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Table 4: 491 echo sounder features (Continued)
Manual controls
Gain | 0 to 75 db |
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Clutter | 0 to 9 |
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Signal level | 0 to 5 |
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Noise limiter | ON/OFF |
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White level | Any single color |
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Other | Screen color palette |
| Depth marker |
| Position marker |
| Zoom in/out |
| Shift |
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Ranges | 15, 30, 60, 120, 200, 400, 800, 1000, 2400 feet |
| 5, 10, 20, 40, 80, 150, 300, 500, 800 meters |
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Advance | 1/8 to 2/1 |
speed |
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Depth units | Feet, meters, fathoms |
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Installation | Include speed, temperature, gain, and transducer |
calibrations | type |
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491 Echo Sounder Operations Manual | Page 69 |