Manual

18
ABOUT TRANSDUCER BEAM ANGLES
Beam angle has a large effect on the performance of your
depth finder. There is more to it than simply area of cover-
age. The correct beam angle to use depends entirely on what
you are trying to do with your sonar. If you are fishing for
suspended fish then you probably would be very pleased
with the performance of a 19º. However, if you were going
after fish that are hanging right on the bottom, along a steep
drop-off in very deep water, you would have better results
with a 9º. Here's why;
Dead Zone is an area within the transducer’s cone of
sound that is blind to you. The wider the beam angle the
greater the possible dead zone. The sonar will mark bottom
as the nearest distance it sees. If you are fishing over a slope,
it may see the high side of the slope, at the edge of the cone,
and mark that as bottom. The fish that are hanging on the
bottom in the center of the cone will
be invisible to you because they are
actually within the bottom signal on
your depth finder. A narrower beam
angle will reduce this effect.
A depth finder puts out a constant
amount of power. It does not matter
where you have the gain level set.
Gain simply controls how much you
amplify the signal that is bounced off
of the bottom. Therefore, a narrow
beam transducer will appear to be