FAQs from Rohde & Schwarz

Calibration with Auto Cal Kits and inserted attenuators


I want to perform a full calibration of all 4 ports with the automatic calibration kit ZV-Z52. At one port,

a 10 dB attenuator is inserted. When I go to 'CAL – Start Cal – Calibration unit', that port (where the

attenuator is inserted) is removed from the list. What is the reason for this problem?


When 'CAL – Start Cal – Calibration unit' is selected, the firmware automatically detects which port of

the VNA is connected to which port of the cal unit. If an attenuator of 10 dB or higher is inserted, then

that port cannot be detected and it is therefore not put on the list. But it can be inserted manually:

Select "Modify Calibration Settings". Another window will open.

Set the check mark next to the missing port.

--> An error message appears: "Each VNA test port to be calibrated requires an unambiguously

assigned cal unit port"

--> The missing port has been added to the "Port Assignment" table

To eliminate the error message, the cal unit port has to be assigned:

Select the missing port of the cal unit in the "Cal Unit" row.

Close the window with "OK".

Now the calibration can be started with "Take Cal Sweep".

Calibration with Auto Cal Kits and inserted attenuators