Terrasat IBUC 2, Operation Manual

Page: 98 / 196

6-6
|
Cyber Hardened IBUC
2
, IBUC
2e
, IBUC
2 G
, IBUC
R
, IBUC
G
Operations Manual: Troubleshooting
Engineered to Endure
10 MHz Reference Signal is at the Wrong Level or Missing
A 10 MHz input is used to provide a stable reference frequency to which the
phase - locked local oscillator (or PLDRO) synchronizes. The 10 MHz reference signal
level should be between - 12 dBm to +5 dBm.
When the IBUC senses that the phase-locked local oscillator has gone out of lock, a
PLDRO Lock alarm is triggered. This alarm then initiates a series of routines that
leads to the muting of the power amplifier (that is, the IBUC is automatically shut - off).
Table 6.1 lists four possible scenarios caused by changes in the 10 MHz reference
signal or whether the PLDRO is locked.
Antenna is Pointed Toward Wrong Satellite or is Misaligned
Transmission to the wrong satellite or on the wrong polarization or channel can cause
interference with other satellite users and may result in fines from the satellite
operator.
To ensure that your antenna is aligned with the correct satellite,
1. Follow the antenna manufacturer’s instructions to verify the azimuth, elevation,
and polarization settings.
2. Follow the antenna manufacturer’s instructions to move the antenna into a position
that provides maximum signal strength.
3. Establish a communications link with the satellite network operations center
(NOC).
Table 6.1 Possible Scenarios for IBUCs with an External 10 MHz Reference Signal
10 MHz Reference
Signal Level
Phase-Locked Local
Oscillator
Results
Low Locked
Causes a minor alarm (10 MHz Detector). Unit
is still transmitting. Check the 10 MHz signal
level. Resultant phase noise may be degraded.
Low Out-of-Lock
Causes a major alarm (PLDRO Out of Lock).
Power amplifier is muted and the IBUC is
automatically shut-off. Check the 10 MHz
reference signal level and whether the 10 MHz
reference signal is enabled at the modem.
Within Specifications Locked
Unit is operating normally. No alarms are
present.
Within Specifications Out-of-Lock
Causes a major alarm (PLDRO Out of Lock).
Power amplifier is muted and the IBUC is
automatically shut-off. PLDRO may be faulty
and the IBUC might need to be returned for
repair.