“Footfall”?
Invasion story, asteroid impact, plucky american heroes, and same authors as “Lucifer’s Hammer”.
That’s closer...but as I remember the post, this book began with a SETI broadcast and response. It seemed to have a “be careful what you wish for,” theme to it.
Just recently, Stephen Hawking wrote a screed about the unintended (negative) consequences of a SETI contact.