Hi: I spent a lot of time with the SV6 learning about GPS. http://www.prc68.com/I/Trimpack.shtml#SV6 Note: The Trimpack web page has a bunch of Trimble GPS receivers, not just Trimpacks. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html