Furuno CH-37 - Manual (Page 27)

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2.9 Selecting Training Sector Quickly
Normally the training sector is selected by the SECTOR con-
trol. To the training sector more quickly, however, use the FULL/
HALF key. This key allows switching between full circle and
half circle training sector in a single key stroke.
FULL CIRCLE HALF CIRCLE
SECTOR
key FULL/HALF
Figure 2-9 How the SECTOR control and FULL/HALF key work
2.10 Suppressing Bottom and Sea Surface Reflections
in Shallow Fishing Grounds
In shallow fishing grounds, excessive sea surface and bottom
reflections often interfere with wanted fish echoes and they can-
not be eliminated sufficiently with the aforementioned TVG con-
trols. In such cases, try to reduce the output power from C to B
or A on the SONAR menu, without turning down the gain. The
picture becomes clearer when output power is reduced rather
than when the gain is decreased, as illustrated below.