Operation Manual

122
User Manual
6.2.1 UNDERSTANDING THE ECHOGRAM DISPLAY
The main elements that can be easily distinguished into an Echogram are:
Fig. 6.2.1 - The Fish Finder echogram
Fishes
Fishes are represented as arcs because of the cone angle of the transducer. In fact
as the boat passes over the fish the leading edge of the cone strikes the fish,
causing a display pixel to be turned on. As the boat passes over the fish, the
distance to the fish decreases turning each pixel on at a shallower depth on the
display. When the boat is directly over the fish, the first half of the arch is formed
and since the fish is closer to the boat, the signal is stronger and the arch is
thicker. As the boat moves away from the fish, the distance increases and the
pixels appear at progressively deeper depths forming the remaining half of the
arch.
Thermoclines
Are the zones where two layers of different water temperatures meet. The greater
the temperature differential, the thicker the thermocline is shown on the screen.
Thermoclines are represented as horizontal stripes of noise. They are very
important for fishing since often many species of game fish like to suspend in,
just above, or just below the thermoclines.
White Line
The White Line shows the difference between hard, soft bottoms and even
distinguishes between fishes and structures located near the bottom. In this way
it is easier to tell the difference between a hard and soft bottom and even to
distinguish fishes and structures located nearby the bottom. For example, a soft,
muddy or weedy bottom returns a weaker echo that is shown with a narrow
white line while a hard bottom returns a strong echo that causes a wide white
bottom line.