Humminbird Side Imaging Forums

Side Imaging Forums => 997c SI, 998c SI & 999ci HD SI => Topic started by: bjdpractice on July 21, 2013, 09:44:16 PM

Title: Interference/Junk on SI and DI at 2.5-5 feet while moving in boat
Post by: bjdpractice on July 21, 2013, 09:44:16 PM

I have a new 998 installed on a 2006 165 Navigator Alumnacraft boat.    I'm getting funny garbage/intefernce on screen at the depth of 2.5-5 feet on DI and on the left side of my SI water column.    I had it installed at a local dealer and they called hummingbird and they thought it was interference from the boat/drain/plug.     I do not think it is.

There's no interference when the boat is still.     Any thoughts?   Anyone else have this problem?

Thanks.

P.S.   I can post pictures as well.

P.P.S.   The tech at the local shop said he talked with someone high up at Humminbird and they had no idea.

Title: Re: Interference/Junk on SI and DI at 2.5-5 feet while moving in boat
Post by: Humminbird_Greg on July 22, 2013, 01:55:23 PM

Welcome to the Humminbird Side Imaging Forums bjdpractice.

On your 998 unit; the DI sonar comes from what the left and right Si sonar beams are ‘seeing’.  So if you have “interference/junk” in the left Si sonar it will show up in the DI sonar as well.  So what we are looking for is what will show up in the left Si sonar but not the right Si sonar.  If this only shows up when the boat is moving than it is not the drain plug, motor, livewell intake screens or anything else that may be sticking out from the back of your boat.  What I believe you are seeing are the air bubbles that are being mixed in with the water flowing off the left side of your boat.  You do not see this on the right side because I am betting that the transducer is mounted closer to the right side of the boat.  Unfortunately there are not many solutions for this.  It may be that the transducer is not mounted level when viewed from behind (has a clockwise tilt to it), or that it can be moved to a more central location of that you have to end up installing a second Si transducer.  Post some pictures of your boat’s transom and the installation of the transducer so that we can see where everything is.


“P.P.S.   The tech at the local shop said he talked with someone high up at Humminbird and they had no idea.”
Sometimes you just ‘gotta talk to those who get to do the grunt work to find the answers you need.