What brushpile looks like on sonar

i have a lowrance 4x color sonar, not dsi, no gps. i have been patrolling the local lake in search of brushpiles, sandbass and groups of baitfish but have not had much luck. i am not sure if my ff settings are correct. i put it in manual mode, crank up the sensitivity turn off fish id but still have trouble marking anything. The avg depth of the lake is around 20-30ft. so should i use single or dual frequency? aka shallow or deep setting. its seems to mark fish better in the deeper river channel that runs through the lake is this normal? the channnel is about 50ft deep compared to the 15ft or so the brushpiles are said to be located. please help me with any info youve got. pictures would be a great help

Check out this thread in the Side/Down Imaging forum. There is a DI image so you can see what is down there, and a standard sonar image to compare to. Though most of the images there are Side or Down imaging, you'll find some that have 2D images as well, which is really useful for learning.

Brush pile.

http://i1187.photobucket.com/albums/...p61/shot22.png

Its important to realize the size of the cone shaped sonar beam (beams if it has dual frequency)....

I'm not sure about your specific unit ...but generally, in a dual frequency unit... 1 frequency is a lower frequency with a wider cone (83kHz approx 60degree cone?) - and the 2nd frequency is a higher frequency with a narrower cone (200kHz approx 20degree cone?)...

The wider cone will allow the unit to pick up brush from a wider area under the Xducer ...
The narrower cone will not cover as much bottom area but the image will show with greater detail...

Just remember ...if that structure is not physically in that "cone"...it's not going to show on that screen...

It could be that you just have not gotten "on top" of any brush yet for the brush to show up on your screen...

Also...

Although in a perfect world it would be nice to see 2d images with a clear screen and structure "stand out" on the image, different water conditions/structure compositions don't always allow it...

Like Justin's pic above.. Sometimes you need to run your 2d sensitivity as high as you stand it and still distinguish between the clutter and the structure/fish you are wanting to see...

Rickie

sent pm

Sounds like you have the basics right. On the Lowrance units, I'd suggest running straight 200 kHz, not dual frequency. Just seems to work a lot better. Here's a picture to give you an idea, but the best thing to do is see if you can find someone locally to jump in your boat and check your setup. I do it for a lot of guys around here.

-T9

Attachment 102897

Pretty cool pictures...

Leaves give a different look to the brush. This will change over time.