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Has anyone used the nanovna to make tunes coaxial stubs? I was thinking you'd need to get rid of the jumper which would add length to the overall stub. I picked up an SMA to SO-239 connector which hopefully would do away with the extra cable.
Anyone have any tips for this?
Thanks
Bill K4FX

HI DiSlord,

Thanks very much for the great firmware, it runs fine on my -H4. Can you tell me please the syntax of the bandwith command ?

Thank you,

Jos

Op 31-3-2020 om 00:15 schreef DiSlord:

Just a note for we nit pickers. RESISTANCE is not frequency independent. For example, in transmission lines the skit effect and dielectric losses, affect the resistance. Related effects can be found in inductors and capacitors.....

The coax, unless it's defective, only adds loss (and rotation around the
Smith Chart) to the measurement of the antenna. It doesn't affect the
frequency response.

You could calibrate S11 with the coax connected and applying Short, Open,
Load at the far end of the coax with the antenna disconnected.

Or, just measure it as is - the Return Loss dips will be at the same
frequency as if you measured directly at the antenna. Just the depths of
the dips will be different.

Make sense?

73, Carey, WB4HXE


On Tue, Mar 31, 2020 at 1:30 PM Jeff W6FCC via Groups.Io <w6fcc=
[email protected]> wrote:

Setup: I have a 40 meter dipole at 30 feet. Feeding with 100 ft of RG8X
Measurement: 7.200 Mhz, SWR at RADIO end of COAX can be measured (For the
Analysis System -- coax + antenna)

Question: Can the Reference plane be "calculated" by software. It's the
location of the antenna at the END of the Coax, discounting the Feedline,
perhaps by entering the Feedline Impedance and Velocity Factor and Loss?

Asked a different way:

Can the NanoVNA be used to isolate the antenna at the far end of the COAX
and somehow IGNORE the impact of the COAX itself ?

I realize the best way to check the antenna is AT the feedpoint, but that
is not possible right now. I'm stuck at the Radio End of the COAX and
trying to determine of the DIPOLE is too long or short.

One possible "solution" IF I could take a second piece of 100' RG8X and do
the calibration at the far end (OPEN, SHORT, LOAD) and push the Reference
plane out to the 100' mark.
But can it be done without a second piece of COAX ??

Has anyone calibrated their NanoVNA using a long piece of coax and doing
the CAL at the end of the coax before attaching to an antenna to be tested ?

Jeff, W6FCC, 3-31-2020

--
Carey Fisher
careyfisher@...

Setup: I have a 40 meter dipole at 30 feet. Feeding with 100 ft of RG8X
Measurement: 7.200 Mhz, SWR at RADIO end of COAX can be measured (For the Analysis System -- coax + antenna)

Question: Can the Reference plane be "calculated" by software. It's the location of the antenna at the END of the Coax, discounting the Feedline, perhaps by entering the Feedline Impedance and Velocity Factor and Loss?

Asked a different way:

Can the NanoVNA be used to isolate the antenna at the far end of the COAX and somehow IGNORE the impact of the COAX itself ?

I realize the best way to check the antenna is AT the feedpoint, but that is not possible right now. I'm stuck at the Radio End of the COAX and trying to determine of the DIPOLE is too long or short.

One possible "solution" IF I could take a second piece of 100' RG8X and do the calibration at the far end (OPEN, SHORT, LOAD) and push the Reference plane out to the 100' mark.
But can it be done without a second piece of COAX ??

Has anyone calibrated their NanoVNA using a long piece of coax and doing the CAL at the end of the coax before attaching to an antenna to be tested ?

Jeff, W6FCC, 3-31-2020

-F

Stay virus safe & follow the rules!

Cheers,
Marty Hadfield

On Mar 31, 2020, at 9:38 AM, Larry Rothman <nlroth@...> wrote:

? Welcome to the forum.
What model did you buy? There are 4 models: original, -H, -H4, or -F?

On Tuesday, March 31, 2020, 11:52:24 a.m. GMT-4, Andrew Steen <k6stn.1@...> wrote:

Hello. I am new to the group, having just received my new nanovna yesterday. At first, it was working great with the nanovna saver program. Then, it only shows a light blue screen. No display at all. Anyway to recover, or do I need to replace the unit?
Thanks,
Andrew

Would whoever admins the Wiki put all these links

.. all >>what<< links?

in a conspicuous space

Is this sufficiently conspicuous?
/g/nanovna-users/wiki/External-links#Smith-charts-and-Touchstone-28S1p2C-S2p29-files

Without reviewing them personally, I am likely to add only those specifically rated better than those already linked.

Thanks for all the great advice.
I did pull the usb cable and it powered on with the normal screen.
I had been using it on the desktop, and assumed it was charged.
I now have it on a regular 5v charger, so that should fix the issue.
Again, thanks to all for your great advice on this issue.
Andrew

Welcome to the forum.
What model did you buy?? There are 4 models: original, -H, -H4, or -F?

Have you fully charged it? If you remove the USB cable and power off - then on does it show the boot screen?

Roger

Try loosening the screws that hold it together and apply pressure to the
display, itself. No guarantees, but this problem has previously been
reported with the associated 'fix'.

Dave - W0LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*

Hello. I am new to the group, having just received my new nanovna yesterday. At first, it was working great with the nanovna saver program. Then, it only shows a light blue screen. No display at all. Anyway to recover, or do I need to replace the unit?
Thanks,
Andrew

Bruce,

Adding information to the Wiki, Files and Photos sections of the group is generally done by members.

While the moderators will provide help on how to do that if a member needs that help, we generally limit our activities to ensuring that the list postings remain technical, non-personal and generally on-topic for the lists original purpose.

DaveD (co-moderator/owner)

--
This email has been checked for viruses by Avast antivirus software.

On Tue, Mar 31, 2020 at 03:03 AM, Gyula Molnar wrote:

... please ask me to share the -H4 screenV.py that works for you.
Unfortunately, I got stuck on line 71....
============================================================
Gyula,
After updating to DiSlords latest beta firmware, which corrected a problem with the "capture" console command that caused me to receive the same error message that you are receiving, the attached scripted worked.

Please change line 17 to the port the NanoVNA-H4 is attached to on your PC:
port = 'COM5' # Set the correct comport before running script

From Powershell or the Windows command-line, change directory to the location of the script. Enter the following:
python H4_tk-scrnCapture.py

Every so often I still get a "struc:error" message, but cycling power to the NanoVNA-H4 and re-starting the script usually clears it up.

Good luck and thank you for the contribution to the NanoVNA community that your website provides.

- Herb

Bruce,
The NanoVNA Wiki is a group effort and several of us have added a lot of info there.
So...Why not browse the various threads, gather links you think would be of interest and add them to the wiki or to a PDF document saved to the files section?
Anyone can add to the main wiki page.
Regards,Larry

Would whoever admins the Wiki put all these links in a conspicuous space so that all of them can be easily found without having to search all the messages. That way anyone interested can examine them and use the one(s) of particular interest to them.

BruceN / K4TQL

--
*"To invent, you need a good imagination and a pile of junk"* -- Thomas Alva Edison (1847-1931)

Hi Herb,

please ask me to share the -H4 screenV.py that works for you.
Unfortunately, I got stuck on line 71. Thanks

Otherwise, I had something on the screen in the revision and compiler lines, although I used clearconfig 1234 several times with the terminal program. I wanted to test the screen saver first, but I got stuck.

Thank both of you very much! Great people on this list!

Marko Cebokli

On Mon, Mar 30, 2020 at 03:15 PM, DiSlord wrote:

i fogot copy dsp.c file as result Bandwidth option not work :( (It measure many time, but use only last data)

Now all correct, also i speedup SPI bus, display update should be very fast
=====================================================================
DiSlord,
Bandwidth option seems to be working. I have attached a screenshot showing a 1 kHz BW and 100 Hz BW LOGMAG display (10 kHz - 2 GHz). The noise floor for the 100 Hz BW is noticeably lower.

The SPI bus speedup also is noticeable. The NanoVNA-H4 display update rate is faster than both the NanoVNA (v0.7.1) and NanoVNA-F (v0.1.1) when using the normal 1 kHz BW.

Hope your NanoVNA-H4 arrives soon and maybe 201 pts can be added to the firmware.

Regards,

- Herb

Sorry, then i port code for H4 i fogot copy dsp.c file

As result Bandwidth option not work :( (It measure many time, but use only last data)

Now all correct, also i speedup SPI bus, display update should be very fast