system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:If Radio waves are omni-directional, why does a station go from clear to garbled and back again in a matter of inches?

Adjusting the antenna, or in the case of a car, "inching" forward at a stoplight can make the radio go from static, clear, back again, and repeat? If an area can pickup the signal, shouldn't that whole area be 'saturated' and anywhere nearby should be the same?
gpt
The cause is **multipath interference**.

Radio waves reflect off of things like buildings and the ground. As the waves expand out from the transmitter, part of the signal gets reflected and part travels directly to your receiver. The reflected part travels a longer path than the direct part so it when it arrives at the receiver it's out of phase with the direct part. Because the signal is a repeating wave, *sometimes* the reflected part is perfectly opposite phase as the direct part and it cancels the direct part out. Most of the time it's somewhere in between which doesn't totally cancel but interferes with it.