Eagle 101 User Manual

ing
to
insure that
they
see all
the
underwater
detail as
well as
fish.
Depths greater
than 100 feet can
also be measured on the
Eagle.
For
instance,
as the water
depth
goes
from 90 feet to 110
feet, you
will
see the bottom
signal
on the
dial move
past
the "zero"
signal
to the 10-foot
marlc on the outer
scale.
Thus,
on
the second revo-
lution, depths
of 100 to 200 feet
may
be read
by adding
100 feet
to the
reading
on the dial.
If in doubt as to
depth,
turn unit
off until scan disc
stops.
Thrn
unit back on and watch to see if
bottom
signal completes
one rev-
olution
before
stopping.
If it
does,
you
are at the
depth
shown
plus
100 feet. If the
signal
travels around the dial
two
times, you
will
be
at the
depth
shown
plus
200 feet.
HOW TO USE
YOUR
EAGLE DEPTH
SOUNDER
'rhe word "Sonar" is
an abbrevi-
ation of
Sound,
Navigation,
and
Ranging.
It
was
developed
dur-
ing
World
War
II as a means of
tracking enemy
submarines.
Sound travels at
approximately
4,800
feet
per
second
through
water as
compared
to
approxi-
mately 1,100
feet
per
second
through
air.
transmitted
into the water.
When this wave strikes
an ob-
ject,
it rebounds.
Since the
speed
of sound
through
water is
known,
the
time
lapse
between
the transmitted
signal
and the
received echo
can be measured
and the
distance to the
object
determined.
The
Eagle
depth
sounder
trans-
mits a
high frequency
sound
wave (which
is inaudible to fish
as
well
as
humans)
through
the
water. At the same
time,
a
high
intensity
neon
bulb whirls at a
Some
fish, including
bass, catfish, walleyes,
and
crappies,
occa-
sionally
lie
right
on
the bottom. Even here
the EAGLE will show
them as
you pass
over,
provided
the bottom is
smooth
sand, shell,
or
gravel. Signals
will
appear
on the dial
both above and below
the clear bottom
sig-
nal, just
the same as
over a
rocky
bottom.
The reason for this
is that the
signal
re-
turning
from a
fish
near
the center of the
cone of sound doesn't
travel
so far as the
signal
that hits a fish
near the outer
edge
of
the cone. Con-
sequently,
the
signal
from the
fish in the
middle shows above
the bottom while the
signal
from the fish
near
the
edge
shows
below the
bottom.
HARD
CLAY, SAND, GRAVEL,
SHELL
BOTTOMS
PRINCIPLE
OF SONAR
)flfl)flflflflflflfl)flfl
(((((
(((N
SIGNAL SENT BY LOCATOR BOUNCES BACK 'FRoM
TARGET. TIME
LAPSE INDICATES DISTANCE
TO TARGET
Fig.
11
4.
Sand bottom
Fig.
16
7
12
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Eagle 101 Specifications

General

Brand	Eagle
Model	101
Category	Sonar
Language	English