OPERATING MANUAL
C-6
21833-3.4
NORMARC 7013
INSTRUMENT LANDING SYSTEM
Maintenance Procedures ©1999 Navia Aviation AS
rier power, still connecting the BIRD wattmeter to the course CSB feedline inside the facility.
(e) Determine if the carrier power reduction corresponding to alarm is within the operating
toler-ance in chapter 3.
(f) Remove the wattmeter from the carrier feedline.
6. Dual frequency systems. For dual frequency localizers, repeat the above applicable pro-
cedures for the clearance equipment.
7. Identification alarms.
(a) Using the PMDT Ident. & Mod. Switches window, set the identification tone to CONTINU-
OUS. Confirm that an identification alarm occurs.
(b) Set the 1020 Hz identification to OFF. Confirm that an identification alarm occurs.
(c) Restore the 1020 Hz identification tone to normal.
8. Far-field monitor alarms. This procedure must be performed during periods of low activ-
ity to avoid reflections that can cause inaccurate results. This procedure requires a person
at the localizer and at the far-field monitor.
(a) Connect the PIR to COU CSB test connetcor on the facility front, and setup to read modu-
lation equality of the radiated signal. Note the DDM reading for reference.
(b) Adjust the modulation balance (PDMT Test DDM window) in one direction until all far-field
monitors are in alarm.
(c) Calculate the difference in DDM between the reference DDM and the DDM in alarm.
Determine if the difference is within the operating tolerance of paragraph 3-20f.
(d) Repeat steps (b) and (c) adjusting the modulation balance in the opposite direction.
(e) Adjust the modulation balance to the reference reading obtained in step (a).
(f) Momentarily disconnect the antenna from each far-field monitor receiver. Confirm that the
far-field monitor alarms.
(g) Return the equipment to normal.
5-14 90 AND 150 HZ MODULATION PERCENTAGES.
a. Object.
This procedure provides a method to determine the amplitude modulation percentages of the
90 and 150 Hz navigational tones.
b. Discussion.
1. The FA-9438 modulation meter (or equivalent) is the primary standard for the measure-
ment of modulation percentage. Other equivalent pieces of test equipment could include a
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