Chapter 2 - Quick Start: Using the Echo Sounder
490 Echo Sounder Operations Manual Rev. B2
Page 2-7
Manually
overriding
automatic mode
You can always manually change any of the echo sounder’s
settings: the gain, clutter, noise limiter, shift, and range.
(Manually setting the gain causes the range to be controlled
manually.)
Changing the appearance of the picture (colors, gain, clutter,
and the noise limiter) is described in Chapter 3.
Setting the range and shift is described in Chapter 6.
Changing the frequency of echoes
The 490 uses two transducer frequencies: 50 kHz and 200
kHz. The advantages and disadvantages of each frequency are
shown below.
You can choose from four settings for the transducer
frequency:
•
50 kHz displayed on a full screen
•
200 kHz displayed on a full screen
•
50 kHz on the left half of the screen, and 200 on the right
•
200 kHz on the left half of the screen, and 50 on the right
There are two reasons why you might want to operate with
your preferred frequency on the
right
side of the screen:
Table 2: 50 kHz vs. 200 kHz
50 kHz
200 kHz
Longer wavelength goes deeper,
but with somewhat lower resolu-
tion.
Shorter wavelength provides a
sharper picture, but can’t go as
deep.
Less resolution is better at finding
big fish, but may miss the bait
fish.
Finer resolution is better at find-
ing small fish (baitfish) and subtle
bottom details.
Wider beam is good for seeing
fish not directly beneath the boat.
Narrower beam is very focused.
Reduces the influence of a rough
sea.
Содержание 490 Echosounder
Страница 1: ...Northstar 490 Echo Sounder Operations Manual ...
Страница 38: ...Chapter 3 Adjusting the Echo Sounder Picture Page 3 8 490 Echo Sounder Operations Manual Rev B2 ...
Страница 44: ...Chapter 4 Understanding Depth Settings Page 4 6 490 Echo Sounder Operations Manual Rev B2 ...
Страница 54: ...Chapter 5 Other Functions Using the MORE key Page 5 10 490 Echo Sounder Operations Manual Rev B2 ...
Страница 74: ...Appendix A Specifications Page A 4 490 Echo Sounder Operations Manual Rev B2 ...