Inland fishfinding has changed, with high-frequency (455 or 800kHz) transducers that look to the side, straight down or can aim over a 360-degree range. Fishfinder manufacturers offer the inland angler a growing (and often confusing) assortment of choices in frequencies, beamwidths, even the underwater direction you can look. Inland anglers who search for fish in shallow lakes don’t need the power to see down to 5,000', but can gain a big advantage by looking out to the sides, so Garmin, Raymarine and Lowrance have products using multi-beam transducers for that purpose. Here’s where the Marketing Jargon takes over, with names like StructureScan HD™ and CHIRP DownVision.
The display is all about pixels. With more pixels you will be able to see more details, so it’s also an important factor to consider. More pixels also means higher price of the fish detector. We would suggest going minimum 240(v) x 160(h) pixels of the screen. However, this screen will give a pretty blocky image. To have a sharper image and better resolution, you will need to invest more.
In operation, an electrical impulse from a transmitter is converted into a sound wave by an underwater transducer, called a hydrophone, and sent into the water.[3] When the wave strikes something such as a fish, it is reflected back and displays size, composition, and shape of the object. The exact extent of what can be discerned depends on the frequency and power of the pulse transmitted. Knowing the speed of the wave in the water, the distance to the object that reflected the wave can be determined. The speed of sound through the water column depends on the temperature, salinity and pressure (depth). This is approximately c = 1404.85 + 4.618T - 0.0523T2 + 1.25S + 0.017D (where c = sound speed (m/s), T = temperature (degrees Celsius), S = salinity (per mille) and D = depth).[4] Typical values used by commercial fish finders are 4921 ft/s (1500 m/s) in seawater and 4800 ft/s (1463 m/s) in freshwater.
The last model we would like to mention in our top 12 list is a model also from the Humminbird brand. It’s also one of the best inexpensive fish finder models. It comes with a black and white display. The sonar is dual beam and its frequency (200/455 kHz) allows viewing readings of depths of up to 600 feet. It’s also a small fish finder with the display being just 4 inches. The clear edge grayscale display clearly shows everything even in direct sunlight.
While many fish finders point directly underneath your boat, higher end units like this one will sweep to the sides as well. Considering that you are casting out from the ship rather than dangling lines beneath it, side sweeping is much more valuable as it allows you to find fish wherever you are, rather than finding them, moving the boat, and then trying to catch them.
The intensity of the sonar return from a hard bottom will be different to one from a hard bottom. Your fish finder uses colour to show this difference. In the standard colour palette of the Deeper display, the colour varies from dull brown (softest) to intense orange (hardest). In the day mode colour palette (see screen shot), the difference is even easier to see, with the colour ranging from purple (softest) to red to orange to yellow (hardest).

Ultrasound frequency used by a fish finder generally ranges from 15 kHz to 200 kHz. However, the majority of the conventional fish finders oriented for recreational craft utilize 50 kHz and 200 kHz. Such fish finders available in the market incorporate electronic circuitry that can transmit and receive ultrasound in these two frequencies. Also, a transducer mounted on the bottom of the craft is configured to handle these two frequencies.
The use of the hook in angling is descended, historically, from what would today be called a "gorge". The word "gorge", in this context, comes from an archaic word meaning "throat". Gorges were used by ancient peoples to capture fish. A gorge was a long, thin piece of bone or stone attached by its midpoint to a thin line. The gorge would be fixed with a bait so that it would rest parallel to the lay of the line. When a fish swallowed the bait, a tug on the line caused the gorge to orient itself at right angles to the line, thereby sticking in the fish's gullet.
Few things aggravate ice anglers more than frozen rod guides. Chipping away with fingernails, teeth, or anything else lying around can easily damage both the frame and rings of the guides, but you have to keep them clear because iced guides will weaken line, especially super-­light monofilament or fluorocarbon. There are a number of homebrew remedies for tackling this problem, but none are more effective than lip balm, which creates a film on guides that inhibits them from freezing and building ice. It’s waterproof and takes quite a while for wet line or precipitation to break it down and necessitate reapplication. A small stick or tin stores easily in your pocket, and just a few swipes with your finger on guide rings will protect them from ice-up for several hours.
While catching a fish is often a case of matching wits—and great patience—a fisherman is at a distinct disadvantage without the right gear. eBay stocks the fishing supplies you need, like spinning rods, casting rods and more by St. Croix, Shimano and other top brands. There are plenty of saltwater and freshwater choices, so it doesn’t matter if you’re after salmon, trout or marlin.