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 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, 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 traffic, 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 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 and

FTC settings are configured 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 specific conditions, manually adjust the gain (page 86).

Clutter is interference caused by the unwanted reflection of radar signals off of unimportant targets. Common sources of clutter include precipitation, sea waves, and nearby radar sources.

Settings Configurations 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 configured 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 configured 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

Configure separately

Configure separately

Configure separately

Sea Clutter

Configure separately

Configure separately

Configure separately

Rain Clutter

Configure separately

Configure separately

Configure separately

FTC

Configure separately

Configure once for both left and right screens

Crosstalk

Configure once for all modes

 

 

GPSMAP® 6000/7000 Series Owner’s Manual