Specifications

level whereas the
highest
value Print Alternate function
which, I I. In
Ifl LI A
Lower Limit
Discrimination
(4)
is
the
strongest
level and
should be used
only
when severe
noise is
present.
To use the
Discrimination func-
tion,
simply press
the level of
noise
rejection
desired,
from 1 to
4,
then
press
the DISC
(Discrimi-
nation) Key.
There should be an
immediate
change
in the amount
of
noise
present
on the
paper.
The
Discrimination
setting
is
printed
at
the bottom of the
paper
each time
the level is entered and at
inter-
vals thereafter.
The Discrimination
function can
be disabled at
any
time
by press-
ing
0
-
DISC.
Example:
Enter a
Discrimination
level of 2.
Press: 2- DISC
Result:
— —
2
-—--——--____________
2'l
Jh
— ______
b0——-U-E
—----L
LU
-
Figure
40
Transmit and Print Alternate
When
using
the Z-15 in
deep
water,
or if
you
wish to
simply
con-
serve
paper,
it
may
be desirable to
slow the
paper speed
even more
than the automatic
system
allows.
However,
when
doing
so,
you may
get
over
print"
or
very
dark,
heavy printing
over an area that is
difficult to read. Much
detail can
also be lost
due to this.
A feature that is
available on
the
Z-15
is the
Transmit and
when
activated,
causes the
stylus
to
print every
other
revolution
in-
stead of
every
revolution.
This
accomplishes
four
things:
1. Since the
stylus only prints
every
other
revolution,
the
recorded information doesn't
have
the
"over
print" problem,
therefore
good
records are
attainable at slower
paper
speeds.
Also,
the scale num-
bers are
spread
out
more,
mak-
ing
them more
legible.
2. Reduces the
possibility
of
"wrap-around".
This is the un-
desirable occurrence of the
second or third bottom echo
printed
on the
paper
at the
top
or middle of the
page. Many
times this can interfere with fish
or other
targets
that
you
wish
to see.
3. Reduces the reverberation ef-
fect. This
happens mainly
on
lower
frequency
units,
but it
can
happen
on
higher
fre-
quency
models. Reverberation
is
heavy,
scattered noise marks
caused
by
the transmitted
sig-
nal
becoming trapped
between
the surface and the
bottom,
usually
scattered in
heavy
plankton layers
or baitfish
schools. This causes a
great
many
lines to be
printed
on
the
page. By enabling
the Transmit
and Print
function,
the
transmit-
ter is
triggered
only
half
as
many
times as
normal,
putting
less
energy
into
the water
(same
amount of
power,
just
not as
often)
which reduces
the
amount of noise seen.
4. Slows the
paper speed.
A
sig-
nificant amount of
paper
can
be saved
by using
the Alter-
nate Transmit and Print feature.
21
Specifications
1
Service Information
1
Introduction
2
How It Works
2
Installation
3
Transducer
Selection 4
Basic
Operation
4
Suppressor 5
Paper Speed
6
GRAYLINE®
7
Range
7
7
Upper
Limit
B
Lines
9
Marker
9
Scale
e
End
Of
Paper
10
Zero
Adjust
.. .
10
How To Read
Graphs.
10
Paper Loading
11
Stylus Replacement
14
Stylus
Belt
Replacement....
15
Do's and Dont's
16
Troubleshooting
16
Advanced
Operation
17
Surface
Clarity
Control
(SCC)
17
Feet,
Fathoms,
Meters
18
Transmitter Pulse Width
18
Transmit and Print Alternate
20
21
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