There are number of variables associated with reception distance including broadcast power, receiver sensitivity, broadcast interference, physical obstacles, solar activity, weather, etc. To keep things simple though FM stations are considered line of sight so the fewer obstacles between the broadcast antenna and the receiver, the better the reception. Have you ever tried to listen to an FM station in a retail store? Not good! The net of this is that the curvature of the Earth is the ultimate source of FM blocking so the practical maximum distance for FM broadcasts is 90-100 miles under ideal conditions.
AM is a completely different animal though still subject to the previously stated radio reception variables. High powered (50,000 watts maximum in the U.S.) AM stations are commonly heard 500 to 1,000 miles away at night when conditions are good and sometimes even go significantly farther. This is because a portion of the original AM signal is reflected back to earth by the ionosphere and so is not limited to line of sight reception.
Weather stations in the U.S. are an extension of the FM band and therefore share the distance limitations of their other family members.
11 years, 5 months ago
by
Olaff
Suburban Chicago