Educational Articles » lowrance

What do Small Fish Look Like on Sonar Posted on June 17, 2013

You may ask yourself - what do small fish look like on sonar?  It is not an easy answer. Sonar determines size as echo strength and displays echo strength as different colors and how thick the fish arch is. Echo strength is different from targets at 5 feet or 20 feet from the transducer because sound get weaker as it travels through water. This is why auto sensitivity turns the sensitivity higher in deeper water. I have some examples of perch on this tutorial.


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by Bruce Samson under lowrance lowrance sonar

Sonar and Rocks - Hard Bottom on a Fish Finder Posted on June 17, 2013

Fish like rocks and one of my favorite fish to catch likes boulders (Smallmouth Bass). After we figure out the fish are relating to boulders, we need to find more spots with rocks and boulders so we have more choices. Maps help because if the best rocks are at 15 feet, we can find 15 foot spots on the maps. You must have high definition map cards  (Navionics, LakeMaster and Lowrance Insight Pro/HD) to have accurate 15 foot depth contours.


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by Bruce Samson under lowrance lowrance sonar

How to Resolve Sonar Crosstalk Posted on June 17, 2013

Why does my screen show vertical lines on it when I turn on my other sonar unit or when someone is fishing near my boat? When two sonar units are sending sound at the same frequency you can get crosstalk. Each transducer is sending (pinging) and receiving sound. Sometimes one sonar unit will display the other sonar units pings sonar and you will see vertical lines. Since the cone shape of the sound from a transducer gets larger as it goes deeper you get more overlap of cones in deep water. In shallow water you get less or no crosstalk. 


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by Bruce Samson under lowrance lowrance sonar

Finding Fish at High Boat Speeds Posted on June 17, 2013

You find fish at 20 mph with old flashers, Lowrance LCX/LMS models and the new HDS models.

The first images shows fish with the LCX from 2007. I would tweak the setting to get these images by using the maximum ping speed, slightly increase the Colorline and manual sensitivity and use the blue background palette. Finding fish at high boat speeds was difficult to unless I tweaked the settings.


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by Bruce Samson under lowrance lowrance sonar

Weird Sonar Images - Air Bubbles and Lines on Sonar Posted on June 17, 2013

If you see lines coming from the bottom to almost the surface at an angle, they are air bubbles. Notice the speed of 0.4 mph, I rarely see bubbles unless I am moving slowly. It is easy to confirm on calm days by watching the water surface for the bubbles.


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by Bruce Samson under lowrance lowrance sonar

Identifying Fish and Their Size With Sonar Posted on June 12, 2013

What are they and how big are they?

We want sonar to give us the answers to these questions but it isn’t easy. You must know the location, type of fish in your system, and how to determine size with sonar.

Sonar only gives you the echo strength of the target and displays it-it won't make identifying fish and their size with sonar easy. Sensitivity can change the echo strength and depth range changes the way the fish are displayed (fish in a 10 foot scale are larger than fish on a 100 foot scale).


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by Bruce Samson under lowrance lowrance sonar

What Big Fish Look Like on Sonar Posted on June 06, 2013

Determining size of fish is difficult with sonar - but surely, you want to know what big fish look like on sonar. This image shows big fish I was targeting this day and this is what I would see on the sonar. Notice the DownScan and the traditional sonar show a thick band and this is the best way to tell size.


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by Bruce Samson under lowrance lowrance sonar

Fishing Near Drop Offs -- Catching Fish Near Drop Offs Posted on June 04, 2013

We rarely see fish on drop-offs because the closest “bottom” to the transducer is the drop-off, so the fish are not displayed. Sonar displays the echo strength of the target and the distance the target is from the transducer. The first example has the fish a farther distance from the transducer than the bottom so the fish echo is added to the “bottom“ echo and not seen. The “bottom” under the transducer is 25 ft, fish at 23 ft, and the drop off “bottom” is 20 ft. Now visualize what the sonar will show you. The picture is my rough drawing so it is not to scale; it is just to get you thinking.


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by Bruce Samson under lowrance lowrance sonar

Sonar Mastery Article Posted on June 02, 2013

Sonar Mastery Article


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by Bruce Samson under lowrance lowrance sonar

Finding Fish Near the Bottom with Sonar Posted on June 01, 2013

If you can’t find fish near the bottom with sonar - you can’t catch them!  I will show you one way to find hidden fish.

Fish close to the bottom are sometimes displayed as bumps. You have 2 ways to decide if a bump on the bottom is a fish. You can drop an underwater camera or use high definition color sonar. Fish return weaker echoes so they display a different color than the bottom depending on the setting of your colorline and sensitivity.


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by Bruce Samson under lowrance lowrance sonar