Hello Rudi,
hello Oristo,
thank you very much for your reply!
If I use i.e. RG58 with a length of abt. 1m I don't see the problem as well due to the high loss of this cable (RG58 1m.jpg). But if you take a low loss coax cable like RG402 ( RG402 semi rigid.jpg) you will see the quality of your calibration standard settings. The expert Kurt Poulsen, is working the issue, and I am confident that he will solve it.
Best regards
Norbert, DG1KPN