On Sat, 17 Jul 2010 11:22:42 +0100, Boo
wrote:

I understood that "selective availability mk2" (or whatever it's known as) is
the capability to selectively deny access to GPS signals over limited
geographical areas, maybe this has some bearing ?

It would be limited mostly to "line of sight" distances, and Cuba is
not known for being a technical power house with unlimited financial
resources.