What to Look for When Shopping for a Fishfinder

Like the name would imply, a fishfinder is a device that will help you find fish. It does this by using sonar, putting out soundwaves in a conical pattern and reading the sound waves that bounce back to the device. If you’re shopping for a fishfinder you’ll have a lot of options and these handy devices can range in price from about $40 to $500 or more. Generally speaking, the more money you spend the more bells and whistles you’ll get, but are all of those bells and whistles really worth the money? Keep reading and we will tell you what to look for when shopping for a fishfinder.


Do You Need a Standalone, Combination, or Network Fishfinder?

A standalone fishfinder has one function, to find fish. A combination fishfinder not only give you the ability to find fish, but also includes a chart plotter that will use GPS navigation to help get you to where the fish are. A fully networked fishfinder comes with a whole host of additional features. Not only will you be able to find fish and get directions to where the fish are, but you’ll also have features like radar, raster and vector, Bluetooth, Wi-Fi, and even satellite radio.

Of course the more bells and whistles you get, the more money are going to pay. If you’re on a budget and all of the additional features are not necessary, an inexpensive standalone fishfinder will get the job done.


How Much Power Do You Need?

When looking at fishfinders you’ll come across the term peak to peak when manufacturers are describing the output power of the sonar transmitter. The peak to peak figure is a measurement of the AC voltage from its peak negative value to its peak positive value.

Another term you are likely to come across is RMS which stands for root mean square. This is a measurement of the DC voltage that the unit will produce.

The amount of power you’ll require depends on the depth and the clarity of the water that you will be fishing in. If you are fishing in deep, murky water, you’ll need a more powerful unit to penetrate all the way to the bottom.



The cheapest fishfinders on the market will have small, black and white displays with a small pixel count. A small pixel count means images that are less than crystal clear. The more pixels that can be packed into a square inch, the more detail you’ll be able to see. A higher resolution screen is going to cost a little more money, but it may be well worth the investment.



A transducer acts like an antenna to send out sonar signals and then listen for the echoes. Transducers are available with different operating frequencies, cone angles, and different types of installation. The type of transducer you will need depends on the type of fishing you plan to do. A transducer with a wider cone angle will give you a wider field of view, but will be less sensitive in deeper water.

Some of the newer fishfinders use what is known as CHIRP, or compressed high intensity radar pulse technology. Other fishfinders use just one or two frequencies, but fishfinders using CHIRP technology transmit a single across a wide band of frequencies using modulated pulses for much better resolution and target detection.


Devices with CHIRP technology can transmit signals at low and high frequencies at the same time. Lower frequencies will give you a greater depth of penetration and higher frequency signals can give you better detail in shallower water.


Different Types of Mounts

Through hull mounts are the most challenging to install, but often provide the best signal quality.

A transom mount uses an adjustable angle bracket that is fastened below and behind the hull. This type of mount is very easy to install, but the transducer may encounter some water turbulence.


In hull transducers are able to send a signal through the hull and don’t need to be in contact with the water. They are generally glued inside the hull with silicone or epoxy. This type of transducer will only work with solid fiberglass hulls.

Trolling motor mounted transducers can either be clamped to the outside of a trolling motor or permanently installed inside the propeller hub.


Side Scan Technology

A lot of fishfinders will be able to detect what is directly under the boat. But side scan technology is now available and this will allow you to see what is on either side of the boat, giving you a birds eye view.

Some of the more expensive fishfinders on the market will give you incredibly clear, almost photographic images of what is under the water. These devices can easily “see” through murky water, showing you every detail of what lies beneath.


Mapping and Charting Capabilities

Some fishfinders offer mapping and charting capabilities and you can even use SD cards to expand this capability if you’re going to be fishing in a different area.


Do Some Comparison Shopping Online

On this page we’ve given you a quick overview of the different options you’ll have when looking for a fishfinder. You may have an idea of some of the features you would like to have, but how do you choose the right make and model?


If you do some comparison shopping online you’ll be able to find options at different price points and you’ll be able to quickly compare the features that the different models have. You’ll also be able to read customer reviews from people who have used all of the different models you might be interested in.


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