I typically get between 2 (poor) and 10 or 11 (good) with most satellites around the 7 or 8 mark. I'm at 37 degrees south latitidue and 174 degrees east longitude. Not sure if latitude affects the S/N readings...

Also, note your HDOP and PDOP. PDOP = Positional Dilution of Precision, HDOP = horizontal... etc. They both reflect GPS acccuracy. A PDOP of 1.0 is very good, anything above 3 tends to be inaccurate. My PDOP tends to be about 1.2 to 1.5

I would suggest that, for the relatively low cost, you procure another GPS antenna and try it in a temporary location on your rear parcel tray.

Jochen