Topic: 2d Sonar: Interference and filtering.

[Rotus623]

Hey guys just wondering what you think about this. This is about the 2d function of the Humminbird. I am one of the fellas that runs my unit off of my starting battery, with a 12v regulator. I keep my filter set on low. When cruising around at 7MPH or so, I get crisp, clean SI and 2d. Looks beautiful really. When I start cruising around 15MPH and above, I start to get lots of little speckles on my 2d screen, with a good bottom reading. Around 30MPH, I get an accurate bottom reading, but the bottom looks a little more faint. I think this is because of the ping rate. Anyways, what do you guys think the speckling is from? The rivets of the aluminum hull, angle of the ducer, motor interference? If anyone has any experience with this it will give me somewhere to start. I am already considering adding a stand alone battery, although I dont believe that to be the cause of this issue.

[Humminbird_Greg]

Rotus623,
You should be able to check for motor interference by taking the motor out of gear and revving it to the same RPM level that you would be at when running 15+MPH.  If the speckles show up than the interference is coming from the motor/battery charging system.  If not, than it is sonar related and adjusting your transducer may help.

[ezfishn]

Speckles sounds more like water turbulence around the transducer.