Direct To Home Television (DTH)
WHAT IS A DTH SYSTEM?
DTH stands for Direct-To-Home television. DTH helps in keeping broadcasters in direct touch with consumers thus, eliminating the need of local cable operators. DTH technology works through direct reception of satellite programmes with a personal dish.
The basic technology of dth network includes satellites, multiplexers, broadcasting center,
modulators, encoders and dth receivers. Technologically speaking, the process starts with
dth service provider leasing Ku-band transponders from the satellite. Thereafter, encoder
gets into the process of converting video, audio, and data signals into the digital format.
Once encoding is done, multiplexer mixes these signals. Users have to install a small dish
antenna and set-top boxes which decode those mixed signals and lastly users get to view
numerous TV channels. Primarily, dth is an encrypted transmission received directly from the satellite by the consumer at his place with the help of dish antenna.
The DIRECT TO HOME Satellite Broadcast system enables viewers to receive many channels of high quality TV programmers via high powered KU-BAND satellites.
There are no distribution cables but the receiver connects through MODEM to the customer’s telephone line for communication with the subscription service computer for billing purposes.
Thus, the DTH system does not need a cable network that at present distributes TV signals to customers. From economical point of view, the data should be compressed till significant digital drawbacks appear. As such, programmers containing frames with many fast moving objects, such as in a game of basket ball, can be compressed 3 or 4 to a transponder of 36MHz channel width. Similarly programmers containing mostly large still images can be accommodated to about 5 to 6 to a transponder.
For DTH service, KU-BAND frequencies are preferred because these are not prone to interference from ground point to point communication and also need much smaller diameter dish antenna. Low powered KU-BAND satellite transmits in the 11.7 to 12.5 GHz range while the new high powered versions are assigned 12.2 to 12.7 GHz band for a video efficient operation of DTH transmissions. Access (Smart) card slot accepts the smart card. It is a credit-card sized device which on plugging in the slot allows the decoder to receive
authorized programming.
DIFFERENCE BETWEEN BROADCAST TV & SATELLITE TV SERVICES:
Conceptually, satellite TV is a lot like broadcast TV. It’s a wireless system for delivering
television programming directly to a viewer’s house. Both broadcast television and satellite stations transmit programming via a radio signal.
Broadcast stations use a powerful antenna to transmit radio waves to the surrounding area. Viewers can pick up the signal with a much smaller antenna.
The main limitation of broadcast TV is range.The radio signals used to broadcast television shoot out from the broadcast antenna in a straight line. In order to receive these signals, you have to be in the direct line of sight of the antenna. Small obstacles like trees or small buildings aren’t a problem; but a big obstacle, such as the Earth, will reflect these radio waves. if the Earth were perfectly flat, you could pick up broadcast TV thousands of miles from the source. But because the planet is curved, it eventually breaks the signal’s line of sight.
The other problem with broadcast TV is that the signal is often distorted, even in the
viewing area. To get a perfectly clear signal like you find on cable, you have to be pretty
close to the broadcast antenna without too many obstacles in the way.
The Satellite TV Solution
Satellite TV solves the problems of range and distortion by transmitting broadcast signals
from satellites orbiting the Earth. Since satellites are high in the sky, there are a lot
more customers in the line of sight. Satellite TV systems transmit and receive radio signals using specialized antennas called satellite dishes.
The TV satellites are all in geosynchronous orbit, meaning that they stay in one place in
the sky relative to the Earth. Each satellite is launched into space at about 7,000 mph
(11,000 kph), reaching approximately 22,200 miles (35,700 km) above the Earth. At this speed and altitude, the satellite will revolve around the planet once every 24 hours — the same period of time it takes the Earth to make one full rotation. In other words, the satellite keeps pace with our moving planet exactly. This way, you only have to direct the dish at the satellite once, and from then on it picks up the signal without adjustment, at least when everything works.
Satellites are higher in the sky than TV antennas, so they have a much larger line of sight
range.
COMPONENTS OF A DTH SYSTEM:
There are five major components involved in a direct to home (DTH) or direct broadcasting (DBS) satellite system: the programming source, the broadcast center, the satellite, the satellite dish and the receiver.
• Programming sources are simply the channels that provide programming for broadcast.
The provider doesn’t create original programming itself; it pays other companies (HBO, for example, or ESPN) for the right to broadcast their content via satellite. In this way, the
provider is kind of like a broker between you and the actual programming sources. (Cable TV companies work on the same principle.)
• The broadcast center is the central hub of the system. At the broadcast center, the
TV provider receives signals from various programming sources and beams a broadcast signal to satellites in geosynchronous orbit.
• The satellites receive the signals from the broadcast station and rebroadcast them
to Earth.
• The viewer’s dish picks up the signal from the satellite (or multiple satellites in
the same part of the sky) and passes it on to the receiver in the viewer’s house.
• The receiver processes the signal and passes it on to a standard TV.
DTH SERVICES IN INDIA :
The history of dth services in India dates back to 1996. But, the proposal couldn’t get
through policy hurdles because of concern over national security. It was finally allowed in
July 2006. As of now, number of total customers stand at 14 million whereas total cable TV households number is 75 million. That reflects the huge potential of this industry in the
long run.
Major Indian DTH players are; Dish TV which is also the largest private dth player. DD
direct, Tata Sky, Sun Direct, Big Digital TV etc are other major players. New entrants are
Airtel Digital TV and Videocon. Old and established players like Dish TV and Tata Sky employ MPEG-2 technology while majority of other players use MPEG-4 technology.
MPEG-4 technology is more efficient in broadcasting superb quality video and more channels as well.
Indian DTH space is a rapidly rising industry. Since the time, it first arrived in India,
more and more new players are joining the bandwagon. Because of arrival of new entrants, this industry has become very competitive which ultimately results in customers having more benefits and options.
EVOLUTION OF DTH SERVICES IN INDIA:
When satellite television first hit the market in the early 1990s, home dishes were
expensive metal units that took up a huge chunk of yard space. In these early years, only
the most die-hard TV fans would go through all the hassle and expense of putting in their
own dish. Satellite TV was a lot harder to get than broadcast and cable TV.
Today, you see compact satellite dishes perched on rooftops all over the India. Drive
through rural areas beyond the reach of the cable companies, and you’ll find dishes on just
about every house. The major satellite TV companies are luring in more consumers every day with movies, sporting events and news from around the world and the promise of movie-quality picture and sound.
Satellite TV offers many solutions to broadcast and cable TV problems. Though satellite TV technology is still evolving, it has already become a popular choice for many TV viewers.
LIST OF DTH SERVICE PROVIDERS IN INDIA:
• Dish Tv,
• Sun Direct,
• Airtel Digital Tv,
• Sun Direct,
• DD Direct,
• Tata Sky,
• Videocon Dth etc.,
Indian DTH space is a rapidly rising industry. Since the time, it first arrived in India,
more and more new players are joining the bandwagon. Because of arrival of new entrants, this industry has become very competitive which ultimately results in customers having more benefits and options. Thus we are not far away from a day that the entire length and breadth of the country is covered by Dth services that too at a very affordable price even for the common man.
Submitted by Karthiyayini Murugan, II MSc Psychology, August, 2009
William said,
August 31, 2009 @ 5:34 pm
Most of the popular Dish Tv Network offer digital video recording equipment and services. The popularity of digital dish TV leaves them the current leader among the people living in United States with over ten million subscribers in comparison to cable TV.
Dhan Subba said,
October 4, 2009 @ 3:02 pm
I have small hotel of 12 rooms. The local cable charges very high, almost Rs. 3000 pm. I tried dish antenna but it turned out to be cumbersome. Is there anyway I can have single dish with multiple horns. Take signals from these horns to “some system” which coverts it to various channels and thereon the channels go to individual TVs in the rooms ? What gadgets are required ? Kindly help beat the monopoly of cable people.