Hey! you gave me an idea.
Just send retransmitters into space at regular intervals.
Since it takes time for data to come back. There would always be one of the bounced back signals that would be as fresh as when it was sent. Sagan used the old signals idea when Aliens sent back a message in "Contact".
There are old TV shows that weren't taped because the technology was so expensive. Old timers remember them but that's all we have; and maybe a script on paper(Again)
If someone found a way to go deep in space really fast they could record all radiophonic and televised history. Sometimes I gett really ashamed of what was broadcast.