Interphase PC/View, Руководство по эксплуатации

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42
reduction will help to minimize the sidelobe effect.
However, in some situations, you may want to
ignore the sidelobe effect and increase the gain to
achieve a better display of the bottom far-forward of
the vessel.
In general, PC/View’s adjustable gain settings help
to minimize the sidelobe effect. This is because
each gain setting represents a time-varied-gain
(TVG) curve. These curves use lower gains for
earlier returns, which may include unwanted
sidelobe echoes, and higher gains for later returns
which include the desired echoes. Refer to page 30
for a discussion of gain settings.
Interpreting the
Horizontal Display
In the horizontal scanning mode the PC/View scans
from left to right across the vessel’s bow. The
forward scanning elements in the transducer are
positioned so that the plane of the horizontal scan is
angled downward approximately 10 degrees from
the water’s surface (see the diagrams at left and on
p.21). This downward angle is designed to help
reduce the effects of surface noise clutter when the
water is choppy and to allow easier mounting of the
transducer to the transom of smaller boats.
Imaging the Bottom
As the acoustic beam is projected away from the
boat, the cross-sectional area of the beam increases.
At a range of approximately 3 to 3.5 times the depth
of the water the sound beam will begin intersecting
the bottom and some of the sound energy that
intersects the bottom will be reflected back and will
appear on the PC/View’s screen as bottom echoes.
Refer to the diagram at left.
It is important to understand that the PC/View will
often see the bottom and will show it on the forward
display. This display information can be used to
help understand the structure of the bottom ahead of
the boat, but the bottom echoes can also mask or be
confused with other desired targets. In the diagram
Bait
200 ft Forward Range, Water Depth of 36 Ft
“False” Echoes Caused by Sidelobe Returns.