If it rains where the receiver is, the amount of radiation reaching the antenna is reduced.
The animal rights nuts will go ballistic whenever a goose flys through the beam and dinner is delivered--pre-cooked--out of the sky.
Not to mention the NIMBYs opposing siting of the antennas, Earth Firsters sabotaging them, airplanes flying through the beams and having various systems roasted, etc, etc.
An idea whose time is went.
--Boris