SURFACECLUTTER
The
markings
at the top
of the screen represent
the surface of the water
which can extend
many
feet below the surface. This can interfere with
fish signals
or other targets. It's called Surface Clutter and is caused
by
algae, plankton, air bubbles caused by
wave action or boat wakes,
bait
fish, or temperature
inversions.
These marks are normal and can be seen at
any
time
during the
year.
It's
usually
the worst in the spring
and summer,
slacking off in the fall and
winter.
Figure 23
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 near
the temperature
of the surrounding
water.
During
the
winter,
this slows
down their metabolism so that
they can only utilize about a fourth as
much food as
they consume in the summer.
Most fish don't spawn unless the water temperature
is within rather nar-
row limits. Trout can't survive in streams that get
too
warm; bass and
other fish eventually die out when stocked in lakes that remain too cold
during the summer. So fish will do without food rather than venture into
water that is too hot or too cold; others will shift position
for a
tempera-
ture
change as
slight as one-half of one degree. While some fish have a
wider
temperature
tolerance than others,
each of them has a certain
range
within which it tries to stay. Schooling fish suspended over deep
water lie at the level that
provides
this temperature
in
which, we assume,
they
are the most comfortable.
101
CLEAR I CLEJ
If
you press a key that is not what
you
wanted,
you can wait six seconds
before pressing another key
and the X-3 will automatically
clear or
"forget"
the last key
entered.
For example,
if.
you wish to turn on the lights,
the proper keys to
press
are 2nd
-9. However, if
you accidentally pressed
the 0 key instead
of the
2nd key by
accident, you could wait six seconds until the
0
disappears
from the
screen, then
press 2nd-9. Another quick way
to clear an incor-
rect entry is to press
2nd-O and the last
key entered will be erased.
The entire
display may
be erased by pressing 2nd-0-O. Everything
except the
digital numbers
(if
turned on)
will be cleared from the
display.
RANGE
Although the X-3 will automatically
change the range
whenever the bot-
tom gets
shallower or goes deeper,
there
are times when it is desirable
to expand the range, or look at a different
segment
of the water below.
The
range can be set
anywhere
from 0 to 989 feet
on the upper limit and
10 to 999 feet on the lower limit, provided
the lower limit is no closer to
the
upper limit than 10 feet.
18
tAUTO RNG
AUTO RANGE
When the X-3 is first
turned on, the AUTO RANGE function is enabled. It
may be turned off anytime by pressing
the 2nd key, then the 8 key. (In this
manual, pressing keys in sequence
as
just
described will be shown like
this: 2nd-B.) The AUTO RANGING annunciator in the bottom right hand
corner of the display
will
disappear, signifying
the automatic
ranging cap-
ability has been tumed off. To return to the AUTO RANGE mode,
simply
press the 2nd-8
keys again and the unit will automatically
track the bot-
tom and place
it in the lower 4/5 of the screen.
27 8
SURFACE
cLurrER
F
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