Specifications

If a
partial
arch
occurs most of the time on
your
unit
(the
mark
curves
up,
but not back
down,
or
vice-versa)
It
could be the transducer is
not
pointing straightdown.
Adjust
atransom
mounted transducer until the
fish
show the distinctive
arch. This
may
take some trial and
error until
you
achieve the correct
mounting.
SENSITIVITY
When first tumed
on,
the Z-7200 is in the AUTO
SEARCH mode.
The
micro-computer
automatically adjusts
the
sensitivity
and
range
to find
and lock onto the bottom.
You can leave the
sensitivity
in
the automatic
mode or
manually adjust
It
to suit conditions.
A horizontal bar at the
top
of the screen
displays
the
sensitivity
level. When the
sensitivity
isat
minimum,
the bar is
very
short.
Increasing
the
sensitivity
causes the bar to
travel to the
right,
increasing
In
length
correspondingly. Setting
the
sensitivity
to maximum will
cause the bar to
extend across the
top
of
the
display. (There
are 32
steps
of
sensitivity
available.)
To
place
the
Z-7200
in
manual
mode,
press
the
AUTO
key
once.
This
turns auto
sensitivity
off.
The word AUTO at the
top
of
the
display
will
disappear, signifying
that
the Z-7200 is In the manual
mode. To increase
the
sensitivity, press
and hold
the
right
arrow
key
until the
sensitivity
is at
the
desired level. The left
arrow decreases
sensitivity
in the
same manner.
Notice how
the
sensitivity
bar
moves as
you change settings.
When
you
press
the
right
arrow
key,
the bar
moves to the
right,
indicating
an increase
insensitivity. Pressing
the left
arrow
key
movesthe bar to
the
left,
showing
the
sensitivity
has
decreased
accordingly.
You'll also
see the
change
on
the
display.
On the next
page,
the
photo
on
the left shows a
graph
with too little
sensitivity.
On the
right,
the
graph
has a
proper
sensitivity setting.
A fish
along
with
highersurface
clutter are now
visible, and the bottom
signal
has
widened.
When the
horizontal bar reaches the
far
right
hand side of the
screen,
the
sensitivity
level is at maximum. With
high sensitivity settings,
a second bottom
echo
(second echo)
may appear.
This Is normal.
It's
caused
by
the
returning
signal reflecting
off the surface of the water.
Then
it makes a second
trip
to the bottom and back
again.
TotumAuto
Sensitivity
back
on,
press
the AUTO
key. Remember,
pressing
the AUTO
key
turns both automatic
sensitivity
and auto
ranging
functions on and off
at the same time.
Remember,
there
must be some movement between
the boat and
the fish
to
develop
the
arch.
Usually,
this means
trolling
at
very
slow
speeds
with the main
engine
in
gear
at a
minimum throttle
selling.
The
depth
of
the water will affect the size and
shape
of the fish arch
duetothe cone
anglediameter.
For
example,
If the cone
passes
overa fish
in
shallow
water,
the
signal
displayed
on the
Z-7200
may
not arch at all.
This isdue tothe narrow
conediameter and the
resolution limitations of the
display.
Even the 20
degree
transducer has
only
a
3 foot diameter at
this
depth.
Compared
to
a
paper
graph,
a Z7200
cannot show as fine of
detail.
The reason for
this is the
pixels (dots
on the
screen)
are much
larger
than
a
paper graph's
markings.
Therefore,
the Z-7200
cannot show fish
arches as well as a
graph. Plus,
it
requires
a bit more
work
initially
to read
and
interpret
the screen than
a
paper graph.
Very
small fish
probably
will not arch at all.
Medium sized fish will
show a
partial
arch,
or a
shape
similar to an arch if
they're
in
deep
water.
Large
fish will
arch,
but turn
the
sensitivity up
in
deeper
water to see
the
arch.
Because of water
conditions,
suôh as
heavy
surface
clutter,
th-
ermoclines, etc.,
the
sensitivity
sometimes
cannot be increased
enough
to
get
fish arches.
One of the best
ways
to
get
fish arches is
to
expand
or
"zoom" a
segment
of the water.
For
example,
40 to6ofeet.
The smaller the
segment,
the better
the screen resolution will
be.
Then,
turn
up
the
sensitivity
as
high
as
possible
without
getting
too much noise on the
screen. In medium
to
deep water,
this
method should work to
display
fish arches.
WATER
TEMPERATURE AND
THERMOCLINES
Water
temperature
has an
important-if
not
controlling-influence
upon
the
activities of all fish. Fish are
cold blooded and their
bodies are
always
the
temperature
of the
surrounding
water.
During
the
winter,
colder water
slows down their
metabolism. At this
time, they
need about
a fourth as
much food as
they
consume in the summer.
8
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