Humminbird 385ci - Manual (Page 17)

5
Down Imaging™ Sonar
(Down Imaging™ models only [385ci DI])
Your 385ci DI Fishfinder uses Down
Imaging™ technology. The Down Imaging™
transducer scans the water with razor-thin,
high-definition beams. The beams are wide
(side to side) but very thin front to back.
The Down Imaging™ 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. Select 800 kHz for
the sharpest image. See Sonar Menu Tab:
Imaging Frequency for more information.
The transducer also uses conical beams to
provide data in traditional 2D format (see
What’s on the Sonar Display). Select 455
kHz for a narrowly focused 16° center beam,
or select 200 kHz for a wider 25° beam (see
Sonar Menu Tab: Beam Select).
Depth capability is affected by such factors
as boat speed, wave action, bottom hardness,
water conditions, and transducer installation.
75 Degree Total Coverage
16°
75°
25°
455kHz
200kHz
455kHz
45° 800kHz
How Sonar Works