Raymarine DS400 & DS500 Fish Finder User Manual


 
Chapter 4: Menu Operation 45
Hunt Mode
The DS400/500 features a digital Hunt mode that automatically searches
for the bottom while the sounder is in Auto Range. If bottom cannot be
determined while AUTO RANGE is selected, the DS400/500 pings the last
known depth, and then incrementally increases the ping depth until the
bottom is found. If bottom is not found, the sounder returns to the original
depth and repeats the process.
If AUTO FREQUENCY is also selected (see the section describing Frequency
on page 45) when the sounder completes the auto range hunt process, the
process is repeated in the other frequency. If MANUAL FREQUENCY is
selected, hunt mode only continues in the selected frequency. This process
continues until bottom is detected or you switch to manual range mode.
The maximum depth to which Hunt mode searches is as follows:
200 kHz 500ft (150m)
50 kHz 2000 ft (600m)
For example, lets say a
DS400/500
is set for auto range & auto frequency and
bottom is currently detected at 250 ft using 200 kHz. The bottom signal becomes
lost, so the sounder switches to Hunt mode. Pinging begins at 250 ft (the last-
known good depth) using 200 kHz and increments to 500 ft. If bottom is not
detected, the sounder switches to 50 kHz, repeats pinging at 250 ft, and
increments up to a maximum of 2000 ft. If bottom is still not detected, the
DS400/500
returns to 250 ft using 200 kHz to continue the process.
When bottom is found, Hunt mode ceases and the sounder adjusts to the
range and frequency appropriate for the new depth.
The default setting is AUTOMATIC.
Frequency
The DS400/500 uses dual frequency sonar50 kHz and 200 kHzand can
be used in either auto or manual modes.
The DS400/500 can automatically select the appropriate frequency, based on
the current display range. As the depth increases while in Auto Frequency
mode, the fishfinder shifts from 200 kHz to 50 kHz. As the depth decreases,
the fishfinder switches from 50 kHz to 200 kHz.
You can select the transducer frequency for automatic or manual operation at
50 kHz, 200 kHz or both frequencies simultaneously.