5. RETURN LOSS VERIFICATION
The following test can be used to verify the accuracy of return loss measurements. Verification is per- formed by measuring the Source Match and Cor- rected Directivity. This method eliminates the uncer- tainties of measuring standard offset. Measurement calibration of the Site Master is required for this test.
Refer to the RF Measurement Chart on page 12, and the Return Loss Verification worksheet on page 13.
a.Equipment Required:
19K50 Precision Airline
22KF50 Open / Short
22K50 Open / Short
28K50 Precision Termination
b.Procedure:
1.Press and hold the ESCAPE/CLEAR key, then press the ON/OFF key to turn on the Site Master. (This sets the instrument to the factory preset state.)
NOTE
Before continuing, allow a five minute warm up for the internal circuitry to stabilize.
2.Perform an OSL calibration over the fre- quency range of the unit using the 22K50 Open/Short and the 28K50 Precision Ter- mination. Verify that noise spikes are be- low 44 dB and that the trace is smooth.
Repeat as required.
3.Remove the 28K50 Termination.
4.Connect a 19K50 Precision Airline to the test port.
5.Connect a 22KF50 Open / Short to the open end of the airline.
6.Press the AUTOSCALE key.
7.Measure and record the worst case
8.Use the RF Measurement Chart to corre- late the
9.Remove the 22KF50 Open / Short.
10.Connect the
11.Press the AUTOSCALE key.
12.Measure and record the worst case
13.Add this value to the mean value of the
14.Use the RF Measurement Chart to corre- late the reading to a return loss value in dB. The measured value should be:
15.Remove the airline and Precision Offset Termination.
Site Master S820A MM | 3 |
