Humminbird 787C2 Operation Manual page 64

531476-1_A - 787c2_Eng.qxd 11/22/2005
Target Separation: Target Separation is the measurement of minimum distance that a
fishfinder needs to be able to recognize two very close objects as two distinct targets (i.e.
two fish hanging very close, or a fish hanging very close to structure). Humminbird®
findfinders provide a very good 2 1/2 inches of target separation in shallower than 100
feet of depth. Target separation decreases as depth increases due to the need for longer
Pulse Width to achieve greater depth. See Pulse Width.
Thermoclines: Thermoclines are water layer(s) of distinctly different temperatures that
create a sonar reflection due to the density of the differing water temperatures. Typically
a thermocline will appear as a continuous band across the display at some distance
above the bottom contour. Thermoclines are of interest to anglers because fish will
suspend above or below the thermocline as they seek the optimum temperature and
oxygen levels.
Time Variable Gain: Time Variable Gain is a processing step applied to the sonar return
to "normalize" the data so that objects of equal size (i.e. fish) appear to be the same size,
even if they are separated by a good distance. Time Variable Gain is a fundamental
attribute of good sonar, but is often promoted as a feature.
Total Screen Update®: A Humminbird® feature that refreshes and updates all the sonar
information on the display when a range change occurs. Without Total Screen Update®,
only the most recent sonar information would be drawn to the new range, and the old
sonar information would continue to scroll off the screen at the old range.
Transducer: The transducer is part of the sonar system, which mounts on the boat and
is in contact with the water, that converts the electrical energy from the transmitter into
sound energy, and that forms the sonar beam in turn. Internally, the transducer consists
of one or more piezo electric disks that expand by very minute amounts to create the
sound wave. This element also works in reverse, converting the returned sound energy
back into an electrical signal that the receiver interprets. Transducers are available for
many specific mounting applications for the boat, such as a transom mount, trolling
motor mount, etc. Humminbird® offers many sophisticated transducers, often with
multiple piezo electric elements designed to form specifically-shaped sonar beams,
providing the angler with superior tools for finding and catching fish. See Transmitter
and SONAR.
Transmitter: The transmitter and receiver are matched parts of the sonar system that
send (transmit) and listen to (receive) the sonar signals, and work in conjunction with
the transducer. Humminbird® transmitters have an extremely fast cycling design that
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can send signals up to 60 times per second, as well as produce the varying levels of
power output needed for different depths and conditions. Additionally, the transmitter
has the capability to create very precise sonar pulses needed for a high degree of target
separation. Humminbird® receivers are extremely sensitive, but within a narrow
"bandwidth" to discriminate against noise from external sources. Additionally, the
receiver offers a wide "dynamic range" which provides the ability to receive very strong
signals alternating with very weak signals, without the strong signal overwhelming the
weak signal. See Transducer and Noise.
TripLog: TripLog is a Humminbird® feature that provides an on-screen counter for
Elapsed Time, Average Speed and Total Distance traveled, and requires a speed input to
activate the feature. TripLog appears on the Big Digits View, and can be reset to zero
through the TripLog menu.
TrueArch®: TrueArch® is a Humminbird® feature that provides true fish arches, not
artificial arches or symbols. Humminbird® units are capable of producing fish arches due
to the wide 60° sonar beam of DualBeam PLUS™, an extremely sensitive sonar receiver.
See Fish Arch.
Viewing Angle: Viewing Angle is an attribute of an LCD that characterizes visibility of the
display when viewing from off the central access, such as when standing to the side of
the fishfinder. Wider viewing angles are better because the information remains visible
even when viewing from the side.
WhiteLine®: WhiteLine® is a Humminbird® feature that highlights the strongest sonar
return on the display using a very light gray band. This is preferred by some anglers who
have grown accustomed to the feature on paper graph chart recorders.
WideSide®: WideSide® is a Humminbird® sonar configuration used in an optional
transducer. WideSide® uses three sonar beams pointing to the left, right and down.
Beams pointing to the left and right are effective for spotting fish and structure near the
surface or on the bank. The downlooking beam provides depth information directly
below the boat.
X-Press™ Menu: X-Press™ Menus are a Humminbird® feature that make the most
commonly-used menu selections available with one press of the MENU key. Items that
appear on the X-Press™ Menu are related to the current view, and present the most logical
choices for that view. Sonar View X-Press™ menus will differ from Chart View
X-Press™ menus, etc. X-Press™ menus are one of the principal reasons that Humminbird®
products are easier to use.
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