Vexilar FL-22 - Manual (Page 40)

40
abOut transducers
Cone of Sound
The cone of sound is the area the sound waves cover as they are emitted from the
transducer. Generally, this area is thought of as three-dimensional cone, such as an
upside-down ice cream cone. In actuality, the cone of sound is not so precisely defined.
It is an irregular shape with edges that taper rather than end abruptly. Additionally, the
cone of sound will vary slightly from transducer to transducer.
Transducer
Side Lobe
Not all of the sound
waves come out
of the transducer’s
bottom. Some sound
comes out the sides
and even the top.
Main Lobe
The main lobe is
where most of the
sound waves go.
They extend out in
all directions, some
sides more than
others.
Theoretical Cone Angle
The theoretical cone
angle is what the
transducer’s specification
defines. This is the area
where the intensity of the
sounds waves drop to a
specific point (-6dB).
Most objects are visible inside the theoretical cone, but you can also see objects outside
the theoretical angle yet within the side and main lobes. These objects must be large
enough to sufficiently reflect the sonar signal. Some of these objects can be things like the
face of a sharp dropping bottom, a large rock, or even a good size fish or tight group of
smaller fish.