To verify the performance of the transmission feed line system and analyze typical problems, three types of line sweeps can be performed:
• Return Loss
• Cable Loss
• Distance-To-Fault
Note
Anritsu recommends using a phase-stable test port cable, attached to the Site Master RF port. Calibrate at the open end of the cable.
Return Loss/VSWR Measurement
This is a measurement made when the antenna is connected at the end of the transmission line. It provides an analysis of how the various components of the system are interacting.
Return Loss measures the reflected power of the system in decibels (dB). This measurement can also be taken in the Standing Wave Ratio (SWR) mode, which is the ratio of voltage peaks to voltage valleys caused by reflections.
Antenna Return Loss Trace
Same Antenna Trace in VSWR
To make Return Loss or VSWR measurements:
1. Press the Measurement main menu key and select Return Loss or VSWR.
2. Press Freq/Dist and enter the start and stop frequencies.
3. Press Amplitude, then enter the top and bottom power levels for the display or press Fullscale.
4. For the most accurate results, press the Calibration main menu key and perform a manual calibration of the instrument. Refer to Calibration Procedure.
Alternatively, you can skip this step and the instrument will automatically apply the factory calibration (1-Port ReadyCal).
5. Connect the Site Master to the Device Under Test.
6. Press the Marker main menu key and set the appropriate markers as described in Markers.
7. Press the Limit main menu key and set the limit lines as described in Limit Lines.
8. Press Save (7), then Save to save the measurement data to file. Refer to Save File for details on setting the save location.
