Do you find all of the technology involved with Fishfinders confusing? I will try to cover the various technologies, what they mean, and what the benefits are. After reading this guide you should have a good idea of what product will best suit your needs, but if you still have questions I am more than happy to help. Just go to my Ebay Store and you can email me from there, Visit my Ebay Store. If you would like my opinion on what product may be best for your needs, I will need to know what kind of boat you have, how big, where you plan to mount the products, do you trailer your boat,  what type of fishing you do, how deep, what type of navigation do you do, budget, etc. The more information I have, the better recommendation I can make.

Fishfinders:

Screens:

There are several factors to consider with screens. Size, Color or Monochrome, and Resolution.

Size - I always recommend to buy as big a screen as your budget allows. Consider how far away from the screen you will be at any given time and will you be able to read it. If you are considering a Fishfinder/GPS Combination, screen size is even more important because many times the Fishfinder and GPS will be sharing the same screen so a bigger screen is very important. The bigger the screen, the easier it is to read and typically your larger screens will produce more detail and make it easier to determine what your fishfinder is telling you.

Color or Monochrome? - This one is easy. COLOR! Why? Momchrome screens show you the intensity of your sonar return in 4 to 16 different shades of gray. Color screens show you the intensity of your return in 64 to 256 different colors. It makes it so much easier to interpret what the fishfinder is telling you.  It will help you determine what kind of bottom you have ( hard, soft, gravel, rocks, etc ), what kind of structure you are looking at, and weeds. But best of all it will help you find fish. For example, baitfish and small fish might have a light green or blue color, but when the color changes to red, you've got fish! The brighter the red, the bigger the fish! You might be over a big school of baitfish, but are fish feeding on it? It would be virtually impossible to tell on a monchrome fishfinder, but in color if the school of bait is blue/green, move on because there are no fish feeding on the bait. If you see a school of bait that is blue/green and you see flecks of red in it, then you know fish are actively feeding on it. Same idea applies to spotting fish on or near the bottom or in weeds. Color is the single biggest advancement in fishfinders in a long time.

Resolution - The higher the better. If you have ever looked at two different TV's right next to each other and one has a lot better picture it is because the one with the better picture is higher resolution. Higher resolution simply means better detail and more information displayed on your screen. Resolution is measured in pixels. The more pixels the better.

What other information can a fishfinder display? - Depending on the model fishfinder, you can get depth, temperature, speed, distance, navigational information, fuel consumption, battery charge condition, and more.

Transducers - You have to have a transducer. The transducer emits and receives the sonar signal and sends it to the fishfinder. Your fishfinder will not work without a transducer. As your are shopping for a fishfinder you will find some models come with a transducer and some don't. If it is not clear whether a fishfinder comes with a transducer, always ask. What kind of transducer do you need? I will cover that next.

Transom mount transducer - This is probably the most common. The transducer mounts on the transom ( back ) of your boat away from the motor but where it will make good contact with the water. This is typically the best solution for smaller fishing boats and pleasure craft. When I say smaller, I mean 25 feet or less. If you trailer your boat you will probably want a transom mount transducer. If your fishfinder will display temperature, speed, or distance, you need to make sure your transducer has these sensors built in. Some transom mount transducers will adapt to a trolling motor mount if you are using the fishfinder in the front of your boat with a trolling motor.

Thru-hull transducer - This transducer mounts just like it says, through the hull. A hole is drilled in the hull and the transducer mounts in that hole. The advantage of this kind of transducer is it is not subject to cavitation interference caused by the motor and hull of the boat as it passes through the water. Also for larger vessels that draw a lot of water it gives you actual depth below the keel of the boat. This type of transducer is generally used on larger vessels that are not trailered, vessels that draw a lot of water, sailboats, commercial vessels, etc. A thru-hull transducer is typically more expensive than a transom mount transducer. A fairing block may also be required to protect the transducer. Check with your dealer to see if one is necessary for your situation. Temperature and speed are available with this type of transducer.

In-hull or Shoot thru hull transducer - This type of transducer is not very common. This transducer actually is mounted inside the boat and shoots through the hull. It is very expensive and I have never received any feedback as to how well they work. You can't get temperature or speed with this type of transducer.

Most manufacturers design their fishfinders to work with their transducers. Rarely are transducers interchangeable.

Sonar Power - This is a measure of how powerful the sonar is. It is measured in watts, and the higher the power the better. The more power a fishfinder has, the stronger the return signal is. This is especially important in deeper water. If you really want to find fish, get as much power as you can afford. You will find the power of a fishfinder listed two ways, RMS and Peak to Peak. Peak to Peak is eight times RMS. For example, if you have a fishfinder rated at 500 watts RMS, it would be 4000 watts peak to peak. Sometimes a manufacturer will list both RMS and peak to peak power, sometimes just RMS and sometimes just peak to peak. Some manufactures and sellers will just list a number and not tell you whether it is RMS or peak to peak. For example, you may see a fishfinder touting 3000 watts. This tells you nothing if you don't know if it is RMS or peak to peak. A lower power fishfinder might have 50 to 150 watts RMS, and a higher power fishfinder might have 300 to 500 watts RMS. Some high end models might have 1000 to 3000 watts of power, RMS. Most fishfinders average between 250 to 500 watts RMS. If you see a fishfinder that displays their peak to peak power, just divide by 8 to determine the RMS power.

Dual Frequecy or single frequency? - A single frequency fishfinder transmits its signal at a frequency of 200khz which is rather narrow. Basically it gives you a narrower view of what's below your boat. In shallow water this is not a bad thing, but as the water gets deeper, the less you see. A dual frequency fishfinder transmits it's signal at 200khz and 50khz, and it is designed to used whichever frequency is best for the water you are in. This way you are always getting the best possible view of the water under your boat. You can also choose if you want to view 200khz or 50khz. Some models will show you a split screen of both frequencies. Usually, a dual frequency fishfinder is not too much more expensive than a single frequency fishfinder and for the relatively small difference in price I think a dual frequency unit is well worth the extra money! Note: If you buy a dual frequency fishfinder you must make sure that the transducer is also dual frequency. Some higher end models may transmit at frequencies other than what I described above.

The graphic above shows the 200khz frequency in yellow and the 50khz frequency in blue.

Muti Function Display - This is a growing trend in fishfinders. With a multi function display you have a Display Screen, and you add components to it as your needs grow. You can add a fishfinder, sounder, GPS Antenna, and Radar. Basically all of your sonar and navigational needs on one display.

I hope you found this information useful. Please visit my Ebay Store to see the latest in fishfinders and GPS from all of the top name brands.

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