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How Does Fm Radio Work


How Does Fm Radio Work

Every day, thousands of various techniques are used for “radio waves” to transport music, talks, photos, and data silently through the air across great distances. Despite the fact that radio waves are unseen and impossible for humans to detect, they have had a profound impact on society. All wireless technology, including cell phones, baby monitors, cordless phones, and thousands of other devices, use radio waves to transmit.

What Is an FM Radio Device?

A radio is an electrical device that picks up radio waves and transforms the data they carry into a form that may be used. With an antenna, it is utilized. Waveforms of radio frequency are intercepted by the antenna, which then transforms them into minute alternating currents that are transferred to the receiver, which then extracts the needed information. The receiver employs electronic filters to distinguish the intended radio signal from all of the other signals picked up along the way, an electronic amp to boost the signal’s power for additional processing, and then demodulation to extract the desired information.

All radio-using systems require radio receivers as a necessary component. The receiver can output digital data, sound, or video (for television) as its output. A radio receiver can be a standalone electrical device or a circuit integrated into another electronic device. 

How is FM Radio Operated?

Do you enjoy hearing the radio? Ever pondered the route that sounds takes from a radio channel to a receiver? How can the sounds go from you to the station through the air, buildings, and everything in between? Electromagnetic waves provide the solution.


A sine wave’s frequency is one of its characteristics. The numerous times a sine wave fluctuates up and down each second is known as its frequency. Your radio is tuned to a sine wave with a frequency of roughly 1,000,000 cycles per second when you listen to an AM radio broadcast. A 680 on the AM dial, for instance, is 680,000 cycles per second. Since FM radio transmissions operate in the hertz range of 100,000,000, the transmitter at frequency 101.5 on the FM dial is producing sine waves at a rate of 101,500,000 cycles per second.

Waves in Spectrum

Magnetic fields vibrate to create electromagnetic waves. Along with moving energy through matter, they also move it through space. The wavelengths and frequencies of electromagnetic waves vary, and higher-frequency oscillations have greater energy. The electromagnetic spectrum refers to the entire spectrum of electromagnetic wave wavelengths.

The electromagnetic radiation with the longest frequencies is radio waves. Their wavelengths might be longer than a football pitch. They have the lowest frequencies of all electromagnetic waves. They have the lowest power of all electromagnetic fields due to their low frequency. Radio waves are still quite helpful, though. In addition to numerous other uses, they are utilized for radio and tv.

Radio Formats

Both AM and FM Radio

In radio transmissions, sounds are converted into radio waves, which are then transmitted from a broadcast tower into the atmosphere. The waves are picked up by a radio receiver, which converts them back to sounds. You might have listened to FM and AM radio stations simultaneously. AM and FM transmissions use different sound encoding techniques.

Amplitude Modulation is Referred to as AM

Amplitude modulation is referred to as AM. By altering the amplitude, or height limit, of radio waves, sound impulses are encoded in AM transmissions. Compared to FM broadcasts, AM transmissions employ radio waves with a longer wavelength. AM waves reflect off the ionosphere, a region of the high atmosphere, due to their longer wavelengths. Radio receivers located far from the broadcast tower might receive the waves because of reflection.

Frequency Modulation is Referred to as FM 

By altering the wavelength of radio waves, sound messages are encoded in FM broadcasts. FM transmissions typically provide clearer sound than AM transmissions because frequency modulation enables FM waves to carry more information than amplitude modulation can. However, unlike AM waves, FM waves don’t reflect off the ionosphere due to their relatively short wavelengths. FM waves, on the other hand, go past the ionosphere and into space. FM waves can’t therefore travel very far to reach receivers.

Power for Transmission

One of the factors that determine how far a signal will go is the power output of an FM radio transmitter. The transmitting antenna’s height and antenna gain are two more crucial factors. In order to cover the necessary region without interfering with stations farther away, transmitter strengths should be carefully selected. From a few megawatts of power to 80 kW, practical transmitter powers are available. Transmitter operating costs skyrocket above a few kw, making them only economically feasible for large stations. For FM-only transmission, the effectiveness of larger broadcasters is currently greater than 70%. Before the use of LDMOS amplifiers and highly efficient switch-mode power supply, this percentage was 50%. Any additional digital HD Radio service drastically reduces efficiency.

Radio Transmission Technology

In order for you to comprehend how intangible radio waves enable so many things, we shall examine radio technology.

The Easy Radio

Around the beginning of the century, early experimentation was made feasible for just about everybody thanks to how simple radio may be. How much easier can it be? Here’s an illustration:

• Gather a dime and a brand-new 9-volt battery.

• Locate an AM stereo and set the dial to a location where you can hear static.

• Gently tap the two battery terminals with the coin while holding the battery close to the antenna.

• As the coin is connected and disconnected, you will notice a crackling in the radio.

Your penny and battery are radio transmitters! Because it isn’t designed for distance, it won’t transmit very far (only a few inches) and isn’t transmitting anything helpful (just static). However, you can communicate effectively over a few inches with this rudimentary equipment if you use the current to tap out Radio transmissions!

 For further explanations, you can see a video via this link

Taking in an AM Signal

Here’s a case from the real world. The transmitter’s wave form is transmitting at a frequency of 680,000 hertz when you adjust your vehicle’s AM radio to a station, like 680 on the AM dial.  By altering the sine wave’s amplitude in the transmitter, the DJ’s voice is encoded onto that carrier wave. For a powerful AM station, an amplifier boosts the signal to about 50,000 watts. The radio waves are then launched into space by the antenna.

So how does the receiver in your car’s AM radio decode the transmitter’s 680,000-hertz signal to obtain the data (the DJ’s voice)? The following steps:

  • Your receiver requires an antenna to assist it pick up the transmitter’s radio signals from the air, unless you are seated directly next to the transmitter. A wire or metal rod that increases the quantity of metals the transmitter’s waves may interact with is all that an AM antenna is.
  • You need a tuner for your radio receiver. Hundreds of sine waves will be received by the antenna. A tuner’s task is to distinguish one sine wave from the tens of thousands of radio transmissions the antenna picks up. The tuner is set in this instance to pick up the 680,000-hertz signal. Resonance is a principle that is used in tuning devices. In other words, tuners amplify and resonate at a single frequency while ignoring all other waves in the air. A resistor and an inductor can be used to quickly build a resonator.
  • The radio only picks up one sine wave wavelength thanks to the tuner. The DJ’s voice must now be separated from that sine wave by the radio. This is accomplished by the radio’s detector or demodulator. An electronic component known as a diode is used to create the detector in the instance of an AM radio. A diode rips off one half of the wave because it only permits electricity to flow in one direction and not the other.
  • The radio then boosts the signal that was clipped and feeds it to the listeners (or a headphone). One or more semiconductors make up the amplifier.

The DJ’s voice is audible through the speakers.

The detector is changed in an Airwaves, but the rest is the same. The antenna, tuner, and amplifier are substantially the same in FM, but the detector converts frequency shifts into sound.

Basics of Radio Antenna

You’ve probably noticed that practically every radio you encounter has an antenna, including your cell phone and the radio in your car. 

Antennas come in a variety of sizes and shapes. The transmitter can be anything from a lengthy, stiff cable (like the AM/FM radio antennas seen in the majority of cars) to an oddity like a satellite dish. Incredibly tall antenna towers are another method used by radio transmitters to broadcast their transmissions.

A radio transmitter’s antenna is intended to send radio signals into space. The goal of a receiver is to gather as much power from the transmitter as possible and provide it to the tuner. NASA employs massive dish antennas with a diameter of up to 200 ft (60 meters) to communicate with satellite that are miles and miles away!

The wavelength of the transmission that a radio antenna is seeking to broadcast or receive determines the size of the antenna that will work best. The explanation for this link has to do with distance that electrons may travel as a result of the speed of light. 186,000 miles per second is the speed of light (300,000 Km/s).

To understand it better, visit this link on YouTube


How can I use my Computer to listeen to FM Radio?

You can tune in to your preferred nearby over-the-air Fm radio stations in Windows 7 Media Player if you have a compatible tuner card and linked FM antenna.

You must install and configure a Television or radio tuner card first before FM radio option in Windows Media Center becomes accessible. A radio tuner might already be installed on your computer if you have a TV tuner card. FM tuners are frequently included into TV tuner cards.

Launch Windows Media Center and move the cursor above “Music” to “Radio.”

The moment the radio starts playing, the white box will display the current station’s identification. Standard “Seek” and “Tune” controls, as well as “Preset” options, are located just below. Similar to an ordinary FM radio, tuning is simple. To “Tune” or “Seek” up and down the dial, click on the (-) or (+) buttons. Use the keyboard or remote control’s numeric keypad to enter the numbers if you already know the station’s frequency

For a better understanding, visit this link to see how it is done


How do I use my Mobile Phone to liaten to Radio?

If your phone includes an inbuilt chipset and the necessary hardware to link that chip to an FM antenna, you can easily convert it into an FM radio. All you need is a signal-tuning app like NextRadio and an antenna, like a set of wired or unwired headphones, to pick up the signal.

Can we get Sick from Radio Waves?

Non-ionizing radioactivity has not been proven to harm humans when exposure levels are at or below the radio wave exposure boundaries imposed by the FCC, according to the agreement of scientists.

Can Radio Waves haves an Impacton the Brain?

In conclusion, these investigations show that EMR, depending on the level of radiation exposure, might cause metabolic abnormalities of monoamine neurotransmission, which could theoretically result in inappropriate emotional behavior.

This video explains it better

How do Radio Waves impact the Environment and People?

Along with other aspects of the earth system, radio waves can measure lake and ocean wave heights, tropical storm, and ocean currents. Additionally, using particular radio frequencies that cannot be substituted is necessary to determine atmospheric conditions.

For a better visual understanding, visit this YouTube channel

FM Radio Stations Send Music to Listeners in What ways?

Radio waves are used to transmit both over the air. These are electromagnetic radiation, which are present everywhere yet have varying frequencies.

How are Listeners Identified by Radio Stations?

Any technique used to count the number of individuals listening to an online radio broadcast is known as internet radio audience measurement. Usually, the audio streaming server of the broadcaster provides this data.

This video link will provide a better understanding

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