Topic: 1197 transducer interference

[Salmonid]

Having probs with my new 1197 where the screen fills with interference at about 25 MPH, I am sure it has something to do with the rivets on the bottom of my 19ft Sea Nymph,  (model 195TC) so after inintial mounting of tranduer, it was a .25" above the hull bottom and so I moved it all the way down so its now about .5" below the hull with no difference at all.  Before I turn my transom into swiss cheese, any thoughts on if I should move it higher above the hull or lower which i hate to do since I primarily fish Ohio River tourneys  and am always plowing through huge logs and drift.

I am sure many others have had this same problem so if you did, what did you do to fix it?

Many thanks, Salmonid

[Humminbird_Greg]

Salmonid,
I would first make sure that it is not motor interference but taking the motor out of gear and revving it to the same RPM level that 25 MPH or faster would be.  If there is no visible interference than chances are that you are getting air bubbles across the transducer.  Metal boats are notorious for this.  Basically you have to get your transducer in an area that has minimal air mixed in with the water.  For most that means closer to the center of the boat and lower in the water.  To help avoid the “Swiss cheese” syndrome you could try installing a transducer mounting plate.

[Salmonid]

Greg, thanks Ill try the engine rev next time out before I move it and I had already moved the unit way off o the right of the motor as per instructions so maybe I can resuse some of the old holes( 14-16" to the left of the present location) which would put it closer to the center and lower in the water column as you stated, Thanks again for the help... Ill be sure to post any results when I get them.
Salmonid