Setting Guard Zones And Alarms - Raymarine SL72 Owner's Handbook Manual

Chapter 3: Standard Radar Operations

3.5 Setting Guard Zones and Alarms

The Pathfinder Plus Radar display allows you to set up one or two guard
zones, using the ALARMS key. You can set up sector zones or 360° (circular)
zones as shown in Figure 3-13.
Note: You can only view and control guard zones if you are using the Master
display (that is, the display to which the scanner is connected).
3nm
Figure 3-13: Guard Zone Display
Guard zones are fixed with respect to the ship's heading marker (SHM),
moving as the SHM moves. They also move if you offset the centre, or if you
change the range scale, so that the area you have marked is maintained.
The guard alarm sounds when a target enters a guard zone, exceeding the
target density threshold within the zone; the alarm also sounds on a repeater
display. The alarm sensitivity control allows you to set the threshold above
which a new target will trigger an alarm, and also to turn the alarm on or off.
Note: A guard zone only operates when the whole zone is displayed on the
screen, or could be displayed by offsetting the centre. In addition, a guard
zone is inactive for 10 seconds after it is placed or re-sized, to avoid inappro-
priate alarms during positioning.
This section covers the following topics:
• Placing a guard zone
• Moving, reshaping or deleting a guard zone
• Controlling guard zone alarms
126°T
GRD
031°
2.24
Guard zone 1, sector zone
(short-dashed line)
Guard zone 2, circular zone
(long-dashed line)
3-19
D3975-1