Eagle Electronics TRIFINDER 2 - Manual (Page 33)

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Press UP ARROW to increase the level or press DOWN ARROW to de-
crease it. The percentage of Grayline in use shows in this menu. Echoes
scrolling onto the screen will also show the effects of the Grayline
change. If you reach the maximum or minimum level, a tone sounds
alerting you to the limits. Press
PWR to clear the menu.
FISH I.D.

The Fish I.D.
 feature identifies targets that meet certain conditions
as fish. The microcomputer analyzes all echoes and eliminates surface
clutter, thermoclines and other signals that are undesirable. In most
instances, remaining targets are fish.
The Fish I.D. feature displays symbols on the screen in place of the ac-
tual fish echoes. There are three symbol sizes: small, medium, and
large. These show the relative size between targets. In other words, it
displays a small fish symbol when it thinks a target is a small fish, a
medium fish symbol on a larger target and so forth.
At left, underwater scene in normal fish arch mode. Right, Fish I.D.
menu with the feature turned on.
Fish I.D. is an easier way for a sonar novice to recognize a fishy signal
return when he sees it. However, locating fish by symbol
only has some
limitations.
Your sonar unit's microcomputer is sophisticated, but it can be fooled.
It can't distinguish between fish and other suspended objects such as
trotlines, turtles, submerged floats, air bubbles, etc. Individual tree
limbs extending outward from a group of limbs are the hardest objects
for the Fish I.D. feature to distinguish from fish.
To see what's under your boat in maximum detail, we recommend you
turn off Fish I.D. and begin learning to interpret fish arches.
Fish I.D.
symbol
Fish arches