NORMARC NM 7000 Series, Инструкция по установке и пусконаладке

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Connect the NM3710 (use 20 dB attenuator at NM3710 I/P) to the directional coupler’s for-
ward port.
Adjust the SBO attenuator (for the Tx to air) until the DDM value equals the previously calcu-
lated value for the CS.
Move the directional coupler to A4, A5 and compare readings with calculated values. If mea-
sured DDM is lower than the calculated values for A4, A5 then increase the SBO power, or
vice versa, until a fairly good matching set of values are obtained.
Adjust the SBO attenuator for the other Tx to the same setting.
Remove the 90°-stub.
5.3.2 Clearance SBO power
Switch off the course transmitter.
Insert the 90°-stub in the CLR SBO path. Connect the Field Test Set to the BNC test connec-
tor (antenna 4 sample) in the ADU. (Use 20...30 dB attenuator at the Field Test Set I/P).
Switch on the clearance transmitter. Adjust the CLR SBO attenuator in the cabinet (associ-
ated with Tx to air) until a reading of 43.6% SDM is obtained.
Carry out the same procedure for the other transmitter.
5.3.3 DDM field check
Set the localizer to normal radiation (clearance transmitter on). From the centreline of the
opposite threshold determine points perpendicular to the CL 105 meter to both sides of the
runway. Use the NM3710 with portable antenna and measure DDM at these points. The read-
ings should be close to -15.5% at the 90-side and 15.5% at the 150-side. However, some
unsymmetry may be expected due to reflections and tolerances in the antenna system.
Check the CL DDM at two or three positions in order to estimate an average value.
Expected value: 0.0%
±
0.2% DDM.
5.4 Monitor combining unit (MCU) adjustments
5.4.1 Course Line
Connect the Field Test Set to the CL output connector of the MCU.
Adjust the CL line stretcher to obtain 0.0% DDM.
5.4.2 Course Sector
Connect the Field Test Set to the CS output of the MCU.
Adjust the CS line stretcher to obtain a reading of 15.5% DDM.