OPERATING MANUAL
C-10
21833-3.4
NORMARC 7013
INSTRUMENT LANDING SYSTEM
Maintenance Procedures ©1999 Navia Aviation AS
(b) The facility 90° phasing section.
2. In-line phasing. A PIR.
d. Conditions.
A facility shutdown is required for both far-field and in-line checks.
e. Far-Field Quadrature Phasing, Detailed Procedure.
1. Dummy-load the sideband output. At two-frequency localizers, disable the clearance sys-
tem.
2. Position the PIR at the established far-field phasing point, and note the reference DDM
reading. The far-field phasing point shall be established per paragraph 5-173.
3. Remove the dummy load and insert the 90° phasing section in the sideband feedline.
4. Note and record the reference DDM on Form xxx. Compare the DDM value to the refer-
ence value.
5. Remove the 90° phasing section and reconnect the sideband feedline. If out of tolerance,
corrective action shall be taken.
6. At two-frequency localizers, restore the clearance system to normal and disable the course
system. Dummy-load the clearance system sideband output, and repeat steps (2) through
(5).
7. Restore the facility to service.
f. In-Line Phasing, Detailed Procedure.
1. Connect the PIR to the BNC test connector at the lower end of the antenna distribution net-
work . (It may be necessary to add a 20 dB attenuator at the PIR input) At two-frequency
localizers, disable the clearance system.
2. Note the DDM reading on the PIR. The difference between established reference value and current
reading should be equal or less than ±0.05 DDM.
3. At two-frequency localizers, restore the clearance system to normal and disable the course
system. Dummy-load the clearance system sideband output, and repeat steps (1) and (2)
4. Restore the facility to service.
5-17 MONITOR PHASING AND AMPLITUDE.
a. Object.
This procedure provides a method to determine the monitor carrier to sideband-only phase
and amplitude relationship.
b. Discussion.
To ensure that the monitor will properly sense system dephasing and sideband amplitude
changes, the monitor phasing and amplitude adjustment should be near optimum. This pro-
cedure measures the monitoring system sideband phase and amplitude, not the radiated sig-
nal sideband and amplitude. Before this measurement, the localizer system phasing and
course width must be adjusted to optimum.
c. Test Equipment Required.
1. A portable ILS receiver (PIR).
2. The facility 90° phasing section.
d. Conditions.
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