Radio owes its development to two other inventions, the telegraph and the telephone; all
three technologies are closely related. Radio technology began as "wireless telegraphy".
Radio can refer to either the electronic appliance that we listen with or the content
listened to. However, it all started with the discovery of "radio waves" - electromagnetic waves
that have the capacity to transmit music, speech, pictures and other data invisibly through the air.
Many devices work by using electromagnetic waves including: radio, microwaves, cordless
phones, remote controlled toys, television broadcasts, and more.
The Roots of Radio
During the 1860s, Scottish physicist, James Clerk Maxwell predicted the existence of
radio waves; and in 1886, German physicist, Heinrich Rudolph Hertz demonstrated that rapid
variations of electric current could be projected into space in the form of radio waves similar to
those of light and heat.
In 1866, Mahlon Loomis, an American dentist, successfully demonstrated "wireless telegraphy."
Loomis was able to make a meter connected to one kite cause another one to move, marking the
first known instance of wireless aerial communication.
Guglielmo Marconi, an Italian inventor, proved the feasibility of radio communication. He sent
and received his first radio signal in Italy in 1895. By 1899 he flashed the first wireless signal
across the English Channel and two years later received the letter "S", telegraphed from England
to Newfoundland. This was the first successful transatlantic radiotelegraph message in 1902.
In addition to Marconi, two of his contemporaries Nikola Tesla and Nathan Stufflefield
took out patents for wireless radio transmitters. Nikola Tesla is now credited with being the first
person to patent radio technology; the Supreme Court overturned Marconi's patent in 1943 in
favor of Tesla.
Growth of Radio - Radiotelegraph and Spark-Gap Transmitters
Radio-telegraphy is the sending by radio waves the same dot-dash message used in
a telegraph. Transmitters at that time were called spark-gap machines. It was developed mainly
for ship-to-shore and ship-to-ship communication. This was a way of communicating between
two points; however, it was not public radio broadcasting as we know it today.
2. Wireless signals proved effective in communication for rescue work when a sea disaster
occurred. In 1899 the United States Army established wireless communications with a lightship
off Fire Island, New York. Two years later the Navy adopted a wireless system. Up to then, the
Navy had been using visual signaling and homing pigeons for communication.
In 1910 Marconi opened regular American-European radiotelegraph service. In 1912, the
first transpacific radiotelegraph service linked San Francisco with Hawaii.
Improvements to Radio Transmitters
Overseas radiotelegraph service developed slowly, primarily because the initial
radiotelegraph transmitter discharged electricity within the circuit and between the electrodes
was unstable causing a high amount of interference. The Alexanderson high-frequency alternator
and the De Forest tube resolved many of these early technical problems.
Lee DeForest - AM Radio
Lee Deforest invented space telegraphy, the triode amplifier and the Audion. In the early
1900s, the great requirement for further development of radio was an efficient and delicate
detector of electromagnetic radiation. Lee De Forest provided that detector. It made it possible to
amplify the radio frequency signal picked up by the antenna before application to the receiver
detector; thus, much weaker signals could be utilized than had previously been possible. De
Forest was also the person who first used the word "radio".
The result of Lee DeForest's work was the invention of amplitude-modulated or AM
radio that allowed for a multitude of radio stations. The earlier spark-gap transmitters did not
allow for this.
Military Use and Patent Control
When the United States entered the First World War in 1917, all radio development was
controlled by the U.S. Navy to prevent its possible use by enemy spies. The U.S. government
took over control of all patents related to radio technology.
In 1919, after the government released its control of all patents, the Radio Corporation of
America (RCA) was established with the purpose of distributing control of the radio patents that
had been restricted during the war.
The first time the human voice was transmitted by radio is debatable. Claims to that
distinction range from the phase, "Hello Rainey" spoken by Natan B. Stubblefield in 1892, to an
experimental program of talk and music by Fessenden, in 1906, which was heard by radio-
equipped ships within several hundred miles.
3. Reginald A. Fessenden
Canadian, Reginald A. Fessenden is best known for his invention of the modulation of
radio waves and the fathometer. Fessenden started his own company where he invented the
modulation of radio waves, the "heterodyne principle" which allowed the reception and
transmission on the same aerial without interference.
True Broadcasting Begins
Until 1929 the high seas public radiotelephone service was not inaugurated. At that time
telephone contact could be made only with ships within 1,500 miles of shore. Today there is the
ability to telephone nearly every large ship wherever it may be on the globe.
Commercial radiotelephony linking North America with Europe was opened in 1927 and
with South America three years later. In 1935 the first telephone call was made around the world,
using a combination of wire and radio circuits.
Edwin Howard Armstrong invented frequency-modulated or FM radio in 1933. FM
improved the audio signal of radio by controlling the noise static caused by electrical equipment
and the earth's atmosphere. Telephone connection by radio and cable is now accessible with 187
Radio technology has grown significantly since its early development. In 1947, Bell Labs
scientists invented the transistor. In 1954, a then small Japanese company called Sony introduced
the transistor radio.
FM Antenna System
In 1965, the first Master FM Antenna system in the world designed to allow individual
FM stations to broadcast simultaneously from one source was erected on the Empire State
Building in NYC.
1920 to 1950 – Golden ages of Radio – Drama, Music, Comedy and other entertainment
programs got immense popularity.
Immense developments in radio communication technology after World War II helped
make possible space exploration, most dramatically in the Apollo moon-landing missions (1969-
72) and communications satellites.
Most radio historians assert that radio broadcasting began in 1920 with the historic
broadcast of KDKA. The public, however, was overcome by a radio craze after the initial
4. broadcast. Radio became a product of the mass market. Manufacturers were overwhelmed by
the demand for receivers, as customers stood in line to complete order forms for radios after
dealers had sold out. Between 1923 and 1930, 60 percent of American families purchased
radios. Families gathered around their radios for night-time entertainment. As radio ownership
increased, so did the number of radio stations. In 1920, KDKA was not actually the only
operating radio station, but it remains a benchmark in most accounts. And by 1922, 600 radio
stations had sprung up around the United States. The advance of radio technology also created a
tension between modernity and the traditions and habits of Americans.
The rapid spread of radio listeners and programs lead to inevitable confusion and
disruption. Radio waves were up for grabs, as stations competed with one another for time and
listeners. Many programs overlapped. Listeners of one program were frequently interrupted by
overlapping programs. In addition, the public, the government, and emerging radio corporations
viewed radio as a means of public service, rarely as a vehicle for personal profit. Radio
manufacturers alone experienced financial gain from the radio boom. Radio announcers,
deejays, and stations worked on a non-profit basis. Advertising was not introduced until later in
the 1920s, changing the public service face of radio, to one of private gain.
The federal government hesitated to regulate the airwaves. Radio stations, listeners, and
emerging broadcasting corporations all asked the government for some sort of intervention to
end the free-for-all that radio had become. The government responded slowly, gradually passing
laws to govern the radio. The Federal Radio Commission was set up in 1926; the Radio Act of
1927 organized the Federal Radio Commission. This Act became the basis for the
Communications Act passed after the rise of television. As the government spent more time
investigating radio stations, apportioning time to different groups and programs, and monitoring
the growth of the radio industry, they became more and more comfortable with the
responsibilities of regulation. These federal bodies eventually ceased to doubt their right to
March 1926 The Indian Broadcasting Company (IBC) ‚ a private Company‚ was formed
in subcontinent. 23rd July‚ 1927 IBC started a station at Bombay‚ thus beginning organized
broadcasting in Indo-Pakistan‚ sub-continent. Nov 12‚ 1939 Quaid-e-Azam's first radio
broadcast from Bombay radio station on Eid day. 3 June 1947 Quaid-e-Azam Muhammad Ali
Jinnah makes historic address on AIR and announces the creation of the newly independent state
of PAKISTAN for the Muslims of the sub-continent. Aug 14‚1947 Pakistan comes into being
and the announcement of its creation is made by the new organization‚ the Pakistan Broadcasting
Service which comes into existence at the same time and later designated as Radio Pakistan
At the time of the emergence of Pakistan there were just three radio stations, i.e.; radio
station Lahore, radio station Dhaka and radio station Rawalpindi, in the newly born country.
Some specific areas were figured out in which the broadcasting in Pakistan concentrated in the
coming years. Right from the start until the early 90s of the last century, Radio Pakistan, which
5. was later turned to be called Pakistan Broadcasting Corporation in 1972, enjoyed complete
monopoly in the realm of radio broadcasting. This monopoly was though disturbed with the
emergence of F.M. broadcast in the private sector, but still the public sector medium enjoys the
maximum approach to people with a wide range of radio stations, F.M. and A.M. both, in every
nook and corner of the country.
Social scientists are feeling that Pakistani society is converting into information society,
gradually. The majority of Pakistani population is economically poor .The governments have not
paid proper attention towards education. As a result, they can't gain education properly. Despite
all these things, the Pakistani society is in process of change slowly, because media is
influencing on it. Like other low literate societies of world, the radio's role in Pakistani society is
also very significant. Radio's role as an effective source of information, education and
entertainment is always acknowledged in this country. Since independence various AM
broadcasting stations have been developed in different parts of the country to cater the
information and entertainment needs of the nation. However along with AM radio stations, FM
radio stations are also working all over the country. In Pakistan, FM transmission started in
1990s and gained popularity immediately after its introduction for two reasons; one it was
directly targeting youth second, it used music as a tool to catch audiences. For quite a time now
private FM channels are being introduced that has allowed competition in the market and has
also played a part in reviving radio’s status as a popular mass medium.
AM and FM Radio
AM (or Amplitude Modulation) and FM (or Frequency Modulation) are ways of
broadcasting radio signals. Both transmit the information in the form of electromagnetic waves.
AM method of audio transmission was first successfully carried out in the mid 1870s. FM
radio was developed in the United states mainly by Edwin Armstrong in the 1930s.
In AM, a radio wave known as the "carrier" or "carrier wave" is modulated
in amplitude by the signal that is to be transmitted. In FM, a radio wave known as the "carrier" or
"carrier wave" is modulated in frequency by the signal that is to be transmitted.
AM and FM are used in both analog and digital communication and telemetry.
Pros and cons:
6. AM has poorer sound quality compared to FM, but is cheaper and can be transmitted over
long distances. It has a smaller bandwidth so it can have more stations available in any frequency
range.FM is less prone to interference than AM. However, FM signals are impacted by physical
barriers. FM has greater sound quality due to higher bandwidth.
AM stands for Amplitude Modulation. FM stands for Frequency Modulation
AM radio ranges from 535 to 1705 kilohertz (OR) Up to 1200 Bits per second. FM radio ranges
in a higher spectrum from 88 to 108 megahertz. (OR) 1200 to 2400 bits per second Bandwidth
AM has twice the highest modulating frequency. In AM radio broadcasting, the modulating
signal has bandwidth of 15 kHz, and hence the bandwidth of an amplitude-modulated signal is
30 kHz. FM has twice the sum of the modulating signal frequency and the frequency deviation.
If the frequency deviation is 75 kHz and the modulating signal frequency is 15 kHz, the
bandwidth required is 180 kHz.
Zero crossing in modulated signal:
AM is equidistant while FM is not equidistant.
In AM, transmitter and receiver are simple but in case of SSBSC AM carrier
synchronization is needed. In FM, transmitter and receiver are more complex as variation of
modulating signal has to converted and detected from corresponding variation in frequencies.(i.e.
voltage to frequency and frequency to voltage conversion has to be done) which are quite
AM is more susceptible to noise because noise affects amplitude, which is where
information is "stored" in an AM signal. FM is less susceptible to noise because information in
an FM signal is transmitted through varying the frequency, and not the amplitude.
Community radio is a radio service offering a third model of radio broadcasting in
addition to commercial and public broadcasting.
7. They broadcast content that is popular and relevant to a local, specific audience but is
often overlooked by commercial or mass-media broadcasters. Community radio stations are
operated, owned, and influenced by the communities they serve. They are generally non-
profit and provide a mechanism for enabling individuals, groups, and communities to tell their
own stories, to share experiences and, in a media-rich world, to become creators and contributors
In many parts of the world, community radio acts as a vehicle for the community and
voluntary, civil society, agencies, NGOs and citizens to work in partnership to further
community aims, in addition to broadcasting.
Modern community radio stations serve their listeners by offering a variety of content
that is not necessarily provided by the larger commercial radio stations. Community radio outlets
may carry news and information programming geared toward the local area. Specialized musical
shows are also often a feature of many community radio stations.
Educational stations are used for educational purposes and do not accept on air
advertisements. Radio is a powerful mass medium used in education for disseminating
information, imparting instruction and giving entertainment. It serves with equal ease in both
developed and developing countries. It spreads information to a greater group of population
thereby saving time, energy, money and man-power in an effective way.
Educational Broadcast was occasionally started by All India Radio long back in 1928 and
regularized after a decade. Radio came to India through amateurs with educational purpose first
in1923 in a small way and after four years it could find its root here. In India, then it was used
for educational purposes in almost all the possible fields. Being the only instrument to reach to
masses in this country for a long time, its educational role was exploited thoroughly. All India
Radio was a government medium and had the opportunity of covering the entire Country. It has
been mostly used for developmental activities after independence. As such All India Radio has
an objective to broadcast education with information and entertainment. So in most of its
broadcasts the educational element used to be there. While the accent of all the programs
whether for the general listener, or specific groups like farmers, women, children, students,
teachers or industrial workers, is on education in the widest sense, some programs planned with a
specific educational objective. Educational elements in broadcasts consist in the form of
informal, non- formal and formal nature. In every program some massage or morals are given
with a purpose to educate the listener but in an informal way. Non-formal educational programs
are broadcast for school drop outs, neo-literates, illiterate adults, farmers etc. The formal
educational broadcast programs are for the Primary Schools, Secondary Schools and
8. In Pakistan, ZabFM 106.6; SZABIST launched the first educational radio, a non-
commercial radio broadcast station, exclusively to impart and disseminate education to the
Radio is the only cheap entertainment thing which can be easily afforded by every
person. you can buy a small radio cost 100 rupees and take it with yourself anywhere any time it
will provide you with song's, drama's, news, music all time favorites ,latest music and program's
for youngsters and adults. No panic that is the important element. I think that radio is the perfect
thing for entertainment. But yes we do need some betterment in radio programs. New concept of
programming should be introduced. There should be some difference in night and morning
programming. According to my opinion I think that radio have a very bright future in Pakistan.
As it have a lot more listeners. Radio is the only medium which gives information to the people
who lives in rural and mountainous areas. Radio has its own specific audience who loves to
listen it, and those audiences can never stop listening to radio. Radio is the only entertainment
and information box which you can carry anytime to anywhere.