unfortunately, Radio Shack doesn't exactly have subspace radio equipment,
does it?

let's try to be practical here.  The Holy Grail is really just a myth that
could be real, just like FTL transmission and tachyons.  And besides, if we
had an FTL-radio dish, wouldn't we get the message before it was sent?  Time
travel and practical astrobiology/astro-psychology (who sends the message
and why) should be kept separate. one's probably real, the other probably
isn't