Using automatic mode
To operate the echo sounder automatically, just press AUTO. All of the 491’s adjustments will be set to produce a useful picture under most conditions. When you’re too busy to optimize the settings manually, the echo sounder can automatically set the optimal gain, clutter, and range settings, to show an excellent picture, from the surface to the bottom.
When you select auto, the range setting may change from time to time to keep the seabed in view as the water depth changes.
| It is recommended that the 491 be operated automatically |
| whenever possible. The 491 can reliably detect the seabed |
| depth only when it controls the gain and clutter settings. |
| You can always press AUTO on the ECHO screen to remove |
| any manual settings you’ve made and return to the standard |
| automatic configuration. |
Cruising or fishing | Automatic mode has two variations: autocruising and |
| autofishing. |
| • autocruising optimizes the gain and clutter for tracking |
| the bottom, with less emphasis on any fish in the water |
| • autofishing optimizes the gain and clutter for searching |
| for fish |
| Press AUTO to switch between autocruising and autofishing. |
| The colored tab below the menu key indicates whether the |
| unit is optimized for cruising or fishing. |
The status tabs | Colored status tabs just below the AUTO and PICTURE keys |
| are green when the echo sounder is operating fully |
| automatically. They turn yellow when any of the settings has |
| been set manually. (In some cases, the picture tab may be |
| yellow while the auto tab is still green, if the Noise Limiter is |
| turned on, for example.) |
Page 16 | 491 Echo Sounder Operations Manual |
