The S331P is calibrated at the factory at room temperature. This default calibration, named 1‑Port ReadyCal, is automatically applied to all Cable and Antenna measurements – except Transmission (Ext Sensor) measurements – when the instrument has not been manually calibrated or user calibration (User Cal) is turned off.

ReadyCal simplifies the measurement process and can reduce overall test time while maintaining measurement integrity. Anritsu recommends an annual re-calibration at the factory if you routinely apply ReadyCal when making measurements.

When the best possible accuracy is required or the ambient temperature is greatly different from normal room temperature, you should perform a user calibration to override the default ReadyCal. Refer to Calibration Methods.