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ability to spot fish and structure over a wide 90° area, and to identify on which side
of the boat they are located. See DualBeam PLUS™.
Quick Disconnect Mount: The Quick Disconnect Mounting system is an exclusive
Humminbird® feature that permits the unit to be easily removed from the mounting
base by pressing a release button, and re-installed by simply snapping it back into
place. All cable connections are made when installing, so that no separate wiring
connections are required. Additionally, the mount offers 90° tilt and 360° swivel
capability to adjust the viewing angle of the unit as you move about the boat.
Real Time Sonar: Real Time Sonar is a Humminbird® technology that delivers ultra-
fast sonar transmitter/receiver operation and results in a more detailed
instantaneous view of what is under the boat. The Real Time Sonar window is a
vertical band at the right side of the display that shows the instantaneous sonar
return from the transducer at a particular instant. The RTS® Window menu option
permits the user to adjust the window to show the full sonar signal return, or just a
narrower band that indicates intensity using grayscale. Real Time Sonar relies on
very fast Sonar Update Rate (Ping Speed). See Sonar Update Rate.
Receiver: See Transmitter.
Second Return: The Second Return is a term that describes the appearance of a
second sonar return below the primary sonar return (bottom contour) at exactly
twice the true depth. The second return is caused by the same sonar energy
bouncing off the bottom once, rebounding to the water surface and then traveling
back down to the bottom to be reflected again. Second returns are more common in
shallow water and over hard bottoms; it is actually possible to see a third sonar
return under some circumstances. The second return provides useful information to
help determine bottom hardness, as areas with harder bottoms will generally create
a second return. The second return can be used as a guide to set Sensitivity when in
shallower water.
Sensitivity: Sensitivity is a user feature that adjusts the sensitivity of the sonar
system to show more or less detail in the water. Higher sensitivities are often
preferred; however, when the water contains debris (silt, storm debris, etc.) it can be
difficult to pick out targets. Conversely, if sensitivity is set too low, relevant targets
may be missed.
SONAR: SONAR is the acronym for SOund and NAvigation Ranging. Sonar
technology uses precision sound bursts transmitted underwater to determine the
distance and other attributes of objects in the water. Distance can be determined
because the speed of sound in water is constant, and the time for the signal to
return is measured. Sound also travels very quickly underwater, making sonar a
responsive, cost-effective tool. Sonar is the basic technology behind all recreational
and commercial fishfinding and depthfinding devices.
Sonar Echo Enhancement: Sonar Echo Enhancement is a Humminbird® feature that
describes the high degree of sonar sensitivity achieved through a combination of
transmitter/receiver and software algorithms. The result of Sonar Echo Enhancement
is to display virtually everything in the water that is of interest to the angler, including
bait fish, game fish, thermoclines, weed beds, subtle structure, and more.
Sonar Update Rate: Sonar Update Rate is the number of times per second that the
transmitter/receiver sends and receives sonar signals. A very fast sonar update rate
collects more information and provides a more detailed image of the bottom, fish
and structure. Many Humminbird® units operate at up to 40 times per second when
in single frequency operation. Due to the limitation of the speed of sound in water,
the update rate begins to slow as depth increases to deeper than 50 feet. In very
shallow water (less than 10 feet), however, update rates as much as 60 times per
second can be achieved.
Speed: Speed is the rate at which the boat moves through the water. Boat speed can
be measured as Speed Over Ground or Speed Through Water. Speed Over Ground is
provided by GPS, and is the measurement of the boats progress across a given
distance. Speed Through Water is provided by a speed paddlewheel, and is the
measurement of the flow past the boat, which may vary depending on current
speed and direction. Speed Through Water is most critical for anglers using
downriggers, as it impacts the running depth of the down riggers. Speed Over
Ground is optimal for navigation, as accurate destination times can be derived from
this measurement. Humminbird® products allow for input and display of both
sources.
Structure: Structure is a general term for objects on the bottom that present a
discontinuity and are a likely attractor for fish. This includes bottom contour features
(drop-offs, humps, and holes), standing structure (stumps, timbers, brush piles) and
a wide range of other potential objects (sunken boats, reefs). Humminbird® units
