However, fish finders for professional use, i.e., those used by commercial fishermen, can make use of other frequencies. Such frequencies include 15, 22, 28, 38, 45, 50, 68, 75, 88, 107, 150 and 200 kHz. There are some special fish finders that utilize the frequency of 400 kHz, but it is quite a rare case. As you can see, there is an extensive range of configurable frequencies available for fish finders for fishery vessels, and a fish finder generally makes use of a combination of two frequencies (high and low frequencies). The selection of the frequencies depends upon the intended purposes of the fish finder, which include, inter alia, finding specific fish species; grasping the seabed condition; conducting a wide-area-search with the search angle of 90 degrees at one go; conducting detailed search for fish schools; detecting fish schools that give weak echo returns; avoiding interference/conflict with other fish finders used nearby. The searchable range (depth) and search area are dependent upon the frequency used. On the one hand, high frequency ultrasound is suitable for a detailed search, although it cannot be used for search in deep water. Low frequency ultrasound, on the other hand, is suited for general searches in a wider area as well as searching in deep water.
Harpoons are spears which have a barb at the end. Their use was widespread in palaeolithic times.[11] Cosquer cave in Southern France contains cave art over 16,000 years old, including drawings of seals which appear to have been harpooned. Tridents are spears which have three prongs at the business end. They are also called leisters or gigs. They feature widely in early mythology and history.
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.
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.
As with many products, you’ll have to pay close attention to the specific features delivered for the price, simply because the investment for combination fishfinder and GPS can range from $500 to $1200 or more. Fishfinders and GPS units are well advanced when compared to equipment used just a few years ago. Most of the time you can get excellent 3D mapping, scanning, charting and navigation at a very reasonable price. It’s not necessary to spend hundreds more unless you really want to go after the top-of-the-line unit.
While not every object will be as easy to distinguish, you can always get clues from the shape and also the strength of the sonar return. Notice the multiple orange sonar returns underneath the car – these tell you that this is a very hard object. The sonar scans have hit the car, bounced up to the surface of the water, bounced off the surface and hit the car again.
It’s often been said that the act of fishing isn’t actually about catching a fish. Rather, it’s about a quiet moment with nature and a chance to sit, think and relax, whether on your bass fishing boat or on the banks of a river. Of course, if you’re a sport fisherman reeling in that prize monster on a white-capped ocean, there isn’t much relaxation to be had. If you prefer ice fishing or fly fishing, shop eBay for everything you need for a day on the water. We have the right gear for you, regardless of whether your allegiance lies with Orvis, Shimano or Abu Garcia.