Peter - didn't they say that the checking station is also listening to the satellites? That way they can tell that you are playing back signals that you taped earlier because they won't match what the satellites are broadcasting right now. I think your idea would work if you wanted to pretend to be at a point which was _farther_ from each of the satellites than where you actually are. Then you could delay all of the signals. But the only way to be farther would be to be deep underground. You might be able to pretend to be at the center of the earth, but that is not very useful. Actually I suppose this only applies to those satellites which are shared between you and the checkin station. If you are far away then maybe you only share one or two. If you know which ones those are, you can lie to your heart's content about other ones, and for the shared ones you can again delay the signal and claim to be farther than you are. If their authenticated repeaters are used then you have to assume the checking station has all the satellite signals and again the best you can do is pretend to be a Mole Man. Hal