23
TRANSDUCER CONE ANGLES
The sound waves from the transducer spread out into the water in a
cone shaped beam. This looks much like the beam from a flashlight.
The angle between the outside edges of the cone is the cone angle.
Eagle offers a choice of transducers with either an 8 or 20 degree cone
angle. The transducer supplied with the Magna III has a 20 degree cone
angle. Typically, wide cone angle transducers (20 degrees) are ideal for
operating in shallow to medium water depths. The 20 degree cone
angle allows you to see more of the underwater world. In 15 feet of
water the 20 degree cone covers an area about six feet across. The 8
degree transducer covers only about a two foot circle.
The 20 degree transducer is almost always the best to use in fresh
water, the 8 degree mostly in salt water. In a deep water environment,
(300 feet - fresh water, 100 feet - salt water) the narrow cone angle is
more desirable. Since the sound energy is concentrated in a smaller
area, it can penetrate to much deeper depths. Both 8 degree and 20
degree transducers give accurate bottom readings, even though the
bottom signal is much wider on the 20 degree model. This is because
you are seeing more of the bottom. Remember, the shallow edge of the
signal shows you the true depth. The rest of the signal tells you whether
you are over rocks, mud, etc.
20 DEGREE
8 DEGREE
100'
75'
50'
25'
