On the TV set in the motel room there's news footage of the Tiananmen Square protests where the (never identified) man is standing in front of a tank. That happened in 1989, sixteen years after this series is set.
shareThere were quite a few images on the TV that occurred after 1973, notably the one you mentioned and also Nixon's resignation speech, which took place in 1974. They must have pulled up signals from the future.
If time is fluid and not linear, that would explain it. If radio and TV signals and waves can continue to travel distances through space years after they've been transmitted, it stands to reason that aliens might also be able to perceive those same waves through time. We just haven't sent them yet.
And then there was also a time travel of ca. 5 minutes.
Remember, he finds himself standing in the room and we hear the last chords of the anthem before the channel shuts off for the day. That had already happened before he had his encounter.
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All I can see is an owl, but I know it's not an owl.