Why should I plug in a headset to hear the FM radio on my phone?

Do you feel very annoying every time your phone requires a headset to be able to hear FM? Why can we create a phone that connects around the world without thinking of a more efficient way to listen to the radio?

After all, the radio has existed for a century, but the 21st century phones can't use this old app without the help of a simple headset?

Before trying to answer this question, we will look at the radio operation principle.

Radio works in a way that sends energy from one place to another without using any direct wired connection. Radio waves are transmitted from a device called a transmitter, transmitted wirelessly and then captured by another device called a receiver .

The mechanism can be understood like this: first, you record audio from a sound recording or voice, then convert it into electrical energy. This electrical signal is then modulated with a wave signal, fed into the antenna to increase the intensity. You can control the process of increasing the intensity to match the desired distance the signal is transmitted from the location of the antenna. Here, the wave is transmitted at the speed of light to the receiving antenna and the receiver continues to convert the radio back into electric current. The electric energy is then decoded into radio sound that we still hear!

An antenna is rolled inside, an antenna is stretched to the outside.

If you observe that modern semiconductor stations will see they usually have 2 different antennas. An antenna is rolled inside, an antenna is stretched to the outside. Why do we need two separate antennas?

This is because radios are usually emitted at two frequencies equivalent to two modulation methods: intensity modulation (AM - Amplitude Modulation) and frequency modulation (FM - Frequency Modulation) . In particular, FM transmits in short distances but at high frequencies (about 85-100 MHz). AM uses transmission waves with greater distances and at much lower frequencies (about 1000 kHz).

Even a car must have an external antenna to hear the FM radio.

A single antenna cannot receive both such large difference frequencies. The frequency of radio waves determines the length of the antenna. Basically, a larger wavelength corresponds to a longer antenna. For example, to catch an FM signal, you need an antenna about 90cm long.

Modern phones simply don't have built-in internal antennas. Of course they may be, but there is a more interesting option is the headset with the ability to act as a perfect antenna! The headset is an insulated metal wire with one end covering the magnet and metal jack at the other end. It acts as an antenna, taking energy from the radio waves then transmitting to the tuner. Not only that, headphones are longer than 90 cm - ideal conditions for receiving FM signals!

In fact, we only need a simple metal wire. That's why you can listen to the radio even when connecting your phone to the speakerphone with a regular USB cord. Therefore, in fact, you do not need to have a headset to listen to the FM radio on your mobile phone.

In fact, you don't have to have a headset to listen to FM radio on your mobile phone.

However, with the development of current technology, it is impossible to integrate internal antennas instead of relying on headphones? Honestly, this is possible. Some phones offer the option to listen to the FM radio without a headset. However, most phone manufacturers choose not to use.

Think about this. Most of us use headphones to listen to music from mobile phones, because most phones do not have "big" external speakers like removable sound systems. Even if you do not have a habit of using headphones, phone manufacturers still offer headphones in the product box when you buy a new mobile phone. This also means you cannot use a Bluetooth headset to replace a wired headset to make an FM antenna.

The integration of the antenna will only make the phone heavier, bulky and less attractive. Instead, there is a simpler, but much more interesting way to use the headset as an antenna to listen to the FM radio.