....There's always GLONASS, I guess... Both systems have considerable built-in redundancy. It might be that eventualities which would produce a general outage would affect both GPS & GLONASS. Of course that leaves the Japanese & putative Chinese systems... --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .