What Frequencies Are DTV?
By Timothy Burns
The technology involved in DirecTV satellite TV broadcasting is much more complex than the average consumer realizes. Direct TV owns a fleet of 12 satellites orbiting the Earth broadcasting thousands of TV programs in English and dozens of other foreign languages. Broadcasts include satellite radio, standard-definition television, and high-definition television.
The DirecTV standard-definition broadcasting signal is relatively forgiving when compared to the HD broadcasting signal. The DirecTV standard-definition broadcasting comes from three satellite positions above the earth. The satellite signal is received by the DirecTV satellite dish, and the low noise block down converter converts the Digital satellite signal into a signal which can be decoded by the DirecTV satellite converter box. This signal is called the KU band frequency and extends from 11 MHz to 14 MHz. Current technology sends most of Direct TV's standard-definition TV broadcasting to the satellite dish in a smaller range of 12.2 MHz to 12.7 MHz.
The HD broadcasting signal is a much narrower and higher frequency satellite signal. The DirecTV HD satellite dishes must be finely tuned to receive and accurately decode the HD satellite TV broadcasting. The satellite dish must be tuned to within one half of 1 degree of the peak signal strength or the HDTV broadcasting will pixelate and breakup intermittently. The DTV KA band frequency carries DirecTV's HDTV broadcasting. The HDTV channels contain much more digital information than a standard-definition broadcast. The KA and frequency is capable of handling the increased information more effectively than the KU band frequencies. The DirecTV KA band frequencies extend your range from 18.3 MHz to 20.2 MHz.
Previous Signal Frequencies
The DTV KU LNB receivers are capable of processing a signal from 250 MHz up to 1,650 MHz. While current DirecTV technology broadcasts most of the standard-definition TV on a small portion of this wide frequency spectrum, previous generation equipment used most of this band spectrum. As the technology evolved, DirecTV abandoned the lower frequencies because higher frequency signals are more reliable and can carry more information and more channels on a single signal.
Internal Switching Frequencies
The DTV receiver communicates with the LNB on the DTV dish each time a channel changes. The DTV dish is capable of receiving signals from five satellites at one time. Each satellite is broadcasting from five to eight channels on each of 30 or more transponders. To sort out the signal at the dish, an internal multi-switch is controlled by a 22 KHz tone sent from the DirecTV converter box to the DirecTV satellite dish. This tone carries instructions for the dish and tells the dish which satellite and which transponder to tune into to display a particular channel that you request.
Since 2003, Timothy Burns' writing has appeared in magazines, management and leadership papers. He has contributed to nationally published books and he leads the Word Weavers of West Michigan writers' group. Burns wrote "Forged in the Fire" in 2004, and has published numerous articles online. As a trained conference speaker, Burns speaks nationally on the art, science and inspiration of freelance writing.