Flasher Knowledge
By Gary Carter

A Flasher will only display objects while they are inside the sonar cone. Don't set and reset the sensitivity. Set the flasher sensitivity in 20 feet of water and leave it alone. Only increase the sensitivity when moving into water over 60 feet.

1. ZERO LIGHT - This confirms that the unit is on and functioning. The light may fluctuate depending on the amount of surface clutter.
2. BAIT or SMALL FISH - Bait & small fish will appear as thin strands. They will probably be dimmer than a standard fish signal.
3. FISH - Fish will be wider signals depending upon the size of the fish.
4. BOTTOM SIGNAL - The edge of the signal nearest zero is the actual depth and bottom.
5. SECOND ECHO - This is the rebound of the sound wave and appears at double the bottom depth. Tune the Flasher so second echo fades out when the depth is 30 feet or more. This will avoid the "wrap around" signal effect.

• A. SOFT BOTTOM - Silt, mud. When the signal is narrow and more faint.
• B. HARD BOTTOM - Sand, rock. When the signal is wide and bright.
• C. STRUCTURE - Ledge or drop-off. When signal is wider than that of a normal, hard bottom.

Sonar Cone. Sonar waves coming from the transducer form a cone shaped signal. The signal is narrow at the transducer and wider as it gets deeper. The signal that is transmitted to the bottom would look very much like a flashlight beam. As a rule of thumb, the bottom coverage is about one-third the depth. In other words, if you are sitting in 20 feet of water the fish finder will cover a six-foot circle of the bottom under the boat. As you get deeper this circle will get larger, and as you move shallower the circle will be smaller. This all depends on how the manufacturer designed the transducer. Transducers are available that produce 20 degree angle and 15 degree angle cones. Acknowledgements to Don Iovino for his kind help.