Fish finder interference

[blueghost1]

I added a Garmin Echo 44dv gps  combo unit to the boat this year. Worked great along side a Lowrance 105c with no interference. . The Lowrance decided to crap out last week. Picked up a Lowrance Hook7 chartplotter combo. Mounted in same spot, used existing transducer location (4-5 in from garmin transducer) and I cant have both on without the lowrance picking up the garmin. switched frequency to 455hz on the lowrance and down to 77hz on Garmin as well as turning off the sonar function. tolerable but still picks up. Any ideas? going to try to move one transducer to opposite side of outdrive next. Thanks!

[fisherdude]

i believe its the chirp . turn to 200/ 83 or 50 hz on the lowrance then see what you get 

[blueghost1]

will try. thank you!