Garmin AQUAMAP 80 Series Owner's Manual

Radar OverlayWhen you connect your chartplotter to an optional Garminmarine radar, you can use the Radar overlay to overlay radarinformation on the Navigation chart or on the Fishing chart.The Radar overlay superimposes radar information on theNavigation chart or the Fishing chart. Data appears on theRadar overlay based on the most recently used radar mode(such as Harbor, Offshore, or Sentry), and all settingsconfigurations applied to the Radar overlay are also applied tothe last-used radar mode. For example, if you use Harbor modeand then you switch to the Radar overlay, the Radar overlaywould show Harbor mode radar data. If you changed the gainsetting using the Radar overlay menu, the gain setting forHarbor mode would change automatically.Radar Overlay and Chart Data AlignmentWhen using the Radar overlay, the chartplotter aligns radar datawith chart data based on the boat heading, which is based bydefault on data from a magnetic heading sensor connectedusing a NMEA 0183 or NMEA 2000 network. If a heading sensoris not available, the boat heading is based on GPS trackingdata.GPS tracking data indicates the direction in which the boat ismoving, not the direction in which the boat is pointing. If the boatis drifting backward or sideways due to a current or wind, theRadar overlay may not perfectly align with the chart data. Thissituation should be avoided by using boat-heading data from anelectronic compass.If the boat heading is based on data from a magnetic headingsensor or an automatic pilot, the heading data could becompromised due to incorrect setup, mechanical malfunction,magnetic interference, or other factors. If the heading data iscompromised, the Radar overlay may not align perfectly with thechart data.Stopping the Transmission of Radar SignalsFrom a Radar screen, select MENU > Radar to Standby.TIP: Press from any screen to quickly stop radartransmission.Optimizing the Radar DisplayYou can adjust the radar display settings for reduced clutter andincreased accuracy.NOTE: You can optimize the radar display for each radar mode.1 Select a radar range (Range of Radar Signals, page 20).2 Restore the default value of the gain setting (Adjusting Gainon the Radar Screen Automatically, page 20).3 Adjust the gain setting manually (Adjusting Gain on theRadar Screen Manually, page 20).Range of Radar SignalsThe range of the radar signal indicates the length of the pulsedsignal transmitted and received by the radar. As the rangeincreases, the radar transmits longer pulses in order to reachdistant targets. Closer targets, especially rain and waves, alsoreflect the longer pulses, which can add noise to the Radarscreen. Viewing information about longer-range targets can alsodecrease the amount of space available on the Radar screen forviewing information about shorter-range targets.Radar Gain and ClutterAdjusting Gain on the Radar Screen AutomaticallyThe automatic gain setting for each radar mode is optimized forthat mode, and may differ from the automatic gain setting usedfor another mode.NOTE: Depending upon the radar in use, the gain settingconfigured for use in one radar mode may or may not be appliedto other radar modes or to the Radar overlay.NOTE: Not all options and settings are available on all radar andchartplotter 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, basedon average conditions, the range of the radar signal, andthe selected radar mode. The chartplotter does not adjustthe gain automatically in response to changing conditions.• Select Auto Harbor or Auto Offshore.The chartplotter automatically adjusts the gain for theconditions.Adjusting Gain on the Radar Screen ManuallyFor optimal radar performance, you can manually adjust thegain.NOTE: Depending upon the radar in use, the gain settingconfigured for use in one radar mode may or may not be appliedto 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 acrossthe Radar screen.Data on the Radar screen is refreshed every few seconds. Asa result, the effects of manually adjusting the gain may notappear 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 Downto lower the gain until the targets begin to blink.5 Select Up to raise the gain until the boats, land, or othertargets appear steadily lit on the Radar screen.6 Minimize the appearance of nearby large objects, ifnecessary.7 Minimize the appearance of side-lobe echoes, if necessary.Minimizing Nearby Large-Object InterferenceNearby targets of significant size, such as jetty walls, can causea 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 settingconfigured for use in one radar mode may or may not be appliedto 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 areclearly visible on the Radar screen.Reducing the gain to eliminate nearby large-objectinterference may cause smaller or distant targets to blink ordisappear from the Radar screen.Minimizing Side-Lobe Interference on the Radar ScreenSide-lobe interference may appear to streak outward from atarget in a semi-circular pattern. Side-lobe effects can beavoided by reducing the gain or reducing the radar range.NOTE: Depending upon the radar in use, the gain settingconfigured for use in one radar mode may or may not be appliedto 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 maycause smaller or distant targets to blink or disappear from theRadar screen.20 Radar