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Name: Amanda M.
Status: student
Age: 17
Location: N/A
Country: N/A
Date: 2001-2002


Question:
How can you receive a Chicago AM radio station in North Carolina? Why is that possible?


Replies:
The short simple answer is that certain radio frequencies reflect off the ionosphere and the ground so that the radio wave keeps bouncing back and forth. This is of course going to be sensitive to atmospheric conditions for weak signals, and a given receiver may pick up interference of radio waves of like frequencies. This is why the NIST does not have numerous radio transmissions of "standard time" -- to many signals get in the way of each other.

Under certain atmospheric conditions some transmissions of short wave lengths can also propagate "over the horizon". I personally was able to receive a TV station from Havana, Cuba in South Carolina. I'm not sure what these "strange" conditions are however.

Vince Calder



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