Operation Manual

Table Of Contents
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the transmitter SBO attenuator value and record in Table “CEGS Monitor Reference Data”.
Compare the values to the reference values. If found outside the tolerance ivestigation should
be carried out.
(b) Decrease the sideband power (increase the SBO attenuator value) until the monitor is in
alarm. Confirm that this attenuator value is not greater than the flight checked reference value.
Record this SBO attenuator value. If the alarm value has been exceeded, corrective action
should be taken.
(c) Measure and record the width monitor DDM on Navia Aviation Form "CEGS Monitor Ref-
erence Data". The width DDM is availible in the PMDT Monitor 1 window
.
Note that no toler-
ance exists on this entry. It is used to detect trends.
(d) Increase the sideband power (decrease the SBO attenuator value) until the monitor is in
alarm. Confirm that this attenuator value is not less than the flight checked reference value.
Record this SBO attenuator value. If the alarm value has been exceeded, corrective action
should be taken.
(e) Measure and record the width monitor DDM on Navia Aviation Form “CEGS Monitor Refer-
ence Data”. The width DDM is availible in the PMDT Monitor 1 window
.
Note that no tolerance
exists on this entry. It is used to detect trends.
(g) Return the sideband power to normal.
3. Path angle alarms (integral).
(a) Connect the PIR to measure DDM in the carrier feedline (Facility CSB test connector).
(b) Using the PMDT, open Test DDM window, click on TX1 dominance Off button to activate 90
Hz predominance (assuming transmitter 1 is active to the antennas). If necessary adjust Inc or
Dec until the monitor course position channel has just passed the threshold of alarm. Measure
and record the carrier feedline DDM value on Navia Aviation Form “CEGS Monitor Reference
Data”. Confirm that the carrier feedline DDM is not more than established reference value. If
not within tolerance, corrective action is required.
(c) Measure and record the course monitor DDM on Navia Aviation Form “CEGS Monitor
Reference Data”. The course monitor DDM can be observed in the currently active Test DDM
window as parameter MON1 CL DDM Nom. Note that no tolerance is established for this
entry. It is used only to detect trends.
(d) Repeat the procedure in steps (b) and (c) with the TX1 dominance button activated to 150
Hz.
(e) Restore the TX1 dominance button to off.
4. SBO dephasing alarms.
(a) Insert a N type elbow in the CSB carrier feedline. (CSB phase retarded)
(b) Confirm that the phase change is within the operating tolerance in chapter 3.
(c) Repeat the procedure in step (b) with the SBO phase retarded.