The NA520xA PNA-X Pro rear-panel layout is shown below. Click to view full-sized image.
Connect your DC Power Supply to apply Bias to the VNA ports through these BNC connectors.
The bias fuses are rated for 500 mA at 250 V. You are responsible to ensure that devices connected to the test port do NOT draw more current than 500 mA. This will occur, for example, if a calibration SHORT is connected to the test port with bias power ON. The fuse Keysight part number for the NA520xA PNA-X Pro is 2110-0824.
The VNA will meet all of its RF specifications with bias up to 200 mA. As the DC bias is increased, corrected source match and directivity will degrade at low RF frequencies.