At present, the main methods of Chinese broadcasting coverage are: medium wave broadcasting, short wave broadcasting, FM broadcasting, cable broadcasting and satellite broadcasting. The satellite broadcasting is not a satellite live broadcasting in the actual sense, but a means of using satellite as a transmission of a broadcast program.
So what about using satellites for direct broadcast?
Tomleequan, general manager of FMUSER, believes that coverage is the key to broadcasting. It is necessary to use satellite live broadcast technology to expand the coverage of broadcasting. Moreover, with the development of synchronous broadcast satellite technology and digital audio technology, it is also feasible in practical applications.
The rapid development of cable radio and television has greatly improved the coverage of radio and television. In the increasingly fierce competition in the media, radio stations must survive and develop. In addition to continuing to improve wireless transmission coverage, they must make full use of the transmission advantages of wired networks, the interactive advantages of Internet broadcasting, and the quality advantages of digital audio broadcasting. Powerful wired transmission, wireless transmission of the stereo coverage network, satellite transmission and direct satellite coverage, wired transmission and wireless transmission organically, is the need for reasonable transmission and efficient coverage of radio broadcasting.
First, the diversity of broadcast transmission coverage
With the development of science and technology, the means and methods of transmission of radio broadcasting have diversified characteristics, and they are mutually infiltrated and complement each other.
(1) Wireless transmission coverage
Wireless coverage is a means of covering a wide geographical area and scattered and mobile users. Especially suitable for rural pastoral areas, the audience directly listens to the first purpose, such as frequency modulation and medium and short wave broadcasting. FM radio is objectively combined with signal relay transmission. effect.
Advantages of wireless transmission coverage:
1 Wide coverage, economical and practical;
2 Easy to receive, mobile and portable reception, and a large non-fixed user base;
3 Receiving equipment is relatively cheap and saves energy;
4 It is convenient to add new users (about 540 million receivers in the country, the audience is huge); 5 The existing coverage network is relatively perfect, especially for short- and medium-wave broadcasting.
The disadvantages of wireless transmission are:
1 High-power emission is likely to cause environmental electromagnetic pollution;
2 The service area of radio waves is difficult to control;
3 has multipath interference;
4 The attenuation through the wall is obvious;
5 Affected by the electromagnetic environment in the air.
(ii) Wired transmission coverage
Wired transmission coverage refers to the transmission and reception of broadcast audio signals using a cable television network. It is a means of transmission coverage for urban rural and dense users, mainly through the form of FM broadcasting, using cable television networks to transmit radio broadcast signals and other professional data information. Taking signal transmission as the basic starting point, the signal is delivered to the destination (transmitting station) as the first purpose, and objectively has the function of direct signal coverage. It is an important means for radio broadcast signal transmission and coverage.
Advantages of FM radio:
1 High transmission quality, high frequency bandwidth, high spectrum utilization, and digital audio broadcasting;
2 can be used for program exchange and program transmission, which is the basic way for radio broadcast signal transmission;
3 low network loss, strong anti-electromagnetic interference capability, stable transmission system performance; 4 can provide Internet access, webcasting and data services after two-way transformation.
FM radio disadvantages:
1 When listening to radio broadcasts, you must use a wire to connect to a radio or other professional receiver; 2 only for fixed reception.
(iii) Internet transmission coverage
Online broadcasting is the use of the Internet to achieve the transmission and coverage of radio broadcast signals. It uses data processing to transmit the audio signals broadcast by the radio to the user’s computer via the Internet, which makes the audio broadcast undergo a qualitative change and integrates the advantages of each network infrastructure.
Advantages of Internet broadcast transmission coverage:
1 wide area coverage;
2 Real-time and timeliness,
3 Independently receive and interact, receive more programs (channels), and choose a larger space;
4 The information capacity is large, the query is convenient, and the on-demand can be repeated.
5 Easy to copy, with data, text, graphics, images, voice and other forms of expression;
6 Technology implementation is relatively easy, and network broadcast equipment investment is relatively low.
Disadvantages of Internet broadcast transmission coverage:
1 must be received by computer, and the current popularity of computers is not as good as radio;
2 The receiving cost is higher;
3 Sound quality is greatly affected by network bandwidth.
(iv) Satellite transmission coverage
China has a vast territory and diverse landscapes. Satellites are the most effective means of transmitting and covering broadcast programs. In some areas of China, the population is quite scattered, and relay-style wireless transmission methods are difficult to ensure efficient coverage. The short-wave broadcast quality is poor, which can not meet the requirements of the audience; the coverage of FM radio with better sound quality is limited; the software and hardware requirements and receiving cost of online broadcast listening are higher. With satellite transmission technology, coverage, sound quality and listening problems can be solved simultaneously. The satellite transmission technology can transmit the broadcast audio signal to the local relay station, the transmitting station and the cable television network as the audio signal source, thereby solving the problem of transmission of large-area and long-distance signals. Hulunbeier Radio Station covers a vast area, with a horizontal and vertical length of more than 1,000 kilometers and an area of 253,000 square kilometers. Hulunbeier’s broadcast coverage has long been restricted by the geographical environment. Signal transmission has always been a problem of broadcast coverage, which has been solved by satellite transmission. Therefore, we must seize the current opportunity, the state-sponsored development of radio and television coverage and the successful operation of the national direct broadcast satellite, and strive for the broadcast of the stars, thus fundamentally solving the effective coverage of Hulunbeier.
1 Advantages of broadcasting coverage using satellite live broadcast technology
(1) Wide coverage
The biggest benefit of satellite broadcasting is the wide coverage. The coverage of a satellite can reach tens of millions of square kilometers. In theory, three satellites can be globally covered. If satellite live broadcast technology is used for broadcast coverage, China’s broadcast population coverage rate can easily reach the target of 95% of the population coverage set by the 11th Five-Year Plan from 90.77% now.
(2) Saving investment
At present, the broadcast coverage of satellite coverage meets or exceeds FM radio. Let’s make a comparison with a set of broadcasts:
Assume that a 5KW FM transmitter is used for national broadcast coverage. The full-power single-machine coverage radius of the 5KW FM transmitter is 50 kilometers, and the single-machine coverage area is nearly 8,000 square kilometers, covering 9.6 million square kilometers nationwide, and about 1200 5KW FM transmitters are needed. Based on an investment of 400,000 yuan per unit, only one investment of one transmitter will cost RMB 480 million. In addition, the annual electricity cost, maintenance and value of the operator’s cost of the transmitter will be about 233,000 yuan per unit, and the operating cost of 1200 FM transmitters will be about 280 million yuan. The above investment does not include the construction of the computer room, the transmitter attached equipment, and the cost of transmitting the broadcast program signal to 1,200 FM transmitters. In addition, what we mean by the country is 9.6 million square kilometers, which refers to the land area, and does not include coastal areas and islands.
The fees covered by satellite broadcasting mainly include: 64kbps broadcast channel annual subscription fee, satellite uplink station annual subscription fee, and broadcast program transmission fee. These fees do not exceed RMB 6 million a year. In a simple comparison, we found that satellite radio coverage is better than terrestrial FM coverage, but the overall cost is only one percent of the ground coverage.
(3) Reduce intermediate links for management
At present, China’s medium, short-wave and FM radio coverage systems are the products of the planned economy system, and are the products of the central, provincial, prefecture, city and county administrative departments. In fact, there are not enough launching stations under the central government. The coverage of CCTV’s radio programs throughout the country relies heavily on the retransmission of local stations. Under the current market economy conditions, some grass-roots launchers and relay stations have “three dissatisfaction” in terms of saving funds, that is, dissatisfaction with boot time, dissatisfaction with power-on and power-off. The coverage of the first radio program of CCTV in the country is not good, and the actual coverage is less than 81.43%. Because of the inconsistent economic interests, it is very difficult to solve the “three dissatisfaction” problem by relying solely on management and coordination.
In addition, in order to solve the actual coverage effect, we were forced to invest a lot of manpower, material resources and financial resources to establish many monitoring stations and stations.
However, with satellite broadcast coverage, these intermediate links do not exist. We only need to manage and control the satellites, which makes the management of broadcast coverage more singular and more reliable. In addition, the use of satellite for broadcast coverage also has the advantages of good transmission quality, large program capacity, and short system construction period.
Satellite coverage is an effective supplement to traditional broadcasting coverage, and is more suitable for China’s national conditions. From the perspective of technology and management, satellite broadcasting coverage is not contradictory to traditional medium, short wave and FM broadcasting coverage, but it is an effective complement. The focus of satellite coverage is on islands, borders, mountains, Gobi, and places where traditional coverage is unfavourable. Therefore, there is no problem of repeated investment and redundant construction.
China’s basic national conditions are vast and vast, with vast territory, complex terrain and large population. At present, China’s broadcast population coverage rate is 90.77%, which means that nearly 10% of the population still does not hear the broadcast. Then the broadcasting coverage of Hulunbeier City, especially the city-level program coverage only accounts for 42% of the city’s population, and 68% of the population does not hear the city-level broadcast.
It is not easy to solve these 10% and 68% problems. These places where we can’t hear the broadcasts are mainly in remote areas. In particular, our Hulunbeier area is vast, where the land is sparsely populated, and traditional coverage is costly and ineffective. For example, the total power of medium and short wave broadcast transmitters in Hulunbuir City is twice as high as that of a province in the mainland, but the broadcast coverage of a province is several times higher than that of Hulunbeier. The effect of topography and population distribution on traditional coverage is visible. In Tibet, for example, there are only two people per square kilometer. From this point of view, satellite broadcasting coverage is more suitable for China’s national conditions, suitable for remote areas and the vast and sparse Hulunbuir prairie.
Subject to the characteristics of satellite live broadcast, live satellite digital audio broadcasting in the urban high-density building environment, even in rooms with different orientations in the same building, the receiving effect will be affected to varying degrees;
There is multipath fading interference.
Second, the development direction of broadcast transmission and coverage
(i) Launching digital audio broadcasting
Advantages of Digital Audio Broadcasting (DAB): 1 Anti-fading, anti-multipath interference capability; 2 Fixed, portable and high-speed mobile reception; 3 Coverage with terrestrial wireless, cable network and satellite; 4 pure sound quality, up to CD level, 5 can operate on a single frequency network, saving spectrum; 6 can provide multimedia broadcasting, can transmit sound programs, can also transmit video, and can also transmit data; 7 compared with analog FM radio, transmitter under the same coverage The power is much smaller. The implementation of DAB can meet the needs of people listening to high-quality broadcast, mobile reception and multimedia broadcast reception.
(2) Conducting frequency modulation/amplitude modulation simultaneous broadcasting
FM radio can meet the popular high-quality listening needs and is the main means of radio broadcast coverage. With FM synchronous broadcasting, it can form a traffic broadcasting system along the expressway or railway. With the development of the economy and the increase in capacity, the demand for FM synchronous broadcasting will continue to increase. FM synchronous broadcasting is a technical means of using multiple transmitters and using the same carrier frequency and broadcast programs to achieve specific area coverage. The use of multi-point low-power coverage to achieve a wide range of “seamless” coverage is currently technically difficult.
Short- and medium-wave broadcasting has been widely used throughout the country and is still the main and economical means of broadcasting coverage. The large area coverage of broadcasting should still be dominated by medium and short waves. The amplitude-modulated medium-wave synchronous broadcast using the new technology of adaptive phase-based single-frequency networking can make up for the shortage of the frequency resources occupied by the current frequency synchronous broadcast network. The development of digital broadcasting in the AM band can save tight frequency resources and energy, and can also improve sound quality. The digital AM broadcast is compatible with analog transmission. It can transmit an analog signal and a digital signal within a specified bandwidth to achieve analog-to-digital simultaneous broadcasting. A set of programs only needs one frequency coverage, so that the listener can listen to the same program in different regions. To achieve “seamless” medium wave synchronous broadcast coverage.
(3) Conducting satellite live broadcast
The application of satellite live broadcast technology conforms to the development direction of China’s “development from satellite radio and television to satellite live broadcast”. The use of live broadcast satellite to transmit radio and television programs and multimedia information not only covers a wide range, but also is convenient, economical and high quality. The use of satellite coverage systems to achieve national coverage of broadcast programmes is an economical approach that is particularly important for improving the coverage and competitiveness of programme coverage and radio stations to meet broadcast coverage targeting national and global coverage. Hulunbeier People’s Broadcasting Station uses #####satellite for live broadcast, which is a new leap in the history of broadcasting technology coverage.
(iv) Development of webcasts
Online broadcasting has broken through the obstacles of radio wave propagation and is regarded as a supplement and extension of wireless broadcasting. With the use of online broadcasting technology, it can realize the national coverage of radio stations at all levels, and can display broadcast programs with rich and colorful content broadcasted everywhere, and can meet the individualized listening needs of the audience. Interactivity is the biggest advantage of online broadcasting, and there are more professional channels to meet people’s needs for interactivity.
(5) Expanding business
Radio stations should use their technological advantages to stabilize basic services, actively expand and expand new services, and gradually develop value-added services. The first is to carry out FM subcarrier data services and make full use of existing resources. The development of wireless data broadcasting and professional orientation services using FM idle spectrum is the basis for value-added services. For example, it conducts additional services such as stock information and distance education and data transmission services. The second is to provide rental services using the geographical advantages of FM/TV towers. The third is to develop wireless broadband high-speed data access services and two-way transmission of wireless access services.
(6) Accelerating digital transformation
In the next 10 years, the broadcast television system will complete the transition from analog to digital
Digitally transform existing analog broadcast program production, broadcast, and transmission equipment, perform solid-state update and modification of medium-wave and FM transmitters, and carry out digital broadcasting, which can greatly improve signal transmission reliability and broadcast quality, and strengthen broadcast signals. An important part of the transmission and coverage work is also an important basis for future broadcast transmission coverage.
To achieve wide-area broadcast transmission and coverage, wired and wireless, satellite and network, and sky and ground must be combined. Broadcast wireless transmission coverage, wired transmission coverage and network interaction coverage complement each other and promote each other. The combination of broadcasting and the Internet complements the wireless and wired broadcasting, and the combination of broadcast wireless transmission and satellite live broadcasting, thereby achieving full-scale stereo broadcasting coverage.