Specifications

La
I
CHART SPEED
At
power on,
the chart
speed
scrolls at a
pre-determined speed.
For a
higher
speed, press
and hold the
FAST
key
in the CHART section of
the
keyboard.
When the scroll
speed
reaches
the desired
speed,
release
the FAST
key.
To slowthe
display, press
and hold the SLOW
key. Pressing
either of these
keys
causes the
sensitivity
bar at
the
top
of the
display
to
change
to
a dashed line. The letters "CHT" will
also
appear
in a window
near the
top
of
the
display.
The bar
represents
the chart
speed.
If
you
press
and hold
the FAST
key
for
example,
the bar will
start
moving
to the
right.
This
signifies
that the chart
speed
is
increasing.
There are 10
steps
of chart
speed. By
holding
eitherthe FAST or SLOW
keys,
the
display
can
be
speeded up
or
slowed down. When the horizontal bar
reaches the far
right
side of the
screen,
the chart
speed
is at
its maximum value. The Z-
7200 will sound a
tone
indicating
maximum
chart
speed.
At times it
is desirable to
stop
or "freeze" the
display
to examine
an echo
before
it
scrolls off the screen.
Pressing
both arrow
keys
in the
CHART section at
the same time will
freeze the
display.
Now the
top
line
on the
display
will
flash on and off to
signify
that the unit is in the freeze
mode.
Pressing
both
keys
at the same time
again
wiil
start the
display
moving
at the last
chart
speed selling.
If
the
digital
sonar is
on,
the bottom
depth
will
continue to be
displayed.
The
digital
does not
stop
when the
chart is in
the "freeze" mode.
SCALE
There are
ten scale markers
printed
on both
sides of the
display.
This
helps
to determine the
depth
of a
target.
For
example,
if the
range
is
0 to 60
feet,
then
each mark is
equal
to six feet. If a
target (such
as a
fish)
is next to
the 5th
line,
then it is 30 feet
deep. (5
lines times 6 feet
=
30
feet.)
RANGE
LTh1
When the Z-7200 is in
automatic,
the
ranges change
to
keep
the
bottom
signal
on the
display
as the
bottom
depth
varies. At
times,
however,
it
may
be desirable
to
expand
the
range
or zoom in on a
target
Pressing
the ZOOM
key
doubles the size of
targets
on the
screen.
The 20
degree
transducer is
almost
always
the best to use in fresh
water,
the 8
degree
mostly
in salt water. In a
deep
water
environment,
(300
feet
-
fresh
water,
100 feet
-
salt
water)
the
narrow cone
angle
Is more
desirable.
Sincethesound
energy
isconcentrated
inasmallerarea,
itcan
penetrate
to
much
deeper depths,
Both 8
degree
and 20
degree
transducers
give
accurate bottom
readings,
even
though
the bottom
signal
is much
wider on the 20
degree
model. This is
because
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
whether
you
are over
rocks,
mud,
etc.
Paint
transducers on sait water boats with
a thin coat of anti-
foulant
paint
to
prevent organisms
from
growing.
If
unchecked,
barnacles
and other marine
growth
will cause a decrease in the
transducer's sensi-
tMty.
Do not
use a metal based anti-foulant
paint
as
it will
decrease the
transducer's
sensitivity.
There are
special
anti-foulant
paints specifically
designed
for
transducers.
They're readily
available at most marine deal-
ers.
SIGNAL
INTERPRETATION
Since
your
2-7200 is both
extremely
sensitive and
powerful,
it
gives
an accurate
picture
of the bottom that
your
boat is
passing.
A bottom
of firm
sand,
gravel, shell,
or hard
clay
returns a
fairly
wide
signal.
If the
automatic
sensitivity
is off and the
signal
narrows
down,
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.
If
you
have the automatic
sensitivityturned on,
watch the
sensitMty
bar. As
the boat
passes
overthe
mud
bottom,
the Z-7200 wiil
automatically
increase the
sensitivity
to
maintain a
good
bottom
signal.
The
sensitivity
bar will
help you
In
determining
if
the bottom is soft or hard. If it
increases while in the same
depth
of
water,
then the boat has moved over
a soft bottom. If it
decreases,
then it is over a
hard bottom. Of
course,
as the water
depth
increases or
decreases, the
sensitivity
will also
change.
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,
it
will be
deafly
visible as a
short line
extending
above the bottom
signal.
A
steep slope
returnsawide
signal,
the
steeperthe
wider.
Signals
returned from a
high
underwater cliff
are
usually
the widest of all.
10 27
PDF compression, OCR, web-optimization with CVISION's PdfCompressor