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Name: Ryne H.
Status: student
Age: 9
Location: N/A
Country: N/A
Date: 2000-2001

How come distant AM radio stations come in better at night then during the day? Local stations come in better during the day then at night. Why?

Distant AM radio stations are better received at night because the ionosphere that reflects AM stations is protected from ionizing radiation and ionized particles from the Sun.

I am not sure local stations do come in better during the day than at night -- at least I have not experienced that.

Vince Calder

When the sun comes out, it sort of heats up the air, helping to make a part of the air that can reflect radio waves, like the radio waves that come from an AM radio station. When the sun goes away at night, these parts of the atmosphere, or air, change. So things can be different between the day time and the night time. Radio waves can bounce around better during the night, when there is NOT this extra part of the air reflecting waves around. Sunlight changes the properties of the ionosphere.

Also, people know this, and make rules about how radio stations must work. People say that some radio stations must cut their power at night, so as not to interfere with far away places. But some radio stations can keep the same power, or even go up at night. These clear channel radio stations then are sending their night time signals all around, even out of the state.

Steve Ross

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