Marc

Thank you for your response I am just starting out and appreciate the information.
My question came from the realization that I will have 3 GPS units (Power FLARM, Nano, and Nexus 7) in my glider and thought that it might just be a bit of over-kill as I remember the old days flying in Papua New Guinea with a wet compass and an incomplete map that said something like "maximum elevation not believed to be over 14,000".