Technical information

EQ-55 Operators Manual 950-70017001/Iss 1.
2
Principles of Operation of an Echo Sounder Page 3.5
Kongsberg Simrad Mesotech Ltd.
Port Coquitlam, BC - Canada
The sound waves move through the
water until they encounter a change in
density, such as a fish or the bottom.
This causes the sound waves to " echo "
back up through the water. When the
reflected sound waves (echoes) hit the
transducer the ceramic disks vibrate at
the same frequency. This voltage goes
back up through the cables to the
receiver. The EQ-55 processes the
signals and presents them on the
display screen. See Figure 3.2
Figure 3.2 Echoes returning to the receiver
3.3 TRANSDUCER BEAMWIDTH
The transducer mounted to the hull of your vessel serves as both a "speaker"
when transmitting, and as a "microphone" when the echo sounder is receiving.
Similar to the way a flashlight focuses light, most of the sound from your
transducer is focused downwards with a smaller amount going out to the sides.
The amount of focusing of the sound beam is expressed as a "beamwidth".