188 8163A/B, 8164A/B, 8166A/B User’s Guide7 Return Loss MeasurementFigure 106 Termination CalibrationCalibrating the Return Loss ModuleWhenever a Return Loss module is in the mainframe, a return loss value isdisplayed. The calibration values used are either the most recentlymeasured, where these are available, or factory default values.If you are unsure of any of the calibration values that you are using, or ifyou have changed the measurement setup, take the appropriatecalibration measurements again.• First, calibrate the return loss module against a component of knownreflectance.• The Keysight 81000BR Reference Reflector allows you to make aReflectance Calibration and a Termination Calibration.• These procedures are described in Calibration using the Keysight81000BR Reference Reflector on page 189.• The Keysight 81610CC Reference Cable also allows you to make aReflectance Calibration. Use the measurement patchcord to make aTermination Calibration.• To measure insertion loss and the front panel delta of the system(see Calculating the Front Panel Delta on page 209), you must alsomeasure the insertion loss of the Reference Cable and mesurementpatchcord. This is usually the preferred procedure for this reason.• These procedures are decribed in Calibration using the Keysight81610CC Reference Cable on page 192.
