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Structure ID®: Structure ID® is a Humminbird® feature that describes the traditional
grayscale method of presenting sonar information. See Grayscale.
Surface Clutter: Surface Clutter is a phenomenon where sonar returns are reflected
off of tiny objects near the surface of the water, including algae and even air
bubbles. Typically, saltwater environments have significantly greater surface clutter
than freshwater due to continuous wind and wave action that causes aeration at the
surface. The Surface Clutter menu provides manual control to bias the default
settings under extreme conditions.
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® fishfinders 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 a 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.
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 mounts on the boat and is in contact with the water. It
converts the electrical energy from the transmitter into sound energy, forming the
sonar beam. 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 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, as
opposed to artificial arches or symbols. Humminbird® units are capable of producing
fish arches due to the extremely sensitive DualBeam PLUS™ sonar receiver with its
wide 60° sonar beam. 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 axis, 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.
