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For your first question, regarding how wide is too wide for HF VSWR
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measurements: I have one saved calibration setup from 1MHz - 30MHz, which I use to see the basic characteristics of a multiband HF vertical antenna (i.e. do I see good dips on all the bands it is made for). Then I often set the range smaller to see more closely what the VSWR is at my desired part of just one or two bands. This works fine, no need to recalibrate for this general VSWR use. Note that the nanovna firmware interpolates quite well between calibration points, so reasonably accurate VSWR results are given. Note also that the frequency position of the VSWR 'dips' (minimums) is not dependent on calibration - finer calibration will only give a bit more accuracy of the value of the SWR at that frequency. So for this HF VSWR purpose, a single saved calibration works well across the HF bands. You can experiment with this, by doing a detailed calibration for just one band, say 13.5-14.5MHz, and comparing the VSWR value with what you get from the 1-30MHz calibration, and you won't see large differences. However, if you are doing other measurements, e.g. ones that require specific complex impedance values, you should always calibrate over the frequency range you are measuring. For your second question, regarding number of points: Note that with recent firmware, many nanovna hardware models support 401 points. It sounds like that is what you have, since you are getting 2.5kHz steps across a 1MHz range. The actual number of points used is settable via the menus. Which version of firmware do you have? and which model of nanovna? (can be seen on the startup screen, or on the config->version menu screen for more recent firmware). I hope that helps a bit. On Wed, Feb 1, 2023 at 5:35 PM Bill Klymus W5PB <bktx75@...> wrote:
I know that the nanoVNA has about 101 (measurement points between the |
