What is a Portable Satellite Radio?

Satellite broadcasting is a broadcast method in which broadcast satellites relay television or sound broadcast signals to the ground for direct reception by the general public. Since July 1963, the United States successfully launched the world's first synchronous communications satellite, Synchro II, and satellite communications have developed rapidly. By the mid-1970s, countries had begun launching experimental broadcast satellites. By the 1980s, satellite broadcasting had entered a practical stage.

Satellite Radio (Satellite Radio) sends wireless broadcast data from satellites to home receiving terminals, vehicle receiving terminals, and other portable receiving devices. When the data message is sent, there is no need for any terrestrial broadcasting station base station to participate in the whole process. Digital broadcasting data is uploaded to satellites through terrestrial broadcasting stations, and then radiated downwards from the sky by satellites to fully cover the ground area. Sometimes, in some areas of the city, due to the complex composition of wireless signals, satellite signals may be interfered. At this time, the ground repeater station will directly transmit the synchronized data signals to users who cannot normally receive satellite data. Because satellite broadcasting transmits digital signals, the sound quality of the sound is much better than traditional AM or FM broadcasting.

In 1997, the United States Federal Communications Commission (FCC) granted Sirius Satellite Radio and XM Radio the authority to engage in satellite broadcasting. In July 2008, under the re-authorization of the Federal Communications Commission, the two companies merged into an independent satellite broadcaster, named Sirius XM Radio. Users of the company can listen to hundreds of channels from satellite broadcasting services, including music, news, interviews, sports, and cultural and entertainment programs. In addition, many channels broadcast some popular sections at different times. Most channels will not charge any additional fees to users who have already paid for the service, but satellite radio will also add some titled commercials to the program, which accounts for the same proportion as traditional terrestrial broadcasting. The programs once broadcast only on traditional radio stations also kept up with the trend of the times and were transplanted to satellite broadcasting platforms. The Howard Stem Show is a good example. Because satellite broadcasting occupies a different band than traditional wireless broadcasting, users need to purchase special receivers to listen to satellite broadcasting. Satellite broadcasting receiving terminals are divided into home, car and portable mobile, and the price is not expensive. Many car manufacturers have made satellite radios standard on new cars when they leave the factory. Of course, computer users can listen to satellite radio via the Internet. ^[1]

Satellite broadcast reception includes both individual reception and collective reception. The individual receiving system has a large transmitting power and strong radio waves reaching the ground. It can be received with a small antenna and a simple device with a diameter of less than 1 meter. The main form; the transmit power of the satellite of the collective receiving system is small, and the ground needs to receive with a larger antenna and more complex equipment. The satellite broadcasting system is composed of broadcasting satellite, ground receiving network, uplink station and measurement and control station. It has the characteristics of large coverage area, high broadcast quality, and low investment and maintenance costs.

Since the successful launch of the world's first synchronous communications satellite, Synchro II, in July 1963,

Broadcast satellite is a

Satellite broadcasting advantages

Satellite broadcasting systems have many advantages over terrestrial broadcasting systems. When receiving a signal transmitted by a broadcasting satellite on the equatorial synchronous orbit, because the elevation angle is high and the radio waves are less obstructed by mountains or buildings, satellite broadcasting can directly cover the entire land, and there is no need to build a national microwave relay program transmission on the ground Network, saving construction funds from a macro perspective. Compared with the terrestrial microwave relay network, satellite broadcasting has fewer transmission links and is less susceptible to damage from natural disasters. The received images will not have ghosting. Coupled with the wide-band FM modulation method, it has the characteristics of high definition and low distortion, which is higher than the quality of TV broadcasting with residual sideband amplitude modulation used on the ground. Satellite broadcasting increases the flexibility and timeliness of news reporting, and can use the mobile uplink station that has been set up on site to send programs directly to satellites. Programs from other places can also be sent directly to satellites, or a number of television centers across the country will periodically send programs to satellites and broadcast to the whole country.

Satellite broadcasting broadcast band

The International Telecommunication Union divides the world into 3 regions according to regulations, and allocates frequency bands used by various telecommunication services by region. Region 1 includes Africa, Europe, the Asian part of the Soviet Union, Mongolia, and Asian countries west of the western border of Iran; Region 2 includes South and North America; and Region 3 includes most of Asia and Oceania. China is in District 3.

Most of the satellite broadcasting frequency bands are shared with other telecommunication services. In order to avoid interference, the International Telecommunication Union has specified the maximum ground power flux density of each satellite broadcasting frequency band. In 1979, the International Telecommunication Union held the World Radio Administrative Conference to amend the "International Radio Regulations", which divided the frequency bands used by satellite broadcasting downlink (from satellite to ground) lines in various regions

The uplink for transmitting programs from the ground to broadcasting satellites belongs to the fixed-satellite communication service. The frequency band used should be selected from the available frequency bands of the satellite communication uplink, for example, 5.925 to 6.425, 14.0 to 14.5, 17.3 to 18.1 GHz, and so on.