What does your car radio sometimes lose signal when you come to a stop sign or stoplight, then comes in clear again when you roll forwards a few inches/feet?

Question

see above

In: Engineering

Answer 1

interference. radio is transmitted by electromagnetic wave, which gets reflected by all kind of obstacles, especially buildings. When two waves at different angles meet, they create an “interference pattern”, at some points the wave will be strong, at some other points it will be weak.

Your car is constantly moving through those interference patterns so you don’t notice it much (merely by short noise bursts), but when it stops you may stand on some location where it will be significantly weaker. You can roll your car a few cm to catch a better spot.