Table of Contents
Advertisement
Radar Overlay
When you connect your chartplotter to an optional Garmin
marine radar, you can use the Radar overlay to overlay radar
information on the Navigation chart or on the Fishing chart.
The Radar overlay superimposes radar information on the
Navigation chart or the Fishing chart. Data appears on the
Radar overlay based on the most recently used radar mode
(such as Harbor, Offshore, or Sentry), and all settings
configurations applied to the Radar overlay are also applied to
the last-used radar mode. For example, if you use Harbor mode
and then you switch to the Radar overlay, the Radar overlay
would show Harbor mode radar data. If you changed the gain
setting using the Radar overlay menu, the gain setting for
Harbor mode would change automatically.
Radar Overlay and Chart Data Alignment
When using the Radar overlay, the chartplotter aligns radar data
with chart data based on the boat heading, which is based by
default on data from a magnetic heading sensor connected
using a NMEA 0183 or NMEA 2000 network. If a heading sensor
is not available, the boat heading is based on GPS tracking
data.
GPS tracking data indicates the direction in which the boat is
moving, not the direction in which the boat is pointing. If the boat
is drifting backward or sideways due to a current or wind, the
Radar overlay may not perfectly align with the chart data. This
situation should be avoided by using boat-heading data from an
electronic compass.
If the boat heading is based on data from a magnetic heading
sensor or an automatic pilot, the heading data could be
compromised due to incorrect setup, mechanical malfunction,
magnetic interference, or other factors. If the heading data is
compromised, the Radar overlay may not align perfectly with the
chart data.
Stopping the Transmission of Radar Signals
From a Radar screen, select MENU > Radar to Standby.
TIP: Press
from any screen to quickly stop radar
transmission.
Optimizing the Radar Display
You can adjust the radar display settings for reduced clutter and
increased accuracy.
NOTE: You can optimize the radar display for each radar mode.
1
Select a radar range
(Range of Radar Signals, page
2
Restore the default value of the gain setting
on the Radar Screen Automatically, page
3
Adjust the gain setting manually
Radar Screen Manually, page
Range of Radar Signals
The range of the radar signal indicates the length of the pulsed
signal transmitted and received by the radar. As the range
increases, the radar transmits longer pulses in order to reach
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.
Radar Gain and Clutter
Adjusting Gain on the Radar Screen Automatically
The automatic gain setting for each radar mode is optimized for
that mode, and may differ from the automatic gain setting used
for another mode.
NOTE: Depending upon the radar in use, the gain setting
configured for use in one radar mode may or may not be applied
to other radar modes or to the Radar overlay.
20
20).
(Adjusting Gain
20).
(Adjusting Gain on the
20).
NOTE: Not all options and settings are available on all radar and
chartplotter models.
1
From a Radar screen or the Radar overlay, select MENU >
Gain.
2
Select an available option:
• Select Auto.
The chartplotter sets the gain automatically once, based
on average conditions, the range of the radar signal, and
the selected radar mode. The chartplotter does not adjust
the gain automatically in response to changing conditions.
• Select Auto Harbor or Auto Offshore.
The chartplotter automatically adjusts the gain for the
conditions.
Adjusting Gain on the Radar Screen Manually
For optimal radar performance, you can manually adjust the
gain.
NOTE: Depending upon the radar in use, the gain setting
configured for use in one radar mode may or may not be applied
to other radar modes or to the Radar overlay.
1
From a Radar screen or the Radar overlay, select MENU >
Gain.
2
Select Up to raise the gain, until light speckles appear across
the Radar screen.
Data on the Radar screen is refreshed every few seconds. As
a result, the effects of manually adjusting the gain may not
appear instantly. Adjust the gain slowly.
3
Select Down to lower the gain until the speckles disappear.
4
If boats, land, or other targets are within range, select Down
to lower the gain until the targets begin to blink.
5
Select Up to raise the gain until the boats, land, or other
targets appear steadily lit on the Radar screen.
6
Minimize the appearance of nearby large objects, if
necessary.
7
Minimize the appearance of side-lobe echoes, if necessary.
Minimizing Nearby Large-Object Interference
Nearby targets of significant size, such as jetty walls, can cause
a very bright image of the target to appear on the Radar screen.
This image can obscure smaller targets located near it.
NOTE: Depending upon the radar in use, the gain setting
configured for use in one radar mode may or may not be applied
to other radar modes or to the Radar overlay.
1
From a Radar screen or the Radar overlay, select MENU >
Gain.
2
Select Down to lower the gain until the smaller targets are
clearly visible on the Radar screen.
Reducing the gain to eliminate nearby large-object
interference may cause smaller or distant targets to blink or
disappear from the Radar screen.
Minimizing Side-Lobe Interference on the Radar Screen
Side-lobe interference may appear to streak outward from a
target in a semi-circular pattern. Side-lobe effects can be
avoided by reducing the gain or reducing the radar range.
NOTE: Depending upon the radar in use, the gain setting
configured for use in one radar mode may or may not be applied
to other radar modes or to the Radar overlay.
1
From a Radar screen or the Radar overlay, select MENU >
Gain.
2
Select Down to lower the gain until the semi-circular,
streaked pattern disappears from the Radar screen.
Reducing the gain to eliminate side-lobe interference may
cause smaller or distant targets to blink or disappear from the
Radar screen.
Radar
Advertisement
Table of Contents
