Bird Technologies SA-6000XT-Manual - Manual (Page 38)

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Performing a Cable Loss Measurement
1.
Enable the Measure Match Mode. See “Selecting the Measure Match
Mode” on page 13.
2. Select the Freq softkey.
3. Set the frequency start and stop to a range that is well beyond the normal
range of the antenna. See “Setting the Measurement Frequency” on
page 14.
Example - For a 450 MHz antenna, set the start frequency at
400 and the stop frequency at 500 MHz. For an 800 MHz
antenna, set the start frequency at 700 and the stop frequency
at 1,100 MHz.
4. Connect a phase stable cable to the Site Analyzer antenna test port.
5. Connect a Cal Combo to the other end of the cable.
6. Calibrate the Site Analyzer. See “Calibration” on page 11.
Note: After calibration, with the load still connected, the output
must below -25 dB. If it is not, there is a problem.
7. Remove the Cal Combo unit from the cable.
Note: Do not disconnect the phase stable cable from the Site Analyzer.
8. Connect the phase stable cable to one end of the cable under test.
9. Connect the Short connection on the Cal Combo unit to the other end of
the cable being tested.
10. Wait at least 10 seconds to allow the trace to update.
11. Hold the trace on the screen. See “Measurement Hold” on page 51.
12. Place a triangle-style marker (mark 1) at the minimum loss point within the
frequency band on the trace. See “Markers” on page 52.
13. Place a triangle-style marker (mark 2) at the maximum loss point within the
frequency band on the trace.
14. Save and label the trace, if appropriate. See “Saving a Trace” on page 58.
Interpreting a Cable Loss Measurement
The graph below shows a typical cable loss measurement. Note that the scale is
greatly reduced to show the cable’s variation across frequency.