How did Katies friends die if they weren anywhere near a TV?
If we adhere to the idea that Samara must emerge from a television, one could posit that Scott and Stacy had some sort of global navigation system in their car that Samara could have utilized. Or perhaps Samara can transmit herself as a signal that can similarly emerge from a radio. And when no such electrical equipment is available she can to make do with another form of transmitter — the electrical output of the human brain. If this were the case, though, it does raise the question of why she’d bother using a TV at all.