Furuno GP-1870F, Operator'S Manual

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7. FISH FINDER OPERATIONS
7-5
Marker zoom display
The marker zoom display expands a selected area of the normal fish finder picture to
full vertical size of the screen on the left-half window. You can select the part to ex-
pand with 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 be
shown or hidden and with [ZOOM MARKER] in the [FISH FINDER] menu. The marker
zoom range can be adjusted by selecting [RANGES] then [ZOOM RANGE] in the
[FISH FINDER] menu (Default setting is 30 ft).
7.5.3 A-scope display
The A-scope display appears at the right 1/16 of the screen and is available in any fish
finder mode. This display shows the echoes at each transmission with the amplitudes
and tone in balance with their intensities. This display helps you identify possible fish
species and bottom structure. To show or hide the A-scope display, open the full Ro-
toKey menu then select [A-scope] to activate or deactivate the display.
A-scope peak hold
You can show the "normal" A-scope display plus the peak-hold amplitude picture for
the last five seconds in dots. To show the peak hold display, turn on [A-SCOPE PEAK
HOLD] in the [FISH FINDER] menu.
Marker zoom display
This area zoomed on
left half of screen
Single freq. display
VRM
School of fish
Zoomed
fish echo
Zoom marker
A-scope display
Fish echo
Single frequency display
"Peak"
shows past
amplitude
with dots.
Strong
reflection
(bottom)
Weak reflection
(small fish or noise)