You have probably listened to music on the radio in your car, but have you ever wondered how radio actually works? Electronically charged objects produce an electric field. Some of these fields take the form of electromagnetic waves, or em-waves. EM-waves, just like waves in the beach, have a wave shape. The height of each wave is called the amplitude. The length of each wave is called the wave length. In addition, the number of waves that pass any given point on the graph is the frequency. Radio transmitters produce radio waves on a range of frequencies. By changing the frequency and amplitude of these waves, it can transmit voice or data. Once the transmitter creates the waves, they travel through a cable called a feed line to the antenna.
There are many types of antennas. Each are designed for a specific set of frequencies. Some antennas, called omnidirectional antennas, send and receive signals in all directions. Others, called directional antennas, reduce noise and increase power by focusing on one direction. These are called directional antennas. Once a signal is transmitted, it can reach its destination in a number of ways. Very high frequency waves only travel in straight lines and have a very short range. Lower frequency waves are able to bounce off the E and F regions of the atmosphere and can bounce their way around the world to other stations. Radio receivers sort through all of the waves they receive from the antenna and select the range that the user wants to receive and convert it to audio or data. The way that radios convert data into radio waves is called modulation. For more information about radios and radio waves, visit yarca.org.