the sonar can separate two tar-
gets
that are 11/2 inches apart.
This
is considered good resolution.
However, if a sonar' pulse length
was 500 micro-seconds, then the
sonar could only separate targets
that are at least 12 inches apart.
That is why it is so important to
pick a sonar unit that
gives you
the capability to change to narrow
pulse lengths for good resolution.
The X-16 allows pulse lengths
down to 30 micro-seconds or one
inch!
SECOND ECHO A second echo
can appear on the display at
roughly twice the depth of the
actual bottom signal. This is
caused by the transmitted signal
travelling
thru the
water, reflecting
off of the bottom, returning to the
surface, reflecting off the surface,
hitting the bottofti once again, and
finally striking the surface and the
transducer.
Actually, the sonar sig-
nal can do this many times as you
can see if you are in shallow water
and turn up the sensitivity. Some-
times
three, four, or more echoes
can be displayed.
SENSITIVITY The ability of a
sonar unit
to display targets. If a
unit can display small targets deep
in the water or very
small detail,
then it is said to have high
sensitivity.
A sensitivity control
adjusts the level of the receiver for
different conditions. Also called
gain.
SCALE Depth markings printed
on or near the chart paper
These
can be shown in feet, fathoms, or
meters. Often confused with
Range.
SIGNAL-TO-NOISE
RATIO The
noise level divided by the signal
level in a circuit is expressed by
the term signal to noise ratio. In
sonar, a high signal to noise ratio
is desirable because less noise
suppression is required and it is
easier for the unit to display only
the true
signals returning from the
targets, rather than a mixture of
signals and noise.
STYLUS This is the fine wire that
does the actual marking on a
graph recorder's
paper. A high
voltage is applied to the stylus
which causes it to burn through
the white outer coating of the
paper, exposing the black carbon
underneath. Use care when han-
dling
a stylus. Never touch it when
the unit is operating.
STYLUS SKIP This is a condition
that occurs when the stylus
doesn't contact the entire surface
of the chart paper. It then leaves
gaps in the record where the
stylus "skip' over spots. Usually,
the problem can be rectified by
removing and bending the stylus
into the proper shape, although
sometimes it is caused by a worn-
out stylus which must then be
replaced.
SUPPRESSOR A Lowrance
exclusive,
patented probess to
eliminate noise from a sonar unit's
display. It works on the principal
that noise pulses are typically
short in duration. By increasing
the transmitters pulse length, and
tracking it with the receiver, the
short noise pulses are cancelled
out.
STYLUS BELT A belt that travels
over two motor driven pulleys. It
typically
has a holder that retains
the stylus and a magnet on the
opposite side that
triggers
thd
transmitter.
Pulse
Alternate Transmit and Print
Paper Save
Print Intensity
Loran Interface
Power Booster
Summary of Commands
Glossary
Accessories
23
24
24
25
26
26
26
29
SPECIFICATIONS
Dimensions (with gimbal mount)
Dimensions (instrument only)
Weight
Chart
Paper
Transmitter
Frequency
Pulse Width (Adjustable)
1 0¼"W x 8¼"H x 65/s"D
12¼"W x 9"H x 65/ct
8.5 pounds
LPG-606
(2) 4" x 50' roll
192 kHz
30 s - 2000 p.s
1600 watts p-p
200 watts RMS
Output Power
Receiver Sensitivity
Chart Speed
Voltage Range
Current Drain
Fuse
—85 db
.10 -3.0 in/mm
10 - 15 vdc
amps, approximately
4 amp
28 1
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