when using 800 KHz set the distance to 50 ft or less and it will improve the picture and then set the screen scolling speed higher and the sensitivity up. Adjust contrast and sharpness as needed.

I was looking for a PVC crappie tree that I played around the launch ramp and I knew where it was but was having a hard time seeing it until I adjusted the distance to a shorter number and increase the sensitivity and then increase the scroll speed and went to 800Khz. Then I finally got a good screen shot of the PVC Stealth crappie tree. Yes it was a Stealth PVC crappie tree as the sound waves wrapped around the round part of the PVC Pipe and didn't return back to the transducer very well.