ones. 2. Results are closer to the TDR method when an open termination is used. The impedance being measured is low and in a better range for the NanoVNA. With a low impedance there is less common mode. 3. A proper balun was not investigated and takes more effort to construct and test. Roger
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Re: RTC NanoVNA-H4 too fast and out of date on restart
Roger, Try setting the time using OneOfEleven's Nanovna-App. It's under Settings. I had a similar issue with my H4 with 1.0.44 through 1.0.47 FW. The app uses the binary mode to set the time.? Note that if you select the version screen while connected to the PC, the connection will drop and you'll have to refresh.? ... Larry On Fri., 30 Jul. 2021 at 7:01 p.m., Roger Need via groups.io<sailtamarack@...> wrote: On Wed, Jul 28, 2021 at 06:16 AM, Paolo Garbin IV3BVK wrote:
Hello guys,
I am writing this message to understand why my VNA-H4 has the internal
clock that runs a lot, compared to that of the PC.
I'll explain better what I mean.
After the firmware update to DiSlord version 1.0.69, I proceeded to
configure the internal date and time of the instrument, via serial
connection (linux terminal command: minicom -D /dev/ttyACM0 ).
I typed the single following commands, to configure the date and time.
time y 21
time m 7
time d 28
time h 15
time min 07
time sec 30
I own a -H4 that does not have the Xtal installed.? The time under Version says 2000/01/01 00:00:07 (LSE) I have tried to use the commands above to set the time and they appear to be accepted without an error message but the time does not change.? Just stays stuck on 2000/01/01 00:00:07. What am I doing wrong? The reason I am trying to get the time going is because I thought it might have something to do with writing files to the SD card.? I can successfully write screenshot bmp, s1p and s2p files but only with one name? "VNA_000101_000007".? If I attempt to output a second screenshot it just overwrites the existing file.? I thought maybe it had something to do with time stamping the file. Any help appreciated... Roger
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Re: RTC NanoVNA-H4 too fast and out of date on restart
On Wed, Jul 28, 2021 at 06:16 AM, Paolo Garbin IV3BVK wrote:
Hello guys,
I am writing this message to understand why my VNA-H4 has the internal
clock that runs a lot, compared to that of the PC.
I'll explain better what I mean.
After the firmware update to DiSlord version 1.0.69, I proceeded to
configure the internal date and time of the instrument, via serial
connection (linux terminal command: minicom -D /dev/ttyACM0 ).
I typed the single following commands, to configure the date and time.
time y 21
time m 7
time d 28
time h 15
time min 07
time sec 30
I own a -H4 that does not have the Xtal installed. The time under Version says 2000/01/01 00:00:07 (LSE) I have tried to use the commands above to set the time and they appear to be accepted without an error message but the time does not change. Just stays stuck on 2000/01/01 00:00:07. What am I doing wrong? The reason I am trying to get the time going is because I thought it might have something to do with writing files to the SD card. I can successfully write screenshot bmp, s1p and s2p files but only with one name "VNA_000101_000007". If I attempt to output a second screenshot it just overwrites the existing file. I thought maybe it had something to do with time stamping the file. Any help appreciated... Roger
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Re: Save Trace Style and Channel?
Chris,
The only time you should use the Reset button in the Calibration menu is immediately prior to performing a calibration. Reset clears calibration entries in RAM so if you use it immediately before saving to a slot, you're saving cleared constants from RAM.?
...and yes, you should set your Freq range, reset & calibrate and save. Then, configure the traces and their functions and then save again back to the same storage slot.?
You'll be able to recall without issue after that.?
... Larry
On Fri., 30 Jul. 2021 at 5:41 p.m., Christopher Maness<christopher.maness@...> wrote: Looks like it is saved in the calibration settings not in the
configuration settings.? That is what I had wrong.? Also, I want to
confirm that you have to reset a channel before you save to it.? That
seems to be the only way I have made the calibration stick.? Or I could
be just missing something simple.? This thing is amazing for tuning an
antenna manually with a T network.? It mostly follows the lines on the
smith chart, with shunt inductance and series capacitance.? Then check
with a redundant antenna analyzer and it is dead on the money at VSWR
1.01:1.
Thanks,
Chris Maness
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On 7/30/2021 2:03 PM, Christopher Maness via groups.io wrote: I have version 1.0.45 Build Jan 30 2021
On Fri, Jul 30, 2021 at 12:07 PM Larry Rothman <nlroth@...> wrote:
? Hi Chris,
Please let us know the model/version of Nano you have and the version of firmware from the Config>Version screen.
What you're doing should work as that is how I configure my unit.
Thanks
? ? ? On Friday, July 30, 2021, 2:56:44 p.m. EDT, Christopher Maness <christopher.maness@...> wrote:
? I want to save Trace 3 to do SWR instead of phase.? Even though I save it
in a profile and the general settings.? It always pops back to phase.? How
do I make these changes permanent?
Also, when I want to save calibration settings, do I have to delete the old
ones first?? That seems to be the case with mint unit.
Thanks Chris
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Re: Save Trace Style and Channel?
Looks like it is saved in the calibration settings not in the configuration settings.? That is what I had wrong.? Also, I want to confirm that you have to reset a channel before you save to it.? That seems to be the only way I have made the calibration stick.? Or I could be just missing something simple.? This thing is amazing for tuning an antenna manually with a T network.? It mostly follows the lines on the smith chart, with shunt inductance and series capacitance.? Then check with a redundant antenna analyzer and it is dead on the money at VSWR 1.01:1.
Thanks,
Chris Maness
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On 7/30/2021 2:03 PM, Christopher Maness via groups.io wrote: I have version 1.0.45 Build Jan 30 2021
On Fri, Jul 30, 2021 at 12:07 PM Larry Rothman <nlroth@...> wrote:
Hi Chris,
Please let us know the model/version of Nano you have and the version of firmware from the Config>Version screen.
What you're doing should work as that is how I configure my unit.
Thanks
On Friday, July 30, 2021, 2:56:44 p.m. EDT, Christopher Maness <christopher.maness@...> wrote:
I want to save Trace 3 to do SWR instead of phase. Even though I save it
in a profile and the general settings. It always pops back to phase. How
do I make these changes permanent?
Also, when I want to save calibration settings, do I have to delete the old
ones first? That seems to be the case with mint unit.
Thanks Chris
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Re: Measuring a 1/4 wave balanced line
#cables
It occurs to me that it might be easier to characterize a longer piece of line (which allows one to work at lower frequencies and have fewer capacitance problems) and then cut the desired length¡¡.
Just thinking¡¯ outloud¡¡
Ward
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Re: Save Trace Style and Channel?
I have version 1.0.45 Build Jan 30 2021
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On Fri, Jul 30, 2021 at 12:07 PM Larry Rothman <nlroth@...> wrote:
Hi Chris,
Please let us know the model/version of Nano you have and the version of firmware from the Config>Version screen.
What you're doing should work as that is how I configure my unit.
Thanks
On Friday, July 30, 2021, 2:56:44 p.m. EDT, Christopher Maness <christopher.maness@...> wrote:
I want to save Trace 3 to do SWR instead of phase. Even though I save it
in a profile and the general settings. It always pops back to phase. How
do I make these changes permanent?
Also, when I want to save calibration settings, do I have to delete the old
ones first? That seems to be the case with mint unit.
Thanks Chris
|
Re: Measuring a 1/4 wave balanced line
#cables
I absolutely agree I was talking about ideal lines... and ideal VNAs.
One must always take these things into account.
Thanks for keeping me honest....
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Re: Save Trace Style and Channel?
Hi Chris,
Please let us know the model/version of Nano you have and the version of firmware from the Config>Version screen.
What you're doing should work as that is how I configure my unit.
Thanks
toggle quoted message
Show quoted text
On Friday, July 30, 2021, 2:56:44 p.m. EDT, Christopher Maness <christopher.maness@...> wrote:
I want to save Trace 3 to do SWR instead of phase.? Even though I save it
in a profile and the general settings.? It always pops back to phase.? How
do I make these changes permanent?
Also, when I want to save calibration settings, do I have to delete the old
ones first?? That seems to be the case with mint unit.
Thanks Chris
|
Save Trace Style and Channel?
I want to save Trace 3 to do SWR instead of phase. Even though I save it
in a profile and the general settings. It always pops back to phase. How
do I make these changes permanent?
Also, when I want to save calibration settings, do I have to delete the old
ones first? That seems to be the case with mint unit.
Thanks Chris
|
I confirm my email address roberto.delchiaro@... ---------- Forwarded message --------- Da: Groups.io < [email protected]> Date: ven 30 lug 2021 alle ore 12:14 Subject: [nanovna-users] Confirm your roberto.delchiaro@... email address To: <roberto.delchiaro@...> Hello, Thank you for your interest in the /g/nanovna-users group at Groups.io. If you did not request or do not want to join [email protected], please ignore this message. If you only want to send and receive messages from [email protected], reply to this email to confirm your email address and activate your membership. - Messages will be sent to you at roberto.delchiaro@... - Send messages to [email protected]If you want to use the resources and read messages on the website, please click on the link below to confirm your email address, set up a password, and choose other subscription settings: Confirm account < /confirm?email=roberto.delchiaro%40gmail.com&cookie=4234111311013003023> Cheers, The Groups.io Team
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Re: Measuring a 1/4 wave balanced line
#cables
On Thu, Jul 29, 2021 at 10:21 AM, ward harriman wrote:
If all you are interested in is the correct length for 1/4 wave, you can
make life a bit easier... no math necessary. Leave the line 'open' and simply
measure S21 and S11. The frequency at which the line is 1/4 wave will cause
the 1/4 wave to be a 'short'. At that frequency, S11 will be '0' and S21 will
be '1'.
If someone knows of any pitfalls to this approach, please let us know!!!
Ward, What you say is true for theoretical transmission lines with no attenuation. A physical TL has attenuation and you don't get exactly 0 ohms at the end of a open 1/4 wavelength transmission line or infinite impedance with a shorted line. I don't know if you read my latest post where I pointed out that common mode results in incorrect S11 and S21 measurements when measuring a balanced TL with an unbalanced VNA. You need to reduce it with a suitable balun or RF chokes on the coaxial cable especially if you are operating at VHF or higher like the OP posed in his question. Even with a proper balun then there are some issues with accuracy. You might find the attached article by Rohde and Schwartz interesting.
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Re: Measuring a 1/4 wave balanced line
#cables
On 7/30/21 10:40 AM, ward harriman wrote: To measure 1/2 wave you could simply short the far end.
Sweep the frequency.
When s11 is -1 (impedance is zero) you're at the 1/2 wavelength frequency (or a multiple thereof, start the sweep very low). or open.? Either way, you get mag s11 = 1 when it's a 1/2 wavelength long. However, the OP wanted 1/4 wavelength. So you could use the fact that 1/4 wave transforms the impedance at the far end. So it also will be either a short (if far end open) or a open (far end shorted), both of which show mag S11 = 1 (or maximum... there *is* some loss)
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Re: Measuring a 1/4 wave balanced line
#cables
To measure 1/2 wave you could simply short the far end.
Sweep the frequency.
When s11 is -1 (impedance is zero) you're at the 1/2 wavelength frequency (or a multiple thereof, start the sweep very low).
You can learn all sorts of things by playing with a transmission line simulator. LTSpice is good.
(Unapologetic pitch for my stuff) SimSmith is better.
www.ae6ty.com/Smith_Charts.html
ward
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Roger Need
