User manual

distant targets. Closer targets, especially rain and waves, also
reflect the longer pulses, which can add noise to the Radar
screen. Viewing information about longer-range targets can also
decrease the amount of space available on the Radar screen for
viewing information about shorter-range targets.
• Select to decrease the range.
• Select to increase the range.
Tips for Selecting a Radar Range
• Determine what information you need to see on the Radar
screen.
For example, do you need information about nearby weather
conditions or targets and traffic, or are you more concerned
about distant weather conditions?
• Assess the environmental conditions where the radar is being
used.
Especially in inclement weather, longer-range radar signals
can increase the clutter on the Radar screen and make it
more difficult to view information about shorter-range targets.
In rain, shorter-range radar signals can enable you to view
information about nearby objects more effectively, if the rain
clutter setting is configured optimally.
• Select the shortest effective range, given your reason for
using radar and the present environmental conditions.
MotionScope
™
Doppler Radar Technology
The GMR Fantom radar uses the Doppler effect to detect and
highlight moving targets to help you avoid potential collisions,
find flocks of birds, and track weather formations. The Doppler
effect is the frequency shift in the radar echo due to the relative
motion of the target. This allows for instant detection of any
targets moving toward or away from the radar.
The MotionScope feature highlights the moving targets on the
radar display so you can navigate around other boats or severe
weather, or toward fishing spots where birds are feeding at the
surface.
The moving targets are color-coded so you can tell at a glance
which targets are moving toward or away from you. On most
color schemes, green indicates the target is moving away from
you and red indicates the target is moving toward you.
On some models, you can also adjust the M-Scope Sensitivity
setting to change the speed threshold for target highlighting. A
higher setting highlights slower targets, and a lower setting
highlights only faster targets.
Enabling a Guard Zone
You can enable a guard zone to alert you when anything comes
within a specified area around your boat.
From a radar screen, select Menu > Radar Options > Guard
Zone.
Defining a Circular Guard Zone
Before you can define the boundaries of the guard zone, you
must enable a guard zone (Enabling a Guard Zone, page 36).
You can define a circular guard zone that completely surrounds
your boat.
1
From a radar screen, select Menu > Radar Options > Guard
Zone > > Circle.
2
Select the location of the outer guard zone circle.
3
Select the location of the inner guard zone circle to define the
width of the guard zone.
Defining a Partial Guard Zone
Before you can define the boundaries of the guard zone, you
must enable a guard zone (Enabling a Guard Zone, page 36).
You can define the boundaries of a guard zone that does not
completely surround your boat.
1
From a radar screen, select Menu > Radar Options > Guard
Zone > > Corner 1.
2
Touch and drag the location of the outer guard-zone corner
.
3
Select Corner 2.
4
Select the location of the inner guard-zone corner to
define the width of the guard zone.
5
Select Done.
MARPA
Mini-automatic radar plotting aid (MARPA) enables you to
identify and track targets and is primarily used for collision
avoidance. To use MARPA, you assign a MARPA tag to a
target. The radar system automatically tracks the tagged object
and provides you with information about the object, including the
range, bearing, speed, GPS heading, nearest approach, and
time to nearest approach. MARPA indicates the status of each
tagged object (acquiring, lost, tracking, or dangerous), and the
chartplotter can sound a collision alarm if the object enters your
safe zone.
Before you can use MARPA, you must have a heading sensor
connected and an active GPS signal. The heading sensor must
provide the NMEA 2000 parameter group number (PGN)
127250 or the NMEA 0183 HDM or HDG output sentence.
MARPA Targeting Symbols
Acquiring a target. Concentric, dashed green rings radiate from
the target while the radar is locking onto it.
Target has been acquired. A solid green ring indicates the
location of a target that the radar has locked onto. A dashed
green line attached to the circle indicates the projected course
over ground or the GPS heading of the target.
Dangerous target is in range. A red ring flashes from the target
while an alarm sounds and a message banner appears. After the
alarm has been acknowledged, a solid red dot with a dashed red
line attached to it indicates the location and the projected course
over ground or the GPS heading of the target. If the safe-zone
collision alarm has been set to Off, the target flashes, but the
audible alarm does not sound and the alarm banner does not
appear.
Target has been lost. A solid green ring with an X through it
indicates that the radar could not lock onto the target.
Closest point of approach and time to closest point of approach to
a dangerous target.
Acquiring MARPA Targets Automatically
You can acquire MARPA targets automatically based on
MotionScope, guard zones, or boundaries.
36 Radar