DTH and its Myths

While researching for one of the reports I met quite a few people from the media sector, who exposed the technology behind DTH systems. DTH, or Direct To Home, is the Satellite T.V. technology. In this technology, satellite transmissions are received directly by each consumer/subscriber using a small dish antenna. You must have seen those grey or black dish antenna typically ranging in size from 18 inches to 24 inches in diameter. They are either fitted close to the customers window, or on the terrace, depending upon the signal strength. The dish is connected to a Set Op Box which in turn is connected to the television. Transmission from the satellite to the home dish takes place in the Ku band frequency, which offers moderate speed data transmission.
(Geeks: http://en.wikipedia.org/wiki/Ku_band)
Now comes the interesting part, if the transmission only takes place from the Satellite to the Dish, and not backwards then how are we able to use 'Video-On-Demand' (VOD) services through DTH?
VOD is a service which is supposed to offer videos on your demand, your selected movie, on your selected day, at your selected time, in 'real' time. That means there has to be some way of backward communication between the customer and the satellite. That can't be done in a DTH, the puny 18 inch dish does not have the capacity to transmit data backwards. Infact VOD via DTH is not a real VOD service.
Surprised? Let me explain.

In a DTH system, within the Set Op Box lies an encrypted storage disk. The set of movies which the DTH company is currently providing will be displayed on the selection screen along with its date and timings, which the customer can choose. Here is the catch, long before the customer even got the option to watch those movies, the Satellite had already begun transmitting the data to all the dishes in that zone, and all those movies got downloaded to the hidden storage within the Set Op Box. As transmission from the satellite is extremely expensive, and the storage within the box is limited, DTH providers only provide a set of movies for a specific time period. When the customer gets the option to watch the movie, and selects the date and timing, the movie plays from within the Set Op Box, and not directly from the satellite. The storage within the Set Op Box already contains the other movies, as the whole set got downloaded. If the customer wants, he can select another movie and once again, the movie will play on the selected date and timing, but from within the Set Op Box itself. 

You may want to call this technology a lie VOD, fake VOD, etc. But that's what they provide, labeling it as 'almost VOD'. Today with the upcoming technologies, DTH providers have found a way to provide real VOD, but the customer requires an extra internet connection for that, which gets attached to the Set Op Box. This enables backward communication through the internet line, and the video data is sent via the internet, highly increasing the transmission speed and enabling real time VOD services.

For all those who still believe that satellite TV is the future, you are wrong. Digitization of Cable is the future, which provides fully interactive services and real VOD facilities.