Radio Waves

    Radio waves are some of the most interesting electromagnetic waves that are utilized by people. Radio waves are the main Electromagnetic wave involving communication. The music from our radios, the texts we send, the calls we make, and much more are all the result of radio waves. Humans learned along time ago how to transfer a signal using these waves and are still used everyday by most people.

    Radio wave frequencies can range anywhere from 3kHz to 300GHz. This is why radio waves are so convenient for sending signals. We can fine tune our frequency to exactly what we want in the large range and the device receiving the signal can interpret the wave in many different ways. Radio waves are sent and received by antennas. The source of a radio wave is called the transmitter and the receiving end is called the receiver. So when a radio station plays a song they are the transmitter and your car would be the receiver. This works the same way for phones but instead the phone transmits the signal to a satellite which then increases the strength of the signal and transmits the signal down to the receiver of the call.

http://www.explainthatstuff.com/antennas.html

    So how does all this actually work? Well a radio can receive a signal in two different ways, AM(Amplitude Modulation) and FM(Frequency Modulation). When a radio broadcaster talks through his/her microphone an electric signal is then produced. This signal is then transmitted through an antenna to the vicinity around the station. Now depending on if you set your radio to AM or FM you will receive a different broadcast.

    AM radio relies on a consistent frequency and a variable amplitude. AM radio usually falls in a frequency range of 520kHz to 1710kHz. On the radio the user will set the radio to a desired frequency which will be dependant on which station they would want to listen to. The information in the signal is actually created by the wave changing amplitude. AM radio is convenient for long ranges and being able to have more stations within a smaller range of frequencies. The downsides to AM radio is that it is easier to disrupt the signal and AM has a very limited audio range which is not great for music.

    FM radio is the opposite of AM radio. Instead of having a constant frequency FM radio has a constant amplitude. This means that the information being sent through the signal is actually dependent on frequency. When tuning into an FM station you are actually turning into a steady amplitude. FM radio is great for music due to having a large audio range but the signal cannot be sent over a very large range.