GPSMAP
®
6000/7000 Series Owner’s Manual 85
Radar
About the 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 reect 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, unless you are
using Dual Range mode (page 75).
Tips for Selecting a Radar Range
Determine what information you need to see on the radar display. For example, do you need
information about nearby weather conditions or targets and trafc, or are you more concerned
about distant weather conditions?
Assess the environmental conditions in which 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
difcult 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 and
FTC settings are congured optimally.
Select the shortest effective range, given your reason for using radar and the current
environmental conditions.
Selecting a Radar Range
See “Adjusting the Zoom Scale on the Radar Screen” (page 72).
About Gain and Clutter
The gain controls the sensitivity of the radar receiver. The default setting for the gain, Auto, sets
the gain automatically one time, based on average conditions, the range of the radar signal, and
the selected radar mode. The chartplotter does not readjust the gain automatically in response to
changing conditions. To optimize the radar appearance for specic conditions, manually adjust the
gain (page 86).
Clutter is interference caused by the unwanted reection of radar signals off of unimportant targets.
Common sources of clutter include precipitation, sea waves, and nearby radar sources.
Settings Congurations and Radar Type
When using a GMR 20, 21, 40, 41, 18, 18 HD, 24, 24 HD, 404, or 406, all gain and clutter settings
congured for use in one radar mode are applied to every other radar mode and to the Radar
Overlay.
When using a GMR 604 xHD, 606 xHD, 1204 xHD, or 1206 xHD radar, gain and clutter settings
congured for use in one radar mode may or may not be applied to other radar modes, according to
this table.
Setting Radar Mode
Harbor, Offshore, Sentry Dual Range: Left Screen Dual Range: Right Screen
Gain Congure separately Congure separately Congure separately
Sea Clutter Congure separately Congure separately Congure separately
Rain Clutter Congure separately Congure separately Congure separately
FTC Congure separately Congure once for both left and right screens
Crosstalk Congure once for all modes
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