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TRANSDUCER SELECTION
Lbwrance
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 v4ater 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
arouhd
you.
. . not
lust
below
you.
However,
the 20
degree
trans-
ducer wont
penetrate
to
greater
depths
as well
as-tjie
8
degree
transducer,
nor
will t 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 df
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.
Ill
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 controi 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-
200'
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
viewtng
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
MARK/SCC control
key
on the front
panel
keyboard.
To use the
5CC, press
key
1
thru 4 and then
the MARK/SCC
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
SCC is
used,
then S-i is
printed.
Two
levels,
5-2,
etc.
The effect on
surface clutter
should
immediately
be seen. Use
only
the amount of
SCC
required
to reduce the
clutter,
as fish
sig-
nals can be
eliminated
by using
this
method,
also.
If
you
wish to
turn the 5CC
function
OFF
simply press
0-MARK/SCC and the 5CC
function will be
disabled.
Example:
ENTER A SCC
LEVEL OF 2.
Press: 2
-
SCC
Result:
(See Figure 37.)
4
17
Depth
S
23'
'2 Itt. tIn.
520 14
31
III 21 13
224 20 II
—
12—
———.-- ——-—-—-—--——---
—lie
bO—--S—2 U
——-—----——---bO—--fl----—-
Figure
37
5CC 11211
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