NORMARC NM 7000 Series, Installation & Commissioning Handbook

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Measure and record phase/amplitude for upper antenna transfer signals. Then determine if
one of the monitor cables must be trimmed in order to comply with phase tolerance for the set
of cables.
Tolerance: ±1°.
Amplitude tolerance: ±1.0 dB. If the amplitude tolerance is exceeded something might be
wrong in the Antenna monitor circuit or connector/cable.
Record final result in Ground Commissioning Records.
6.2.4 Antenna return loss
Utilise a vector voltmeter or network analyser in a test set-up
Figure 6-3. Measure return loss for each Antenna.
Measure and record in Ground Commissioning Record the return loss value for each Antenna
including antenna cable.
Tolerance: 20 dB minimum
.
Figure 6-3 Antenna return loss measurement set-up.
6.3 CSB/SBO Phasing and sector width adjustment
See Figure 6-4
6.3.1 CSB/SBO phasing
A 180° hybrid can be utilised to adjust (preset) the phase between CSB and SBO.
Connect the O/P CSB cable from the Cabinet to port 1. Connect the O/P SBO cable from the
Cabinet to port 3.
Insert the 90°-stub into the SBO path.
20dB
A B
VECTOR VOLTMETER
From cabinet
CSB BNC o/p
DIR. COUPL.
Antenna cable under test
Antenna