[c-five]

...broadcast omnidirectional signal loses power proportional to the cube of the distance from the antenna. 4 Watts can jam to 200KM??

Square, I think. But anyway, the same law applies to the orbiting transmitters, which are much further away from the receiver than the jammer.

[OReilly]

4 Watts can jam to 200KM??

4 Watts is like 4 KW when you compare the signal levels that GPS receivers in the JDams are working with.

[dennisw]

Thanks