Is it true that AM radio can broadcast farther than FM radio?

Question

Is it true? Because when I'm on a trip, I usually hear the same FM radio for miles and miles, but then again, I don't know how long is a mile (I know it in ft I just cant tell how far i've gone lol) since I'm 14. So is it true?

Also, give me more information on AM radio that a 14 year old like me can understand.

Answer 1

For power to power, the AM station will go further due to It's "wave length".... Basically the lower you go in frequency the furthur it will go, however you also deal with more noise and other interference to destroy that station's reception. (You will remember the talk about wavelengths from school and how the lower you go the longer they are)

Fm stations go for miles and miles are usually full legal limit (50,000 in some parts of America, 100,000 in the rest) radio stations that are on very tall towers. Most of those stations will cover a 50+ mile radius (meaning you could drive 100 miles listening to the same station as you drive from say the northern edge of the signal pass the tower and to the end of the signal area)

AM stations rely on the atmosphere (AM stations use the earth's ground during the day to get the signal out and night uses the ionespere to make it go furthur) as well as their long waves to get out. for most stations on AM I've heard them 200+ miles on a sunny day from their tower... not at a very comfortable listening (as the station may have noise if say a thunderstorm was between me and the station) range mobile but still be able to receive what on a FM station would have been faded out 150 miles back (remember 50 miles like I told you earlier from the tower)

http://en.wikipedia.org/wiki/AM_radio

Answer 2

All good answers, don't think i could answer any better :) GB

Answer 3

You're going to get a lot of answers about wave length and atmospheric bounce. Someone's also bound to quote Wiki chapter and verse. But the short (non-technical) answer is that AM signals do travel farther, but they're not as easily controlled as FM. FM is line-of-sight, so in flat country, the signal will indeed follow you for quite a while.

But AM can bounce all over the place giving you stations you never thought possible to receive.

When I was PD of a big 50,000 watt AM in Arkansas, we once got a postcard from the Norwegian Arctic Circle. And another from Cuba!

-a guy named duh

Answer 4

Well, simply, AM is less stable but does travel farther.  And whatever Duh says :)