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2.20 Guard Alarm Zone
The guard alarm allows the operator to set the
desired range and bearing for a guard zone.
When ships, islands, landmasses, etc. violate
the guard zone the offending target flashes and
an aural alarm sounds to call the operator’s
attention. The alarm is triggered against targets
entering or exiting the guard zone depending on
guard zone type as below.
*
The alarm should not be relied upon as the
sole means for detecting possible collision
situations.
*
STC, FTC and GAIN controls should be
properly adjusted to be sure the alarm
system does not overlook target echoes
.
CAUTION
How guard zone type is determined
After the guard zone is set, the radar starts
searching for targets inside the guard zone for
about 8 to 12 seconds. The results of the search
are shown at the top right-hand corner of the
display as “G (IN)” or “G (OUT).”
G (IN):
This is the inward guard alarm and it
means no target was found in the guard zone.
Thereafter the aural alarm sounds against
targets which enter the guard zone.
G (OUT):
This is the outward guard alarm and it
means a target was found in the guard zone.
Thereafter the aural alarm sounds against all
targets which exit the guard zone.
(a) Inward guard alarm (b) Outward guard alarm
Figure 2-18 Inward and outward guard alarms
Setting a guard zone
1. Operate the Omnipad to place the cursor at
the top left-hand corner of the zone and
press the [GUARD] key.
2. Operate the Omnipad to place the cursor at
the bottom right-hand corner of the zone and
press the [GUARD] key.
Guard
zone
to set
* GUARD
1) Drag cursor to
top left corner of
zone and press
[GUARD].
Asterisk blinking
Drag cursor
here.
Mentally create
the guard zone to set.
2) Drag cursor to
bottom right corner
of zone and press
[GUARD].
Guard zone completed.
Guard
zone
Drag cursor
here.
* GUARD
GUARD
Figure 2-19 How to set a guard zone
3. Eight to twelve seconds later the indication G
(IN) or G (OUT) replaces the indication
GUARD.
Note:
When the radar range is less than one
half of the guard zone range, the guard zone
disappears and the indication "UP RNG"
replaces G (IN) or G (OUT). If this happens,
raise the range to redisplay the guard zone.