The following sections describe the typical line sweep measurements that are used to analyze the performance of a transmission feed line system including Return Loss, Cable Loss, and DTF.
Note
Anritsu recommends using phase‑stable test port cables when making measurements. Attach the cables to the port connectors of the Microwave Site Master and calibrate at the open end of the cables.
Return Loss or VSWR Measurement
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.
System Return Loss measurement verifies the performance of the transmission feed line system with the antenna connected at the end of the transmission line. Figure: Antenna Return Loss Trace and Figure: Same Antenna Trace in VSWR show a sample antenna measured using Return Loss and using VSWR.
Device Under Test: Feed line with Antenna
1. Press the Measurement main menu key, under the Standard submenu, select Return Loss or VSWR.
2. Press the Freq/Dist main menu key and enter the start and stop frequencies.
3. Press the Amplitude main menu key and enter the top and bottom values for the display or press Fullscale.
4. Press the Calibration main menu key and perform a calibration of the instrument. Anritsu suggests using a phase‑stable test port cable. See Calibration, CAA for details.
5. Connect the Site Master to the Device Under Test using the calibrated phase‑stable test port cable.
6. Press the Marker main menu key and set the appropriate markers as described in Markers.
7. Press the Limit main menu key to enter and set the limit line as described in Limit Lines.
8. Press File (7) then Save to save the measurement to memory. Refer to File Management for details on setting the save location.
