Al Klein wrote:
Transmitters that use GPS-derived data aren't GPS-based systems, ...

Huh???? Can you prove that assertion? :-)

Most
shipwreck survivors who are rescued aren't rescued by ships that just
happen to be passing, they're rescued by ships that knew about the
wreck and responded. (Before radio, most shipwreck survivors weren't
rescued.)

All that is true. If one was away from the shipping lanes,
one was SOL or USCWAP. However, if one was in the shipping
lanes with a flare, one at least had a chance of being
rescued. According to my nephew, one of our ancestors was
rescued in such a manner. Presumably, if that had not
happened, neither he nor I would exist.
--
73, Cecil http://www.qsl.net/w5dxp