Furuno CH-500 User Manual

1. OPERATIONAL OVERVIEW
1-10
1.8.3 Sidelobe Echo/False Echo (Horizontal Mode)
While the ultrasonic wave is emitted only in the direction set by the TILT control, some
emissions are directed outside the main beam. These are called sidelobes. The ener-
gy of the sidelobe is weak in comparison to the main beam, but when the water is rel-
atively shallow and the seabed is hard, strong echoes are detected by the sidelobes.
These “false” echoes appear on the display in a manner similar to that shown in the
figure below.
1.8.4 False Echo (Vertical Mode)
In shallow water (less than 100 m), unwanted echoes may appear. This phenomenon
is caused by false echoes from the previous transmission.
Reducing [TX Rate] on the [COM1] menu may lessen this effect.
Sidelobe
Mainlobe
Mainlobe echo
Sidelobe echo
Sidelobe echo
Sidelobe echo
False echo
Fish
school
Bottom
Range
Range
Range

Furuno CH-500 Specifications

General

Brand	Furuno
Model	CH-500
Category	Sonar
Language	English