What is AM radio

What does AM mean in radio? AM is short for ‘Amplitude Modulation’. AM or Amplitude Modulation is the way of broadcasting radio signals. this transmits information in the form of electromagnetic waves. AM works by modulating the amplitude of the signal or carrier transmitted according to the information being sent, while the frequency remains constant. this broadcasting is radio broadcasting that uses amplitude modulation transmissions. The Amplitude Modulation band in the United States covers frequencies from 540 kHz up to 1700 kHz, in 10 kHz steps (540, 550, 560 … 1680, 1690, 1700).

AM radio is a radio that uses amplitude modulation to broadcast its content. Its development started at the tail end of the 19th century and continued through the first half of the 20th century.

The predecessor of FM (frequency modulation), this new technology would enable humanity a new, and quick, way to transport information, news, and, most importantly, entertainment. A new age would be ushered in by AM radio, appropriately called the “Golden Age of Radio”.

Keep reading more about What is AM radio?

Definition by fcc.govAM is short for amplitude modulation, which refers to the means of encoding the audio signal on the carrier frequency.  In many countries, AM radio stations are known as “mediumwave” stations. They are also sometimes referred to as “standard broadcast stations” because AM was the first form used to transmit broadcast radio signals to the public.  Many AM stations are either daytime-only stations or stations authorized to operate at very low power levels at night as a result of “sky wave” propagation, which occurs when the AM signal is reflected off the ionosphere and back to the earth.”

Definition by pbs.org “FM radio works the same way that AM radio works. The difference is in how the carrier wave is modulated, or altered. With AM radio, the amplitude, or overall strength, of the signal is varied to incorporate the sound information. With FM, the frequency (the number of times each second that the current changes direction) of the carrier signal is varied.

FM signals have a great advantage over AM signals. Both signals are susceptible to slight changes in amplitude. With an AM broadcast, these changes result in static. With an FM broadcast, slight changes in amplitude don’t matter — since the audio signal is conveyed through changes in frequency, the FM receiver can just ignore changes in amplitude. The result: no static at all.”

AM broadcasting – How did it start?

Ever since the telephone was invented and perfected in the 19th century inventors and great minds of the time were convinced that the next big step in the further development of communication was to find a way to wirelessly broadcast sound. After pondering the question for many years they found their solution in AM radio signals.

Amplitude modulation uses, as the name suggests, amplitude to record sound signals. Its overall value is varied to do this process. It is generally agreed that the person that had put in the most work in developing the AM radio is Canadian inventor Reginald Aubrey Fessenden. The early pioneer of AM had already registered a patent related to amplitude modulation in 1901.AM and FM modulated signals for radio

The great advance of vacuum tube technology in 1915 proved vital for the further development of AM broadcasts. The ability of the vacuum tube to provide high-quality AM signals and operate on higher frequencies than alternators and arc transmitters (which had been used until that point). Despite the fact that civilian radio broadcasts became forbidden in most countries due to World War I, which lasted from 1914 to 1918, advancements in AM broadcasting continued to be made through the war due to their usefulness in warfare.

Still, this sparked even more interest in AM and vacuum tubes, so much in fact that many amateurs started to experiment after the war and broadcasted their own news and music. Vacuum tubes would also remain the foremost technology in radio broadcasting until they were usurped during the 1950s by transistors (they still see use in the most powerful broadcast transmitters).

The first broadcasters and broadcasts

The first AM radio broadcasts were done by the same people that led the development of AM radio technology. Please do note, that not every claim made by these broadcasters can be confidentially verified. We will also not name every single broadcast, only the ones we find most notable.

  • The first claimed AM radio broadcast was, supposedly, broadcasted by the most famous AM developer Reginald Fessenden on Christmas Eve in 1906. The second claimed broadcast was broadcasted on 31st December of the same year. These claims were made in a letter sent to Samuel M. Kintner by Reginald Fessenden himself. They were broadcast from Brant Rock, Massachusetts using an alternator transmitter. He claimed that the broadcasts were mostly aimed at ship captains on the Atlantic Ocean, but the Christmas one was supposedly heard as far as Norfolk, Virginia, and the New Year broadcast even in the West Indies. The broadcast program supposedly contained playing on a phonograph record, then a performance on a violin and signing by Reginald and closing off with a bible verse. Every attempt made to verify these claims, even the ones made on the 50th and 100th anniversaries of the events, came up with empty results. Read More about What Radio Station Plays Christmas Music?
  • The first, proven, AM radio broadcast was broadcasted during the month of February of 1907 by Lee de Forest. His experimental broadcast is the one that brought the publics’ eye to the potential of the AM radio broadcast. He used a series of arc transmitters and transmitted the first entertainment program (electronic telharmonium music) from his New York City laboratory, which was located in Parker Building. A notable performance after this first test would be that of Eugenia Farrar. The famous singer would sing “I Love You Truly” and “Just Awearyin’ for You” live over Lees’ radio. Other prominent people featured on his radio were opera singers Mariette Mazarin and Enrico Caruso. He would also use the Eiffel Tower in Paris to broadcast phonograph music. His company would supply the U.S. Navy’s Great White Fleet with experimental arc radiotelephones for their world cruise in 1908. Forests broadcasts would continue until 1912.
  • In 1913 Robert Goldschmidt would begin an experimental radiotelephone transmission from his Laeken station, near Brussels in Belgium. By the 13 of March 1914, these tests were reportedly heard as far as the Parisian Eifel Tower.
  • On the 15 of January 1920, the first broadcast based in the United Kingdom was broadcasted on a 15 kW experimental tube transmitter, called 2MT, at a frequency of 120 kHz from the Marconi factory in Chelmsford, Essex. Not long after, on June 15, 1920, the famous English newspaper, the Daily Mail, would sponsor the first radio concert, performed by the Australian opera singer Nellie Melba. This transmission would reach a large part of Europe, with the broadcast being picked up in Berlin, Paris, The Hague, Madrid, Spain, and Sweden.
    Nellie Melba making broadcast over Marconi Chelmsford Works radio station in England on 15th June 1920
    Photo: wikipedia.org

    The radio station would continue to broadcast notable performers, but despite its popularity would be forced to shut down by the United Kingdoms’ government due to its, supposed, interference with more important communication, for example, military radios mounted on airplanes.

These few broadcasters who were mentioned and many more who were not and we know very little about paved the way for the next step in radio development: The Golden Age of Radio.

The Golden Age of Radio(AM Radio)

The Golden Age of Radio is a time period in radio and broadcast development that is usually placed between the 20s and 50s of the 20th century. The period is marked by the complete domination of radio broadcasting as the medium of home entertainment. It became common for families to gather around a radio and listen to their favorite radio program. Day or night there was always something to listen to, just like there is always some entertaining show on television.

Other than providing entertainment shows radio also helped connect isolated rural communities with the outside world, allowing so politicians a way to broadcast their speeches to the entire country from a single location and reach millions along the way. Among the first to use this to its full effect was four terms serving American president Franklin Delano Roosevelt who organized the famous fireside chats to speak to the American people during the Great Depression and World War II.

Radio would be extensively be used for propaganda purposes, especially in fascist and communist countries. A survey done by the company C.E. Hooper in 1947 showed that 82 out of 100 Americans had a radio in their household and were avid listeners. The new entertainment formats that were developed by radio broadcasters still exist today, such as children’s shows, play-by-play sports, talk shows, soap operas, and many more.

Some AM radio stations are still active today

“Name”/call sign Frequency (in kHz) Country Format
CHQR 770 Canada News/Talk
KFRO 1370 United States Talk
“Mini Radio” 1512 Italy Electronic music
KCLI 1320 United States Sports
“Zenith Classic Rock” 1584 Ireland Classic Rock
WOAP 1080 United States Adult hits
ZYK280 1080 Brazil College radio


The epilogue of the what is AM radio

The reign of AM radio lasted three-decade until the 1950s. This is the time when FM (which uses frequency modulation instead of amplitude modulation) radio finally started to gain a significant following and when television started to become massively owned by American homeowners. AM simply could not compete with FMs superior quality of sound or television’s superior ability to entertain people with moving images so it started its slow decline. Still, it would never die out completely, millions of loyal fans continue to listen to popular AM channels and there have been movements to preserve the heritage of AM due to its cultural heritage as it was the thing that made the world more connected. To prove this we will end the epilogue with a quote from the great sportscaster Walter Lanier “Red” Barber:

“People who weren’t around in the Twenties when radio exploded can’t know what it meant, this milestone for mankind. Suddenly, with the radio, there was instant human communication. No longer were our homes isolated and lonely and silent. The world came into our homes for the first time. Music came pouring in. Laughter came in. The news came in. The world shrank, with radio.”

What are the advantages of AM radio?

An AM radio station is a terrestrial radio station that broadcasts exclusively in the medium frequency range of the electromagnetic spectrum. what does am stand for radio? The term “AM” stands for amplitude modulation, which is the process through which the sound signal is encoded onto the broadcast waves. Because of their low-frequency range, AM radio stations are able to travel long distances and penetrate buildings and other obstructions better than FM stations. This makes them particularly well-suited for broadcasting local news, weather, sports, and other community programming.

What is Special About AM Radio?


Q-1. What is the difference between AM and FM?

AM and FM are both types of modulation, which is a way of transferring information between two points. AM (amplitude modulation) takes the amplitude or height of the signal and varies it to encode the information. FM (frequency modulation) takes the frequency of the signal and varies it to encode the information.

AM is an older technology that was developed in the early 1900s. It uses less bandwidth than FM, so it can be used for transmitting audio over long distances. However, because AM signals are more susceptible to interference, they are not as good for transmitting high-quality audio.

FM was developed in the 1940s as a way to improve the quality of AM radio signals. It uses more bandwidth than AM, but it is less susceptible to interference. This makes FM better for transmitting high-quality audio signals.

So, FM radio waves have a higher frequency than AM radio waves. This means that FM waves can carry more information than AM waves. FM also stands for frequency modulation, which is the type of signal modulation used by FM radios. read more differences between AM and FM

Q-2. How can I listen to AM radio?

There are a few ways that you can listen to AM radio. One way is to use an old-fashioned radio. You can buy radios that have an AM/FM tuner, or you can buy a standalone AM tuner. Another way to listen to AM radio is to use the internet. There are a few websites that allow you to listen to AM radio stations online. Finally, some smartphones have an AM tuner built-in. If your phone has this feature, you can use it to listen to AM radio stations.

Q-3. What is an AM radio station?

An AM radio station is a terrestrial radio station that broadcasts exclusively in the medium frequency range of the electromagnetic spectrum. The term “AM” stands for amplitude modulation, which is the process through which the sound signal is encoded onto the broadcast waves. Because of their low-frequency range, AM radio stations are able to travel long distances and penetrate buildings and other obstructions better than FM stations. This makes them particularly well-suited for broadcasting local news, weather, sports, and another community programming.

Q-4. What is the equipment needed to listen to an AM radio station?

To listen to an AM radio station, you’ll need to collect a radio. Many newer cars come with AM/FM radios, but they typically only receive FM signals. If you’re looking for an old-school experience, consider purchasing an analog AM radio tuner. This type of equipment is available for purchase at most electronics stores. You’ll also need an antenna to pick up the signal. The best way to do this is to install an outdoor antenna on your roof or use an indoor antenna placed near a window.

Q-5. Why is FM superior to AM? Why did it take over?

FM radio is way superior to AM radio due to its ability to provide high-fidelity sound. High fidelity sound is a term used to refer to high-quality reproduction of sound. Add to that the lower cost and it is easy to see why FM became so widespread in AMs place.

Q-6. Why was civilian radio forbidden during World War I?

Governments of the waring countries sought to forbid the use of civilian radio in order to stop accidental broadcasts of confidential materials and to stop enemy spies from broadcasting demoralizing propaganda.

Q-7. What is the wavelength of AM radio?

AM radio is a type of radio transmission that uses amplitude modulation. The wavelength of AM radio is about 300 meters. This wavelength allows for AM transmissions to travel long distances and cover a wide area. AM radio is used for both commercial and personal purposes.


  • www.fcc.gov/general
  • https://en.wikipedia.org
  • https://fas.org

Enjoy this blog? Please spread the word :)

Scroll to Top