Direct TV descramblers are devices inside the satellite TV receiver that restores the high-density TV signals in the Ku band from the satellite that beamed directly to the home of the viewer, prohibiting the need of a cable operator using a 30cm to 46cm diameter small dish antennae and a Direct TV descrambler. The signals are intentionally scrambled to make sure these TV signals are not usable to people who have not subscribed to the satellite programming package including these signals. Direct TV descramblers use a digitally derived key to unscramble these signals. The Satellite TV service providers transmit the TV signal with a portion of the key code that will unscramble the signal. The rest of the key is programmed into the receivers subscribers have in their homes or offices. The signal is fed into the receiver, the Direct TV descrambler matches up the portion of the key code in the signal with the key code in the receiver. When these codes match, the access card present in the Direct TV descrambler then provides access to that programming authorized by the subscription. So that subscribers are able to decode channels and view a plethora of programs. Subscribers are provided with channel cards that are essentially prepaid debit cards.
The price of set-top box and antenna varies according to Provider Company. Service providers recover their costs through the subscription fee that accrues to them from the sales of channel cards to the subscribers. The DTH operator offers a bouquet of channels, once the subscriber purchases the SIM card. The subscribers will have direct access to high-quality programs on pay channels. People in far flung areas, where cable operators are yet to provide the service, can use dish antennae for receiving TV channels. DTH can also provide satellite-based radio services.
Usually a number of cable TV subscribers are unhappy with the irregular cable TV service providers that keep on shifting the channels, without any prior notification at the expense of other channels. Direct TV descrambler eliminates the requirement of cable service providers altogether and empowers the subscriber to access error-free programs with better picture and audio quality. At the same time it allows the broadcasters to tap homes in rural and remote un-cabled areas. One has the option to choose from as many as 300 to 800 channels. Beside that pay channels have direct and better control over revenues. Broadcasters of the pay channels generally feel that cable operators most of the time misreport the number of actual subscribers, resulting in revenue losses. Direct TV descrambler also assures to benefit hardware manufacturers as increase in subscriber base would lead to increase in demand and supply of Direct TV descrambler components.
The Direct TV descrambler functions on the signal frequencies ranging from 10.7 to 12.75 GHz received from the satellite that is amplified and down-converted into the 950MHz to 2,150MHz range by the LNB. After that the tuner selects the required RF channel in this range and converts it into a 480MHz IF. This signal is then further amplified and demodulated. The analog signals are converted by A to D converter and error correction is realized by forward error correction block.
Selection and descrambling of the data packets for the required program are executed by the descrambler under the control of the conditional access device that includes smart card readers. The demultiplxer unit selects the data packets matching to the program selected by the subscriber, using programmable filters. The audio and video outputs of the demultiplxer are applied to the MPEG block that combines MPEG AV and graphic-control functions for the electronic program guide. Video signals reconstructed by the MPEG decoder are then provided to digital video encoder for conversion and subsequent display on a TV set. A microprocessor interprets user commands from the remote control, and manages the smart card readers and the communications interfaces.
Direct TV descramblers are part of the system used to keep hackers from gaining unauthorized access to these signals being distributed by the Satellites. Hackers are people who try to cheat to get the service for free and for that everyone else pays for. The hackers try to cheat by not paying for this service, or paying a greatly reduced fee. These hackers feel they have a right to the TV signals transmitted through the airwave, whether scrambled or not. They do not seem to recognize that the only reason the huge number channels are available is that the satellite TV companies are able to work with subscribers willing to pay for the service.
Only drawback to Direct TV descrambler is the effect caused by the various modes of interference like rain, sun, adjacent satellites, and terrestrial interference. Moisture blocks signals and also absorbs some of them. Sun spots, the magnetic storm on the sun’s surface, can directly affect satellites placed outside the ionosphere. Users are usually required to have a clear and unobstructed view of the satellite, and the dish must be aligned accurately. Commercial viability and the tremendous expense involved for both service providers as well as subscribers are the other major deterrents to Direct TV descrambler.