As a radio signal travels from the antenna, it weakens due to several effects: Path Loss: Signal strength decreases with distance. In free space, power drops with the square of the distance. Double the distance = 1/4 the power (6 dB loss). Shadowing: Large obstacles (buildings, hills) block or attenuate the signal. Creates "shadow" zones with weak coverage. Multipath Fading: Signals bounce off surfaces and arrive at the receiver via multiple paths with different delays, causing constructive or destructive interference.