Even though people these days don’t always listen to conventional radio, it remains a significant technological landscape in history and their everyday lives. The radio technology transmits and receives electromagnetic waves or signals that broadcast different audio types (i.e. music or speech). Since the 20th century, radio, as one of the most common mediums, has evolved and developed into many different types.
What Are the Different Types of Radio?
People usually categorize radios depending on their use and function. There most used today are AM, FM, Shortwave, Longwave, Satellite, Ham, DAB, Walkie-Talkie, and HD radio. Each of them uses a different technology or bands. A radio band determines the wavelengths and frequency used and is only applicable to analog radio. This article will introduce each of the types that are commonly used in our everyday lives.
Radio waves are the electromagnetic waves of frequencies used for long-distance communication. According to NASA, radio waves have the longest wavelengths in the electromagnetic spectrum. Their wavelengths, according to the radio frequencies range from 1 mm to anywhere over 100 km.
A radio physically works by transmitting and receiving electromagnetic waves rapidly. A transmitter (meaning the stations) radiates the field outwards, using an antenna, and the receiver (meaning the actual radio devices) picks up the field and signal and translates it into sound. The first commercial station went on air in 1920, with a broadcast about the elections. The success of the KDKA broadcast in Pittsburg inspired the technology and future of broadcasting worldwide.
The radio was developed in the 20th century as the breakthrough way to broadcast audio signals for large distances and wide audiences. Although the first period was just experimental, the VHF band (very high frequency) aired commercially 40 years later.
AM & FM
Amplitude modulation (AM radio) is the oldest form of wireless radio broadcasting. Using a process called modulation, an audio signal can modify the strength of the radio waves rapidly, which AM receivers decode into sound. The amplitude is the signal strength of the carrier wave that’s varied in proportion to the message signal.
In the 1960s, the transistor was developed, allowing the smaller-sized amplitude modulation radio to become a reality. But the early types often used vacuum tubes. Although this system is fairly simple, the quality of the sound is underwhelming, especially by today’s standards, and it’s vulnerable to electrical noises. They often have a light called ‘Magic Eye’, which by measuring peak power, helps tune a particular channel precisely.
FM is one of the most commonly known radio bands. Unlike AM radio, FM focuses on the modulation of the radio frequency rather than the strength. The higher frequency used for FM allows a much better audio quality, cuts down on white noise, and doesn’t let any interference in. While technology has developed way beyond AM and FM these days, FM receivers are still used widely and even come built into smartphones today. FM and AM bands are still the main radio source in portable, home or construction site radios.
Shortwave and Long Wave Radio
Private shortwave broadcasting is very rare and is even banned in some countries. For instance, shortwave stations in the United States are not permitted to operate exclusively for domestic and/or local audiences because of the way its frequencies interact with the Earth’s ionosphere.
Shortwave radio is subject to an external antenna and can travel thousands of miles. Whether on digital or analog radio, people can tune in from anywhere in the world once they find the right frequency. The frequencies of a shortwave radio are almost exclusively used as a way for the government and commercial stations to share news and other important information which was a giant leap in technology when it was introduced.
Similar to shortwave, longwave radio can travel thousands of miles. They’re more popular in maritime communications. That type of radio broadcasts wave signals over great distances, even bodies of water using less power. Today, this band is mainly used in Europe, and while a lot of people think it’s an obsolete band, actually millions listen to long-wave stations every day, and there are plans to increase the number of these stations in the future.
Satellite radio is one of the newest forms of radio broadcasting and is becoming the most common form of broadcasting rapidly. It’s a commercial, subscription-based service which uses a network of satellites as a way to transmit signals.
Unlike the more traditional radio types like AM or FM, the satellite radio is digitally encoded and uses special receivers. A computer chip in this receiver denies access for those who are not subscribed. There are several advantages of satellite radio, such as exceptional sound quality, nationwide coverage, and access to contents in the Federal Communications Commission’s ban on profanity.
The main difference between the most well-known radio types and internet radio – sometimes referred to as web, streaming, or e-radio – is that this type of radio is a digital audio service transmitted via the net. It broadcasts thousands of channels and streaming opportunities as a continuous stream of audio that typically can’t be paused or replayed, similar to other broadcast methods.
Using Ham requires special training, licensing, and particular equipment. Normally, the frequencies of ham radio can reach up to about 20 miles, unless a particularly powerful base station is used with a large antenna, then it can have a range of hundreds of miles.
But this is almost irrelevant, as most people today view ham as a form of a unique hobby, learning practical radio skills, and getting to know the world of broadcasting and radio technology. Users can also share the joy of contacting each other around the world. Hams are widely used as a backup plan for when a natural disaster knocks out local networks and services.
Walkie-Talkie is a portable, hand-held device that sends and receives radio signals in a small radius. It’s widely used as a way of communication between two or more people on predefined channels when cell phone services are unavailable. The biggest downside to the Walkie-Talkie is that it can interfere with other radio signals.
Digital Radio (DAB & HD)
Instead of frequency modulation (FM), digital radio depends on digital transmission by radio waves, enabling broadcasting and digital radio services. The first DAB (or Digital Audio Broadcasting) channel went on air in 1995 by the NRK. Soon after, the Swedish radio launched their first DAB broadcasts in the same year.
DAB digital radio is the standard for broadcasts in most countries around the world. This is one of the most reliable radio types, which enables broadcasters to pack together several radio stations (multiplexing).
HD radio is the standard form of digital radio broadcasting in North America. Hybrid Digital Radio is used by either an AM radio station and/or an FM radio station. HDR transmits a digital version of the analog broadcast and provides a second digital channel for alternate radio programming such as weather reports, car navigation updates, and so on.
Digital radios are becoming more and more in demand, therefore most places use them as their standard broadcasting method.