Sonar technology has changed the ways that people explore the areas beneath the waves. Whether you are a person that fishes in the lake during the weekends or if you are a commercial fisherman that fishes for large school of fish miles offshore, or even a person that simply takes a boat out in unfamiliar waters, the sonar unit will determine whether or not you are successful in your fishing endeavors. However, like any technology in the world, sonar units has the potential to develop problems.
The technology relies upon sound waves reflecting off of the medium of the water, which is inherently somewhat unpredictably. Should the water conditions or the settings of the sonar unit work against the sound waves reflecting off of the water, the screen will display a mess of noise that is frustrating to read and understand. The good news, however, is that the problems with sonar units are limited to a few common issue that can be quickly diagnosed and remedied.
Each of the issues that are likely to occur with a sonar unit, along with an explanation of the causes of those issues and the steps that will fix each of those issues, is presented in the paragraphs that follow. This informative text will act as a field guide to help you to achieve a quieter and more trustworthy sounder from your sonar unit. One of the most common issues with sonar units is the detection of false bottoms.
Common Problems With Your Sonar Unit
1. False Bottoms
With this issue, the sonar unit will indicate that there are no fish at the bottom of the lake or sea, but the true bottom is located ten feet below the depth that is indicated by the sonar unit. This issue is common in the summer months due to the thermocline that forms in lakes and seas during those months. The change in the temperature of the water leads to a change in the density of the water, and the sound waves reflect off of this boundary between the two type of water.
The sonar units calculate the depth of the water based off of the echo of the sound wave that is reflected off of the bottom of the lake or sea. Due to this, the sonar unit will not search for the echo that comes from the true bottom of the lake or sea. Therefore, users often experience false bottoms when they dont adjust the settings of their sonar units to account for this.
By either adjusting the sensitivity of the sonar unit or by adjusting the frequency at which the sonar unit emits its sound waves, the sonar unit will direct the echo away from the false bottom echo, allowing the sonar unit to focus upon the true bottom of the lake or sea. Furthermore, most sonar units also allow the user to manually lock the range to the location of the bottom once it has been determined through the use of a map of the area or by dropping the anchor to the lake or sea. Another problem with sonar units is the development of electrical interference.
2. Electrical Interference
This problem is characterized by the presence of random speckles on the screen, horizontal lines across the screen, or wavy bands of light that move across the screen in synchronization with the engine of the boat. The cause of this problem is typically present on the boat itself. Many boats contain trolling motors, bilge pumps, livewell aerators, and various LED lights for navigation that emit the electrical interference that result in these problems.
In order to fix this problem, the sonar unit should be run on a separate battery from that of the boat. This solution will fix half of the cases in which there is electrical interference. Should the problem persist after the sonar unit is running on a separate battery, the technician will reroute the transducer cable on the boat to avoid any electrical issues, and a ferrite choke will be added to the lead of the transducer cable that enters the head unit of the sonar unit.
By rerouting the transducer cable and adding a ferrite choke, the source of the electrical noise will be avoided. This might seem like a mundane solution to those who have experienced this problem, but it will go a long way in reducing the occurrence of the noise that is created by the sonar unit. Air bubbles can also create problems with sonar units.
3. Air Bubbles
The air bubbles will form a blackout zone on the screen of the sonar unit. Within this blackout zone, there will be no fish being detect by the sonar unit, or there will be a thick curtain of noise present within this zone where fish should be detected. Blackout zones are common on boats that have stepped hulls.
Furthermore, the transducer that detects the sonar waves can become fouled and positioned too far forward into areas of turbulent waters created by the bow of the boat. Sound waves cannot travel through air. Each of the air bubbles that appear on the transducer will reflect the sound wave that is emanating from the sonar unit’s transducer, and the echo of those reflected waves will be represented on the screen as white.
By relocating the sonar transducer even by six inches on the boat, the display screen will no longer experience blackout zones. Furthermore, if the boat is on a trailer, the transducer should be inspected to ensure that it is still submerged within the water, even when the boat is traveling at planing speeds. The sonar unit will reveal the presence of air bubbles within the transducer, as the unit will read air rather than water.
Another problem that can develop is side lobes. Side lobes will allow the sonar unit to detect the structure of the lake or sea outside of the area that should be targeted by the sonar unit. These echoes will often be displayed at the same depth on both sides of the boat, even if there are no fish in that area.
4. Side Lobes
These side lobes, though weaker than the main beam of the sonar unit, will still reflect echoes from any structure in the water that is vertical in structure, such as a bridge piling. The solution to this problem is to reduce the power output of the sonar unit or to narrow the beam of the sonar unit. For sonar units that emit different frequencies of sound waves, those settings can be adjusted from 83 kHz to 200 kHz.
This adjustment will allow for the side lobes to be quieted. In exchange for the reduction in the beam width, the echoes that are reflected from the bottom of the lake or sea may be slightly less noticeable. In this case, however, the echoes that are reflected from the targets that are located in the water will be more trustworthy.
In addition to the adjustment of the frequency of the sonar unit, the echoes from the side lobes can be ignored as they are not echoes from fish. For example, if the same arch is visible on both the port and starboard sides of the boat, that echo is not from a fish. Another problem with sonar units is issues with the temperature of the water.
5. Water Temperature Issues
The echo lines that represent the bottom of the lake or sea may appear to drop or rise in depth while the boat is traveling over flat areas of the lake or sea. This problem is created when the beam of the sonar unit refracts due to the change in the temperature of the water. Sound travels at a faster rate in warmer water than in colder water.
This refraction of the beam of the sonar unit may lead to the unit calculating the depth in incorrectly. This issue is why anglers must keep one eye on the surface temperature of the water while utilizing the sonar echo to map the lake or sea floor. The temperature of the water may change dramatically, but it will always impact the beam of the sonar unit.
Transducer fouling can also lead to problems. A layer of algae or silt can scatter the sound waves that are reflected from the lake or sea floor, leading to the reduction in the strength of the echo that is reflected by the sonar unit. This issue may lead to the fish that were previously seen on the screen suddenly dissapears.
6. Transducer Fouling
By wiping the face of the transducer with a soft cloth and mild detergent, the issue of scattered sound waves will be resolved. For boats that remain in the water for long periods, a sacrificial zinc or a foul-release coating may be applied to the transducer. These products will reduce the buildup of algae or silt on the transducer.
This task will pay for itself the first time that you are able to view the submerged wreck in the lake or sea. Incorrect gain settings for the sonar unit can create problems for the reader of the screen of the sonar unit. For beginners, the gain is often set to the maximum so that they may see more fish in the screen of the sonar unit.
7. Incorrect Gain Settings
In reality, though, the maximum setting for the gain will cause all of the particles in the screen to be seen, leading to a cluttered screen that makes it difficult to view and focus upon the targets in the water. Instead of setting the gain to the maximum, the gain should be adjusted until the background noise within the screen is just barely visible in the screen as faint dots. After this setting of the gain, the automatic tracking of the sonar unit will manage the gain settings for the reader.
Because the gain settings are automatically tracked, small adjustments to the gain can be made by adjusting the gain in increments of two or three percent. This setting will help reduce the issues that are caused by incorrect gain settings. One problem that may appear on the screen is if the sonar unit is not mounted in the proper manner to the boat.
8. Improper Transducer Mounting
The beam that is emanated from the transducer should point downward into the lake or sea, but mounting of the transducer at an incorrect angle will cause the beam to point in another direction. Furthermore, images of the lake or sea bottom may appear to be incorrectly sized, and the depth that is reflected in the screen may not match that which is calculated by the bottom of the lake or sea. The angle of the transducer can be checked with a bubble level or a smartphone application.
The face of the transducer should be even with the waterline of the boat. For boats made of aluminum, the hull may flex when the boat is loaded with fuel and gear. In this case, the angle of the transducer should again be checked after the boat has been loaded with the fuel and gear that will be utilized in fishing.
Finally, there may be software glitches within the sonar units that may result in a variety of different problems. For example, there may be issues in which the screens remain frozen, or the depth measurement may jump from one number to another in a random manner. These software glitches may appear after an electrical surge in the sonar unit, or after a period of long storage of the boat.
9. Software Glitches
These software issues may be remedied by updating the firmware that controls the software within the sonar unit. The manufacturer’s website for the brand of sonar unit can be visited to determine the most recent firmware update for that model of sonar unit. The process of updating the firmware will take approximately ten minutes.
By updating the software within the sonar unit, these software glitches will be resolved. Though it may seem like cheating to update the software that controls the sonar unit, it will go a long way in helping to avoid the software issues that can plague the device. By mastering each of these problems that are commonly experienced with sonar units, you will find that each device becomes a tool that you can trust in your fishing endeavors.
The water column will no longer be a guessing game as to what type of life lives beneath the surface of the water. Each water column will reveal its structure, the breaks in the water’s temperature, and where the fish live in each body of water. The next time that you experience issues with your sonar unit, you can implement the steps and solutions discussed in this article.
Each of the problems noted will be resolved, and your sonar unit will function as efficiently as possible. When the water is clear, the screen will be free of noise, and the seas will be calm. But above all else, you will need a properly tuned sonar unit to find the fish when the conditions of the water might work against finding them.