Hi,
I try to use NanaoVNA for measuring a vertical ground-plane antenna at 170MHz for later impedance matching.
A picture of the test setup is attached.
Connecting NanaoVNA to USB affects the measurement quite much, as you can see on the pics (max scale for VSWR here is 10).
Does anybody made the same experiences, as I never read about this being a problem?
The NanaoVNA has been calibrated with the same wire, as attached to the antenna and all calibration points (open, close, load) show the same values on the display, no matter if USB is connected or not. But attached to the antenna, the measurement shows quite different results.
And I'm not really sure if the results are reliable, even with unconnected USB.
The antenna should physically (length of the whip) have an VSWR minimum at 170MHz and not a peak (USB not connected).
Connected to USB, the result makes more sense to me, but I don't know which result to trust.
Any ideas what I'm missing or what I can do?
I have two NanoVNA devices from different suppliers, which both show the same results.
Many thanks!
