JRC JFE-400, Instruction Manual

Page: 90 / 104

10.Appendix
10-4
In either case, the dim or thin echoes are false and produced by side lobes of ultrasonic
beam from the transducer. Any false echo is thinner than and parallel to a real echo.
The echo of a seabed with abrupt slope is recorded as a lone difficult to see and less
discriminative, since it tends to accompany with a false echo due to the side lobe and the
inherent property of directivity.
In particular, a seabed with abrupt slope and heavily rugged surface provided an echo very
difficult to display on the recording.