A GPS receiver is only as good as the antenna:

Since the GPS satellites are transmitting very weak signals at -162.0 dBW, it is very important to install and use an antenna system designed to match your receiver. The GPS1010 GPS antenna and universal mounting bracket is designed for use with the entire line of GPS Creations OpenSource GPS products. Constructed of corrosion-proof materials, the GPS1010 will provide years of trouble free service. All electrical connections are enclosed and weatherproof. See the GPS1010 brochure for more details.

GPS 1010 Brochure in PDF format
Installation Instructions
Download Current Price List:
Price List