Gps Frequency Alarm; Gps Drift Transient Event - Symmetricom TimeSource 2500 Manual

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TimeSource 2500
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GPS Frequency Alarm

The GPS Frequency Event data is processed through a leaky-
bucket alarm manager, to control escalation to an alarm.
Maintenance action required:
1. Check that the latitude, longitude, altitude, elevation mask,
and GPS fix mode information has been entered properly, via
the BTMONitor Installation screen. Entering latitude in the
longitude window, and vice versa, are common user errors. If
the alarm persists, the window or wall may not a have a large
enough view of the sky for the system to stabilize. If possible,
move the antenna to a window or wall with an improved view
of the sky.
2. If an antenna alarm is also present, the cable to the antenna
may have become disconnected. Reconnect the antenna cable.
If the condition persists, replace the antenna cable(s).
3. If a PLL alarm is also present, replace the shelf.

GPS Drift Transient Event

The rate of change of the GPS frequency estimate is calculated, to
determine if the current slew rate is within the expected
measurement window for GPS, given the effects of Selective
Availability and dynamic changes in the number and elevation of
tracked satellites.
Maintenance action required: None.
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