开云体育

I myself wouldn't be sure of the results. I would re-calibrate it for
144-148 MHz. Then store in a different memory slot than the one I stored
144-174 MHz in. It only takes a few minutes to calibrate it.

Zack W9SZ

<>
Virus-free.www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Tue, Apr 22, 2025 at 11:22?AM Jon via groups.io <vu2jo0=
[email protected]> wrote:

As the second range is well within the first range, you may be able to get
away with it, though the ideal way is as Dave has mentioned.

73
Jon, VU2JO

On Tue, Apr 22, 2025 at 8:40?PM Kenneth Roberts via groups.io <kenr313=
[email protected]> wrote:

I'm new to the NanoVNA H-4. If I calibrate for SWR in the range of
144-174, and then I change the range to, say, 144-148, do I need to re
calibrate?

IOW, for the purposes of SWR readings, under what circumstances do I
need to re calibrate?

I would re-calibrate when I change to 144-148 MHz. That way I'd be sure.
I'd probably save that in a different memory slot than the 144-174 MHz.

Zack W9SZ

<>
Virus-free.www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Tue, Apr 22, 2025 at 10:35?AM Kenneth Roberts via groups.io <kenr313=
[email protected]> wrote:

Just received my H4. If I calibrate for a range of, say, 144-174 MHz, can
I change the range to 144-148 without recalibrating? I guess I'm asking
under what circumstances is recalibration necessary?

As the second range is well within the first range, you may be able to get
away with it, though the ideal way is as Dave has mentioned.

73
Jon, VU2JO

On Tue, Apr 22, 2025 at 8:40?PM Kenneth Roberts via groups.io <kenr313=
[email protected]> wrote:

I'm new to the NanoVNA H-4. If I calibrate for SWR in the range of
144-174, and then I change the range to, say, 144-148, do I need to re
calibrate?

IOW, for the purposes of SWR readings, under what circumstances do I
need to re calibrate?

You will only have valid measurements within the frequency range you calibrated. You can decrease the frequency range and the firmware will interpolate between the calibrated points but the accuracy will decrease.

Just received my H4. If I calibrate for a range of, say, 144-174 MHz, can I change the range to 144-148 without recalibrating? I guess I'm asking under what circumstances is recalibration necessary?

When changing sweep ranges, it's always a good idea to recal.

Dave - W?LEV

On Tue, Apr 22, 2025 at 3:10?PM Kenneth Roberts via groups.io <kenr313=
[email protected]> wrote:

I'm new to the NanoVNA H-4. If I calibrate for SWR in the range of
144-174, and then I change the range to, say, 144-148, do I need to re
calibrate?

IOW, for the purposes of SWR readings, under what circumstances do I
need to re calibrate?

--

*Dave - W?LEV*


--
Dave - W?LEV

I'm new to the NanoVNA H-4.? If I calibrate for SWR in the range of 144-174, and then I change the range to, say, 144-148, do I need to re calibrate?

IOW, for the purposes of SWR readings, under what circumstances do I need to re calibrate?

By design, slot 0 is activated on power-up, not any other slot.

Yes, if you calibrate, then change trace and display options, then save calibration again, it save the currently active calibration and current display/trace setup, no matter which slot (or SD card file name) you save it to.

On Tue, Apr 22, 2025 at 06:05 AM, PE0CWK wrote:

Maybe the firmware version of my NanoVNA -H4 is important.

Yes I think the nanovna firmware version needs to be somewhat recent. This capability was added a year or so ago I think. You can also get the current firmware for the H4 from DiSlord's nanovna-d github page.

Stan,

Thank you for your tip about the little camera icon in NanoVNA-app. Interesting. I gave it a try. Clicking on it, the pop up screenshot is there, but it updates the small screen only when I click on the refresh button. The switch is set Remote, but it becomes not a live update. The interaction with the mouse pointer is also not possible. The baudrate showed a value that my Com Port driver does not support, but after setting the baudrate (115200) of the Com port in Device Manager of Windows 10 the same as in the Nano VNA app (115200) and relaunched the NanoVNA app (version1.1.218)? with status connected, then still no interaction. Only the refresh button works. Maybe the firmware version of my NanoVNA -H4 is important. It would have been nice if it worked but I don't make a big deal out of it.
Kees, PE0CWK

Op 22-4-2025 om 02:04 schreef Stan Dye via groups.io:

Stan,

Thank you for your tip about the little camera icon in NanoVNA-app. Interesting. I gave it a try. Clicking on it, the pop up screenshot is there, but it updates the small screen only when I click on the refresh button. The switch is set Remote, but it becomes not a live update. The interaction with the mouse pointer is also not possible. The baudrate showed a value that my Com Port driver does not support, but after setting the baudrate (115200) of the Com port in Device Manager of Windows 10 the same as in the Nano VNA app (115200) and relaunched the NanoVNA app (version1.1.218)? with status connected, then still no interaction. Only the refresh button works. MaybethefirmwareversionofmyNanoVNA -H4isimportant. ItwouldhavebeenniceifitworkedbutIdon'tmakeabigdealoutofit. Kees, PE0CWK
Op 22-4-2025 om 02:04 schreef Stan Dye via groups.io:

It only works for Save 0. Not for other recalls even if I have changed SWR to active trace and made Calibrate > Save. But if I make Calibrate > Calibrate > Done SWR will remain as the active trace. I hope the previous calibration is still there.
73/Torbj?rn

Save calibration again after change trace type and settings

When I have made a calibration that firstly involves a SWR trace and secondly a trace for Smith, then the Smith-trace is the active trace. Is it possible to afterwards when having changed so that the SWR-trace is the active trace to save that change so when restarting the NanoVNA the SWR-trace is the active trace? Config > Save Config does not help. I realize that making the SWR-trace active before calibration and saving would accomplish that, but afterwards?
73/Torbj?rn/SM6AYM

Thank You Stan! I realized that I was using the original One ot Eleven app and changed to latest Dislord update from his GitHub. The new possibilities are very nice to use for presentations of NanoVNA. The live "Screenshot" can also be enlarged to fill the whole PC-screen and thus the screen the spectators are watching. Interaction can be done both on the NanoVNA and on the PC-screen. I use the Smith-circle to correct the aspect ratio. Possibly Dislord could fix so shift-move in a corner adheres to aspect ratio.
73 Torbj?rn/SM6AYM

Torbjorn,
In nanovna-app, click the little 'camera' icon at the top of the main window. It will pop up a screenshot of the nanovna in a new window. That new window has a 'Remote" switch, toggle it on, and the screenshot will become a live update of the nanovna screen, and you can also interact with it using the mouse pointer to move markers, bring up menus, etc., as if you were touching the nanovna screen.

If your nanovna-app does not do this, you may not have a current enough version - you can the latest from DiSlord's github page.
Stan KC7XE

Dave W0LEV, Thank you I have emailed you via your ARRL email address.

Phil and John,

The NanoVNA is an excellent tool for measuring the inductance and capacitance of components. The S11 shunt method using CH0 (port 1) works well for most measurements. In order to get accurate measurements you need to use the following:

Proper test jig
----------------
- This has been discussed many times in this group and what you use depends on the type of components you want to measure and the accuracy you require. There are jig designs with photos in past group posts for SMD, leaded components and larger coils. The higher in frequency you want to measure the more critical the jig. For HF banana clips on the end of coax will give decent results if you calibrate using a non-inductive 50 ohm resistor.

Calibration
------------
Calibration must be done on the test jig itself at the point where you are going to measure the component. You will need to do a Short-Open-Load (SOL). Set the Stimulus frequencies for the appropriate range and remember to do a Reset before starting the calibration procedure. Verify once it is done by measuring the short, open and load and observing on the Smith Chart trace. The Short should have a dot at the far left on the horizontal axis, the 50 ohm load a dot in the middle and the open on the far right on the horizontal axis.

Measurement
---------------
You can observe L and C on the Smith Chart by going into the trace menu and selecting R+L/C and moving the marker along using the jog wheel. On later versions of DiSlord firmware you can set any S11 trace to Serial C or Serial L to for a graph. I prefer to use NanoVNA app on my PC but others like NanoVNA Saver.

Things to be aware of
------------------------
In the real world there are no ideal inductors or capacitors. A physical inductor will have resistance and stray capacitance and a capacitor will have lead inductance, series and parallel resistance. The NanoVNA and the PC programs do a simple calculation of L and C based on the reactance measured. The calculation of L = Xl/(2*pi*freq) and C = 2*pi*C*freq are not the true values and are referred to in the technical literature as apparent inductance or capacitance.

When measuring capacitors keep the lead lengths short or lead inductance will affect your measurements. Keep inductors away from conductive or magnetic surfaces.

When measuring inductors that use a ferrite core one needs to be aware that the inductance will change considerably with frequency. This is because the permeability of the core material changes with frequency and it is different for each "mix". A decrease in inductance is what occurs but stray capacitance will also have an opposite effect on the "apparent" inductance that is measured.

When measuring capacitors it may not be possible to accurately measure them below or above some frequency range using the S11 shunt method because the reactance may be too high or too low. For example a 1 uF ceramic capacitor will have less than 2 ohm of reactance at 100 kHz.

Experiment
-------------
Users should verify that their jig, calibration and frequency range are suitable by measuring some known components. Air wound inductors that are not tightly wound (low self capacitance) are good for initial tests. 10 to 100 pF caps also yield good results across HF frequencies.

Roger,
Can You evolve how that is done. I have never seen that possibility with NanoVNA-App.
Regards/Torbjorn

How do you measure a coax with my nanovna