Well on the day I was talking about we were spider rigging and my partners $300 gps was sitting right beside the transducer and telling us we were moving about .3-.5 mph and my $2000 gps and sonar was saying we were going anywhere from 1.5 - 3 mph....makes you feel real good about your money spent....I'm gonna raise my receiver up above the transducer next outing and hope that helps....