NorthStar 958 Operator's Manual page 148

Chapter 10 - Understanding Radar Functions
Radar markers
page 2
Page 140
You can designate up to three areas that will cause an alarm if
a radar echo is detected within the area. Each zone is bounded
by an inner and an outer arc centered on the vessel, and by
two straight lines extending outward from the vessel.
You can turn each zone on or off, change its size and location,
and set the echo strength that will cause an alarm.
The guard zone is displayed with red lines. Radar echoes
within a guard zone are displayed in red.
Press the following keys to adjust each guard zone.
Press the GUARD ZONE key repeatedly to select zone 1, 2, or
3. You can adjust only one zone at a time.
Press the VISIBILITY key repeatedly to show or hide the zone.
When a zone is hidden, it doesn't display and doesn't alarm;
furthermore, you can't use the EDIT or TRIGGER LEVEL keys
for that zone. You select the visibility of each zone separately.
You can change the location and size of each guard zone by
moving Point A and Point B using the CURSOR PAD. Press the
EDIT key repeatedly to select the point you want to move.
Then press the CURSOR PAD to move the point and create an
arc-shaped zone.
Figure 7: Guard zone
958 Operator's Manual, Rev. A