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TRANSDUCER SELECTION
Lowrance offers
you
the choice
of transducers With either an 8 de-
gree
or 20
degree
cone
angle
that
will
interchange
with
any
of our
192 kHz sonar units. In
other
words, any
Lowrance sonar instru-
ment can
be used
with
any
Low-
rance transducer of the same
frequency
without
retuning
of
any
kind,
and no loss of
performance.
However,
the use of
any
other
manufacturer's transducer will re-
sult in a
loss
of
performance.
Now
you
can select the trans-
ducer
design
and cone
angle
to
best fit
your specific
needs. Gen-
erally,
wide cone
angle
transduc-
ers
(20 degree)
are
ideally
suited
for
operating
in shallow water or
at medium
depths.
The 20
degree
cone
angle
allows
you
to see
more of the underwater world.
In
15 feet of
water,
the 20
degree
cone
angle
allows
you
to see an
area of the bottom that's
approxi-
mately
6 feet across. The 8
degree
transducer covers
only
about a 2 foot circle.
Figure
3
Thus,
you
would use a 20 de-
gree
transducer when
looking
for
fish or
structure,
to
easily
find
drop-offs,
and to see fish that are
around
you.
. . not
just
below
you.
However,
the 20
degree
trans-
ducer won't
penetrate
to
greater
depths
as well as the 8
degree
transducer,
nor will it show a
sharp drop-off
as well. In a
deep-
water environment
(100
feet or
deeper)
the narrow cone
angle
is
more desirable because it can
more
accurately
detect the loca-
tion of the fish or
drop-off
in
deeper
water. Since the sound
energy
is concentrated in a
smaller
area,
it can reach to
deeper depths.
Both the 8
degree
and the 20
degree
Lowrance transducers
give
accurate bottom
readings,
even
though
the bottom
signal
is
much
wider on
the 20
degree
model be-
cause
you
are
seeing
more of the
bottom.
Remember,
the shallow
edge
of the
signal
shows
you
the
true
depth.
The rest of the
signal
tells
you
the
composition
of
the
bottom,
i.e. whether
you
are over
a soft or hard
bottom,
etc.
III
BASIC OPERATION
On-Off and
Sensitivity
Control
—
Rotate the
Sensitivity
knob
50'
clockwise to turn the unit on.
The
Sensitivity
knob works much like
the volume control on a
radio,
that
100' is,
weaker
signals
will be detected
with
higher settings
of the knob.
When
cruising,
or at other times
when
just simple
bottom contour
information is
desired,
the Sen-
sitivity setting
can be low. In
deep
water or over
soft,
muddy
bot-
zoo'
toms, (which
produce
weak
8°at3db
echos),
the
setting
will have to
be
higher.
into the unit and the transducer
is
in contact with the water.
Symptom
The unit is
"ON",
but
paper
does
not move.
What To Do
Tape paper
to cardboard
spool
on
take-up post.
Symptom
Recorder marks are faint or dim.
*
What To Do
Clean
viewing
door;
replace
the
stylus;
check
battery
connections.
Symptom
Recorded marks are
very heavy;
paper
is torn
by stylus.
What
To Do
Bend
the
stylus slightly
to reduce
pressure
on
paper.
VI
ADVANCED OPERATION
Surface
Clarity
Control
(SCC)
The surface
markings
at
the
top
of the chart
paper
can,
at
times,
extend
many
feet below the sur-
face. This often interferes with fish
signals
or other
targets.
This
is
called Surface Clutter and is
caused
by algae
and
plankton,
air
bubbles caused
by
wave action or
boat
wakes,
bait
fish,
or
tempera-
ture inversions.
The surface clutter
markings
can be reduced or eliminated
by
using
the MARKJSCC control
key
on the front
panel keyboard.
To use the
SCC, press
key
1
thru 4 and
then the MARK/SOC
key.
1
has a minimum effect on
surface
clutter,
4
has the max-
imum effect on
reducing
surface
clutter. 2 and
3 have intermediate
effects. The amount of SCC that
is
used is
printed
at the bottom of
the chart
paper.
If one level of
SOC is
used,
then
S-i is
printed.
Two
levels, S-2,
etc.
The effect on surface clutter
should
immediately
be seen. Use
only
the amount of
SOC
required
to reduce the
clutter,
as fish
sig-
nals can be eliminated
by using
this
method,
also.
If
you
wish to turn the SOC
function
OFF,
simply press
0-MARK/SOC and
the
SOC
function will be disabled.
Example:
ENTER A SOC
LEVEL OF 2.
Press: 2
-
SCO
Result:
(See Figure
37.
4
_17
Depth
C,,,
Angle
I
Diameter I
L. it g I
0:- gt
I
1,0,
14 30 I
It" it 53 I
12,0 20 70 I
20'at:
l2-----—-
I—
Figure
37 SCC "2"
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