John,
We use a local/regional service, and we have direct line of site from the antennae on our building, where our offices are located, to the main transmission antennae, only a few miles away. From there it goes directly into the main fiber optic cable. So, direct line of site is best, yes. We do get a bit of fog, rain & snow, & thus far, no issues, other than about 45 minutes of downtime with power outage at main antennae a month ago.