Teleflex TFX320, Operation Manual

Page: 10 / 31

8
USING THE 320 SERIES
CONTROL FUNCTIONS
T
HE
C
HART
W
INDOW
The C
HART
W
INDOW
creates a historical log of
sonar returns from the RTS window. As the
boat moves, variations in the depth and
sonar return change and are charted to form
an image of the bottom contour. The most
recent sonar returns are charted on the right
side of the window; as new information is
received the older information is moved
across the display.
The chart window also indicates the
composition of the bottom. A hard bottom
such as compacted sediment or flat rock
appears as a dark, thin line across the display.
Soft bottoms such as mud or sand appear as a
thicker line having a transition from dark to
light grays. Bottoms made up of many rocks
have a broken, random appearance.
Bottoms having a large degree of slope also present a unique picture. These
generally have a thicker black band representing the bottom directly under the
boat. Equal areas of gray above and below the black band represent sonar
returns from around the boat.
A second sonar return may be visible if the
appropriate depth range is selected. This
appears as a depth contour below the
main bottom contour, at twice the depth.
The second return occurs when the sonar
signal bounces between the bottom and
surface of the water and back again. Some
anglers use the appearance of the second
return to determine bottom hardness.
With a lower gain setting the second
return will be more faint, except in areas
with hard bottom. The
320 has a unique
depth range feature which permits the
second return to be visible in any depth
range. See Modes of Operation for detail.
Hard
Bottom Soft
Bottom Rocky
Bottom
Chart Window
Thermocline
Slope
Second
Return