There are items I want to check to the KC901S+.
When measuring in S11 mode, set the marker frequency with VSWR as the display mode.
After that, if I set the display mode to SMITH, the marker frequency will change.(marker frequency will start frequency)
If I do the same operation with KC901V, the marker frequency will be inherited.
This problem occurs only with KC901S+.
The same issue or very similar was also on earlier versions of the KC901V but got fixed by a software update about mid last year. I did not note if it was related to the marker setting but it might have been. Certainly Smith chart start and stop frequency did not carry over from those on other formats at least.