Humminbird ONIX Operating Manual page 146

86° 86°
455kHz 455kHz
45° 45°
800kHz
75°
455kHz
20°
200kHz
60°
83kHz
180 Degree Total Coverage
Sonar Overview
High Definition Side Imaging Sonar
The HDSI transducer provides Side Imaging sonar, Down Imaging sonar, and DualBeam PLUS
sonar on the control head.
Side Imaging sonar uses two very precise sonar beams that are aimed at right angles to the
path of the boat. The side beam coverage is very thin from front to back, yet very wide from
top to bottom. The beams provide "thin slices" of the bottom for high resolution imaging.
The side beams can be operated at one of two frequencies: 455 kHz or 800 kHz. Select
800 kHz for the sharpest image, and select 455 kHz for greater bottom coverage. The beams
can search an area that is 480 feet wide (240 ft [78 m] to each side), with a typical depth
performance of 150 feet (50 m) when the Side Imaging sonar frequency is set to 455 kHz.
The Down Imaging sonar beams point down and scan the water with razor-thin, high-
definition beams. The beams are wide side to side, but very thin from front to back. The beams
can be operated at two frequencies: 455 kHz (75°) or 800 kHz (45°). Select 455 kHz for the
best overall image quality and depth (350 ft, 107 m). Select 800 kHz for the sharpest image.
The DualBeam PLUS sonar beams provide conical coverage directly below the boat. The
beams on the transducer will use 83/200 kHz or 50/200 kHz, depending on the transducer
model. (see DualBeam PLUS Sonar for more information). DualBeam PLUS sonar returns are
displayed on the Sonar (2D) Views, and they will be used in the Side Imaging View when an
area directly under the boat does not have Side Imaging coverage. The beams can be blended
together, viewed separately, or compared side-by-side.
NOTE: Depth capability is affected by such factors as boat speed, wave action, bottom
hardness, water conditions, and transducer installation.
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