Garmin CHIRP sonar technology

How does CHIRP sonar technology work?

As some of you may know, I recently switched to Garmin sonar electronics for my barra boat, one of the main reasons being I wanted to run CHIRP sonar technology and Garmin are leaders in the field.

Other manufacturers are also taking advantage of CHIRP and I have no doubt they will be good products too, but for me Garmin ticked the most boxes.

To start, I just want to explain a bit about the difference between CHIRP and traditional sounding technology. To get the nitty gritty, I headed to Townsville to speak with Navcom Electronics owner Barry Dionysius, an old mate of mine and a Garmin rep since 1990. I first met Barry when he was fitting out game boat and commercial fleet electronics back in the day. Incidentally, it was on the marlin boats that I learned most of my sounder skills and this industry is always at the forefront embracing and utilizing new technology.

As Barry will explain in the following video, CHIRP stands for Compressed High Intensity Radiated Pulse.

While traditional sonar sends one single frequency or “ping” at a time, CHIRP sends a continuous sweep of frequencies, ranging from low to high.

The CHIRP technology then interprets the frequencies individually upon their return. Since this continuous sweep of frequencies provides CHIRP with a much wider range of information, CHIRP sonar is able to create a much clearer, higher resolution image.

One of the biggest differences I notice is when fish cluster in a school. Traditional sonar shows them as one big blob, whereas CHIRP individualizes every fish making it much easier to tell that it is a school of target species and not just a bait ball or rock.

My conversation with Barry about the new CHIRP technology is recorded in the video below.


Next steps... Watch [FREE] Sounder Interpretation presentation by Ryan Moody. Click Here!





For those of you interested, at present I am running the GPSMap 1020XS and GPSMap 820XS models fully networked with a GCV10 scanning module. I am using two transducers, the Airmar TM150M for traditional/CHIRP sonar and the Garmin GT30-TM for DownVu and SideVu.

To determine what is the best option for you, have a chat to Barry at Navcom Electronics in Townsville on (FREECALL) 1800 632 422.

And as example of how my Garmin unit individualises the fish, check out the photo below. For the uninitiated, the photo below shows a tightly packed school of threadfin salmon clustering near the bottom. The lines represent individual fish. On a traditional sonar, these would show as just a solid red mass.

Sounder Interpretation [FREE] presentation with Ryan Moody. Click Here!


Now as you can see from the photo, a huge component to fully utilising this equipment is interpretation. Having caught a ton of big threadys, I know when and where they hang out and what they look like on a sounder. However, I've been catching them for years without the use of this technology so it's not essential for good fish catches, but it does make it easier.

If you're having trouble reading your sounder at speed, this tip on Mounting Your Transducer may help.

If you spend more time fishing than catching and would love to learn about sounder interpretation, the way fish behave and more, we have a series of online fishing courses to help.

Check out our new fishing education website FISH SMARTER

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About The Author

Ryan Moody

Ryan Moody started his fishing career on the reef boats before catching bucket list marlin for the likes of champion heavy tackle angler Johnno Johnson, INXS and the King of Sweden. Branching out in the late 80's to guided barramundi fishing, Ryan has made a name for himself as a Big Barramundi specialist and to date has put clients onto over 2000 metre plus barra. That is over 2 kilometres of metre plus barra! With attitudes changing from 'keep all you can' towards catch and release, Ryan has decided to share his extensive knowledge and hopefully inspire people of all ages to get out from behind the computer screen/TV and into the fishing outdoors lifestyle he has spent his life perfecting.

Facebook comments


  • Aryan Mishra

    Reply Reply October 19, 2021

    Now that CHIRP is available, you can not only find fish, but you can also learn what it can do for us. It appears to be a very useful tool for anglers.

  • Ryan Wilson

    Reply Reply October 19, 2021

    I found this post very helpful and it will enhance my fishing experience. Thanks for sharing.

  • Tom Banton

    Reply Reply July 8, 2021

    With CHIRP now you not only have a better way to find fish,, so it’s nice to see a helpful explanation of what it can do for us. It really does look like a powerful tool for anglers.

  • Big Bull

    Reply Reply May 26, 2021

    I wonder why some of the manufacturers have still prived the conventional chirp units more than Dual Beam CHIRP. Although I do agree that its not justified to call dual beam chirp as dual beam.

  • fishing girl

    Reply Reply January 13, 2019

    whoah, this blog is great I like studying your articles. Keep up the great work! You already know, lots of individuals are searching around for this information, you can help them…thanks Ryan 🙂

    • Ryan Moody

      Reply Reply January 14, 2019

      Thanks so much for your kind words! Glad your enjoying the content

  • Hildegarde

    Reply Reply December 16, 2018

    I see something really special in this web site.

  • Steve

    Reply Reply October 12, 2018

    This is a very resourceful post and will come in handy in improving my fishing experience. Really appreciated.

  • safedoom

    Reply Reply September 8, 2018

    Am very new to this field and this just gave me a head start. I will try the chirp sonar technology now and give you the results in due time

    • Ryan Moody

      Reply Reply September 9, 2018

      Thanks mate, glad you enjoyed it!!
      Let us know how you go

  • John Bass

    Reply Reply August 31, 2018

    CHIRP Sonar has been a great article about. Which model of humminbird do you recommend? thanks Ryan

    • Ryan Moody

      Reply Reply September 1, 2018

      Hi John,
      Mate as I like and use Garmin I’m not all that up to scratch with the Hummingbird units. I can only recommend you get something with 1200kHz for side imaging that is within your price range. Definitely best to get some advice from your sounder rep in regards to Hummingbird.
      So sorry I cant be of more help. I will attach a link to our UltraHD blog. It may help you as well 🙂

  • TrendySeekers

    Reply Reply August 6, 2018

    During my research I still noticed Garmin model is much more popular than any other fishing finder GPS but however, I am abit intrigued and appreciated to k know CHIRP sonar has been implemented. Nice reading though!

  • john bass

    Reply Reply April 29, 2018

    chirp sonar has been an excellent article about technology. thanks Ryan

  • Ron

    Reply Reply July 11, 2017

    The term CHIRP was around long before the radar and sounder industries got hold of it. CHIRP was the name given to the transmission of morse code signals that varied in frequency(tone/pitch). Faulty transmitters caused the morse code signals to change frequency and sound “chirpy” like a canary’s warbling tweets.

    The tones were changing frequency as the transmitter was keyed on and off. A bit like FM. Different transmitters could be readily identified just by the amount of tone shift (chirp) that could be heard.

    It was an acronym that had no application for use. Bit like a name without a town. Use of radar has been around longer than sounders and radar did indeed use high intensity pulses and radars did indeed vary the pulse repetition frequency (prf) to avoid the trap of a hostile enemy aircraft approaching but not being seen on radar as it was travelling at the radar’s “blind speed”.

    Varying the prf changed the blind speed and thus no a/craft could sneak up by flying at the known blind speed.

    There’s nothing compressed or high intensity about a CHIRP sounder. The term simply sounds impressive. Marketing hype.

    The only advantage of CHIRP in sounders is for much improved range resolution. Don’t get range resolution (the ability to distinguish between targets) confused with target resolution (the size of targets that can be seen) or screen resolution ( how many pixels activate to produce a target).

    The most crucial item of a CHIRP sounder is a flat response transducer with a low “Q” of about 3 – 8. Most recreational CHIRP sounders use a compromise higher Q transducer (up to 30 or so) due to cost. So basically, most CHIRP sounders are only operating at reduced throttle.

  • Marting

    Reply Reply July 3, 2017

    quite valuable information about CHIRP. THe moment they combined it with Dual Beam boom!
    I wonder why some of the manufacturers have still prived the conventional chirp units more than Dual Beam CHIRP. Although I do agree that its not justified to call dual beam chirp as dual beam. After all its a series of signals sent between upper and lower limit.

  • I agree that much can be learned and adopted from this common, Thanks for this interesting blog!

  • Jamie

    Reply Reply March 5, 2017

    Hello Ryan, Amazing experience with the chirp sonar. I love that. Have you used Hummingbird 999c HD SI Combo fish finder? I would like to buy one.

    • Ryan Moody

      Reply Reply March 18, 2017

      Hi Jamie, no sorry mate i haven’t used hummingbird since 998. It was a pretty good unit for the time but I use Garmin now.

  • Timothy W. Pothier

    Reply Reply November 24, 2016

    Hey Ryan, nice share. You’ve made a nice brief about Chirp sonar technology and how it actually works. Actually I’ve been using a Garmin GPS technology based fish finder and it have installed sonar technology within. It’s good to locate where the all fishes are using this device.

  • Maribelinda

    Reply Reply October 18, 2016

    Its a grade information about CHIRP technology. Grate word MR Ryan i get lots of information about it. thanks for your post.

  • Zulia

    Reply Reply September 23, 2016

    Complete details post CHIRP sonar technology. Great work Ryan. Just appreciating your hard work.

  • Robert

    Reply Reply August 12, 2016

    With CHIRP now you not only have a better way to find fish, you can also mark the spots to return to later. In the other hand, you can mark boat ramps and docks so you can find your way back to where you started.

  • Luke

    Reply Reply July 1, 2015

    CHIRP is certainly the newest buzzword for fish finders these days, so it’s nice to see a helpful explanation of what it can do for us. It really does look like a powerful tool for anglers.

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