Just a tip.
I'm in the UK and originally had my gps receiver in the left side front of my windscreen.
I had problems with reception in this position when there were overhangs. I moved it to the right side, and because we drive on the left, this positioned it nearer to the centre of the road.
In this position, the reception was significantly improved.
So for you.....if it's on the right side.......move it to the left
Car : Ford Focus Zetec 1.6
Carpc :Lin-ITX Plus 7" touchscreen/Toad 8" roof screen
Morex 3688 case/M2-ATX PSU/Commell V-672 P4 3.2Ghz/1024DDR2/40GB 2.5" SATA HDD/Sony DVD/CDRW
BU303 GPS/Mercury 11b WiFi/Parking Sensors
Colour I/R Reversing Camera