GP1670F_1870F Operator's Manual - Furuno USA

7. FISH FINDER OPERATIONSMarker zoom displayThe marker zoom display expands a selected area of the normal fish finder picture tofull vertical size of the screen on the left-half window. You can select the part to expandwith the VRM (Variable Range Marker). Move the zoom marker with the Cursor-Pad. The area between the VRM and zoom marker is expanded. The marker can beshown or hidden with [ZOOM MARKER] in the [FISH FINDER] menu.Marker zoom displaySingle freq. displaySchool of fishVRMZoomedfish echoThis area zoomed onleft half of screenZoom marker7.4.3 A-scope displayThe A-scope display appears at the right 1/16 of the screen and is available in any fishfinder mode. This display shows the echoes at each transmission with the amplitudesand tone in balance with their intensities. This display helps you identify possible fishspecies and bottom structure. To show or hide the A-scope display, open the full RotoKeymenu then select [A-scope] to activate or deactivate the display.Weak reflection(small fish or noise)Fish echo"Peak"shows pastamplitudewith dots.Strongreflection(bottom)Single frequency displayA-scope displayA-scope peak holdYou can show the "normal" A-scope display plus the peak-hold amplitude picture forthe last five seconds in dots. To show the peak hold display, turn on [A-SCOPE PEAKHOLD] in the [FISH FINDER] menu.7-5