An essential principle of troubleshooting is to be able to reproduce the phenomenon. As long as another operator has not been able to contater the same thing as KQ4EKK, all the various and varied explanations are doomed to failure.
I tried the tests on my nanoVNA-F and my PC in my environment, nothing happens. Unfortunately, that doesn't prove anything. It's a negative test.
It can come:
Of the environment
- NanoVNA itself, and this one only (failure)
- cord
- of a procedure
- Basically anything.
I had to troubleshoot magical phenomena. We must already convince ourselves that there is an explanation for that. What is positive in what Marc relates is that at home, on his table, the phenomenon is stable. Perhaps you should describe your environment more precisely.
Can you do a much lower frequency test, between 10 and 50 MHz for example. A simple piece of coax in a closed circuit at the end, for example. I see on your images that you sweep from 1.5 GHz to 30 Ghz and it is in the very high frequencies that the difference appears. My tests were not at all in this frequency band
You state: Errors are displayed across the spectrum but are very small at low frequencies and increase exponentially with higher frequencies. I'm doing an S21 logmag plot from 1 MHz to 30 MHz. There also seems to be a significant offset (jump down) around 15 MHz.
We should focus on this type of experience
--
F1AMM
Fran?ois
