JRC JFS-280, Instruction Manual

Page: 93 / 328

4-3 4 Operations
4
4.1 Operations
4.1.1 Tilt angle
Operating Procedure
You can change the tilt angle from -5 ° to 60 ° by turning the [TILT ANGLE] knob. Turn the knob to the
right to make the tilt angle deeper and turn it to the left to make it shallower.
Use this to adjust the tilt angle according to the depth
at which the schools of fish are distributed and the
distance from your ship to the schools of fish.
Schools of fish that are deep under the surface of the
sea can be detected from far away with a shallow tilt
angle. However, as they come closer to the ship, you
need to make the tilt angle deeper.
The sound waves that are emitted from the sonar have a tendency to spread. You can search a
wider range because the width of the emitted sound waves expand as they move away from
your ship. Because of this, you can see schools of fish that are deep under the surface of the
sea. As the fish approach your ship the angle of the cone of the emitted sound waves narrows.
Because of this, the fish will leave the range of detectability as the tilt angle becomes shallower.
It may be necessary to deepen the tilt angle according to the depth of the school of fish.
Shallower
Deeper
Sea floor
You will not be able to see schools of fish that are very deep at the
same tile angle as they approach your ship.
School of fish found far away
Sea floor
Precautions