The History Of Radio Broadcasting

1. The Birth of Broadcasting

After entering the 20th century, radio technology research and experimentation have been carried out in a wider range, and considerable progress has been made, especially the diode invented by the British J. Fleming in 1904 and the American De Faure in 1906. The triode invented by L. De Forest played a decisive role in broadcasting. The diode has two functions: detection and rectification, and the triode adds an amplification function, which can amplify the weak current into a strong current, which solves the problem of radio reception. De Forest also used a triode to successfully develop a tube oscillator, which used it to generate high-frequency electromagnetic waves, which solved the problem of radio transmission. Later, several amplifier transistors were cascaded to make a multi-stage amplifier, and then cooperated with the oscillator. , Made a powerful wireless transmitter. Radio broadcasting is to carry sound signals on radio waves. One of the achievements of electronic tubes is to obtain a continuous radio wave with a certain amplitude and frequency. The electric wave generated by the electric spark discharge used in the past has irregular changes in amplitude and frequency, and only two states of "sending" or "not sending" the electric wave can be used to transmit certain information. Using the continuous electric wave formed by the electron tube, its amplitude and frequency can be artificially changed, so that it can carry useful information for humans. The first application of radio wave modulation technology is the amplitude modulation technology in which sound changes the amplitude of radio waves. 1906 Telefunken in Germany succeeded in experimenting with radio telephones. In 1907, De Reforst conducted an experimental radio broadcast of music and language in New York. These pioneers laid the technical foundation for the advent of broadcasting. During the First World War, radio communications and wireless telephones were widely used by the warring parties. During this time, Armstrong of the United States improved the circuit of the radio receiver and invented the superheterodyne circuit in 1918. This method can prevent two signals with similar frequencies from interfering in the receiver, thereby ensuring that the receiver can receive broadcasts of different frequencies. After the war, the radio industry and technology turned to civilians, and the material and technical conditions of radio stations were available. In October 1920, the privately-run KDKA radio station in Pittsburgh, the United States obtained a business license issued by the government and began broadcasting, becoming the first private commercial radio station in the United States and the world to officially broadcast. In 1922, the United States, Britain, Germany, and the Soviet Union started broadcasting. By 1925, more than 20 countries had officially started broadcasting. Since then, the broadcasting industry has developed rapidly all over the world. Before the Second World War, broadcasting stations were mainly concentrated in European and American countries. After the war, with the independence of many countries in Asia, Africa, and Latin America, the broadcasting industry also developed rapidly in these countries.

2. AM broadcasting and FM broadcasting

Radio channels are a limited natural resource. If two electromagnetic waves are sent at the same or very close frequencies, they will interfere with each other. The medium-wave and short-wave radio waves are the easiest to achieve technically. The way they carry sound is also a relatively simple AM method. Therefore, the original radio broadcasts were medium-wave and short-wave AM broadcasts. Medium waves can propagate along the surface of the earth (ground waves). If the power is large, it can cover an area with a radius of more than 100 kilometers. It can also rely on the reflection of the ionosphere in the outer space of the earth (sky waves), which may reach several hundred or more. Thousands of kilometers away. Shortwaves mainly rely on reflections from the ionosphere, and shortwaves with higher power can travel thousands of kilometers away. Since the 1940s, new broadcasting forms have been produced one after another, mainly the emergence of meter wave FM broadcasting. Compared with medium wave broadcasting, it has the following obvious advantages: it can do high-fidelity broadcasting with beautiful sound; it has high anti-interference ability; the broadcasting frequency band can accommodate a large number of transmitters and broadcast multiple sets of programs; In the case of power transmitters, the service range of the FM broadcast transmitter station is much larger than that of the medium wave transmitter station; stereo broadcasting can be realized relatively easily. Because of these characteristics, developed countries have adopted FM radio as the main listening coverage method for domestic radio. FM stereo broadcasting is developed on the basis of mono FM broadcasting. It uses several microphones in different positions to pick up an artistic broadcasting program, forming a multi-channel signal and broadcasting in the same broadcasting channel, so that the listener can use more A loudspeaker (or earphone) receives the sound from several channels to produce a three-dimensional effect. Due to the direction and level of the sound, it has a strong sense of presence in the auditory, which is more realistic than the monophonic broadcast. Stereo broadcasts that have been actually used include two-channel (left and right two channels) FM stereo broadcasts and stereo sound in TV broadcasts. Beginning in the late 1970s, some countries began to explore FM stereo broadcasting with a stronger sense of three-dimensionality.

Broadcast receivers are usually called radios. In 1922, there were less than 100,000 radios in the United States. Ten years later (1932), there were 3.5 million radios. After another 10 years (1942), it rose to 13 million units. In the early stage, mineral radios and radios using 1-5 tubes were used to receive broadcasts. In addition to diodes and triodes, Hiroshi Ando of Japan and Hal of the United States developed a tetrode in 1919, and Lande of the United Kingdom developed a pentode in 1937. These are generally called vacuum tubes or electron tubes, of which pentode tubes are the most widely used. After the Second World War, W. Shockley, W. Brattain, and J. Bardeen of Bell Laboratories in the United States conducted in-depth research on semiconductors and developed the same technology as electronic tubes. Functional transistor. On June 30, 1948, Bell Laboratories officially announced the successful development of the transistor. This achievement is another milestone in the history of the development of radio technology and has had a revolutionary impact on the electronics industry. For this reason, three American scientists won the 1956 Nobel Prize in Physics. Soon in the production of radios and televisions, transistors immediately replaced electron tubes. Broadcast receivers have developed to the semiconductor stage before they have truly gained unprecedented popularity, which also makes it the most suitable mass media for poor countries, especially in remote areas with weak infrastructure. The FM radio is a much more complicated receiving tool than the AM radio. Since the 1970s, the radio has developed in the direction of being able to receive FM and multi-band AM broadcasts as well as multi-function and high-quality sound recording.


3. The social role of broadcasting

Broadcasting is the first electronic mass media to appear, and it plays a huge role in the political, economic, social, and cultural life of various countries. Once the broadcasting station was born, it showed great superiority in information dissemination. Lenin pointed out that the radio enabled "the whole of Russia to hear Moscow's newspaper of the day". At the beginning of the trial broadcast of Moscow Radio, the first program it launched was "Speaking of Newspapers" and evening news. When the KDKA radio station in the United States was launched, it only broadcasted for one hour a day in the evening, but it reported the campaign activities and results of the US presidential election in a timely manner one week after the broadcast. In October 1924, 26 radio stations on the east and west coasts of the United States simultaneously broadcast President Coolidge’s speech.

From the history of communication, before the advent of television, broadcasting once made people fascinated. American popular media scholar De Fleur described that Americans loved broadcasting back then and said, “Families with distressed sources of income must save money for repairs after the radio breaks down. They may return the furniture to the loan company or default on the rent. But they clung to the radio. "Today, the form of wireless broadcasting is very complete and developed. It has penetrated into people's daily life. Moreover, the radio waves of various countries and regions are intertwined into a dense network around the world, and people can use it. The small and sensitive multi-band semiconductor radio can easily receive radio waves from all directions. A Swede named Ole Alm’s hobby is to receive radios from various countries over long distances. From 1955 to today, he has successfully listened to and identified more than 2,000 radio stations in 215 countries and regions in the world. He not only listened to the programs of Beijing Radio Station, but also the 1,440 kHz medium wave signal of Jiangsu Nantong People's Radio Station, which was 8,000 kilometers away, before the Spring Festival in 1996. This case once again illustrates the point-to-multipoint information propagation characteristics and strong radiation power of broadcasting.

Nowadays, although broadcasting cannot attract young people who are more fascinated by visual images in the increasingly popular multimedia world, broadcasting still has a very wide audience. In times of crisis and war, the value of broadcasting may be best demonstrated, even today for many countries. For example, during the Gulf War, the vast majority of people in Egypt, the UAE, and Saudi Arabia learned that the war had started through broadcast news, and in these three countries, it was better than TV as an in-depth source of information. In terms of media serving multi-ethnic and multi-lingual audiences, it is also difficult for television to compete with radio. For example, Namibia broadcasts in 7 languages, including the main indigenous languages and Afrikaans, to meet the language needs of its listeners. In South Africa, the constitution grants equal status to 11 languages. Broadcasting has programs in all 11 languages, while TV has spent a lot of effort to provide programs in only a few languages. It is difficult for television to truly reflect the diverse cultures of a country. Broadcasting can better meet the needs of various cultures in the country in terms of music and oral language. The demand for music, whether it is classical music, ethnic music or popular music, provides people with a choice that can only be met by broadcasting. In terms of media characteristics, after comparing radio and television, the Swedish researchers concluded that: radio is a flexible medium, which is subject to people’s daily life arrangements; while television is the opposite, it requires people’s daily life arrangements Adapt to it.

Before the 1980s, the launch bases of Western broadcasts to China were mainly located in Thailand and Hong Kong in the south and east of my country (the East Asian broadcast station of the British BBC in Hong Kong was moved to Thailand in 1996), the Philippines, Japan, and South Korea. Zone, the launch network in the shape of a half moon. After the disintegration of the Soviet Union, Western countries began to rent transmitters from Russia and some countries in Central Asia to strengthen broadcasting to my country, and to build another half-moon-shaped transmission network in the north and west of China. Since the 1990s, these two and a half moons have finally been encircled to form a full moon-shaped China Broadcasting Network that emits radio waves from all over my country. This huge transmission network composed of 26 broadcasting stations operates 59 medium and short wave transmitters with a total power of about 20,000 kilowatts (most of the transmitters are used for broadcasting to other Asian countries), and 78 medium and short wave transmitters are used. Frequency (including re-use frequency), my country is carrying out high-power, multi-directional, multi-frequency, long-term multi-broadcast coverage. Regarding the deployment and strength of this launch network, the Director of the US Information Administration believes that it "can enable the entire China to hear the Voice of America and make Beijing's interference powerless."

During the Cold War, the United States established "Radio Free Europe" and "Radio Liberty" in Munich, Federal Republic of Germany, in July 1950 and March 1953, launching propaganda offensives against the former Soviet Union and Eastern European countries. The United States believes that these two radio stations played a vital role in the disintegration of the Soviet Union and the evolution of Eastern Europe. Therefore, after the end of the Cold War, the US Congress provided funds to establish the "Free Asia Broadcasting Station" (launched on September 30, 1996) following the same model, in an attempt to influence China and some Asian countries.

The radio station allocated this large sum of money because lawmakers were frustrated by Beijing's interference on the radio station.

The newly increased funding is mainly used for broadcasting services to China. It will enable the station to increase the current 126 staff to 224 by the summer of 1998, and the Chinese broadcasting time will increase from 5 hours to 12 hours a day. The Tibetan language broadcast increased from 2 hours to 4 hours. The station will also broadcast programs in Cantonese and Uyghur.

4. International Broadcasting

Before World War II, some developed countries successively started broadcasting programs targeting foreign audiences. In May 1927, the Dutch PHOHI broadcast to the Dutch colony of Java with a transmission power of 2.5 kilowatts, and the broadcast was officially launched on October 14 of the same year. This is the first official radio station in the world. Since then, international broadcasting has become a tool that major countries are competing to establish to serve their own foreign policies. In 1929, the Soviet Union launched international radio programs in German, French, and English. At the end of 1932, the United Kingdom began broadcasting to overseas territories, and the first foreign language broadcasting (Arabic program) was launched in 1938. In April 1933, Germany began to broadcast German and English programs in German and English to North America on shortwave directional timing. Japan began broadcasting abroad in 1935. During the Second World War, the international broadcasting of various countries launched a fierce broadcasting propaganda war. In 1942, the United States founded the Voice of America Radio Station (VOA).

After the war, the languages, broadcasting hours, and target regions used by international radio stations in various countries were adjusted with the changes in the international situation, but the general trend was to strengthen, especially the single maximum power of radio transmitters increased from 50-100 kilowatts. To 500-1000 kilowatts. At the same time, more countries started international broadcasting. Since the 1960s, the establishment of global news broadcasting has become a common practice in international broadcasting by major countries. In addition to broadcasting in local languages in various countries and regions, they have also launched non-stop news programs in all directions around the world in English and native languages, called "Global Broadcasting" or "Global Broadcasting", "Global Broadcasting" and "Global Broadcasting". Broadcast to the world" (World Service). This method breaks through the restrictions on target regions and broadcasting time, facilitates timely broadcast of news, and helps expand and strengthen the effect of publicity. This has become a major development in international broadcasting in the past 30 years. Since the 1960s, the United States and the United Kingdom have launched global broadcasting in English, and Japan in English and Japanese. Afterwards, the former Soviet Union used English and Russian in the 1970s, and the Federal Republic of Germany and France started in the 1980s in German and French respectively. broadcast. By 1996, 14 countries in the world started international broadcasting in this way. The six official languages used by the United Nations—Chinese, English, French, Russian, Spanish, and Arabic—except for Chinese, the other five languages have all been used to start global broadcasting. The largest is the global broadcasts in the United States and the United Kingdom, which cover the whole world in all weathers, both in time and space. The scale of global broadcasting in the former Soviet Union once surpassed that of the United States and Britain. After the disintegration of Russia, international broadcasting tended to decline, but its global broadcasting remained largely the same.

Technically, shortwave is the main means of international broadcasting, so shortwave has always been called "the first generation of international radio waves." The frequency range of shortwave transmission is 3-30MHz. When the radio wave is launched into the sky and hits the ionosphere, it will bounce back to the earth. This phenomenon is called "jumping", and it can transmit signals to places between 2000 and 4000 kilometers away. Subsequently, the radio wave is reflected back to the ionosphere by the earth's surface, and when it returns to the earth again, it completes another "jump". After several "jumps", the signal reached the other end of the earth. The stronger the power of the transmitter, the farther the signal transmission distance. However, the propagation of radio waves in the ionosphere is severely affected by the time of day, season, and sunspot activity. Small and rapid changes in the height and structure of the ionosphere will change it.

Leave a message 

Message List