AM radio, short for amplitude modulation, refers to how audio signals are encoded in the carrier frequency. AM was the first form of radio signals available to the public, with experimental transmission beginning in the early 1900s. However, it did not become widely accessible until the 1920s. During this so-called “Golden Age of Radio,” AM was the primary transmission method, until television became prevalent in the 1950s. Nowadays, AM radio is still used worldwide but mainly for medium wave transmissions. However, its audiences have declined over the decades due to competition from FM radio, digital audio broadcasting, satellite radio, HD radio, internet radio, music streaming services, and podcasting.
The Function of AM Radio
AM broadcasting is a transmission method that utilizes amplitude modulation. In AM technology, the carrier signal’s signal strength changes to accommodate the audio signal. Radio wave transmission’s range and distance depend on both the frequency and power of the signal. In AM radio, the signals reflect from the ionosphere and then bounce back to the earth. With this, many AM transmitters either operate at very low power at night or are daytime-only transmitters.
The Development and History of AM Radio
The first experimental transmissions in amplitude modulation happened in the early 1900s. However, it was not well-known until the development of tube receivers and transmitters in the 1920s. As technology improved, so did AM radio’s listenership, leading to the broadcasting period referred to as the “Golden Age of Radio.”
The Decline of AM Radio
AM radio was the primary mode of radio broadcasting until the advent of television in the 1950s. With FM radio’s introduction, its popularity and fidelitous sound made FM the standard for music listening. Nowadays, AM radio audiences have shrunk drastically due to various forms of competition.
What is the difference between AM and FM radio?
The difference between AM (amplitude modulation) and FM (frequency modulation) radio is in how the audio signal is encoded on the carrier wave. In AM, the signal strength changes, while in FM, the frequency changes with an audio signal.
Why is AM radio called “medium wave”?
AM radio stations worldwide are broadcasted on frequencies known as the medium wave range (around 540-1610kHz). The medium wave designation comes from the fact that these signals have wavelengths longer than FM waves but shorter than shortwave signals.
Is AM radio still used today?
Yes, AM radio is still used worldwide, mainly for medium wave transmissions. However, its audiences have declined due to competition from newer technologies such as FM radio, digital audio broadcasting, satellite radio, HD radio, internet radio, music streaming services, and podcasting.
AM radio was the first form of transmitting radio signals to the public and was the primary form of transmission in what was known as the Golden Age of Radio. However, the advent of newer radio transmission technologies and competition from other forms of audio entertainment has resulted in its decline in listenership. Nevertheless, AM continues to be used worldwide for medium-wave transmissions.