Actually, most civilizations that are just a bit more advanced than ours have probably gone dark from our perspective, because radio waves are a fairly primitive technology to makre use of.
What if they use telepathy and some of their thought waves travel here?
Then we won't even need telescopes or radio antennaes. All we'd need to do is listen for the voices in our heads.
Maybe schizophrenics are just better attuned to these telepathic waves.
Or maybe I'm just going crazy!