Dead Air is a movie that has similarities to Frequency sure, but trust me, it is a copy of The Caller (2011), and because of the budget, an inferior one of course.
Yes movies like this have been made before, but by genre, The Caller is the one that got ripped off, well, lets say got an homage in the likes of Dead Air, a movie that tried I guess, but, did managed to over stretch every scene really.
I did got bored a lot, I managed to figure out what was happening in the movie by the 30th min mark I think, so seriously, this is a weak production that brings nothing new. You could watch it if you ever find it that is, but if you don't, don't go looking. There is no satisfaction from viewing Dead Air, as it is a poor attempt at a horror, done before and way better.
So try Frequency and of course The Caller, have a good time with them and forget about this one.
Cheers!