9
F
ISHING WITH THE
B
UDDY
How Your Buddy Works
The Buddy uses active SONAR, short for Sound Navigation and Ranging,
to locate and identify objects in the water. The transducer at the end of the
shaft (see Figure 5) sends out short bursts of ultrasonic sound waves into
the water and then listens for echoes to come back from objects and the
bottom. The further away the object or bottom is, the longer it takes the
echo to return.
These ultrasonic waves “illuminate” the water, forming a beam that is
strongest in the direction that the transducer is pointed (see Figure 4).
Weaker side-lobes split off from the main beam and with enough gain can
be used for finding fish as well. You can calculate the approximate
diameter of the main beam on the bottom as the depth divided by five.
Figure 4.
Bottom SONAR beam (cross-section)
