Raymarine L1250D, Руководство пользователя

Страница: 116 / 246

5-16 HD Series Fishfinders
Se
le
ct
in
g t
he
Fre
que
nc
y
While the HD Series Fishfinder searches in Hunt mode, a constantly changing
‘stairstep’ pattern is displayed as the sounder switches depths and frequencies.
This situation is most likely to happen while the vessel is travelling at a high
rate of speed.
If you do not wish to view this stairstep hunt pattern, switch to
MANUAL
RANGE
to turn off Hunt mode. Then, when you reduce speed, return to
AUTO
RANGE
to continue the hunt for bottom.
Selecting the Frequency
HD Series Fishfinders use dual frequency sonar—50 kHz and 200 kHz—
and can be used in either auto or manual modes.
The fishfinder can automatically select the appropriate frequency, based
on the current display range. As the depth increases while in Auto Fre-
quency mode, the sounder module shifts from 200 kHz to 50 kHz at 250 ft
(80 m). As the depth decreases, the sounder module switches from 50 kHz
to 200 kHz at 150 ft (50 m).
The Auto Frequency setting is also useful for automatically searching for
bottom, as described in
Hunt Mode on page 5-15 .
Alternatively, you can manually select either frequency, or both frequencies
simultaneously (split frequency). Each is suitable for a particular purpose:
50 kHz Frequency
When using this frequency, the transducer scans a wide area. The 50 kHz
signal penetrates water well, so is good for use in deep water.
200 kHz Frequency
When using this frequency, the transducer scans a narrower area, but produces
a more detailed view. The 200 kHz signal is good for finding fish near the
bottom or close together. It is better for use in shallow water.
Split Frequency
The transducer can operate in both 50 kHz and 200 kHz frequencies at the
same time. If you choose split frequency operation, the scrolling bottom
display is split horizontally. The upper half shows the 200 kHz detailed view
and the lower half shows the 50 kHz image.
➤
To change the frequency:
1. Press the
FREQUENCY
soft key. The frequency selection soft keys are dis-
played.
2. Press the appropriate soft key –
50 KHZ, 200 KHZ
or
SPLIT.
The scrolling bot-
tom is displayed in the selected frequency.
FREQUENCY
81213_1.book Page 16 Monday, March 17, 2003 1:14 PM