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How FM Transmitter Works In Cars

Car mp3 player with fm transmitterA frequency modulator (FM) transmitter is an electromagnetic radio device that allows speedy transmission of signals from one end to another receiving end with the help of an antenna. The object that is responsible for transmission in radio is an oscillator which carries signal within a particular frequency with the aid of a modulator.


Frequency Modulator (FM) modulates sound received from the source and transforms it in a better form before transmission and that is the secret behind FM radio stations’ production of high-quality music from their various channels.

We intend to render full review here under of how FM transmitter works and how beneficial it could be to you, your business, your daily activities and for pleasure purposes.


What is the importance of FM transmitter?

FM transmitter can be used for personal purpose to boost the performance of your portable mobile audio device or car radio system that does not come with an auxiliary “AUX” input jack or Bluetooth audio connectivity. They can also be used within the house to broadcast an immobile audio source such as the television, computer or children’s games gadgets.

With our current 3G and 4G smart phones, Wi-Fi network services and the internet, majority of us no longer listen to orthodox radio set but get information and news signals even before they reach the radio stations directly from various satellites via the assistance rendered by the frequency modulator.


FM transmitter

How does FM transmitter work?

Getting to analyze how FM transmitter works, we will attempt to look at it from two angles of origination and transmission.


A signal commences its journey first as sine waves that carries no information. The information comes up on it when it attracts electromagnetic signals which is stronger than mechanical waves and travels through vacuum as fast as lightening.

Reception and Transmission

Transmission occurs when received sound is transformed into sine waves and released as radio signals. Frequency modulation alters the sine waves before transmitting them to the FM receivers through electrical signals pushed through the broadcasting antenna with high speed within an electromagnetic field that radiates electromagnetic waves.

With the help of a tuner, you can choose a desired channel from many radio channels your radio antenna must have received through the carrier waves signals sent out at a particular frequency.

This radio detector then transforms the received sine wave of that chosen radio station into sound then modify and amplify its quality with an increase audio volume.

This is why you see many radio stations putting up strong, high and more powerful towers, this is for reception of quality signals from various frequencies with added determination for wider and better coverage.

Short waves make it impossible for us sometimes to audibly hear a radio station probably because they cannot afford high towers and powerful transmitters that penetrate higher above the earth’s crust dominated by high mountain ranges, thick forests, large expanse of water coverage and so on which hampers radio transmission.

However, availability of new technologies has provided solutions to this problem. Radios now come with in-built antennas or signals received via internet or through the functions of navigation satellites to GPS network.


Can my car use an FM transmitter?

It depends on the type and brand you drive. Cars that do not come with USB, digital radio or monitor end up using an FM transmitter to allow the owner play external music from MP3, iPhone or other smart phones if they do not desire to change the entire audio system of the car.


How can I make my FM transmitter more powerful?

To boost your FM radio transmitter, kindly follow the following steps systematically:

  • Choose free unused frequency. Avoid using any radio frequency on which local radio stations transmit.
  • After choosing the free frequency, position your transmitter there
  • You may need to reduce the length or completely remove the antenna on the receiver
  • Then upgrade the frequency received
  • If the quality of what you get is still not your maximum then build a separate FM radio transmitter antenna through the service of an expert.


MP3 Fm transmitter with remote control isolated on white

What frequency is best for FM transmitter?

It is advisable you use between 88-108 MHz band where all commercial broadcast comes out best on commercial and personal radio receiver. This is necessary cause what you want is wider coverage, clarity, heavy and quality sound production and reception at its best, otherwise, choose any other band.



Do FM transmitters work in all cars?

It depends on the quality, strength and type of your car stereo. Yet with your existing car stereo you can still upgrade to a better FM transmitter that can equally deliver whatever your phone is playing through your car speakers. Just follow the above steps by tuning the transmitter to a free FM signal and off you go.



Can FM transmitter drain my car battery?

Although not that quickly or voraciously as other car accessories that consumes higher voltage of power but It will definitely drain a percentage of your car battery because it takes its power from there.

As much as your charger, without being connected to your phone or your cigarette lighter without being used can draw as much as little current, then obviously your FM transmitter too will.

Your best bet is to get a powerful battery installed in your car and always put off your FM transmitter when not in use or completely disconnect at the end of the day when your car is parked except you drive a modern car that comes with a 12V socket which automatically turns off when you turn off your car engine.



For how long can I run my FM transmitter before it drained my battery?

There are many factors to be considered before we can accurately predict duration in this regard. The factors to be examined are:

  • What is the condition of your battery, is it new or fairly new? because if you have a 12V battery used for an average-sized car, you will consume not less than 600 Watt per hour.
  • What is your battery capacity? Is it 60amps, 70amps, 90amps or 120amps? The higher the capacity of your battery the longer the period you can conveniently use your car accessories including the FM transmitter.
  • How many car electronic accessories are running on your car at a particular time?
  • If your car is still with the OEM stereo system and you have not modified or changed it.
  • The levels of your desired sound as you cruise around.

Considerably if you find average positive answers to the above theories then we can safely say that you can run your FM transmitter for a continuous period of 10 hours before you blink on battery drain as your car audio will not, on the average, draw more than 50w for that period.


portable digital fm transmitter isolated on white background


We have been able to outline above how a frequency modulator transmitter works and how you can enjoy it better in your car while using it to boost the receptivity of your radio signals or any other use you might want to put it. We hope you found our article informative and now you know more on how fm transmitter works, if you have a question or comment drop it in the box below, we will be glad to hear from you.