How do radio stations know that you’re listening to them? Is there a signal sent back somehow?

Question

How do radio stations know that you’re listening to them? Is there a signal sent back somehow?

In: 2349

Answer 1

in my country there was, or maybe there is a thing called “radio diary”. they ask random people to do the radio diary for a week, it’s basically a survey.

I think the participants may get paid as well.