1. Do I have to calibrate each time I measure a new item?
A: This is not necessarily required. Try to store the state of each calibration in the VNA. The name is preferably the calibration state, such as frequency range, input excitation power, etc. If there is a new test item, but its test conditions are similar to the existing state, and after the load state, check the calibration state is good, you can use the previous calibration state without re-calibration.
The advantage of saving and recalling the calibration state is that the calibration kit also has a service life. Multiple calibrations will cause the calibration part to contact the port multiple times, which may contaminate the calibration part and cause the characteristics of the calibration part to change, affecting the next calibration. Try to form the following habit: add a dust cover when the PORT of the network analyzer is not in use; label the test cables so that each port of the VNA is connected to a certain cable as much as possible; when the test cables are not in use, you also need to add a protective cover. Dust jacket; try not to use dirty test cables.

2. How long can one calibration take?
A: Because the vector network analyzer is calibrated in a specific environment, over time, environmental factors and the situation at the time of calibration become inconsistent, resulting in invalid calibration results. Environmental factors include temperature, humidity, and cable bending, which are difficult to quantify. Therefore, after calibration once, until you feel that the calibration effect does not meet the test requirements, then perform the calibration again.