Dual Frequency Display; Marker Zoom Display (50 Khz Or 200 Khz) - Furuno GP-3700F Operator's Manual

11.2.2

Dual frequency display

The dual frequency display provides both low and high frequency pictures. For vertical
split screen, the low frequency picture (50 kHz) is displayed on the left half, the high
frequency picture (200 kHz) on the right half. For horizontal split screen, the low fre-
quency picture (50 kHz) is displayed on the top half, the high frequency picture (200
kHz) on the bottom half. Use the dual frequency display to compare the same picture
with two different sounding frequencies.
11.2.3

Marker zoom display (50 kHz or 200 kHz)

The marker zoom display expands a selected area of the normal echo sounder picture
on the left half of the screen. You may specify the portion to expand by operating the
VRM. The area between the VRM and zoom marker is expanded. (You may set the
zoom range. For further details, see section 11.20.) This mode is useful for determin-
ing the size of fish in the middle water.
Marker zoom display
Zoomed school of fish
11. ECHO SOUNDER
Beam Bottom
Frequency
width tail
50 kHz Wide Long
200 kHz Narrow Short
VRM
This area is zoomed.
Zoom marker
Single frequency display
11-3