Japan Radio Co. JFE-680, Instruction Manual

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Abrupt-Slope Abrupt-Sloped Seabed d Seabed
Sidelobe Sidelobe
False echo False echo
A d A dim echo may some im echo may sometimes appear a times appear along an abru long an abrupt slope of seab pt slope of seabed, as if it were floa ed, as if it were floating ting
above the slope, above the slope, when recording. when recording.
In case of flat seabed, thin second return of seabed may sometimes appear, which is slightly In case of flat seabed, thin second return of seabed may sometimes appear, which is slightly
below the actual
below the actual seabed. seabed.
In either case, the dim or thin echoes are false and produced by sidelobes of ultrasonic beam In either case, the dim or thin echoes are false and produced by sidelobes of ultrasonic beam
from the
from the transducer. transducer. Any false Any false echo is echo is thinner than thinner than and p and parallel to arallel to a a real echo. real echo.
Appendix Appendix 47 47