How sharp or distinct a brush piles looks on sonar can depend on your sonar imaging and settings. Generally lower kHz settings scan a larger area but with less detail. Higher kHz settings provide more detail. Side and down-imaging (right-hand images) usually help anglers more easily identify brush piles
Electronics: I Spy a Brush Pile
by Brad Wiegmann
Most reservoirs, ponds and rivers have brush piles. Modern electronic can easily spot them, but those electronic images can sometimes be deceiving.
Understanding how to interpret sonar images makes the difference in locating and fishing them. A brush pile might be easy to see when approaching it from one angle. However, it might almost disappear or turn into a blob from another angle.
Brush piles, by our definition, can include fallen trees along the shore, standing timber underwater or other types of wood cover such as stumps and logs. How you cast in and around those pieces of structure can make or break a day of fishing.
You can see what direction a brush pile is laying, size and height from the images on your fishfinder. Traditional 2D imaging sonar has been around the longest, but it lacks the super sharp imaging of down imaging, side imaging or LIS. Brush piles often resemble a towering blotch or large blob on the bottom with little detail.
CHIRP sonar has sharper imaging by isolating individual fish close to the bottom or in tight schools of fish compared to traditional 2D sonar, but is still missing the almost photo-like imaging.
One reason anglers still use traditional broadband 2D single frequency sonar or CHIRP with a range of frequencies sonar is because it’s so easy to see a brush pile when driving over it. The best setting when searching for brush piles with traditional 2D sonar is 83kHz allowing for a broader, wider cone. Change to 200kHz to see more detail.
When using CHIRP sonar, select medium CHIRP sonar for searching and change to HIGH CHIRP for better, sharper imaging.
Side or down imaging is available in mega 1.2MHz, 800 kHz and 455kHz. Unlike traditional sonar, side and down imaging transducer beam is a razor-thin, high-definition beam that results in almost photo-like imaging. Brush piles or laydowns along with baitfish or crappie can easily be seen.
The down imaging cone is located directly under the boat. When searching for brush piles or laydowns utilize the wider 455kHz, then change to the narrower 800kHz for high resolution.
Side imaging cone beam coverage is two razor-thin precise sonar beams at right angles from the left and right of the boat. This is by far the best sonar imaging for searching for cover. Again, utilize 455kHz with its larger cone coverage then switch to 800kHz for sharper imaging up to 250 feet. The newer mega 1.2MHz frequency produces the best, sharpest imaging; however, keep in mind that this frequency works best in shallow water or at shorter distances from the boat.
Of course, with the traditional sonar imaging described above, your boat has to be moving for it to work best. With live-imaging sonar, however, you don’t have to be moving for it to produce images. There are no frequencies to change for better image resolution; however, by increasing the gain you will see more detail or decreasing the gain will reduce screen clutter.
(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.)
