A fish finder is a sonar instrument that is designed for the specific purpose of detecting fish underwater. It does so by detecting reflected impulses of sounds energy. All the electronic impulses that are reflected off fish are converted into information that is then display in graphic rendition on the screen of the fish finder. In addition to locating fish, these units also measure the depth of the water, locating underwater debris, and bottom structure. The image on the screen of the fish finder can represent just one fish in the form of a small icon or with a series of arches.
When choosing the fish finder, you also need to choose the unit with the right frequency, which is also an important feature of the transducer. The frequency is directly related to angle of the cone. On most of the transducers you can find the following frequencies: 50, 83, 192 and 200 kHz. A higher frequency will give you more detail on the screen. You can find models that offer dual, single and multiple frequencies.
Transmit Power: Transmit power is expressed in watts RMS (root mean squared) and is related to how well you see in silt-laden water, view down to greater depths and successfully resolve separate targets and bottom structure. A 500-watt (RMS) fishfinder should have plenty of power for most coastal applications. Serious bluewater anglers should look for 1,000 watts or more. Inland lake fishermen can see the shallow bottom with only 200 watts.
Look for equipment that will work with multiple frequency: higher for better detail but not as successful in deep water; lower for depth but less detail on your viewing screen. Of course, if you fish only in shallow water, you’ll be happier with high-frequency output. For deep-water work and for commercial fishing, you may want to use a lower frequency.
The thickness of the line representing the bottom is also a great clue to bottom hardness. Here the rule is simple – the thicker the line, the harder the bottom. But, be careful – sonar sensitivity can affect how thick the line is. The Deeper display has adjustable sensitivity. So if you turn up the sensitivity to 100%, the bottom line may appear thicker, if you turn it down to 10% it may appear thinner. So practice adjusting the sensitivity and get used to judging how much the bottom thickness varies based on this.
Important parameters of a fishing line are its breaking strength and its diameter (thicker, sturdier lines are more visible to fish). Factors that may determine what line an angler chooses for a given fishing environment include breaking strength, diameter,castability, buoyancy, stretch, color, knot strength, UV resistance, limpness, abrasion resistance, and visibility.
Bait: If you're not using live bait or cut bait, you'll want to use artificial bait or lures. Most artificial lures resemble the type of bait fish or other food, such as worms or shrimp, that the fish you're trying to catch normally eat. These artificial baits can be scented and have metal spoons attached to them or be painted in metal flake to reflect light in the water. Other types of bait include jigs and jig heads, spoons, flies and spinnerbaits, which you can attach artificial or real bait to, and attractants to make artificial lures smell lifelike.