15
Grayline
®
is adjustable. Since it shows the
difference between strong and weak echoes,
changing the level may require a different
sensitivity setting.
To change the Grayline level, first press the
MENU key until the Grayline menu appears.
Now press the up arrow key to increase the
level, the down arrow to decrease it. The
percentage of Grayline now 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.
The level chosen by the Magna III when it’s first turned on is usually
adequate for most conditions. Experiment with your unit to find the
Grayline setting that’s best.
FISH ID FEATURE
The Fish ID feature identifies targets that meet certain conditions as fish.
The microcomputer analyses all echoes and eliminates surface clutter,
thermoclines, and other undesirable signals. In most instances, remaining
targets are fish. The Fish ID feature displays symbols on the screen in
place of the actual fish echoes. There are four symbol sizes: tiny, 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, etc.
The microcomputer is sophisticated, but it can be fooled. It can't distin-
guish between fish and other suspended objects such as turtles, sub-
merged floats, air bubbles, etc. Individual tree limbs extending outwards
from a group of limbs are the hardest objects for the Fish ID feature to
distinguish from fish. You may see Fish ID
symbols on the screen when, in fact, there are
no fish. Practice with the unit when the Fish
ID feature is on and off to become more
familiar with Fish ID. When the Magna III is
first turned on, the Fish ID feature is automati-
cally turned on, also. To turn this feature off,
press the menu key until the Fish ID feature’s
menu appears as shown at right. Now press
the down arrow key. This turns the feature off.
To turn it back on, repeat the above steps, but
press the up arrow key instead.
