RADIO â€“ A BREAKTHROUGH IN MASS COMMUNICATION:What to broadcast

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Introduction to Mass Communication MCM 101

LESSON 30

RADIO A BREAKTHROUGH IN MASS COMMUNICATION

People around the world were benefiting from the newspapers as one fine mean of mass

communication since the middle of 15th century that in the last decade of the 19th century scientists came

close to opening gates for an entirely different means of communication which would require no paper and

printing press and transportation of the publication. It was a mean to carry your voice to million others in a

flash of an eye. It was the invention of radio.

It was a miracle in the field of mass communication that a person could address a very number of audiences

and that too, to a distance of thousands of kilometers away.

What is radio?

Radio is a technology that allows the transmission of signals by modulation of electromagnetic

waves with frequencies below those of light.

Science of Radio waves

Radio waves are a form of electromagnetic radiation, and are created whenever a charged object

accelerates with a frequency that lies in the radio frequency (RF) portion of the electromagnetic spectrum.

This is the range from a few tens of hertz to a few giga hertz. Electromagnetic radiation travels by means of

oscillating electric and magnetic fields that pass through the air and the vacuum of space equally well, and

does not require a medium of transport.

By contrast, other types of electromagnetic radiation, with frequencies above the RF range are gamma rays,

X-rays, and infrared, ultraviolet and visible light.

How the miracle came about?

The theoretical basis of the propagation of electromagnetic waves was first described in 1873 by

James Clerk Maxwell in his paper to the Royal Society A dynamical theory of the electromagnetic field, which

followed his work between 1861 and 1865.

In 1878 David E. Hughes was the first to transmit and receive radio waves when he noticed that his

induction balance caused noise in the receiver of his homemade telephone. He demonstrated his discovery

to the Royal Society in 1880 but was told it was merely induction.

It was Heinrich Rudolf Hertz who, between 1886 and 1888, first validated Maxwell's theory through

experiment, demonstrating that radio radiation had all the properties of waves. A great achievement indeed

it proved to be.

Marconi recognized as radio inventor

In 1896 Guglielmo Marconi was awarded what is sometimes recognized as the world's first patent

for radio with British Patent 12039, Improvements in transmitting electrical impulses and signals and in apparatus there-

for. In 1897 he established the world's first Radio Station on the Isle of Wight, England. The same year in

the USA, some key developments in radio's early history were created and patented by Nikola Tesla. The

US Patent Office reversed its decision in 1904, awarding Guglielmo Marconi a patent for the invention of

radio, possibly influenced by Marconi's financial backers in the States, who included Thomas Edison and

Andrew Carnegie. Some believe this was done to allow the US Government to avoid having to pay the

royalties that were being claimed by Nikola Tesla for use of his patents.

In 1909 Marconi, with Karl Ferdinand Braun, was also awarded the Nobel Prize in Physics for

"contributions to the development of wireless telegraphy". Marconi opened the world's first "wireless"

factory in Hall Street, Chelmsford, England in 1898, employing around 50 people. Around 1900, Tesla

opened the Wardenclyffe Tower facility and advertised services. By 1903, the tower structure neared

completion. Various theories exist on how Tesla intended to achieve the goals of this wireless system

(reportedly, a 200 kW system). Tesla claimed that Wardenclyffe, as part of a World System of transmitters,

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would have allowed secure multichannel transceiving of information, universal navigation, time

synchronization, and a global location system.

Others work acknowledgement

In 1894 British physicist Sir Oliver Lodge demonstrated the possibility of signaling using radio

waves using a detecting device called a coherer, a tube filled with iron filings which had been invented by

Temistocle Calzecchi-Onesti at Fermo in Italy in 1884. Edouard Branly of France and Alexander Popov of

Russia later produced improved versions of the coherer. Popov, who developed a practical communication

system based on the coherer, is often considered by his own countrymen to have been the inventor of

radio.

On Christmas Eve, 1906, Reginald Fessenden (using his heterodyne principle) transmitted the first radio

audio broadcast in history from Brant Rock, Massachusetts. Ships at sea heard a broadcast that included

Fessenden playing the song O Holy Night on the violin and reading a passage from the Bible. The world's

first radio news programme was broadcast August 31st 1920 by station 8MK in Detroit, Michigan. The

world's first regular wireless broadcasts for entertainment commenced in 1922 from the Marconi Research

Centre at Writtle near Chelmsford, England, which was also the location of the world's first "wireless"

factory.

Early radios ran the entire power of the transmitter through a carbon microphone. While some early radios

used some type of amplification through electric current or battery, through the mid 1920s the most

common type of receiver was the Crystal set. In the 1920s, amplifying vacuum tubes revolutionized both

radio receivers and radio transmitters.

Advancement on radio technology continues

· Aircraft used commercial AM radio stations for navigation. This continued through the early 1960s

when VOR systems finally became widespread (though AM stations are still marked on United

States aviation charts).

· In the early 1930s, single sideband and frequency modulation were invented by amateur radio

operators. By the end of the decade, they were established commercial modes.

· Radio was used to transmit pictures visible as television as early as the 1920s. Standard analog

transmissions started in North America and Europe in the 1940s.

· In 1954, Regency introduced a pocket transistor radio, the TR-1, powered by a "standard 22.5V

Battery".

· In 1960, Sony introduced their first transistorized radio, small enough to fit in a vest pocket, and

able to be powered by a small battery. It was durable, because there were no tubes to burn out.

Over the next twenty years, transistors displaced tubes almost completely except for very high

power, or very high frequency, uses.

· In 1963 color television was commercially transmitted, and the first (radio) communication satellite,

TELSTAR, was launched.

· In the late 1960s, the U.S. long-distance telephone network began to convert to a digital network,

employing digital radios for many of its links.

· In the 1970s, LORAN became the premier radio navigation system. Soon, the U.S. Navy

experimented with satellite navigation, culminating in the invention and launch of the GPS

constellation in 1987.

· In the early 1990s, amateur radio experimenters began to use personal computers with audio cards

to process radio signals. In 1994, the U.S. Army and DARPA launched an aggressive, successful

project to construct a software radio that could become a different radio on the fly by changing

software.

· Digital transmissions began to be applied to broadcasting in the late 1990s.

World grabs radio for a range of uses

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AM broadcast radio sends music and voice in the Medium Frequency (MF -- 0.300 MHz to 3

MHz) radio spectrum. AM radio uses amplitude modulation, in which louder sounds at the

microphone causes wider fluctuations in the transmitter power while the transmitter frequency

remains unchanged. Transmissions are affected by static because lightning and other sources of

radio add their radio waves to the ones from the transmitter.

FM broadcast radio sends music and voice, with higher fidelity than AM radio. In frequency

modulation, louder sounds at the microphone cause the transmitter frequency to fluctuate farther,

the transmitter power stays constant. FM is transmitted in the Very High Frequency (VHF -- 30

MHz to 300 MHz) radio spectrum. FM requires more radio frequency space than AM and there are

more frequencies available at higher frequencies, so there can be more stations, each sending more

information. Another effect is that the shorter radio waves act more like light, travelling in straight

lines that are not reflected back towards the Earth by the ionosphere, resulting in a shorter effective

reception range.

Aviation voice radios use VHF AM. AM is used so that multiple stations on the same channel can

be received. (Use of FM would result in stronger stations blocking out reception of weaker stations

due to FM's capture effect). Aircraft are often so high that their radios can see hundreds of miles,

even though they are using VHF.

Marine voice radios can use AM in the shortwave High Frequency (HF -- 3 MHz to 30 MHz) radio

spectrum for very long ranges or narrowband FM in the VHF spectrum for much shorter ranges.

TETRA, Terrestrial Trunked Radio is a digital cell phone system for military, police and

ambulances.

Civil and military HF (high frequency) voice services use shortwave radio to contact ships at sea,

aircraft and isolated settlements.

Government, police, fire and commercial voice services use narrowband FM on special frequencies.

Fidelity is sacrificed to use a smaller range of radio frequencies, usually five kilohertz of deviation (5

thousand cycles per second) for maximum pressure, rather than the 75 used by FM broadcasts and

25 used by TV sound.

What to broadcast

Early radio stations faced the problem of target audience, especially in a pluralistic society. The

economic growth in certain parts of the world also helped radio stations to shape their program. So a part

of broadcast was meant to the specific nature of audience along side news and entertainment. In Pakistan all

radio stations begin their transmission with recitation from Quran due to specific nature of the audience.

Other societies with religious dominance do the same.

Distribution of time

For religious programs

News and views

Entertainment ... music, plays, children and women.

Education ... on health and common social life matters.

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