Some space-time been created lately

The astros think they can spot the ancient hydrogen spectral line from early universe. But the signal, still here, is stretched by the addition of more spacetime. It is now in the Ham bands, so, god forbid; and they have to get isolated antennas to find it, or do some very complex filtering.

The universe is a tuning fork, all the spectral lines from past are still here, vibrating. Something is expanding the resonant frequency of the tuning fork.