TERRESTRIAL TO SATELLITE TO CABLE TV:Cable Network, CD Channels

<< COMPARISON BETWEEN RADIO AND TV BROADCAST:The Difference, Script

CAREER IN BROADCASTING:Production, Direction, Lighting Director, Script Writer >>

Introduction to Broadcasting MCM 411

LESSON 43

TERRESTRIAL TO SATELLITE TO CABLE TV

It is not very long ago that the TV transmission was initiated. Not even hundred years of

history could be attached with the television broadcast. The fact that TV broadcast started in

1927 when only mechanical TV sets were doing the magic of showing the moving images of

very primitive nature, looks very strange as we see the rapidly advanced form of television

transmission across the world today.

The TV transmission has passed through different phases of development thanks to the great

work done by scientists in the field of telecommunication.

In the paragraphs below we shall see various forms of TV broadcast and the progress which

has been made in propagating the TV signal in different ways.

Terrestrial TV broadcast

The very first form of TV broadcast is on-the-air. A transmitter high in the air would throw the

electromagnetic waves carrying the TV signals which would travel on the principle of line-in-

sight. This means, the waves would move in a straight line. They would end, or lose their

energy after hitting the ground due to the curvature of the earth. So higher a transmitter more

distance it could cover to send signals which could be caught by the TV sets in most cases.

People would use ordinary antennae which are generally fixed at the roof tops to get a little

stronger signal and through a semi flexible wire the signal would go to the TV set where it

would be decoded accordingly and viewers are able to see the transmission.

The antenna has to be pointed towards the transmitter. And in areas where signal had been

weak, people would do strange things attaching different metallic objects with the antenna to

strengthen the signal and no surprise it worked sometime. Stormy and rainy evenings would

change the antenna direction and spoil the evening joy of watching your favorite program.

Till 1950 the world did not know any other method of catching a TV signal when Community

Access TV (CATV) was introduced in the USA. The new system was just an amended form of

the terrestrial broadcast. The only difference was that a strong antenna was mounted at the

top of a mountain to receive a clear signal from a TV transmitter and then multiple numbers of

TV sets at different houses and offices were linked to it through coaxial wire. But that was

basically sharing of the terrestrial broadcast signal in an amended form.

There are still a high number of television stations around the world which are doing on-the-air

or terrestrial broadcast, especially in the thickly populated urban areas this mode of TV

broadcast is very much in vogue and people can enjoy a TV broadcast without any

interference or to depend on any other source for providing the TV services.

130

Introduction to Broadcasting MCM 411

Satellite TV a revolution in TV broadcasting

The problem of not being able to send TV signal at a greater distance had always been an

issue of concern. The microwave links were created to relay stations and enlarge the scope of

TV broadcast but still it was far from satisfactory.

Experiments to use the spaceships in some manner to pick and redirect TV signals to the

earth in the early 1960s bore fruit.The first satellite television signal was relayed from Europe

to the Telstar satellite over North America in 1962. The world's first commercial

communication satellite, called Early Bird, was launched into the orbit on April 6, 1965. Early

Bird's design was built for the National Aeronautics and Space Administration to demonstrate

the feasibility of communications from the orbit. On station in orbit 22,300 miles above the

equator, Early Bird

provided line of sight

communications

between Europe and

North America.

<=A satellite orbiting

around earth for

sending down TV

signals

Satellite television, like

other communications

relayed by satellite,

starts

with

transmitting

antenna

located at an uplink

facility. Uplink satellite dishes are very large, as much as 9 to 12 meters (30 to 40 feet) in

diameter. The increased diameter results in more accurate aiming and increased signal

strength at the satellite. The uplink dish is pointed toward a specific satellite and the up-linked

signals are transmitted within a specific frequency range, so as to be received by one of the

transponders (devices which receive and redirect signals) tuned to that frequency range

aboard that satellite. The transponder 'retransmits' the signals back to Earth but at a different

frequency band (to avoid interference with the uplink signal), The leg of the signal path from

the satellite to the receiving Earth station is called the downlink.

Ever since many a countries have set up their satellites in the space which keep their fixed

position by moving at a speed which corresponds to the revolution-speed of the earth at its

axis.

The presence of satellites opened gates for hundreds of channels to million of viewers across

the world who could enjoy different TV broadcasts without much cost. The only thing they

needed is to have a small dish at an open place pointed towards a satellite and attached to a

special receiver for decoding the very high frequency signal to ordinary range of frequencies

which a TV set can read easily.

131

Introduction to Broadcasting MCM 411

But the TV channels which were very popular around the world, especially sports and

entertainment channels, started encrypting their service which meant that now a viewer

needed to have a decoder, which cost reasonably, to watch those stations. One by one almost

all the good channels went on to decoders. The free-to-air channels which are available

through satellite are usually news channels or those which enjoy little popularity. The boom of

satellite channels for ordinary and low income viewers was over and the dishes and receiver

sets, bought at a reasonable cost, were rendered a junk.

Cable Network

But before viewers bemoan themselves much, there came the concept of the cable network

operations. These are small organizations which invest on equipment which can catch a range

of TV broadcast the terrestrial, satellite or any other. All the channels are brought to one

point and through fiber optic or coaxial wires which can carry a high number of signals put at

different frequencies, to any point in distance where an ordinary TV set can decode this

signal.

A specimen of coaxial wire

used by cable operators to

carry multiple TV signals =>

With the arrival of cable

service, though always a

limited area operation, the

viewers are in a position to

enjoy TV transmissions of

many dozen stations at a very

nominal cost.

But there have been problems with cable operators. They some time miss a station you want

to see, or run programs which you do not want to see. They sometime do breach of law,

ethics and irritate people by sending in signals of recording programs which are high

offensive. At times, during sporting events, they run commercials at crucial points of the game.

CD Channels

These are not production or broadcasting houses like a TV station. This practice is done by

local area cable operators who need a small place to run recorded materials- songs, dramas,

concerts etc, and pick the signal for transmitting through the coaxial wire to the subscribers.

For a viewer this is like a channel because it would occupy a channel slot of the TV set. Cable

operators may have any number of such channels. They do this practice for saving money of

decoders, or add attraction. In this quest sometime they ignore ethics on piracy and social

norms and are criticized strongly by offenders.

132

Table of Contents: