Hi,
I Ham friend of mine ordered a NavoVNA and he asked me to come over and help him understand how to check the SWR of his antennas. I am not yet very familiar with all the operational procedures of the NanoVNA except for what I could gathered here by reading other posts. But can't seem to remember a similar issue being brought up and a quick search did not help either. Plus I still need to order mine, but have not made up my mind between the v3.4 and the 4H, etc, so didn't have any experience at all playing with this device until now.
What I did first was set the start and stop frequencies (in this case 2-35MHz), then proceeded to make a calibration which included a reset and then seemed to go well on all three steps, as the markers for open, short and 50ohm where all showing in the correct position on the smith chart after the calibration was completed and saved. Afterwards I tried with a narrower frequency range (2-10MHz) then calibrated again, but the results where still the same as described bellow.
After connecting the antenna to CH-0 both the Smith chart and return loss traces seemed to be showing useful indications, but the trace corresponding to the SWR was always shown completely flat at the bottom of the screen and the readout for that trace was in fact showing 1:1 as well along the whole trace. This happened even when the Smith chart clearly was showing a reading of an impedance that was quite different than 50 ohms, plus capacitance or inductance. Besides it would be impossible for a single antenna to have 1:1 on the whole frequency range. Just as a test I connected a dummy load instead of the antenna and then the return loss trace would also be flat, and the smith chart would show the marker very close to where 50ohms would be expected to be.
So my question would be if I am missing to set up something else in order to be able to make the SWR trace work. I tried disabling all other traces but that did not solve anything either. Also not being yet very familiar with practical use of the device, I found that the Scale setting was a bit confusing as it only has the numbers and then a +1 field. Would this be used to define the per division dB value of the vertical scale markings?
Thank you in advance for any pointers.
