My gps has been a problem ever since I bought the boat used. My puck antenna is mounted on the flat portion between the helm and instrument compartment. The GPS will often display "lost position" with a blinking question mark on the map. It has worked fine in the past but for some reason it is becoming more frequent. I'm thinking its mounted in the wrong place or there may be interference with my satellite puck antenna that is mounted next to the GPS puck. Any suggestions?