Both 8 degree and 20 degree transducers give accurate bottom read-
ings, even though the bottom signal is much wider on the 20 degree
model. This is because
you are seeing
more
of the bottom. Remem-
ber,

the shallow edge of the signal shows

you the
true depth. The rest
of the signal tells you whether
you are over rocks, mud, etc.
SIGNAL INTERPRETATION
Your unit
gives
an accurate
picture of the bottom that
your
boat is pass-
ing. A bottom of firm sand, gravel, shell, or hard clay returns a wide
bottom signal. If the automatic feature is off and the bottom signal nar-
rows , then it means that you have moved over a mud bottom. Mud
absorbs the sound wave and returns a weak signal. Turn up the
sensitivity to see a better
bottom
signal.
Big rocks or stumps on a smooth bottom send back signals above

the bottom level signal. The height of the signal depends

on the
target's height. As
you pass
over a post, ft should be
clearly visible as a
short line extending above
the bottom
signal.

A steep slope returns a wide signal, the steeper

the wider. Signals
returned from a high
underwater cliff are usually the widest of all.
Brush usually lies on the bottom
and shows up as clumps rising
above
the bottom signal. Brush signals look similar to large rocks; however
their signal is not as strong
as rock.
FISH ARCHES
Fish arches are created
when the cone of sound passes
over a fish.
The distance to a fish when the cone first strikes
it is shown as "A" on

the next page. When the center of the cone strikes the fish, the

distance is shorter, as shown
in "B". As the cone
leaves the
fish, the
distance increases again
as shown in "C".
When the Fish l.D. feature is off, the
depth of the water will affect
the
size and shape
of the fish arch due to the cone angle diameter. For
example, if the cone passes
over a fish in shallow water,
the signal
displayed on the unit may
not arch at all. This is due to the narrow
cone
diameter and the resolution limitations of the
display!
CHART
SPEED

At

power
on,
the chart speed scrolls at
a preset speed. To
change
the
speed, press the
CHART SPEED key. The word "CHART"
will flash on
the right side of the
display. A vertical
bar will also appear
on the left
side of the screen. This indicates the current
chart speed. Next, press
the up arrow key if you wish to increase
the chart speed. Press the
down arrow key to decrease ft. When the chart reaches the desired
speed, release .the
key. There are five steps
of chart
speed. When the
chart
speed
reaches its maximum or minimum level,
the unit will sound
a tone.
To view the chart
speed
without
changing it, press
the CHART
SPEED
key. The chart speed bar will appear

for

eight
seconds.
At times it is desirable to stop or "freeze" the display to examine an
echo before it scrolls off
the screen. Pressing the SENS. and CHART
SPEED keys
at the same time will freeze the
display. Press the
SENS.
and CHART SPEED keys again
to start the
display moving at
the last
chart speed selling. If the
digital sonar is on, the bottom
depth will still

be

displayed. The
digital
does not stop
when the chart is in the
"freeze"
mode.
18 7
PDF compression, OCR, web-optimization with CVISION's PdfCompressor