Why do I get red error events in WinCal when I calibrate the PNA for fewer ports than are displayed on the PNA?
WinCal XE has this limitation, which will be fixed in a future release. The error set calculated must be applicable to the displayed data on the PNA. If, for example, you have a quad display with all four 2-port S-parameters on the PNA and perform a 1-port SOL, you will get an error message in WinCal (red event) when the PNA tries to correct S21 (cannot be done with SOL). WinCal will consider the calibration a failure, but S11 on the PNA is indeed calibrated.
