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How Does an FM Transmitter Work?

16 Jun 2022 0 Comments


An FM transmitter is a device that transmits audio into radio waves. It plays an important role in our daily life.

Under the pandemic of COVID-19, plenty of people have succeeded in holding events with the help of FM transmitters, such as the service, drive-in movies, and home stereos.

Wondering how an FM transmitter works and how to use it? Signstek can answer your question. 


How does an FM transmitter work? – Take Signstek’s FM transmitter as an example

If you have listened to the radio, you will know that there is a parameter "frequency". You can switch to different channels by adjusting different frequencies. 

That’s because different frequencies correspond with different channels transmitted by FM transmitters. 

How FM transmitter works can fall into 3 parts:

Part 1: Set the frequency

Radio frequencies are similar to television channels. You cannot select from all the frequencies. Radio broadcasts use a large proportion of frequencies. There is a range of frequencies available to the public. You can get to know the available frequencies on local websites.

Before purchasing your own FM transmitter, you need to compare the frequency domain with the available local frequencies.

Signstek's ST-7C FM transmitter can be compatible with the available frequencies in most states.

Part 2: Release electromagnetic waves

Both Signstek’s ST-7C FM Transmitter and ST-05B FM Transmitter can be connected to smart devices, MP3 players, and microphones. 

When you start playing audio on smart devices or speaking via the microphone, the FM transmitter will start transmitting audio in electromagnetic waves. The frequency of the electromagnetic waves equilibrates with the chosen FM frequency.

Part 3: Get the signal

The detector on the stereo, such as radio, can transform the electromagnetic waves into audio.

The audience can listen to your audio at home or in their car by tuning to your frequency in the distance range of the FM transmitter.

Signstek’s ST-7C FM Transmitter enables you to switch from high power mode to low power mode. If you need to broadcast in a short distance range of less than 300 feet, turn on the low power mode. If the audience is dispersed, this best FM transmitter can broadcast the audio within a radius of 900 feet.  


How to select an FM transmitter?


As we mentioned yet, the frequency range of FM transmitters is limited. Make sure that there are available frequencies for you to choose from. 

Distance range:

The distance range is dependent on the usage of the FM transmitter. 

After 2019, many churches are embracing a new way of listening to God's Word: the FM transmitter. 

Churchgoers park their cars in the designated parking lots and tune their car radios on the designated frequencies. This method can not only insure people’s demand but also effectively reduce direct contact.

Sound system:

Only with high fidelity can FM transmitter output clear signal. 


If you don’t want to waste your time selecting it, buy Signstek’s ST-7C FM Transmitter.

Here are some reviews from our true customers. You will be into this best FM transmitter.

Saved our Sunday! – Julie on Jun 25, 2021

This item saved our Sunday services! We were able to hold outside services in our parking lot. During 3 of those services, we had rain storms. Our church services would have been canceled without this device.

Good sound quality – path56 on Jul 23, 2021

We're using this to broadcast church services during Covid restrictions. Some people are not comfortable getting out of their cars so they can listen from their cars! Gets the job done!

Great stereo device, very strong signal. – pghpete on Oct 14, 2021

I haven't needed to raise the volume up over 40% and the signal travels more distance than I'll ever need. Solidly built and also includes a 3.5mm male to male stereo cable that I wasn't expecting.

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