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APRACTICAL TRAINING PRESENTATION

ON

ALL INDIA RADIO(JAIPUR)

Submitted to : (Training seminar coordinator)

Presented By :VIKASH JAKHARElectronics & Communication

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CONTENTS

Introduction History and present scenario Antenna Introduction Radiation Pattern Pattern Lobe and Beam Width Antenna Gain Types of Antenna Antenna Array Key learning's Conclusion

INTRODUCTION TO A.I.R

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A.I.R is one of the largest radio networks in the world.

A national service planned, developed and operated by the Prasar Bharati Broadcasting Corporation of India

All India Radio, Jaipur was established at 9th April,1955.

The Satellite Earth station was established at 21st March,1944.

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HISTORY AND PRESENT SCENERIO

The first radio program in India was broadcast by the Radio Club of Mumbai in June 1923 .

In 1926 the private Indian Broadcasting Company (IBC) was granted permission to operate two radio stations; the Bombay station was inaugurated on July 23, 1927, the Calcutta station followed on August 26, 1927.

The introduction of the commercial channel ‘Vividh Bharti’ in October 1957 increased the interest and popularity of radio.

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2,75,000 receiving sets at the time of Independence, now there are about 132 million estimated radio sets in the country.

AIR today has a network of 237 broadcasting centers with 149 medium frequency (MW), 54 high frequency (SW) and 177 FM transmitters.

The coverage is 91.85% of the area , serving 99.18% of the people in the largest democracy of the world.

AIR covers 24 Languages and 146 dialects in home services.

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To uphold the unity and integrity of the country and the values enshrined in the Constitution.

Present a fair and balanced flow of information of national, regional, local and international interest, including contrasting views, without advocating any opinion or ideology of its own.

Produce and transit varied programs designed to awaken, inform, educate, entertain and enrich all sections of the people.

OBJECTIVE

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SERVICES

SERVICE FREQUENCY CHANNEL

NAME

LOCATION OF TRANSMITTER

FM 100.3 MHZ

105.6 MHZ

RADIO PINKCITY/

VIVIDH BHARTI

GYANVADNI

M.I ROAD,JAIPUR

MW 1269 KHZ

1476 KHZ

AMER CHANNEL M.I ROAD,JAIPUR

SW 4910 KHZ

7325 KHZ

VAISHALI NAGAR,JAIPUR

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Antenna is usually a metallic device (as a rod or a wire) used for radiating or receiving electromagnetic waves.

Transmission - radiates electromagnetic energy into space

Reception - collects electromagnetic energy from space

In two-way communication, the same antenna can be used for transmission and reception

Antenna Introduction

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Radiation Pattern

The radiation pattern of antenna is a representation of the distribution of the power radiated from the antenna or received to the antenna as a function of direction angles from the antenna.

It is independent on the power flow direction.

It is usually different for different frequencies and different polarizations of radio wave radiated / received.

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Radiation Pattern

There are two types of pattern :

1.POWER PATTERN

2.FIELD PATTERNPower or

field-strength meter

Antenna under test

Turntable

Generator

Auxiliaryantenna

Large distance

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Radiation Pattern

Antenna radiation pattern is 3-dimensional.

The 3-D plot of antenna pattern assumes both angles θ and ϕ varying, which is difficult to produce and to interpret

3-D pattern

3-D pattern

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Radiation Pattern

2-D pattern

Usually the antenna pattern is presented as a 2-D plot, with only one of the direction angles, θ or ϕ varies.

It is an intersection of the 3-D one with a given plane usually it is a θ = const. plane or a

ϕ= const. plane that contains the pattern’s maximum

Two 2-D patterns

Pattern lobe is a portion of the radiation pattern with a local maximum.

Lobes are classified as: 1) Major lobes2) Minor lobes3) Side lobes4) Back lobes

Pattern Lobe

Pattern Lobes and Beam Widths

Beam Width

Half-power beam width (HPBW) is the angle between two vectors from the pattern’s origin to the points of the major lobe where the radiation intensity is half its maximum

First-null beam width (FNBW) is the angle between two vectors, originating at the pattern’s origin and tangent to the main beam at its base.

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Pattern Lobes and Beam Width

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Antenna Gain

Antenna gain A measure of the directionality of an antenna. Power output, in a particular direction, compared

to that produced in any direction by a perfect omnidirectional antenna (isotropic antenna)

Effective area Related to physical size and shape of antenna

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Antenna Gain

Relationship between antenna gain and effective area

G = antenna gain

Ae = effective areaf = carrier frequencyc = speed of light (» 3 ´ 108 m/s) = carrier wavelength

2

2

2

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c

AfAG ee

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Types of Antennas

Isotropic antenna (idealized)Radiates power equally in all directions

Dipole antennasHalf-wave dipole antenna (or Hertz antenna)Quarter-wave vertical antenna (or Marconi

antenna)

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Types of Antennas

Yagi Phased arrays Vertical or Horizontal Horns for super ultra

high frequencies Mobile antennas

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Radiation Efficiency

The radiation efficiency e indicates how efficiently the antenna uses the RF power.

It is the ratio of the power radiated by the antenna and the total power delivered to the antenna terminals. In terms of equivalent circuit parameters:

r

r l

Re

R R

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Antenna Array

Consist of multiple antennas collaborating to synthesize radiation characteristics not available with a single antenna. They are able

to match the radiation pattern to the desired coverage area.

to change the radiation pattern electronically through the control of the phase and the amplitude of the signal fed to each element.

to adapt to changing signal conditions.to increase transmission capacity by better use of

the radio resources and reducing interference. .

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Antenna Array

27 antennas along 3 railroad tracks provide baselines up to 35 km. Radio images are formed by correlating the signals garnered by each antenna.

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Advantages of Antenna Array

Possibilities to control electronically Direction of maximum radiationDirections (positions) of nullsBeam-widthDirectivityLevels of side lobes

Using standard antennas (or antenna collections) independently of their radiation patterns. Antenna elements can be distributed along straight lines, arcs, squares, circles, etc.

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KEY LEARNINGS

Important concepts of communication.

Resource management.

Discipline.

Development of a practical point of view towards the work.

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CONCLUSION

It was a wonderful experience , training in A.I.R.

There is great scope for engineers in the field of communication.

Exposure to practical working conditions will be beneficial for our career.

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QUERIES ??? (if any..)

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Thank u…