For accurate results, the BTS Master must be calibrated at the ambient temperature after allowing for warm up time and before making any measurements. The BTS Master must be re-calibrated whenever the setup frequency changes or when a test port extension cable is added, removed or replaced. If FlexCal for 1-port was performed, frequency changes do not require re-calibration.
The 1-port calibration is an Open-Short-Load (OSL) calibration removing source match, directivity, and frequency response errors.
The 2-port calibration is a 1-path 2-port calibration and removes transmission response errors and transmission source match errors in addition to reflection error terms.
Users can perform a standard open, short, load cal, or a FlexCal for 1-port measurements. FlexCal eliminates the need to perform multiple calibrations after changing the frequency. It is more time efficient than the standard cal and Anritsu recommends it for troubleshooting. For optimum accuracy, however, the standard cal should be used. FlexCal is appropriate for large frequency spans but is less precise at very narrow spans due to the frequency span used during the FlexCal operation.
Note
If a Test Port Extension Cable is to be used, the BTS Master must be calibrated with the Test Port Extension Cable in place. The Test Port Extension Cable is a phase stable cable and is used as an extension cable on the test port to ensure accurate and repeatable measurements. This phase stable cable can be moved and bent while making a measurement without causing errors in the measurement.