HuntFrisco,
My story is this. I purchased a used fishawk and put it on the boat at the begining of last season. I liked the fishhawk because I only use downtemp when I am not marking fish, so I only put the probe out when I need it. I mounted the transducer right next to the one for my fishfinder because the boat that was sitting on a trailer next to mine had one set up that way. I guess I should have asked how it worked because my down speed and temp were bouncing. I have a humminbird dual frequency fish finder and tried both frequencies but still had the problem. I discovered when I turned off my fish finder the fish hawk worked fine.
Tim Brommund had a good suggestion, which is to mount the fish hawk transducer at an angle which should minimize interference with the fish finder. I will probably remount my transducer this spring. Sorry I don't have an exact answer but maybe someone else will jump in.