• The difference between AM and FM radio is that FM has shorter range, within the line of sight of the radio transmitter.
• Let's see if I can make the difference more clear: For AM radio, imagine a sine wave swinging back and forth at a single frequency. That is the 'carrier wave'. Now imagine the peaks of those waves being different heights. Then draw a continuous curve between those wave peaks. That curve represents the audio signal. The tuner converts that curve into a voltage signal that drives a speaker. http://www.electronics-radio.com/articles/radio/modulation/amplitude_modulation/am.php For FM radio, imagine that you are graphing the instantaneous *frequency* of the carrier signal, which is centered around a single 'station' but is varying above and below that value. That continuous frequency change represents the audio signal. The FM tuner outputs a voltage proportional to that frequency that drives a speaker. http://www.electronics-radio.com/articles/radio/modulation/frequency_modulation/fm.php AM radio has the advantage of transmitting further than FM, especially at night when AM signals will bounce off of the upper atmosphere. FM radio has the advantage of being inherently more resistant to noise and interference and can produce a higher-fidelity audio signal. . . .
• 12-30-2016 First you have to know what radio means, and that takes a while to explain. Here is a free course in the basics: http://www.phy.davidson.edu/instrumentation/NEETS.htm The simplest difference is the number: 1000 on the AM band corresponds to 1 on the FM band. (Except the FM band goes 88 to 108.)