NORMARC NM 7000 Series, Инструкция по установке и пусконаладке, Страница: 102 / 189

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Figure 5-2 Phase and amplitude transfer measurement set-up.
Measure relative transfer phase and amplitude for each Antenna/Monitor return cable in ref-
erence to A1/M1.
Then determine if one of the monitor cables must be trimmed in order to comply with phase
tolerance for the set of cables.
Tolerance: ±2°.
Amplitude tolerance: ±1.0 dB. If the amplitude tolerance is exceeded something might be
wrong in the LPDA monitor circuit or connector/cable.
Record the final result in Ground Commissioning Record.
5.2.6 Antenna return loss
Utilise a vector voltmeter or network analyser in a test set-up Figure 5-3. Measure return loss
for each LPDA.
Measure and record in Ground Commissioning Record the return loss value for each LPDA
including antenna cable.
Tolerance: 20 dB minimum
.
Figure 5-3 Antenna return loss measurement set-up.
20dB
A B
VECTOR VOLTMETER
A(n)
M(n)
From cabinet
CSB BNC o/p
Ant.
DIR. COUPL.
20dB
A B
VECTOR VOLTMETER
From cabinet
CSB BNC o/p
DIR. COUPL.
Antenna cable under test
Antenna