Humminbird 858c GPS Receiver User Manual


 
Introduction
3
High Definition
Side Imaging
® Sonar
(898c SI and 998c SI only)
The898cSI Combo and 998c SI Combouse
Side Imaging® sonar to provide a wide yet
precise survey of a large area of water,
including detailed bottom topography and
fish-attracting structure orientation. The
Side Imaging® transducer returns are
processed intoan imagesimilarto anaerial
photograph.
Typically, the Side Imaging® sonar can
search anareathatis 480 feet wide (240 to
each side), with a typical depth
performance of 150 feet when the Side
Imaging® Sonar frequency is set for
455kHz.Thesidebeams canbeoperatedat
one of twofrequencies: 455 kHz or 800 kHz.
Selecting 800 kHz produces the sharpest
image, but the search area to each side
and the depth capability are limited as
compared to the 455 kHz frequency. See
What’son the Side Imaging® Displayand
Understanding Side Imaging® for more
information.
The Side Imaging® transducer also
provides down imaging displays on the
screen. See What's on the Down
Imaging™ Display for more information.
DualBeam PLUS™ Sonar
(858c, 898c SI, 958c, 998c SI)
The Fishing System uses a 200/83 kHz
DualBeam PLUS™ sonar system with a wide
(60°) area of coverage. DualBeam PLUS™
sonar has a narrowly focused 20° center
beam, surrounded by a second beam of 60°,
expanding your coverage to an area equal to
your depth. In 20 feet of water, the wider
beam covers an area 20 feet wide.
DualBeam PLUS™ sonar returns can be
blended together, viewed separately, or
compared side-by-side. DualBeam PLUS™ is
ideal for a wide range of conditions - from
shallow to very deep water in both fresh and
salt water. Depth capability is affected by
such factors as boat speed, wave action,
bottom hardness, water conditions, and
transducer installation.
6
8
3kHz
20°
2
00kHz
86°
455kHz
86°
455kHz