how come a.m. radio gets static after dark?

Question

Just a basic question that ive always wondered about. kinda silly but who cares

Answer 1

Your local radio station probably lowers their transmitting power at night to avoid interfering with distant stations on the same frequency. Why at night? During the day, the sun activates an ionized portion of the atmosphere called the ionosphere. One of the layers of the ionosphere during the day absorbs transmissions at the AM broadcast band frequencies and keeps them closer to the Earth's surface limiting the distance they transmit. At night, the sun's ionization disappears and so does the absorption. Another layer of the ionosphere further from the Earth's surface is charged and ionized and reflects signals back to Earth. Since it's so high up it allows these frequencies to go further away. Plus they can bounce back off the Earth's surface and hit the ionosphere again and go very far! The biggest thing that limits the distance an AM station can be heard at night is other stations on the same frequency. Back when AM broadcast was in its infancy, stations could be heard all around the world! Still, clear channel stations can be regularly heard for 1,000 miles at night. Not only does the ionosphere accommodate transmitted radio signals, but the electromagnetic radiation emitted from lightning strikes can propagate in this fashion as well, so you could be hearing static pops from a lightning storm hundreds of miles away as well!

Answer 2

its really basic its P.M. soo yeah i had that question last year but i was only 10 last year so yeah common mistake.