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I have a whole load of rubber duck antennas that I'm checking so see at
what range they should work best.

Ken,
the behavior of rubber duckies depends significantly on the radio they are attached to. So, to get reasonably accurate results when measuring them with the nanoVNA, I suggest that you build a metal bracket about the size of a typical HT, covered with some insulation to mimmick the plastic body of an HT, mount the nanoVNA in that bracket, its measuring port bonded to the bracket, and then hold that contraption in your hand like you would hold an HT, while making the measurements.

You could even use a plastic box the size of an HT, covered with aluminium foil on the inside, properly bonded to the nanoVNA's port.

Of course you need to run the nanoVNA without an USB cable connected.

You will see that depending on how you grab that test contraption, the measured values will shift somewhat. If you mount the antenna directly to the nanoVNA, they will shift more, since the nanoVNA is a lot smaller than an HT, at least the 2.8" screen version. I haven't compared the size of the H4 version to that of an HT. It should be closer, but maybe not close enough.

Perhaps someone else can comment on how accurate the measurements come out when mounting a rubber duckie directly on an H4?

Manfred

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

On Tue, Apr 22, 2025 at 08:10 AM, Kenneth Roberts 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?

I always do, just to obtain as much accuracy as possible.

Also: Be sure to calibrate to the end of the coax at the antenna. Coax will influence the measurements, especially if it is longer than a wavelength. (unless is is electrically an odd multiple of a half wave.) You will find your measurement make more sense at VHF/UHF frequencies with the NanoVNA calibrated to the antenna end of the coax.

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

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

22 apr. 2025 kl. 12:50 skrev DiSlord via groups.io <dislordlive@...>:

Save calibration again after change trace type and settings