Hi Kurt, hi David, thank you very much for your replies!
of course, the coax cables were calibrated at the far end with SOL isolation and through. The first calibration (picture 1), directly on CH0 and CH1 connectors served as a reference without cables, where I expected the best performance. After the various calibrations were finished, the 50 ohm cal standard was placed again at the end of the coax cable connected to CH0. CH1 was terminated as well to see the dynamic range of S21. I do understand that the NanoVNA has no error correction like the VNWA. What I wanted to point out with this test is, that with a certain length of coax cables the overall performance of the NanoVNA can be improved. Like in my case by using standard RG174U with a length of 70 cm or the M17/152 coax cable with 93cm length. I didn't expect the marginal performance of the short 20 cm high quality coax cable. I fabricated those because I thought they would perform at best.
We all know, RF is a science on its own, hi!
Hope that clarifies initial misunderstandings!
Best regards
Norbert, DG1KPN
