Radio Waves WOWIE!

I have always been fascinated with radio wave signals.  When I first started learning about them I thought it was magic.  How can a certain frequency carry information which can then be decoded?  Well the radio stations we listen to include AM and FM.  AM radio is different from FM in that AM radio sends its information using amplitude modification and FM sends its information using frequency modulation.  

Transmitting amplitude modulation signals involves a carrier signal that contains audible frequencies within its bandwidth.  The carrier signal only acts as a messenger while the frequencies inside that AM bandwidth contain the audible sound.  Transmitting frequency modulation signals is similar in that it has a carrier frequency but the audible sounds are decoded by phase changes in the carrier signal.  So the audible sound of an AM signal is detected by amplitude changes in the frequency while the audible sound of an FM signal is detected by frequency changes of the carrier signal.  

The way a signal travels through air is an amazing concept.  Transmitters somehow manage to pulse out signals that can be detected hundreds of miles away.  How people do this depends on the intensity of power of that transmitter.  Transmitters need a lot of power output so the signal can be detected within a certain radius.  Air is a horrible conductor so the waves transmitting through the air really need to be pushed to be detectable by radios within the area.  That is why power is so crucial and to be more specific: power is the voltage multiplied by the current of that signal.  So that's how radio works, ain't it cool?