User`s guide

Making a Return Loss Measurement Getting Started with Return Loss
Agilent 81610A/11A/12A/13A/14A Return Loss Module, Fifth Edition 35
–[RLref], the value of the return loss of the reference relector
used. If you are using a reference cable, this value will be around
14.6 dB
Figure 28 The Calibration Parameters Screens - User Data