The Evolution of Radio: From Marconi to Modern Broadcasting

Radio is one of the most transformative inventions in the history of human communication. From the first crackle of electromagnetic waves transmitted across a room to the crystal-clear digital broadcasts streamed across continents today, the journey of radio technology is a story of scientific brilliance, wartime necessity, and constant reinvention. This post traces that journey – from the pioneering experiments of the late 19th century to the digital broadcasting standards shaping radio’s future.

The pioneers behind radio: Bose and Marconi 🔗

The invention of radio cannot be credited to a single individual. It was the product of contributions from multiple scientists across different countries. However, two names stand out prominently in any discussion of early radio technology: Jagadish Chandra Bose from India and Guglielmo Marconi from Italy.

Jagadish Chandra Bose and the first radio waves 🔗

In 1895, Jagadish Chandra Bose conducted a public demonstration at Presidency College, Calcutta, where he transmitted and received electromagnetic waves at 60 GHz over a distance of 23 metres, passing through two walls to remotely ring a bell and detonate gunpowder. This was a groundbreaking achievement in wireless communication.

Bose developed a complete suite of millimetre-wave components for his experiments – including spark transmitters, coherers, dielectric lenses, polarisers, and horn antennas. He was also the first person to use semiconductor junctions to detect radio waves, laying early groundwork for solid-state electronics. His mercury coherer, a radio wave receiver, proved to be a critical piece of technology that would later play a key role in Marconi’s transatlantic experiments.

What makes Bose’s story particularly notable is his philosophy towards science. Unlike many of his contemporaries, he chose not to pursue patents or commercial gains from his inventions. He believed scientific discoveries should be openly available to all, an approach remarkably similar to today’s open-source movement. Nobel laureate Sir Nevill Mott later observed that Bose was decades ahead of his time in his understanding of semiconductor behaviour.

Guglielmo Marconi and the commercialisation of wireless 🔗

While Bose pursued research for the sake of science, Guglielmo Marconi took a different path – he focused on the practical and commercial applications of wireless communication. In 1896, Marconi filed the first patent for a wireless telegraphy system in London. By 1897, he had successfully transmitted Morse code signals over distances of more than 3.5 miles on Salisbury Plain, England.

Marconi’s crowning achievement came on 12 December 1901, when he received the first transatlantic wireless signal at Signal Hill, Newfoundland, transmitted from Poldhu in Cornwall. Notably, the coherer used in this historic reception was based on Bose’s iron-mercury-iron design, as documented by researchers at the National Radio Astronomy Observatory. Marconi went on to be co-awarded the Nobel Prize for Physics in 1909 for his work in wireless telegraphy.

The key difference between Bose and Marconi was not just geography or funding – it was intent. Bose was driven by scientific curiosity; Marconi was driven by commercial vision. Together, their contributions form the twin pillars on which radio technology was built.

Radio goes to war: military communication in the World Wars 🔗

Radio technology’s true test came during the two World Wars, where it proved to be an indispensable military asset. The demands of wartime communication accelerated radio’s development far beyond what peacetime innovation alone could have achieved.

World War I: wireless on the battlefield 🔗

When World War I broke out in 1914, wireless telegraphy was already recognised as strategically important. The British government took control of key Marconi Company assets, including its transatlantic stations and the factory at Chelmsford. The Marconi Company set up large-scale training programmes for wireless operators to meet wartime demand.

On the battlefield, radio served several critical functions. It was used to coordinate troop movements, direct artillery fire from aircraft, and intercept enemy signals. Direction-finding technology allowed British forces to track the positions of German transmitters and even monitor Zeppelin airship routes. The Royal Flying Corps began using wireless to guide artillery fire as early as 1914, and by 1916, Marconi’s company was producing air-to-ground radio transmitters for combat aircraft.

World War II: radio as a mass communication weapon 🔗

By the Second World War, radio had evolved from a military signalling tool into a full-fledged mass communication medium. It served both tactical and propaganda purposes. Leaders like Franklin D. Roosevelt, Winston Churchill, and Adolf Hitler all used radio to influence public opinion and rally support during the war years.

On the technical side, advances during World War II included more portable radio sets for airborne troops, improved encryption technology, and microwave-based communication systems. The breaking of Germany’s Enigma-encrypted radio transmissions, producing intelligence codenamed “Ultra,” played a major role in the Allied victory.

The birth of public broadcasting and radio in India 🔗

After World War I, radio’s potential as a medium for public communication became increasingly clear. The 1920s saw a boom in radio broadcasting across Europe and America, with universities, churches, and newspapers all jumping onto the new platform. In this global wave, India, too, took its first steps into organised broadcasting.

From radio clubs to the Indian Broadcasting Company 🔗

Radio broadcasting in India started in June 1923 with experimental transmissions by the Radio Club of Bombay. A Calcutta Radio Club followed a few months later. These were amateur efforts by radio enthusiasts who had imported equipment and were eager to explore the medium.

A more organised approach began on 23 July 1927, when the private Indian Broadcasting Company (IBC) was authorised to operate two radio stations – one in Bombay (which launched on the same day) and one in Calcutta (which followed on 26 August 1927). This date is now celebrated as National Broadcasting Day in India.

However, the IBC faced severe financial difficulties. In a country where radio receivers were a luxury, the company could not find a sustainable business model and went into liquidation by March 1930.

Government takeover and the formation of All India Radio 🔗

Recognising radio’s strategic value for a country as vast and diverse as India, the government stepped in. In April 1930, the Indian State Broadcasting Service (ISBS) was launched on an experimental basis under the Department of Industries and Labour. It became a permanent service in May 1932.

In August 1935, Lionel Fielden, a senior producer at the BBC, was appointed as the first Controller of Broadcasting. On 8 June 1936, the ISBS was officially renamed All India Radio (AIR). The Central News Organisation was established in 1937, giving AIR a structured news broadcasting capability.

At the time of India’s independence in 1947, AIR operated just six stations – in Delhi, Bombay, Calcutta, Madras, Lucknow, and Tiruchirappalli – serving only about 2.5% of India’s land area and 11% of its population. In 1956, AIR adopted the name Akashvani, meaning “voice from the sky,” and in 1957, the Vividh Bharati entertainment service was launched to compete with the hugely popular Radio Ceylon.

Today, AIR operates over 470 stations across India, broadcasting in 23 languages and 179 dialects, covering nearly 92% of the country’s geographic area. It remains one of the largest radio networks in the world.

Understanding AM and FM: the analogue foundations 🔗

Before diving into digital radio, it is important to understand the two analogue technologies that dominated radio broadcasting for most of the 20th century: AM (Amplitude Modulation) and FM (Frequency Modulation).

AM broadcasting 🔗

AM was the first method used for radio broadcasting. It works by varying the amplitude (strength) of the carrier wave in accordance with the audio signal. AM signals can travel long distances, especially at night when medium wave (MW) and shortwave (SW) signals bounce off the ionosphere. This made AM ideal for national and international broadcasting. However, AM is highly susceptible to interference from electrical equipment, atmospheric static, and other radio signals, resulting in lower audio quality.

FM broadcasting 🔗

FM was developed as an improvement over AM. Instead of changing the amplitude, FM varies the frequency of the carrier wave. This produces a much cleaner, higher-fidelity sound with better resistance to noise and interference. FM became the preferred choice for music broadcasting because of its superior audio quality. However, FM signals travel in straight lines and do not bounce off the ionosphere, which limits their range to roughly line-of-sight distances – typically 50 to 100 kilometres from the transmitter.

In India, AIR currently uses all three analogue modes – shortwave (SW), medium wave (MW), and FM – to ensure coverage across both urban and remote areas.

The shift to digital: DAB and DRM 🔗

By the late 20th century, the limitations of analogue broadcasting – interference, limited channel capacity, and inconsistent audio quality – drove the industry towards digital solutions. Two major digital broadcasting standards emerged: Digital Audio Broadcasting (DAB) and Digital Radio Mondiale (DRM).

Digital Audio Broadcasting (DAB) 🔗

The DAB standard grew out of a European research initiative. Work on the concept began in the 1980s as a collaboration between the West German Institut für Rundfunktechnik (IRT) and France’s Centre commun d’études de télévision et télécommunications (CCETT). The project was formally designated Eureka-147 in 1987, with the goal of developing a system offering better reception than FM, with additional capacity for text, data, and multimedia services.

The DAB protocol was finalised in the early 1990s and adopted by the ITU in 1994. Norway’s NRK launched the world’s first DAB channel in June 1995, followed by the BBC and Swedish Radio later that year. DAB uses audio compression techniques (originally MPEG-1 Layer II, later upgraded to HE-AAC v2 in the DAB+ standard) to fit more stations into the same bandwidth. A single DAB multiplex can carry up to six stereo programmes in the bandwidth that one FM station would use.

As of today, over 55 countries have launched regular or trial DAB/DAB+ broadcasts. Norway became the first country to begin switching off FM in favour of DAB in 2017, and several other European nations are planning similar transitions.

Digital Radio Mondiale (DRM) 🔗

Digital Radio Mondiale was developed specifically to address the needs of countries that rely heavily on AM (medium wave and shortwave) broadcasting. While DAB was designed for new frequency bands, DRM was built to operate on the existing AM and FM bands, making it a practical upgrade path for broadcasters who cannot afford entirely new transmission infrastructure.

The DRM consortium was formed with the involvement of major international broadcasters including the BBC World Service, Deutsche Welle, Radio France Internationale, and Voice of America. The DRM standard uses the xHE-AAC audio codec to deliver near-FM quality sound even on AM frequencies. It also supports data transmission alongside audio – text, images, and even emergency warning features that can activate radios in standby mode during crises.

DRM comes in two variants. DRM30 covers frequencies below 30 MHz (shortwave, medium wave, and long wave), delivering high-quality audio over very long distances. DRM+ extends the standard to VHF/FM bands above 30 MHz. A key advantage of DRM is that existing analogue transmitters can be modified to switch between digital and analogue modes, allowing broadcasters to phase in digital services gradually without massive capital expenditure.

India has been a particularly active adopter of DRM technology. All India Radio has been transitioning its medium wave and shortwave transmitters to DRM as part of the government’s push towards digital radio broadcasting. For a geographically vast and linguistically diverse country like India, DRM’s ability to deliver quality digital audio over long distances on existing frequencies makes it an especially suitable choice.

DAB vs. DRM: which standard for which need? 🔗

DAB and DRM are not competing standards so much as they are complementary technologies designed for different scenarios. DAB works best in countries with well-developed FM infrastructure and available VHF spectrum – primarily in Europe, Australia, and parts of Asia. DRM, on the other hand, is better suited for nations with extensive AM/SW networks and large rural populations that need long-range coverage.

DAB requires entirely new transmission and reception infrastructure. DRM can coexist with existing analogue systems and even operate on the same frequencies. DRM also has the advantage of being significantly more energy-efficient – broadcasters can achieve the same or better coverage with fewer transmitters and lower power, which translates to cost savings of up to 90% in some cases.

The challenge for DRM has been the availability of affordable receivers. For years, the lack of low-cost consumer radios held back DRM adoption. However, recent developments in chipset technology are finally bringing down receiver costs, which could trigger wider adoption in countries like India, Indonesia, South Africa, and across Africa.

Radio in the age of the internet 🔗

Digital broadcasting is just one part of radio’s modern evolution. Internet radio, podcasting, and music streaming services have all transformed how people consume audio content. Yet traditional radio – whether analogue or digital – continues to serve a critical function, especially in regions with limited internet connectivity.

For roughly a third of the world’s population that still lacks reliable internet access, terrestrial radio remains the primary source of news, education, and entertainment. Digital standards like DRM are particularly significant here because they bring 21st-century audio quality and data services to communities that may never have broadband internet.

Radio’s adaptability is precisely what has kept it relevant for over a century. From Bose’s laboratory in Calcutta to Marconi’s transatlantic signals, from wartime walkie-talkies to AIR’s nationwide Akashvani network, from AM static to crystal-clear DRM broadcasts – the medium has continuously reinvented itself to stay at the centre of human communication.

What do you think? Given the rise of internet streaming and podcasts, do you believe traditional radio broadcasting still has a vital role to play in countries like India? And should governments invest more aggressively in digital radio standards like DRM to bridge the digital divide in rural areas?

References

1. https://ethw.org/Milestones:First_Millimeter-wave_Communication_Experiments_by_J.C._Bose,_1894-96
2. https://www.britannica.com/biography/Jagadish-Chandra-Bose
3. https://interestingengineering.com/culture/jagadish-chandra-bose-father-modern-wi-fi
4. https://www.mhs.ox.ac.uk/marconi/collection/history.php
5. https://www.cv.nrao.edu/~demerson/bose/bose.htm
6. https://www.mhs.ox.ac.uk/marconi/exhibition/worldwarone.htm
7. https://marconiheritage.org/ww1intro-3.html
8. https://www.elon.edu/u/imagining/time-capsule/150-years/back-1890-1930/
9. https://www.pib.gov.in/PressNoteDetails.aspx?NoteId=151941&ModuleId=3
10. https://www.newsonair.gov.in/national-broadcasting-day-marking-1st-ever-radio-broadcast-from-bombay-station-in-1927/
11. https://www.britannica.com/topic/All-India-Radio
12. https://prasarbharati.gov.in/growth-development/
13. https://en.wikipedia.org/wiki/Eureka-147
14. https://www.museum.tv/radio-encyclopedia-3/digital-audio-broadcasting
15. https://www.drm.org/
16. https://www.drm.org/about-drm/drm-technology/
17. https://www.cambridgeconsultants.com/project/affordable-digital-radio-mondiale/