NORMARC NM 7000 Series, Инструкция по установке и пусконаладке

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Figure 5-1 Cable phasing measurement set-up.
5.2.2 CSB/SBO phasing
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Connect the NM3710 Field Test Set to the monitor BNC test connector in the ADU. (Use
20..30 dB attenuator at the I/P of the Field Test Set.)
Adjust SBO phaser in the Cabinet (associated with Tx to air) to obtain 0.0% DDM reading.
Repeat the phasing procedure for the other transmitter.
Switch off the course transmitter.
With the clearance transmitter on repeat the phasing procedure now adjusting the clearance
SBO phaser associated with Tx to air.
5.2.3 Antenna cable lengths (Electrical phase equality)
Each antenna cable should be electrically checked before the end connector is terminated in
the LPDA.
Utilise a vector voltmeter or network analyser. Establish antenna cable (A1) (leftmost seen
from rear) return phase as 0° reference phase.
Measure return phase for each of the remaining antenna cables (A2...A16).
Tolerance: ±1.0° true electrical cable length.
See measurement set-up diagram Figure 5-1
20dB
A B
VECTOR
From cabinet
CSB BNC o/p
CABLE UNDER TEST
OPEN END
DIR. COUPL.