A Short History of Radio: From AM Towers to Streams
Updated
Radio is one of the oldest continuously operating mass communication technologies in human history, and the only one that has survived into the streaming age without fundamentally changing what it does. The technology changed completely. The editorial act — a person or institution choosing what to broadcast, for an audience they're imagining — stayed the same.
Here's how we got from a spark gap in a laboratory to a browser tab playing jazz from Osaka.
The Experimental Era: Late 19th to Early 20th Century
The physics of radio wave transmission was understood theoretically before anyone had built a working transmitter. Heinrich Hertz demonstrated that electromagnetic waves could be generated and detected in the 1880s. Guglielmo Marconi, building on that work, produced the first practical wireless telegraphy system in the mid-1890s — initially capable of transmitting Morse code across modest distances.
The early appeal was entirely practical: wireless communication between ships and shore, between parties who couldn't be connected by cable. The idea of radio as a medium for entertainment or cultural broadcast hadn't yet formed.
That began to change in the first decade of the 20th century. Reginald Fessenden, a Canadian engineer, transmitted the first known audio broadcast — voice and music — on Christmas Eve in 1906, from a station in Massachusetts. The audience was ship radio operators who had been expecting Morse code and instead heard a human voice and a violin.
The moment was more symbolic than commercially significant, but it established the possibility: radio could carry something other than utility. It could carry culture.
The Broadcast Era: 1920s–1950s
Commercial broadcasting emerged rapidly after the First World War. Stations began appearing across North America and Europe in the early 1920s, broadcasting news, music, drama, and sport. The BBC launched as a corporation in 1927, establishing the public broadcast model that still shapes radio policy in many countries.
What broadcasting created, for the first time in history, was simultaneous mass cultural experience. Millions of people in different cities could hear the same programme at the same moment. The radio set became a household fixture — the centre of the family sitting room in the way the television would become a generation later.
This period also established the editorial architecture of radio: programming directors, music directors, schedules, formats. The idea that a station has an identity — a consistent sense of what it broadcasts and when — is a product of the broadcast era's need to hold an audience across time.
The AM (amplitude modulation) band was the dominant technology through this period. Its limitations — susceptibility to atmospheric interference, particularly at night — were accepted as the cost of reach.
FM and the Sound Revolution: 1930s–1970s
FM (frequency modulation) radio was developed by Edwin Armstrong in the 1930s and promised dramatically better audio quality — cleaner, with less static, and capable of stereo. It took decades to reach its potential. Early regulatory decisions in the United States prioritised AM, and FM developed slowly until the 1960s.
The counterculture of the late 1960s found FM radio naturally. Progressive rock stations, freeform formats, long-form albums played without commercial interruption — FM in this period became associated with a kind of broadcasting that felt less commercially structured and more editorially adventurous than the tightly formatted AM pop stations of the same era.
By the 1970s, FM had overtaken AM in audience share in many markets, and the cleaner sound of FM had become the expected standard for music broadcasting.
The Digital Transition: 1980s–2000s
The MP3's arrival in the mid-1990s was the first moment individuals could practically store and play their own music libraries without physical media. The iPod made it portable. "Why listen to radio when I can carry my own music?" became a reasonable question.
What radio's critics underestimated was the persistence of editorial value. Personal libraries are libraries: you can only access what you already own or have chosen. Radio continued to surface what was outside that — introducing artists, providing context, maintaining liveness.
Internet radio emerged in the mid-1990s, initially fragile and niche. But the principle was immediately interesting: radio, freed from geography. A station built around a genre or a sensibility could now reach anyone with an internet connection. The constraint that had defined broadcast radio — you reach whoever can receive your signal — dissolved.
The Streaming Age: 2000s–Present
On-demand platforms changed the listener's relationship with recorded music fundamentally: access replaced ownership, and algorithmic recommendation replaced themed browsing as the primary discovery mechanism.
Internet radio found its role not by competing with on-demand streaming but by occupying the space streaming left open: liveness, themed browsing, non-deliberate discovery, and genuine global reach.
The themed collection — a set of stations organised by mood, genre, or listening moment — became a format of its own. The country browser made browsing by country straightforward. What internet radio is today — browser-based, globally accessible, human-curated — is in some ways closer to the original broadcast vision than anything that came between.
What Radio Kept
Through amplitude modulation, frequency modulation, digital compression, and streaming infrastructure, radio kept one thing constant: someone decides what plays.
The editorial act — the music director, the programme planner, the station founder with a vision — is the same act regardless of whether the signal travels by radio wave or TCP/IP packet. That continuity is not an accident. It's the thing that makes radio radio rather than simply a music delivery mechanism.
What changed is the scale of possibility. A person can now discover radio from every country from a single browser window. A station built by a single person in their home can reach a global audience of shared sensibility. The audience that was once bounded by geography is now bounded only by interest.
That, in retrospect, was the promise of radio from Fessenden's Christmas Eve broadcast onwards: that sound could travel farther than a voice, and that somewhere at the other end, someone would be listening.
Summary
Radio is more than 120 years old as a technology and has survived every medium predicted to replace it. What it preserved through every technological transition — from AM to FM to digital to internet — is the thing that can't be automated: the editorial decision, made by a person, that this is worth broadcasting.
The format that began with a violin heard through Morse code receivers on Christmas Eve in 1906 is now a global stream accessible on any browser. The technology is unrecognisable. The act of curation is the same.