| |
|
Direct Broadcast Satellite TV
|
In the U.S., the band 12.2-12.7 GHz is used for satellite TV, such as DISH Network and DIRECTV. These high-power emissions are designed to be received directly by consumers using small (18") satellite dishes.
Each satellite typically carries 16 to 32 transponders, each with a bandwidth of 27 MHz. Each transponder carries multiple television and audio channels. The transponder signals are transmitted in one of two orthoganal polarizations, which allows the transponder signals to overlap in frequency.
As an example, the Echostar 12 satellite in GEO orbit at 61.5 deg W longitude (one of the satellites used by DISH Network) has the following set of transponders:
| Center Frequency (MHz) | Polarization (Left/Right Circular) |
| 12224 | R |
| 12239 | L |
| 12253 | R |
| 12266 | L |
| 12282 | R |
| 12311 | R |
| 12326 | L |
| 12341 | R |
| 12355 | L |
| 12370 | R |
| 12399 | R |
| 12414 | L |
| 12428 | R |
| 12443 | L |
| 12472 | L |
| 12486 | R |
| 12501 | L |
| 12516 | R |
| 12530 | L |
| 12545 | R |
| 12559 | L |
| 12574 | R |
| 12603 | R |
| 12632 | R |
| 12647 | L |
| 12661 | R |
| 12676 | L |
Various Internet sites list the transponders used by each satellite, and even map the specific TV stations carried on each transponder (see the references).
An attached plot shows the 12.2-12.7 GHz band as observed at a radio astronomy site in West Virginia. The individual transponders are clearly visible, and multiple satellites are visible as the receiving antenna sweeps along the geostationary arc.
|
Frequency Bands |
| Band | Use | Service11 | Table |
| 12.2 - 12.7 GHz | Direct Broadcast Satellite TV | BS | N |
|
|
|
|
|