In the context of broadcast radio, frequency modulation uses a greater bandwidth that amplitude modulation, so as to have enough room to produce higher-quality, stereo audio reception.

Listening to amplitude-modulated mono radio broadcast signals late at night, with the stations only 9kHz apart sometimes, can be painful on the ears and can try one's patience.

"But AM has been proved to be better in book and anlysis"

I grew up with AM and the only plus point I can come up with is that you could listen with a crystal radio constructed by yourselves.

The interference levels was very high if you lived some distance from the transmitter.

AM is better than FM? No way. West Virginia Public Radio is only on FM.

As is 'Classic FM' in the UK.

FM is used more than AM because it is better. FM is practically immune from amplitude distortion, which is the bane of all things AM.

No doubt that the quality of music on FM stations is better. But...a FM station will broadcast a bit over the visible horizon which could be tens of miles, depending on the height of the antenna. An AM station has a broader action radius, and this is, I think, the main advantage that keep the AM station alive.Also, in the band allotted for AM, there are more broadcasting stations than in the FM band.

Exactly. "Horses for courses".

Morse code on CW stations can be 2kHz apart and the meaning can come through. HF stations can go great distances because of the reflective properties of various ionospheric layers at these frequencies.

Amplitude modulation needs twice the bandwidth of the audio, typically 2 x 4.5kHz, to separate the stations. There isn't much room for audio, and certainly no room for a stereo signal of high-fidelity expectation, on LF and MF.

For high-fidelity FM stereo resolution one needs a bandwidth of several times 20kHz, twice (one for left speaker and one for right speaker) to separate the stations. 300kHz would be a typical frequency spacing to separate them, for which there is not enough room on LF, MF, or HF. So VHF is used. The pay-off is that it is a local transmission medium, as the ionosphere is not reflective at these frequencies.

There are plenty of on-line encyclopaedia articles for the original poster to study further!

Rush Limbaugh saved AM radio in the US. It's called talk radio. That and sports is pretty much all AM radio is good for. Music is painful to listen to on AM. I'm old fashion though, I still listen to the BBC on short wave.

Rush Limbaugh = end of civilization

Rush Limbaugh saved AM radio in the US.

So I heard, and even more, some were thanking him wholeheartedly for teaching them facts of life. Oh, maybe not that lady who, when complained of the high price of the gasoline, Limbaugh replied: don't complain, you don't know how much it cost me to fuel my private jet!