Understanding The Fishfinder And Sonar - Garmin Fishfinder 340C Owner's Manual

g s > u
ettIng tArted nderstAndIng the

Understanding the Fishfinder and Sonar

The Fishfinder 340C is a fully automatic, color sonar unit that
allows you to go out on the water and find fish without having
to configure a lot of settings. However, you can customize each
setting as you prefer.
If you have used a Fishfinder before, you might already know how
to interpret the sonar information on the screen, so you can skip
this section. If you have not used a Fishfinder before, you might
want to learn a bit about sonar: what it is, how it works, and what
you might see on the Fishfinder 340C screen. This manual provides
a general understanding of those things that you need to know
about sonar that can help you interpret the screen and find the fish.
Understanding Sonar
During installation, you connect your Fishfinder 340C to a
transducer. The transducer uses sound to determine information
about what is in the water beneath your boat. Then the transducer
sends the information to your Fishfinder to be shown on the screen
for you to view and interpret.

f s
IshfInder And onAr
The transducer sends sound waves down into the water in a cone
shape, similar to a flashlight beam (covering a smaller circular area
at the top and angling out to a larger circular area at the bottom).
These sound waves reflect off of any object that they hit, and then
the waves travel back up to the transducer. These objects could
be fish, branches, the bottom, or any other object that has density
that is different from the water. The transducer receives the sound
wave information, and then sends the information to the Fishfinder.
The Fishfinder shows the information on the screen for you to see
and interpret. The type of transducer and settings that you choose
determine how the information appears on the screen.
Using Dual Frequency
Dual frequency works best for deep water (for example, off-shore)
applications. The 200 kHz frequency allows you access to great
detail about what is underneath your boat. The 50 kHz frequency
provides less detailed information, but penetrates to greater depths
with the same power. You can choose either or both frequencies to
get the information that you want. If you choose dual frequency,
the transducer alternates between the 50 kHz and 200 kHz signals.
This capability allows you to see the best picture available at any
depth.
Fishfinder 340C Owner's Manual