Originally Posted by GraemeInCanada
Sounds like an article to "let people know that there might be blackouts" as they test certain systems to see if they work properly. One of those being encrypted GPS or something..
the military has a switch that changes the codes, they can do it in mins from what i understand. the problem with this they also have a lot of civy equipment being used. i would not put money against the fact that they can do local black outs. the problem is local black outs can shut down half the world.
there is also commercially available jammers that can shut it down over a mile or so area, i am sure they can jam larger areas if need be