What is CHIRP Sonar? Essential Fishfinder Tech Explained

Decades ago, fish finders were expensive luxuries. Now, they’re essential angling technology that gives weekenders and pros alike the tools they need to catch more fish.

Fish finder tech is constantly evolving, and from down-imaging to side-scanning, robust networking to GPS-enabled contour mapping, modern anglers have options that were nothing short of dreams decades ago. These are the new tech standards anglers can expect on top-end fish finders.

One revolution that’s become a standard is CHIRP sonar. Offering vastly better imaging than traditional sonar tech, it’s impossible to recommend a fishfinder that doesn’t offer it.

You’ll see that reflected in our reviews:

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To understand why you need CHIRP, you need to know what it’s all about.

Let’s dig into the details.

What is Sonar?

Even the most basic fishfinder offers pretty amazing technology.

Fishfinders use sonar to detect the bottom and image its shape, as well as identify fish in the water column. Your transducer emits a sound - at far too high a frequency for you to hear - that travels through the water. 

These sound waves strike objects like the bottom, or a fish, and bounce.

Your transducer picks up these bouncing sound waves, and the electronics within convert them into images.

Sonar is just sound. It’s beyond the range of human hearing, but in principle, it’s no different than any other noise.

Sound takes the form of a wave, with crests and troughs or peaks and valleys. Higher frequencies pack more of these oscillations into a given span of time than do lower frequencies. 

Traditional fishfinding sonar is typically capable of dual-frequency broadcasting and reception, meaning that the transducer can transmit and receive two different frequencies simultaneously.

Typically, this pairing involved a low frequency and a high frequency, offering both water column penetration and high-quality imagining and target separation.

frequency of sound waves

Low frequencies

Low frequencies penetrate water better than high frequencies. Fish finders with very low-frequency transducers can “see” through the water better, allowing them greater depth.

The weakness of low frequencies, however, is that every oscillation provides data, and with less crests and troughs per second, they can’t provide as much information as high frequencies.

Think about your mobile phone for a second. It works much the same way, which is why 4G can carry more information - more data per second - than 3G. Higher frequencies equal more information.

High frequencies

High frequencies offer greater detail, allowing your fish finder to “find” fish and tell you their size and location.

They can’t penetrate much water, however, and they can’t tell you much about the bottom, including details like structure and cover.

What is CHIRP Sonar?

CHIRP stands for Compressed High Intensity Radar Pulse, and it’s an improved sonar technique first developed for military applications.

Instead of a short burst or “ping” of sonar at two different frequencies, a CHIRP-capable transducer broadcasts a much longer burst that covers a wide spectrum of frequencies from low to high, covering everything in between.

It transmits much more sound energy into the water than traditional sonar, resulting in more energy returning to the transducer. That gives your fishfinder a lot more information to work with, and it can provide much better imaging quality and accuracy.

traditional vs chirp

AIRMAR, perhaps the world’s leader in transducer tech, says this:

“Traditional marine fishfinders operate at discrete frequencies such as 50 kHz and 200 kHz, use relatively short-duration transmit pulses, and use narrow band sonar transducers. In contrast, Chirp (compressed high-intensity radar pulse) uses a precise sweep pattern of many frequencies within a long-duration transmit pulse from a broadband transducer, so the equivalent sound energy transmitted into the water is 10 to 1,000 times greater than a conventional marine fishfinder. The echo energy returning to the transducer, superior to that generated by a conventional transducer, is then processed by the fishfinder’s DSP (digital signal processing) computer and displayed in ultra-sharp detail on the display. The combination of Chirp, a broadband transducer, and the fish finder’s DSP, results in dramatically better fish and bottom detection, superior depth capability, and significantly better performance at speed.”

What Does CHIRP Do For You?

That may sound like nothing more than a marketing tool, but CHIRP is a whole lot more than “new and improved.”

On the water, CHIRP sonar simply outperforms traditional dual-frequency sonar by a huge margin, offering better image quality, vastly improved target separation, and fine-grained detail.

Jacob Scott, an expert at Lowrance, explains that “One of the most impressive things that CHIRP does for anglers is that it provides anglers an unprecedented representation of the water column and a much better picture of a bait in the water… With CHIRP, we’ve been getting target separations of less than two inches, making it easier than ever to differentiate your weight and bait while drop-shotting. Having that level of detail gives anglers a much better idea of how bass react to their baits and will be a huge hit with the vertical fishing crowd.”

Head-to-head, even the most expensive traditional sonar transducers just can’t keep up with affordable CHIRP tech.

If you want to see more fish, enjoy greater target separation, and experience crisp, clear imaging, there’s simply no choice to be made.

Final Thoughts

CHIRP sonar is so good that we really can’t recommend fishfinders that aren’t capable of it, no matter their precise and technical specs.

We hope that this article has clarified why, and we’d love to hear any questions, comments, or concerns you might have.

Please leave a comment below.

About The Author
Pete Danylewycz
Born and raised in Cleveland, Ohio, Pete grew up fishing on the Great Lakes. Whether he's casting a line in a quiet freshwater stream or battling a monster bass, fishing is his true passion.