I have a LMS 339 DF with gps , I remoldel my bass tracker and put a full windsheild on it. The gps never gave me any problem ,now with that windsheild I sometimes lose signal when going to waypoints especially moving north. It has built in antena,hate to move from console. car has windsheild and they work inside cars. It don't do it often but when I realise it has stop ,no time to adjust for brushpile.