Furuno CSH-53 User Manual

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3-2

4. When sea surface reflections or plankton layers disturb the

picture, decrease appropriate TVG option by one or two steps
by pressing – (minus) key.

5. Locate fish school on a long range setting (about 800 meters)

which is approaching own ship.

6. Adjust the tilt to keep the fish school in the center of the

sonar beam, namely, fish school is displayed in strongest
colors possible. Confirm that the fish echo is displayed in
the same color as it approaches. If the color suddenly changes
to weaker colors as the fish enters MEDIUM and NEAR
areas, the TVG is improperly set. Adjust the TVG. If this
again produces sea surface reflections and noise try to re-
move them with AGC and NL controls.

Note: If the above procedure does not produce satisfactory re-
sults, the TVG curve can be changed on the SYSTEM menu.
The 15 log setting is useful for searching fish schools near shore-
lines or shallow waters. The 30 log setting raises the gain on a
long range and is suitable for tuna and bonito, which are usually
searched with high gain setting.