Canadian over-the-air TV stations have now switched to digital transmission.  We need the "box" or a new tv: this we can manage.  Where I get lost is what antenna we should upgrade to.  Most of the channels we watch the transmitters are 50 - 70 miles away.  We had a couple of clear channels on analog but most were a little snowy.  If my understanding of this is correct:  Digital is line of site and you either get the station or you do not.  Nothing in-between (snowy).
Suggestions on antenna makes and models needed.
TIA!
Robert