Phased Arrays Scanning Sonar for Live Scanning Imaging of Fish and Structure
by Brad Wiegmann
In the beginning sonar was based on a single acoustic wave being sent out from a transducer into the water below the boat bouncing off objects such as trees, rocks and fish. These single pings were then translated and recorded by Multi-functional Devices (MFD). After that Compressed High Intensity Radar Pulse (CHIRP) followed by side scanning sonar and down sonar scanning to now phased array scanning sonar, aka live scanning imaging sonar.
Currently there are three marine electronics companies that are producing live scanning imaging sonar. Garmin was the first to enter the market place with first generation Panoptix followed by second generation Panoptix and what most anglers are using now, third generation Panoptix (LiveScope). Lowrance has released its ActiveTarget Live Sonar with software update. Humminbird now its version called MEGA Live.
All three companies have similar views. Forward live scanning which is the most popular because it allows angers to see structure and fish in front of you. Down live scanning that allows anglers to view under the boat. Scout/Perspective Mode/Landscape scanning that’s a live wide view around the front area of the boat. Note that not all accessories for mounting are included with the live scanning sonar.
Down scanning view of beams
Forward scanning view of beams
Scout mode scanning view of beams
Each MFD utilizes phased array sonar that is the active transmitting and receiving of multiple beams simultaneously to produce a live image.
Important numbers when it comes to live scanning imaging sonar. The higher frequencies for Garmin and Lowrance result in sharper, better detailed images.
- Garmin’s frequency is 530- to 1,100-kHz
- Lowrance at 550- to 1,100-kHz
- Humminbird 1,050-kHz
Several factors have an influence in the final image on the MFD. The total of elements per transducer will decide on how detailed the image is on the MFD.
Garmin has a wide beamwidth at 20 degrees by 135 degrees with a range of 200 feet. Lowrance has a beanwidth of 18 degrees by 135 degrees with a range of 200 feet. Humminbird’s beamwidth is 20 degrees by 20.
How far can you see in forward view? It depends on the unit as the Lowrance and Garmin are 200 feet while the Humminbird is only 150 feet. Having the smaller beam allows Lowrance to see images farther away better, but the Garmin and Humminbird a larger viewing area closer.
When viewing in Garmin LiveScope forward scanning view at 60 feet ahead of the transducer, Garmin noted it would be an area of 22 feet wide. The beam would be an elongated oval shape from the trolling motor to out in front of the boat. Lowrance would be slightly less, but insignificant at 60 feet.
No matter what live scanning imaging sonar unit you are using it’s easy to see how this technology is changing fishing.
(From Springdale, Arkansas, Brad Wiegmann is a professional photographer, videographer and outdoor writer published in dozens of print and electronic media outlets all across the nation. Every month Wiegmann will be providing CrappieNOW readers with the latest and greatest information on the ever-changing world of fishing electronics. He is also a well-known guide, podcaster and social media influencer. Learn more about Wiegmann and his lengthy experience and expertise at BradWiegmann.com.)