I'm still struggling with my faulty nanoVNA SAA-2N :-( In addition to the SAA-2N I have got a nanoVNA-F, a nanoVNA-H4 and a small "very tiny...". The other units are working ok, but I really want to get my SAA-2N back in business! Today I tested the S21 measurements with the SAA-2N. I measured a 18MHz bandpass filter, and the unit seems to work ok in this mode :-)
The next thing I wanted to check was the level of the "output signal" on Port 0. I also have a handy spectrum analyzer, the tinySA. I put the SAA-2N in "CW mode" at a frequency of 8MHz. Connected the tinySA and observed a lot of harmonics, but the "main peak" was at about -23dBm!!! I think this level is too low! I did the same measurement on the H4 - result -8dBm and the nanoVNA-F had +3dBm. The result on the "very tiny..." was -7dBm.
When putting this together, I my first thought was the Si5351, but when I have done the rest of the measurements, I think one of the RF-switches, MXD8641, must be broken. Can someone please tell me if my assumptions correct?
Will be grateful for any response!
Karl Jan - LA3FY
