Wesmar SS590 SERIES, Руководство по установке и эксплуатации

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SS590
WESMAR
Page I - 4
PART A: INTRODUCTION
Scanning sonar has many applications in commercial
fishing, pleasure boating, sportfishing, navigation, diving
and salvage, underwater security, and a host of other uses
only now being developed. The principles of scanning
sonar are fairly straight-forward, but understanding them
is essential to making the equipment produce the results
you want.
PART B: THEORY OF
OPERATION
Sonar equipment transmits sound underwater to locate
objects such as fish schools and dangerous reefs. Inthe
soundome (that part of the sonar that extends through the
bottom of the boat), a transducer sends out a soundwave
through the water. When that soundwave strikes an
object, it bounces back and returns to the transducer,
which "hears" thereturning energy, That is how an object
is found by sonar.
When the transducer ‘hears’ a returning soundwave, it
converts that energy into an electrical current and sends it
to the console. The console, finally translates the
information one converts that energy into an electrical
current and sends it to the console more time and
displays it on a VGA video screen. Wherever an object
appears on the screen, it means that the soundwave has
bounced back to the transducer from exactly that angle
and at that strength. A red target on the screen means
that the return echo was very strong, in other words, the
soundwave struck a definite or firm object. The less
intense targets show that the transducer did not receive
as strong a return signal-the soundwave struck a softer
object, Dark blue indicates clear water, no return.
Obviously, rocks return a stronger signal to the transducer
than fish do because fish are softer. Fish will return a
signal to the sonar, but unless there are many fish
together, the signal is weak. With the larger schools of
fish, more soundwaves are bouncing back to the
transducer. That means that. when a school of fish
appears on the sonar display screen in bright red, you
have found a school with a lot of fish in it and the fish are
swimming close together.