Keysight N9915CU/309 - DC Bias Variable Voltage Source Option for N9915C
Option 309 is the DC bias variable voltage source option for FieldFox analyzers. This option is used to provide DC power to amplifiers under test and bias tower mounted amplifiers (TMA) when you need to sweep through the TMA to reach the antenna.
N9910X-713 cable is recommended / sold separately (bias-tee power cable SMB (f) to BNC (m)).