How to Choose a Fish Finder

Fish finders use Sonar to locate objects, preferably fish, underwater. Sonar is an abbreviation for “SOund, NAvigation, and Ranging”. Sonar consists of 4 parts: the transmitter, transducer, receiver and display. Basically Sonar works by sending an electrical impulse from the transmitter, converting it into a sound wave by the transducer and then sending that sound wave into the water. When the wave strikes an object it rebounds off the object sending this echo back to the transducer. The transducer than converts the echo back into an electrical signal. The receiver amplifies this signal and sends it to the display for the fisherman to see. Now the fisherman knows where to drop a line.

Many people ask, “How do I select the proper fish finder for my needs?” There are 5 aspects of a fishfinder to keep in mind when making a purchase.

The Transducer

There are 2 types of transducers: single frequency and dual frequency. Single frequency is generally best for lakes and shallow coastal fishing. Dual frequency transducers are generally better for deep sea fishing. Dual beam (a Hummingbird term) and dual frequency are essentially the same thing. Dual beam transducers limit the beam size for the high frequency beam so these depth finders are truly best for deep water.

Power

In general, the higher the power of your fish finder the better. Higher powered fish finders generally cost more so you will have to weigh power with cost. Remember that even in shallow water such as lakes, higher power will still help with better imaging. Most expert fishermen recommend giving the most weight to the power rating of your unit.

Depth

A fish finder being able to reach greater depths is directly related to the Power and the quality of the transducer. In general, the more expensive models penetrate the water better. Keep in mind while shopping that the depths shown in the product specifications are for clear water. Salt water and murky water will limit the depths the sonar can penetrate. As a general rule of thumb, purchase a fish finder with a depth range about 10% greater than what you intend to fish. Having a slightly greater depth range should help adjust for less than clear water.

Display Size

Fish finder displays vary from four inches to seven inches (and some larger). Obviously the larger the screen, the higher the cost. The advantage to a larger screen can be ease in seeing the results in bright sunlight.

Display Resolution

The display resolution pertains to how clear the image is on the fish finder screen. The higher the resolution the better the image will be. Color screens are often better for direct sunlight as they are easier to see. Again, the higher the resolution, the higher the cost, in general.

Now that we’ve covered the basics of how a fish finder works and what the key pieces of fish depth finders are, let’s offer some suggestions on how to choose the perfect fishfinder for you.

Most fishermen recommend doubling whatever you were planning to spend on your fish finder. We leave the amount you wish to spend completely up to you.

Next decide where are you planning to fish the most often- on a lake, along coastal areas or are you mostly a deep sea fisherman? Are you planning to use your fishfinder on only one boat or do you want to be able to use it on a friend’s boat? Answering these two questions will let you know if you want a fishfinder that works best in shallow or deep water and whether or not you want a fixed mount fish finder or a portable fish finder.

If you want a fixed mount fish finder then you will next need to decide if you want a transom mount transducer or a hull transducer. Transom mount transducer are easier to install and usually less expensive. You can purchase a transom mount transducer in single or dual frequency models. They work best in water that is somewhat calmer and are not terribly effective at much more than 10 knots.

Through hull transducers are the best for clarity and performance, but are harder to install and cost more. You really need to have a need for high speed bottom reading to make them worth the extra cost.

In general if you are going offshore or into deep fresh water, the hull transducer with dual frequency is probably the best bet for accurate fish readings. If you are using a smaller boat and are not planning to do high speed fish finding then a transom mount or portable fishfinder will save you some money and should meet your needs just fine.