In this article, we are going to introduce the DBS band from five points.
The definition of DBS, how it is transmitted, how it features, how it develops, & satellite frequency bands.
Definition:
DBS, or Direct Broadcasting Satellite Service, usually refers to the use of geosynchronous orbit satellites to radiate a certain area on the ground with high power, and transmit information such as TV entertainment and multimedia data to small groups and family units, benefiting the majority of users. A satellite broadcasting service.
Full name: Direct Broadcasting Satellite Service
Abbr.: DBS
Diagram of Transmitting
DBS features:
Compared with traditional communication satellites, live broadcast satellites have the following characteristics:
1. Satellite beams are narrow and cover a certain country or region only;
2. Satellite radiation power is large, the common EIRP (equivalent isotropic radiated power) is greater than 48dBw;
3. User antennas are small and large in number, Typical receiving antenna diameter D = (0.5 ~ 1.0) m, low cost.
The Development of DBS:
Due to the broad prospects of DBS, WARC (World Radio Administrative Conference) in the 1970s stipulated the working frequency band of live broadcast satellites.
In the mid-1980s, DBS which is based on analog technology was spreading widely. Europe and Japan took the lead in establishing Ku-band live broadcast satellite systems.
In the 1990s, the development and application of digital compression technology injected new vitality into DBS.
People can digitize TV images (source coding) and compress the image bandwidth of hundreds of Mbit/s to several Mbit/s (channel coding), so that each satellite transponder can transmit several or even a dozen channels of image information, so as to realize more effective image data transmission, storage and interaction, which remarks DBS entering the digital era.
Satellite Frequency bands:
Here listed the common satellite frequency band for references.
Among them, the European DBS band are: 11.7~12.5GHz downlink, 17.3~18.4GHz uplink; American DBS band are: 12.2~12.7GHz downlink, 17.3~17.8GHz uplink.
| EARTHSTATION FREQUENCIES | ||
| BAND | FREQUENCY | |
| IF | 70 – 150 MHz | |
| L | 800 – 2150 MHz | |
| SATELLITE FREQUENCIES (GHz) | ||
| BAND | DOWNLINK | UPLINK |
| C | 3.700 – 4.200 | 5.925 – 6.425 |
| X (Military) |
7.250 – 7.745 | 7.900 – 8.395 |
| Ku (Europe) |
FSS: 10.700 – 11.700
DBS: 11.700 – 12.500
Telecom: 12.500 – 12.750 |
FSS & Telecom: 14.000 – 14.800
DBS: 17.300 – 18.100 |
| Ku (America) |
FSS: 11.700 – 12.200 DBS: 12.200 – 12.700 |
FSS: 14.000 – 14.500 DBS: 17.300 – 17.800 |
| Ka | ~18 – ~31 GHz | |
| EHF | 30 – 300 | |
| V | 36 – 51.4 | |
Note: DBS = Direct Broadcast Satellite; FSS = Fixed Service Satellite