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

It is due to multipath interference. Radio waves bounce off metallic objects like other cars, buildings, sign poles, etc. If they arrive at your car antenna out of phase with the direct (not reflected) radio signal, they will cancel it out. A few inches can move you into a location where they no longer cancel.

https://en.wikipedia.org/wiki/Multipath_propagation#Interference