Garmin GPSMAP 740 Owner's Manual

Also see for GPSMAP 720: Technical reference Important safety information Owner's manual Installation instructions Quick reference guide

Contents

Garmin GPSMAP 740 Owner's Manual Manual pdf 66 page image

62 GPSMAP 700 Series Owner’s ManualRadarRadar Overlay and Chart Data AlignmentWhen 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 NMEA2000 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 boatis pointing. If the boat is drifting backward or sideways due to a current or wind, the Radar Overlay maynot perfectly align with the chart data. This situation should be avoided by using boat-heading data from anelectronic compass.If the boat heading is based on data from a magnetic heading sensor or an automatic pilot, the heading datacould 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.Showing the Radar OverlayThe Radar Overlay displays data based on the most-recently used radar mode.From the Home screen, select Radar > Radar overlay.The radar picture appears in orange and overlays the Navigation chart.Zooming In and Out on the Radar OverlayZooming while panning the map only affects the zoom scale of the map. The radar range remains the same.Zooming while the map is locked on the boat (not panning) affects the zoom scale of the map and the radarrange.Touch the and buttons to zoom out and zoom in.Optimizing the Radar DisplayYou can optimize the radar display for each radar mode.1. From the Home screen, select Radar.2. Select Cruising, Harbor, offshore, or Sentry.3. Select a radar range (page 62).4. Restore the default value of the gain setting (page 63).5. Restore the default value of the sea clutter setting (page 64).6. Restore the default value of the rain clutter setting (page 65).7. Restore the default value of the FTC setting (page 65).8. Restore the default value of the crosstalk setting (page 66).9. Adjust the gain setting manually (page 64).10. Adjust the sea clutter setting manually (page 65).11. Adjust the rain clutter and FTC settings manually (page 65).About the Range of Radar SignalsThe range of the radar signal indicates the length of the pulsed signal transmitted and received by the radar. Asthe range increases, the radar transmits longer pulses in order to reach distant targets. Closer targets, especiallyrain and waves, also reflect the longer pulses, which can add noise to the Radar screen. Viewing informationabout longer-range targets can also decrease the amount of space available on the Radar screen for viewinginformation about shorter-range targets.