INDEX
Lower Limit . level whereas the
highest
value
(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
Figure 40
Transmit and Print Alternate
When using
the X-15A in deep
17 water, or if
you wish to simply con-
serve
paper, it may
be desirable to
17 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 X-15A is the Transmit and
Print Alternate function which,
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
printt' 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
8
9
9
9
10
10
10
11
..14
.15
.16
.16
Result:
2-——
--• - -- 2
2'I- -••--— ______
Upper Limit
Lines
Marker
Scale
End Of Paper
Zero Adjust
How
To Read
Graphs
Paper Loading
Stylus Replacement
Stylus Belt
Replacement
Do's and Dont's
Troubleshooting
Advanced Operation
Surface
Clarity
Control (SCC)
Feet, Fathoms, Meters 18
Transmitter Pulse Width 18
Discrimination 20
Transmit and Print Alternate 21
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