What’s the Frequency? Understanding Satellite Radio Technology
Satellite radio technology is the equivalent of cable or satellite television and it is definitely here to stay. There are several reasons for this: the quality of the broadcasts is higher, the quality of the apparatus's reception is higher and the general coverage of the channel, that is to say the so-called satellite's footprint is far greater as well.
This has the effect that if you travel long distances, you will be able to stay with the same channel without having to look for a new one every forty or fifty miles as you have to do with AM or FM radio stations.
In order to reach this quality, the recording and playback speed needs to be around the 384 kbps level. The music tracks are catalogued in a comparable way to the MP3 system, which uses names called ID3 tags.
Each station on satellite radio attempts to create its own identity. A music station may try this by playing music only of one type or from only one era or decade. This means that you may get a satellite radio station called 1970's Punk music or Twentieth Century Classical Music.
On some channels, the music controller or disc jockey will choose, say, fifty minutes worth of music, will listen to it in order to determine that the quality and the order are correct and then let the computer play it over the airwaves. This allows ten minutes every hour for the news and then the sequence can be repeated automatically.
Satellite transmission uses digital recordings and each station is encoded on a different frequency. Similarly, each decoder, say, in your car or your home needs to recognize and decode each channel separately too. This coding and decoding is done extremely quickly, in fact in what is called 'real time'.
The resulting binary or digital code is then translated into analogue signals so that your speakers can replay it. This process produces sound which is just about of CD quality.
The transmitting satellites are in a geo-static orbit at 23,000 miles above the equator and have a large footprint which is the name given to the area of ground that is capable of receiving their broadcasts.
In America, for instance, the two areas concentrated on at first were the densely populated east and west coasts in order to maximize possible income. One satellite would be incapable of covering the entirety of the United States in that orbit.
In order to receive satellite transmissions, you will have to use a special antenna on your decoder. This antenna must be capable of receiving L-band broadcasts for it to be of use.
These new antennas are a huge improvement on the parabolic dishes (similar to those used for satellite television) that one used to have to have in order to take advantage of satellite radio technology.