How Do Radio Waves Work?

An item many people use every day and totally take for granted is their radio. You simply reach over and turn it on to get your music, news or sports. Have you ever wondered how you get that news, sports or music to play on the radio? Where and why do radio waves actually come from?

• Understand what radio waves are. These are what carry the information from the radio station to your radio. The station encodes that info which is know as modulation and sends it out on a certain frequency. You choose your channel and pick up their signal and play it on your radio.


• Choose whether you want to listen to AM or FM. AM (amplitude modulation) and FM (frequency modulation). These are the ways your radio decodes the information from the station sending it out. All that modulation means is a change in some property of the radio carrier so you can receive the information being sent.


• Check the difference in sound quality between AM and FM. You may notice that FM usually sounds better than AM, correct? But it is also true that you can hear an AM stations can usually be heard much further distance-wise than FM stations can. Why the differences?


• Hearing a better sound is due to stronger signal strength with FM stations. AM can only broadcast a maximum of 50 kilowatts of power. FM on the other hand can go up to 100 kilowatts. Secondly FM uses higher frequency ranges. AM only has 10 kHz of bandwidth on which they can broadcast and FM has 200 kHz meaning a FM station can broadcast 15 times as much info as AM stations can. The third reason is the fact that AM has much more interference than FM does. One of those reasons is that the sun is a major source of interference. (Notice that AM stations seem much more clearer at night?)


• Keep in mind as you drive around that many things affect your reception; the type of modulation, what time of day it is, geographical location and broadcast power of the station.