Dear Colleen,

When I was little, I liked to move the radio dial in the car. I could hear different channels with music or talking. Plus, static in between.

My friend Ben Belzer reminded me of that when we talked about your question. He’s an engineer at Washington State University.

“Your cell phone is basically a digital radio,” Belzer said.

Any place with cell phone coverage gets divided into cells. They could be six-sided hexagons like the cells in a beehive. Or they could be any shape with flat sides. The size of the cell depends on how many people live there. A … » More …