ELI5 How come a foot or two of brick/plaster can stop a cell phone signal but (moderate) hills and densely packed buildings in urban areas do not?

Question

ELI5 How come a foot or two of brick/plaster can stop a cell phone signal but (moderate) hills and densely packed buildings in urban areas do not?

In: Technology

Answer 1

A phone signal (or any EM radiation) is fundamentally the same idea as a flickering light. A light will shine through some materials, and bounce/reflect off and around objects in an otherwise open space. Your phone signal acts similarly.

Answer 2

Hills and buildings in urban areas do block cell phone signals. A Lot.

In cities cell companies put relays on the tops of buildings to spread coverage from the main towers and prevent dead zones.

In areas with hills they will but relays or towers on said hills.

But in both cases you will have bad coverage in some parts of a city, and you will have hills making dead zones in rural areas.