Garmin GPSMAP 702 series, Руководство пользователя, Страница: 33 / 83

surface noise and reduce bottom signal continuity during rough
sea conditions. Wider beam widths generate larger arches for
fish target returns, making them ideal for locating fish. Wider
beam widths also perform better in deep water, because the
lower frequency has better deep water penetration.
CHIRP frequencies allow you to sweep each pulse through a
range of frequencies, resulting in better target separation in
deep water. CHIRP can be used to distinctly identify targets, like
individual fish in a school, and for deep water applications.
CHIRP generally performs better than single frequency
applications. Because some fish targets may show up better
using a fixed frequency, you should consider your goals and
water conditions when using CHIRP frequencies.
Some sonar black boxes and transducers also provide the ability
to customize preset frequencies for each transducer element,
which enables you to change the frequency quickly using the
presets as the water and your goals change.
Viewing two frequencies concurrently using the split-frequency
view allows you to see deeper with the lower frequency return
and, at the same time, see more detail from the higher
frequency return.
Selecting Frequencies
NOTE: You cannot adjust the frequency for all sonar views and
transducers.
You can indicate which frequencies appear on the sonar screen.
1
From a sonar view, select Menu > Frequency .
2
Select a frequency suited to your needs and water depth.
For more information on frequencies, see (
Sonar
Frequencies , page 24 ).
Creating a Frequency Preset
NOTE: Not available with all transducers.
You can create a preset to save a specific sonar frequency,
which allows you to change frequencies quickly.
1
From a sonar view, select Menu > Frequency .
2
Select Manage Frequencies > New Preset .
3
Enter a frequency.
Turning On the A-Scope
NOTE: This feature is available in the Traditional sonar views.
The a-scope is a vertical flasher along the right side of the view,
showing you what is underneath the transducer right now. You
can use the a-scope to identify target returns that may be
missed when the sonar data is quickly scrolling across the
screen, such as when your boat is moving at high speeds. It can
also be helpful for detecting fish that are close to the bottom.
The a-scope above shows fish returns
À
and a soft bottom
return
Á
.
1
From a sonar view, select Menu > Sonar Setup >
Appearance > A-Scope > On .
2 Select a hold time.
You can increase the hold time to increase the length of time
the sonar returns are displayed.
Panoptix Sonar Setup
Adjusting the RealVü Viewing Angle and Zoom Level
You can change the viewing angle of the RealVü sonar views.
You can also zoom in and out of the view.
From a RealVü sonar view, select an option:
• To adjust the viewing angle diagonally, select
.
• To adjust the viewing angle horizontally, select .
• To adjust the viewing angle vertically, select .
• To adjust the viewing angle, swipe the screen in any
direction.
• To zoom in, spread two fingers apart.
• To zoom out, pinch two fingers together.
Adjusting the RealVü Sweep Speed
You can update how quickly the transducer sweeps back and
forth. A faster sweep rate creates a less detailed image, but the
screen refreshes faster. A slower sweep rate creates a more
detailed image, but the screen refreshes more slowly.
NOTE: This feature is not available for the RealVü 3D Historical
sonar view.
1
From a RealVü sonar view, select Menu > Sweep Speed .
2
Select an option.
LiveVü Forward and FrontVü Sonar Menu
From the LiveVü Forward or FrontVü sonar view, select Menu.
Gain : Controls the level of detail and noise shown on the sonar
screen.
If you want to see the highest intensity signal returns on the
screen, you can lower the gain to remove lower intensity
returns and noise. If you want to see all return information,
you can increase the gain to see more information on the
screen. This also increases noise, and can make it more
difficult to recognize actual returns.
Depth Range : Adjusts the range of the depth scale.
Allowing the device to adjust the range automatically keeps
the bottom within the lower portion of the sonar screen, and
can be useful for tracking a bottom that has minimal or
moderate terrain changes.
Manually adjusting the range enables you to view a specified
range, which can be useful for tracking a bottom that has
large terrain changes, such as a drop-offs or cliffs. The
bottom can appear on the screen as long as it appears within
the range you have set.
Forward Range : Adjusts the range of the forward scale.
Allowing the device to adjust the range automatically adjusts
the forward scale in relation to the depth. Manually adjusting
the range enables you to view a specified range. The bottom
can appear on the screen as long as it appears within the
range you have set. Manually reducing this option can reduce
the effectiveness of the FrontVü Alarm, reducing your
reaction time to low depth readings.
Transmit Angle : Adjusts the focus of the transducer to the port
or starboard side. This is available only with RealVü capable
Panoptix FrontVü transducers, such as the PS30, PS31, and
PS60.
Transmit : Stops the transducer from transmitting.
FrontVü Alarm : Sets an alarm to sound when the depth in front
of the vessel is less than the specified value ( Setting the
FrontVü Depth Alarm , page 26 ). This is available only with
Panoptix FrontVü transducers.
Sonar Setup : Adjusts the setup of the transducer and the
appearance of the sonar returns.
Edit Overlays : Adjusts the data shown on the screen
( Customizing the Data Overlays , page 3 ).
Sonar Fishfinder 25