America Inc. Fish Finder User Manual

■ Indirect echoes

Indirect echoes may be returned from either a passing

ship, or returned from a reﬂecting surface, such as a

mast on your own ship.

An indirect echo from a reﬂecting surface will appear

on a different bearing from the direct (true) echo, but

the distance will be approximately the same for both.

Indirect echo

True echo

False echo

An echo is reflected at this point.

Own ship

Target

Bridge

Target

Scanner

Mast or

similar obstruction

■ Side-lobe echoes

Radiation can escape on each side of the beam inside

the lobes. If a target reﬂects this radiation, it will be dis-

played on the screen as an echo.

Side-lobe echoes usually occur at short ranges and as

a result of large (strongly reﬂective) targets. They can

be reduced with proper adjustment of the

[SEA]/[ ] control.

See p. 10 for the [SEA]/[ ] control.

False

echoes

True

echo

Main beam

Side lobes

Radar uses a form of electromagnetic radiation, which like light, can be reﬂected. Because of this property, some

objects may cause false echoes on the screen where in fact no targets actually exist.

These echoes may appear if a large vessel, bridge, or tank is in proximity. Operators should be familiar with the ef-

fects of these phenomena. In some cases, echoes can be reduced.

BASIC RADAR THEORY

MR-1000R2_T2.qxd 04.2.24 10:22 Page 21