On Fri, Mar 4, 2022 at 07:43 AM, Miro, N9LR wrote:
Now question - what happens when I "reset calibration" on nano - will that in
effect be equivalent to calibrating nano directly at the port?
If not, what is the quickest way to get calibration that will get me going
quickly, without the need for SOL?
There are numerous articles and videos available which discuss why a VNA requires calibration. A quick Google search will provide articles in whatever technical depth you want.
I suggest that you just calibrate your NanoVNA right at the S11 port for the widest frequency range that you operate. Save it to slot 0 and you are done. On power up it will use the calibration in slot 0 and you can make your measurements. No additional calibration is necessary in most cases This was suggested by Colin McDonald in his reply to you as well. You can even zoom into the frequency range of interest and many of the NanoVNA products will interpolate for you. The SWR and Return loss will be good enough for tuning purposes and for HF the length of any pigtails will not make a significant difference in the results. I posted some detailed reports on how well this works for measuring SWR of HF and VHF antennas in this group a while ago.
The SWR and Return Loss will be worse at the antenna than measured at the end of your feedline. If you want an estimate of Return Loss or SWR at the antenna and you know (or can estimate) the attenuation of the cable it is easy to calculate the Return Loss at the feedpoint. By knowing the feedpoint RL you can calculate the SWR or look it up on one of the SWR-RL conversion tables. Or you can use this handy chart.
Roger
Roger Need
