Proper use of a sonar can turn chaotic wanderings around a body of water into a purposeful hunt for trophies. Many anglers mistakenly believe that it is enough to just turn on the device and throw the rod, but without competent interpretation of the data from the screen, the effectiveness of the gadget is minimized. echoer It is a complex tool that requires an understanding of the physics of ultrasound propagation in aquatic environments.
Modern models, whether they are budgetary Lowrance Hook advanced Garmin EchomapThey provide a huge amount of information that you need to be able to read. The signal reflected from the bottom, the driftwood or the school of fish, is processed and displayed as graphic objects. To avoid missing the predator's parking lot, you need to know what these objects look like and what they mean in the current environment.
In this article, we will look at all the steps of working with sonar, from the correct installation of the sensor to fine-tuning the sensitivity for different depths, learn how to distinguish real fish arcs from false signals, understand the difference between 2D scanning and DownVision technologies, and learn how to minimize the impact of interference on the result.
The principle of operation and basic settings of the device
The basis of any sonar is a transducer that emits ultrasonic pulses and receives their reflections, and the frequency of these pulses directly affects the quality of the image and the depth of detection. 50 kHz deep and 200 kHz Higher frequencies give a clearer picture, but have a smaller viewing angle and fade faster in the water.
The first thing you'll encounter after you turn on is setting the depth range.Auto Range) It often works incorrectly if you change your parking space from 10 meters to 2 meters deep, in which case the device can "lose" the bottom or compress the scale, making objects indistinguishable. Manually setting the upper limit of the depth scale allows you to detail the bottom layer, where the fish most often stand.
The critical parameter is sensitivity (Sensitivity).SensitivityToo high sensitivity saturates the screen with noise and false arcs, and too low hides small fish. Optimal adjustment is achieved when the screen shows a second echo from the bottom, but the screen is not filled with chaotic dots.
What is the second echo signal?
The second echo is the re-reflection of the ultrasonic wave from the bottom, which returns to the sensor after the first reflection has been received. The presence of a clear second echo at depths up to 10-15 meters is an indicator of the correct sensitivity and good water density. If the second signal disappears when you add sensitivity, you are on the right path, if the screen turns into porridge, sensitivity is excessive.
For an initial understanding of the device menu, it is useful to know the basic navigation commands, usually located under the screen or in the sidebar:
- 🔹 Menu/Esc Enter the main menu or exit the current section.
- 🔹 Pages Switching between different screens (map, sonar, structure).
- 🔹 Zoom Increase the selected screen area for detailed study.
- 🔹 Mark/Waypoint - setting the label to the current location.
Installation of the sensor and preparation for water access
The quality of the image depends on 80% of the installed transducer If the sensor is not installed correctly, even the most expensive sonar will show useless ripples, the main task is to ensure a smooth flow of water around the working surface of the transducer, any swirls, air bubbles or turbulence will lead to loss of signal.
When placing a PVC or aluminum boat on a transom, the sensor must be placed in a strict geometry, lowered below the bottom level, but not too deep so as not to increase the water resistance during the course. The optimal position is when the bottom edge of the sensor is 3-5 mm below the keel line, which prevents impacts on the bottom when pulling the boat ashore.
☑️ Verification of sensor installation
Special attention should be paid to cables. The wiring should not sag with loops into which water can enter, and should not be near the wires from the motor to avoid electromagnetic tips. It is recommended to use thermal shrinkage with adhesive layer to seal the connections, and not just the isolating tape, which eventually dries up.
If you use an outboard motor, make sure that the sensor does not fall into the rotor’s operating area (“gas jet”). Getting into the air bubbles from the screw completely “blinds” the sonar. In such cases, you may need to shift the sensor closer to the cheekbone of the boat or install a remote sensor on a separate bracket.
Image interpretation: fish, bottom and structures
Learning to read a sounder means understanding the difference between hard and soft objects. A solid bottom (stone, dense clay) reflects the signal strongly and looks like a wide greasy band on the screen. A soft bottom (silt, algae) absorbs part of the signal, so the strip of the bottom will be thin and less bright. A fish with a swimming bladder reflects the signal well and displays as a characteristic arc.
Why does a fish look like an arc? When a boat goes over a school, the distance to the fish first decreases, then becomes minimal (the fish in the center of the cone), and then increases again. The sonar captures these changes in distance by drawing an arch on the screen. If the boat is anchored or anchored, and the fish is passive, you'll see horizontal lines, not arcs.
⚠️ Attention: Not every arc on the screen is a fish. Dense algae clusters, pop-up methane bubbles from the bottom, or just turbulence from the flow can create similar images. Always analyze the context: if the arc is hanging in the water column and has no clear structure, it is likely a hindrance.
The size of the object on the screen depends not only on the actual size of the fish, but also on its position in the cone of radiation. The fish passing along the edge of the cone will look smaller than the fish under the center of the sensor. CHIRP (compressed pulsed radiation) allow you to separate targets that at normal frequencies would merge into a single spot.
Key point: Fish directly at the bottom often merge with the bottom echo, and to see it, you need to use Bottom Zoom and slightly reduce sensitivity to cut off the fatty line of the bottom.
Work at different depths and speeds
Fishing in shallow waters (up to 3-4 meters) and at depths (over 10 meters) requires radically different approaches to setting up: in shallow water, the sonar cone covers a large area of the bottom, which is good for finding, but can create blind spots right under the boat, where high frequencies and narrow beams work more efficiently.
At great depths, the signal fades, and the detail of the image drops.50 kHz or 83 kHz), which have greater penetrating power, but the angle of view is widened and the resolution drops. For deep-sea fishing, it is critical to turn off automatic gain adjustment so that the instrument does not try to compensate for depth with noise.
The speed of the boat also affects the readability of the picture. At high speed, the scrolling of the screen accelerates, and the arcs of the fish can stretch or, conversely, become too short, turning into dots. The optimal speed for scanning the terrain and searching for fish is from 3 to 6 km / h.
Comparison of operating modes for different conditions:
| Parameter | Shallow water (< 5 m) | Average depth (5-15 m) | Deep water (> 15 m) |
|---|---|---|---|
| Frequency | High (200+ kHz) | Medium/High | Low (50-83 kHz) |
| Sensitivity | Low/Mediocre | Medium | High. |
| Scrolling speed | Maximum | Medium | Minimum (for detail) |
| Zoom (Zoom) | Not mandatory. | Bottom layer | Mandatory for details |
Control of interference and external factors
One of the most common problems is the appearance of chaotic stripes or points on the screen that interfere with view. Often the source of interference is a working outboard motor, especially a two-stroke, or a radio station installed nearby. The sounder power cable should be as far away from the voltage sources as possible, and the device should be powered by a separate battery or through a quality filter stabilizer.
A thermoclin is a layer of water with a sharp temperature difference, which often looks on the screen as a solid line, similar to the bottom, but hanging in the water column. Fish often stand at the border of the thermoclin. It is important not to confuse it with the real bottom, especially when using the sonar for the first time on an unfamiliar body of water.
⚠️ Attention: If you see vertical stripes on the screen going from top to bottom, it could be a sign of the sensor's cavitation, and check if the sensor is protruding too much into the water stream, or if its working surface is damaged.
In overgrown water bodies, the signal may be lost due to dense vegetation, in which case an increase in the frequency of screen refresh helps (in this case, the frequency of screen refreshing helps).Screen Update Rate) and lowering the threshold of reception of the signal: this will allow the sonar to ignore the faint reflections from the thin stems of the grass and show only solid objects.
Use of GPS and navigation functions
The modern sonar is not only sonar, but also a full-fledged cartplotter. GPS You can see the fish, you can also go back to the catch points. After you find a promising place (brow, dump, snag), be sure to put a waypoint (see below).WaypointThis will save you hours of time in the future.
Using a track (motion history) helps you analyze the area you've already traveled, and you can see how the bottom relief has changed, and you can compare it to the bites. If the peck started at a depth of 4.5 meters, and after 10 meters the depth became 6 meters, then the fish is holding on to a particular depth difference, and remembering this relief on the sounder, you can find similar places in other parts of the reservoir.
Save screenshots of the sonar screen when you catch a trophy fish. Record the depth, water temperature and bottom structure. Next season, this information will help you find fish in similar conditions faster.
For accurate positioning, you can use the “Trekback” function (if supported by the model), which allows you to return along the way to the saved point with an accuracy of up to a meter, taking into account the demolition of the boat by wind and current.
Frequently Asked Questions (FAQ)
Why doesn't the sonar show the fish, even though it's there?
There are several reasons: too fast boat speed, which causes the fish to not have time to get into the cone; incorrectly tuned sensitivity (too low); or fish standing in the "dead zone" under the sensor itself.
Can I use a sounder in winter from ice?
Yes, but there are some nuances. Most household sonars are not designed to work in subzero temperatures -- the screen can leak and the battery can run out quickly -- and the sensor has to be submerged in water, not on ice. Practitioner, which operate at -20°C.
What do red and yellow colors mean on the screen?
The color indicates the strength of the reflected signal. Red and yellow represent dense objects (large fish, hard bottom, rocks); green and blue correspond to weak reflections (small fish, soft silt, algae); adjusting the color palette helps to read information more easily.
Should I calibrate the sonar?
There is no special calibration per se, but there is a Reset to Default procedure that is useful when changing a body of water or fishing type, and it is also recommended to periodically check the speed of sound in the water if your model allows you to enter salinity and temperature data manually, although modern instruments do this automatically.