The Keysight N9926A-309 Option 309 adds an integrated built-in variable voltage DC bias source to the FieldFox analyzer. The source provides 1 to 32 VDC with maximum current of 650 mA and 7 watts maximum power. The DC bias source can provide DC power to amplifiers under test and bias tower mounted amplifiers (TMA) when engineers need to sweep through the TMA to reach the antenna. The bias-tee is available separately. The DC output has an SMB (m) connector.