Sonar Units Sound Off

Before you can have much of a chance of landing fish you have to find them. Fishermen have developed a whole range of techniques to do that, some of which amount virtually to voodoo. But a little science can be a big help, even to the most artistic of fishermen. Sonar units or 'Fish Finders' are one great way to even the odds.

The basic principle of sonar is simplicity itself: send out a series of sound wave pulses. The waves bounce off objects in the water and echo back, somewhat like a shout in a canyon. But, naturally, the details are more complicated.

At first glance it might seem that they find too much. How do you distinguish a fish from a rock 50 feet under the water? You don't have to, the fish finder does it for you. With specially tuned electronics and color coding a good sonar unit makes it a snap to distinguish different objects. Sound waves bounce off fish differently than they do off rocks.

Sonar units can locate a variety of things under the water, though, not just fish. Underwater sandbars and jetties, rocks and other obstructions can interfere with or damage your boat. They can be spotted easily, too. That makes navigation a snap, which can be especially important near the shore or along many rivers.

A good sonar unit will readily penetrate deep waters and create sharp images. A depth of 125 feet/38 meters should be nothing for even a modest-cost unit. Some will penetrate as deep as 900 feet/275 meters and still send back highly useful information. That's a big plus for fishing those really deep inland lakes or for deep-sea saltwater fishing.

Contemporary designs have come a long way from their ancestors of WWII. Many now sport 256 colors, screens several inches across and an amazing level of detail. Some models will allow three simultaneous views - side, front and back. For navigating through tricky waters that's a big plus. It also helps avoid losing track of the fish as you wind your way through a passageway full of underwater features.

Keep in mind that fish finders are most valuable when the boat is moving. That means the scenery underneath is changing and the unit has to be able to keep up. Fast refresh is a must. At the same time, the images can't get mushy or the detail will be lost. A good sonar unit will solve those problems handily.

Many have extra features that make the units that much more valuable.

Some have integrated GPS, a great addition for those in unfamiliar territory, out on open waters, or who just want to be able to find the exact spot they succeeded in last summer. With that feature often comes the ability to download maps of a specific area. That provides even more information about the conditions in a particular place. Some units make it possible to upload or print the sonar maps they create. That can be useful for those who want to study the underwater environment a little more at leisure.

Check out the latest fish finders and give your angling art a little boost from science.

Humminbird SmartCast RF15 Fish Finder

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Big 3 7/8" diagonal display with 160V x 132H resolution; Rugged carry case with non-skid bottom and RSS storage; True 4-Level Grayscale delivers clearly better images of the bottom, fish and structure. 100 ft remote operating range, 100 ft depth capability; Large, easy to see digital depth readout; Backlight for night fishing; New illuminated Advanced RSS? with water surface temperature included. Display powered by 8 replaceable AA batteries (not included) Includes one waterproof programable RSS for either Channel A or B operation mode
Land Big Fish

Humminbird 110 Fishin' Buddy

You don't even need a boat to take this buddy fishin'. Use it on your boat, your buddys boat, a dock, or even a float tube. Fishin Buddy Fishfinders give everyone the ultimate in portability, with an ergonomic clamp mount design.
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Humminbird SmartCast RF 35 Wrist-Mount Fish Finder

SmartCast RF35 wrist mount provides a dual function fishfinder and watch with go anywhere design. Key Features Fully functional watch with date and time capability. High visiblity 1 1/4" diagonal display with 48V x 32H resolution
Land Big Fish

Vexilar® LPS-1 Hand-held Digital Sonar Depth Finder

It shoots through the ice for ice angling, no hole needed... and travels so easy for canoe trips, backcountry fishing, float tubing and even scuba diving! 200kHz, 22 degree built-in transducer reads depths from 1 4/5 ft. to 200 ft. with accuracy; Weighs just 11 ozs. and floats; Waterproof high-impact case; So easy... just point, push button and let go. It locks the reading on the display and then shuts off automatically; Uses one 9V battery (not included); Backlit display for night use. Big depth info in a small package... get yours now!
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