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, trees, rocks and fish. These single pings were then translated and recorded by Multi-functional Devices (MFD). After that Compressed High Intensity Radar Pulse (CHRIP) followed by side scanning sonar and down sonar scanning to now phased array scanning sonar aka live imaging sonar.
Currently there are 3 marine electronics companies that are producing live scanning imaging sonar. Garmin (Go to Garmin for more information www.garmin.com) was the first to enter the market place with 1st Gen Panoptix followed by 2nd Gen Panoptix and what most anglers are using 3rd Gen Panoptix (LiveScope). Lowrance (Go to Lowrance for more information www.lowrance.com) has released its ActiveTarget Live Sonar with software update. Humminbird (Go to www.humminbird.com) now has its version called MEGA Live.
All 3 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.
Each MFD utilizes phased array sonar that’s the active transmitting and receive 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
Down scanning view of beams.
Forward scanning view of beams
Scout mode scanning view of beams.
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 18 degrees by 135 beamwidith with a range of 200 feet. Humminbird’s beamwidth is 20 degrees by 20.
One of the most popular option for live imaging sonar is to add a separate pole to mount the transducer to allow for independent steering.
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.
(Editor’s Note: Please welcome writer, photographer and crappie fishing expert extraordinaire, Brad Wiegmann, to the elite stable of CatfishNOW Magazine contributors. Every month Wiegmann will be providing the absolute latest and greatest information on the ever-changing world of fishing electronics.)