Fish Arches and Boat Speed Posted on May 06, 2014
Learn how fish arches change with boat speed.Read More >>
Another article using fish arches to help you understand sonar.
How to determine how far behind the boat
Sonar displays targets based on the distance of the target from the transducer.
Read about how to determine targets in this illuminating article.
This tutorial is to provide rudimentary education into sonar principles and applications, based on accepted electronic theory and principles, to explain how, what,and why your sounder displays sonar echo data.
I get many questions about adjusting the color lines on sonar. The correct setting depends on your preferences and sonar model you are using. ColorLine was developed to show differences in the strength of echo returns. By adjusting the color lines on sonar, we can tell differences in bottom hardness and determine if the bump on the bottom is a fish or the bottom. I have a nice example showing fish as bumps on the bottom.
Some fish are structure related to boulders and using sonar to understand the bottom of a lake is key to catching them.
This is an example on how sonar paints images that aren’t what the bottom really looks like. A person has to learn how to read a drop off on a sonar. Sonar can only paint an image with information using how far the target is from the transducer and how strong the sound returns (echo strength). This image is from a drop-off..
Looking for fish near weeds can be difficult because the fish and weeds look similar with sonar. Whether you have DownScan or not, these examples will help you understand your sonar better. My understanding of using sonar to fish near weeds has improved with the DownScan feature on my Lowrance HDS. The cone is narrower with the DownScan and the transducer is a higher frequency so you get improved target separation. I would not be surprised if Lowrance offers DownScan only instead of traditional sonar in the future.
Sonar sensitivity settings or "auto sensitivity" on Lowrance sonar is very important. This feature has changed over the years from manual to having the model do it automatically.
The sensitivity is like the volume on the radio. The radio receives the signal from a tower and the volume control raises or lowers the level we hear. The sonar receives the signal from the transducer and the sensitivity control raises or lowers the level we see on the display.
