Both use 200hz transducers so unless they process the signals differently I would guess they would interfere with each other. The people who would know would be Lowrance and Navman. Don't bother with Navman though as you will never get an answer from their supposed customer service department.
The other company that may be able to help are http://www.airmar.com/ they are the ones who make the transducers.
The practical way, and probably quickest, is to take the Navman unit out with you and connect up the power leads to the battery and hold the transducer underwater, turn the Lowrance display on and off and see if it makes any difference to the Navman display and vice versa.
The other company that may be able to help are http://www.airmar.com/ they are the ones who make the transducers.
The practical way, and probably quickest, is to take the Navman unit out with you and connect up the power leads to the battery and hold the transducer underwater, turn the Lowrance display on and off and see if it makes any difference to the Navman display and vice versa.
