Despite the existence of smartphones, in some apartments you can still hear the radio working. In addition to this, a huge number of radio stations are popular among motorists – in addition to music, they transmit traffic data and important news. On each radio, you can select two operating modes: FM and AM. Most radio stations operate in the first mode, which provides the highest quality sound. And in AM mode there are very few stations available, and they work very poorly, with terrible interference. The question arises: what is the difference between them and why not leave only one mode with the best sound?
FM and AM radios work differently, and each has its own pros and cons. Source: mentoday.ru
Contents
- 1 How radio works
- 2 Differences between FM and AM radio
- 2.1 What is FM radio
- 2.2 What is AM radio
- 3 What is AM radio for
- 4 How radio saves lives
How radio works
Before you can understand the difference between FM and AM, you first need to understand how a radio works. We will not delve into the history of the invention of this technology – the name of Alexander Popov has long been familiar to everyone. Also, we will not touch on the technical difficulties, because Now we need to understand how the radio works in simple words.
There are many opinions about who invented the radio, but the version about Alexander Popov is closest to us. Source: dzen.ru
Radio transmits sounds over long distances using radio waves. Each radio station has a source of sound signals – a studio with presenters who broadcast and play music. In special equipment, all these sounds are converted into radio waves, which can travel through the air.
The unusual building of the Slovak Radio. Source: architime.ru
Radio stations distribute these waves using a huge antenna. Each radio also has a smaller antenna that picks up these waves. The receiver also has electronics inside that convert the waves into an audio signal. As you can see, if you don’t delve into the technical jungle, everything works extremely simply.
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Differences FM and AM radio
FM (Frequency Modulation) and AM (Amplitude Modulation) are two different ways of transmitting sounds using radio waves. Most radio stations transmit signals using frequency modulation (FM), while some use amplitude modulation (AM). Each method has its own pros and cons.
Each radio has a dial with a frequency range. Source: wallhere.com
What is FM radio
When a radio uses FM waves, it transmits information by changing the frequency of the wave. When a presenter speaks into a microphone or music plays, these signals change the frequency of radio waves, it increases and decreases in an order appropriate to the information.
Typically, FM radio operates in a high frequency range, from 88 to 108 megahertz. Thanks to this, it is capable of transmitting sounds in high quality – music on such radio stations sounds good. However, FM frequency modulation is bad because it has a short range. If there are obstacles such as mountains between the radio station and the receiver, the signal will be weak or not at all, and mostly noise will be heard in the speakers.
FM waves change range, but not amplitude. AM waves change in amplitude, but not in range. Source: radiokot.ru
What is AM radio
There are radio stations that transmit signals using amplitude modulation (AM). They encode sounds not in frequency, but in amplitude – depending on the information, the magnitude of the radio waves increases and decreases.
Amplitude radio stations operate in the range from 530 to 1700 kilohertz. AM station signals can be transmitted over very long distances. They can even overcome the horizon, reflecting from layers of the atmosphere. But the sound quality leaves much to be desired, because such stations experience interference due to interference from external sources such as household appliances and meteorological phenomena.
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What is an AM radio for?
As you can understand, FM radio is of higher quality and is used most often. So why don't people completely abandon AM radio, which no one even really turns on?
FM and AM radio stations perform different tasks. Source: wallpaperbat.com
The thing is that amplitude modulation is great for transmitting emergency messages over long distances. Usually, radio stations that use this method of transmitting data transmit talk programs. But there is no point in broadcasting music on them, because radio receivers will reproduce an incoherent mess of interference.
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How Radio Saves Lives
Because of its long range, AM radio can sometimes save lives in emergency situations. We are not talking about professional radio stations, but those created by enthusiasts.
In 2022, two cases became known when radio amateurs saved the lives of people who were in trouble. In the US state of Wisconsin, a radio amateur was able to transmit a distress signal, finding a person who had fallen and was seriously injured.
Sometimes radio can be used to warn people about natural disasters like tornadoes. Source: Sometimes radio can be used to warn people about natural disasters like tornadoes. Source: mk.ru
And in the US state of Idaho, two men used AM waves to report an accident involving two teenagers on ATVs. The accident occurred far from civilization, where there was no cellular coverage.
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So AM radio is not something useless, sometimes it saves lives. Some receiver manufacturers make it so that their equipment cannot accept amplitude modulation, which is why they are subject to slight criticism.