CHAPTER ONE

1.0 Introduction.
Experts are of the opinion that there is yearning gap between the learning
acquired by graduates of Nigeria Universities and the skills repertoire required in the
workplace. Clearly, academic learning and theoretical knowledge alone would not
usually prepare an educated person for the world of work; this is why the student
Industrial Work Experience Scheme (SIWES) was created, to provide an avenue for
students to acquire practical industrial exposure in their respective discipline during the
course of their studies.
The student Industrial Work Experience Scheme (SIWES) is the accepted skill

training programmed, which forms part of the approved minimum academic standards in

the various degree programmed for all the Nigeria Universities. It is an effort to bridge

the gap between theories and practice of engineering and technology, science, agriculture,

management, medical and other professional educational programmed in the Nigerian

tertiary institutions. It is aimed at exposing students to machines equipment, professional

work methods and ways of safeguarding the work areas and workers in industries and

other organization. The scheme is a tripartite programmed involving the students, the

Universities and the industry (employers of labour). It is founded by the Federal

Government of Nigeria and jointly coordinated by the Industrial Training Found (ITF)

and the National University Commission (NUC).

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1.1 Duration:

400 level students who have completed the course-work for the first semester of

the 400 level of a five year Engineering programmed may take part in the students

Indusial Work Experience Scheme (SIWES), for six (6) months during second semester

and long vacation. At 400 levels, it is expected that the students have acquired enough

theoretical engineering parts and system/processes.

1.2 Goal of SIWES

It is designed to expose the student to engineering design, testing and fabrication

which would help them in their final your project upon their return to the University

1.3 Objectives of SIWES

Specifically, the objectives of the student Industrial Work Experience Scheme

(SIWES) are to:

1) Help in preparing student for the future work they may likely come across after

school.

2) Give students privilege to apply their theoretical experience in real work situation

thereby bridging the existing gap between school, work and real practice.

3) Make the transition from the University to the outside world (Labour market)

easier thereby enhancing student opportunity for employment.

4) Provide an avenue for students in Nigeria tertiary institutions of learning to

acquire industrial skills and experience.

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 5) Enlist and strengthen employer’s involvement in the process of preparing tertiary

institution graduates for Job placement.

6) Expose students to methods and technique of handling equipment and machines

in industry.

1.4 History of the Organization

What is today known as Enugu State Broadcasting Services (ESBS) has

undergone a great deal of metamorphosis. It was first opened on October 1, 1960, as one

of the memorable ceremonies marking Nigerians attainment of independence, and was

then called Eastern Nigeria Broadcasting Cooperation (ENBC).

The ENBC consisted of Radio- Television Station housed in the ACB Building at No: 1

Ogui Road, Enugu. At its embryonic stage, the Radio system consisted of a single

continuity studio with one medium wave and one short wave transmitter, located at the

Hill Top in Ngwo. There was also a Landrover-borne OB Van with leveled rigged-up-

battery operated equipment and an Fm link.

The ENBC Television was a double-camera Studio and control room, one

Televise room and one slid projector. Its transmitter was a 100 watts gates transmitter

which was powerful enough to cover only Enugu Capital territory. But latter, following

the acquisition of a 6 kilowatt RCA TV Transmitter which was installed on Okpatu Hills

along Enugu/Nsuka road, and a second identical transmitter installed on Ogbor Hills in

Aba, the television was made to cover the whole of the then Eastern Nigeria and beyond.

The ENBC Radio also received a boost in 1964/65 when the then regional Government of

the Late Dr. M.I Okpara acquired and installed 2 No 245 kW continental Electronics

medium wave transmitters at the Ninth-Mile corner. Shortly afterwards, the ENBC

3
Radio- Television studios were moved from Ogui Road to the present premises housing

the ESBS Radio and Nigeria Television Authority at Independence Layout, Enugu.

But, before the installation of equipment could be completed, the civil war broke out, and

the transmission equipment began its unprecedented adventure in and out of the jungle,

until the cessation of hostilities in January, 1970.

At the end of the civil war in 1970, the then badly aged and over-used ENBC

10kW short wave transmitter returned to Enugu but in line with the first exercise of the

state creation in Nigeria its name had to change to East Central state Broadcasting

Services (ECBS). The TV wing was however, temporarily dead.

In October, 1975. TV transmission resumed simultaneously in Enugu and Aba,

and a music studio was added to the Radio wing. However, a plan to further boost the

Radio station with two 50kW medium wave transmitter did not immediately materialize

because. Following the creation of Imo state in 1976, the new state acquired the newly

ordered equipment to establish the Imo Broadcasting Service.

Meanwhile, the ECBS had to change its name again to Anambra Broadcasting

Service (ABS) and in 1977 to Anambra Broadcasting cooperation (ABC) following the

establishment of a second station at the Ninth Mile corner, known as ABC1 while the Hill

Top station confirmed as ABC11.

In 1978, following the decision of the then Federal Military Government to take

over all TV stations in the country, the Television arm of the ABC Broadcasting outfit

became the present NTA channel 8 Enugu.

In 1980, the ABC11 was opened at Onitsha as a commercial station to mark the

20th anniversary 0f broadcasting, East of the Niger.

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The Jim Nwobodo Administration followed this up with the establishment of the ultra-

modern Anambra Television channel – 50 (ATV CHANNEL FIVE-0) in 1981. And, in

1985, both ABC radio and the ATV-50 were merged into what was known as Anambra

Broadcasting Service (ABS) with radio-TV stations in Enugu and Onitsha. Today, the

Enugu studios of the former ABS has come to be known as the Enugu State Broadcasting

Service (ESBS) with Am and Fm studios, the studio having been opened earlier in 1989.

Also ESBS is known using a digital TV transmitter of 20kW.

One thing that must be said of the ESBS is that throughout its history, during

which it metamorphosed from ENBC to its present nomenclature, even during the civil

war period, it never compromised excellence in its determination to serve the people. It

has been consistent in maintaining its foundation call-sign of second to none in Africa.

ESBS Radio (called Sunrise FM station) now broadcast on air at 5:00 am to 12:00

mid night and TV called Star TV broadcast on air at 8:00am to 12:00 mid night.

The present management of the ESBS is determined to uphold that tradition and is

assuring the people of Enugu state and beyond that their darling station will remain “THE

STAR STATION” and SUNRISE STATION they have always been.

1.5 Visions

Becoming African Leading Broadcasting Service

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1.6 Mission

We shall remain a prime driver of broadcasting standards and best practice, rendering

world class services and delivering enduring stakeholder value in perpetuity.

1.7 Organizational Structure

ESBS-50 independence Layout, Enugu has seven (7) divisions known as directorates.

They are responsible for various activities carried out in the station. These are:

I. News and current affairs

II. Programmes

III. Engineering

IV. Administration

V. Finance

VI. Commercial/marketing

VII. Planning, research and statistics

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DD=Deputy Direct
Fig 1.0 Organogram of ESBS
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 CHAPTER TWO

The Brief Report of Section Worked

2.0 Introduction:

The Enugu State Broadcasting Service (ESBS) as was stated in chapter one is made

up of the following organizations:

1) News and Current Affairs: This is involved with the gathering of news,

information and current affairs. Information gathered are real, factual and void of

fallacy.

2) Programmes: Discussion and entertainment are carried out here for the

satisfactory of viewers especially.

3) Engineering: this directorate deals with transmission of live programmes with the

uses of outside broadcasting van (OB van). It is subdivided into units which are

transmission, studio and maintenance.

4) Administration: This directorate handles issues that pertain to worker. Examples

are workers salaries, welfare and posting.

5) Finance: As the name implies it is the directorate that keeps account of all the

finance of the station.

6) Commercial/Marketing: this deals with customers who sponsor a particular

programme to be covered by ESBS and also people who want to advertise their

products

7) Planning Research and Statistics: This section is responsible for the planning,

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 Researching and statistical analysis of information of the organization

As an engineering student, I was posted to engineering section for my industrial

training activities. There at the engineering section, I was first posted to the maintenance

and repair unit where I had the opportunity to be practically involved in the assembly,

repair and maintenance of some electronics (DVD, Radio, Fan, TV, e.t.c). Subsequently,

I was posted to the studio/control unit of both TV and Radio broadcasting house where l

obtained elaborate knowledge of the principles involved in the transmission of both

Radio and Television broadcast, and finally l was posted to the transmitter unit.

This chapter states in brief the meaning of these various sections I had my

activities. The detailed explanation will be given in the next chapter.

2.1 Repairs and Maintenance Unit

The repair and maintenance unit of ESBS is the unit that over look the general

maintenance of the station’s electrical and electronics’ gadgets, which include: recording

machines, VCD players, Transmitter, television/radio receiver as well as signal

monitoring equipment like Oscilloscopes. It also goes out of its way to serve as an

electric solution to house hold appliances of staff. It serves as a good purpose of exposing

me to trouble shooting techniques in electrical electronics appliances, and also bringing

me closer to fundamental circuit elements like transistors, inductors, capacitors, resistors,

diode e.t.c

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2.2 Television Room (Studio, Studio Control and Master Control Unit)

The Television room is the most important and powerful form of communication

in broadcasting station. It is where information is generated, processed and controlled

before they are sent into the transmitter for further processing, filtering and amplification

for millions of people to watch.

2.3 Editing Room

This is a room where television programmes, films, music or movies which have

been recorded are put together either in pieces or in order. Most programmes that are pre-

recorded in bits and pieces, either in studio or on location are finally put together in a

video tape for editing. The editing room consists of monitors, computers and different

playback machines for replay of air program.

2.4 Transmitter Section

Enugu state Broadcasting Service (ESBS), both the TV and Radio station use two

stages of transmission consisting of two transmitters and two transmitting antennas. This

is because the studio and master control room of both the TV and Radio is located at

differently direction from the main transmitter. The first transmitter called microwaves

transmitter acts as the linking medium between the master control room and the main

transmitter.

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 CHAPTER THREE

Details of Industrial Training

3.0 Introduction.

Like as it was stated in Chapter two, engineering department of ESBS rendered

the following tasks to the establishment for its effective performance.

These tasks can be referred to as sub-units which are:

a) Repairs and maintenance unit

b) Television and Radio room (studios, control and master control unit)

c) Transmitter unit.

3.1.0 Repairs and Maintenance Unit

The repair and maintenance unit of ESBS is the unit that over look the general

maintenance of the station’s electrical and electronics’ gadgets, which include: recording

machines, VCD players, Transmitter, television/radio receiver as well as signal

monitoring equipment like Oscilloscopes. It also goes out of its way to serve as an

electric solution to house hold appliances of staff. It serves as a good purpose of exposing

me to trouble shooting techniques in electrical electronics appliances, and also bringing

me closer to fundamental circuit elements like transistors, inductors, capacitors, resistors,

diode e.t.c

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3.1.2 Trouble-shooting Techniques

Trouble-shooting is simply a series of steps earned out in an attempt to discover

the problem in a system. To achieve this aim, the various behavious of components that

make the basic building block of electrical and electronics system needed to be known.

This is because if you do not know how a component looks normally; you will not know

when it begins to malfunction. In view of this I was introduced to the following.

(A) Power units: the power units of electrical and electronics systems are made up of

basically transformers, amplifier capacitors, regulators e.t.c.

I. Transformers: Transformers are suspected faulty when either the primary

winding or the secondary winding or both of the windings are not continuous

when tested with a multi-tester. In other words, a faulty transformer fails a

continuity test.

II. Rectifiers: The rectifiers are made up of diodes and a diode is a linear

unidirectional element i.e. it reads continuity only in one direction when tested. If

it reads contrary, it means it is faulty.

III. Transistor: when a normal transistor is tested, it reads continuity from base to

emitter only. If is reads otherwise, then it is a bad one.

IV. Capacitors: Capacitors charges and discharges quickly when tested using a multi-

tester. If it does not behave this way, it is suspected badly. Some times by visual

inspection, a capacitor can be found faulty if it has bulges.

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 V. Inductors: they are coils wounded using specific dimensions to achieve different

objectives in circuits. They are delicate sources, a slight alteration of their

designed dimensions and positions may alter the entire output of the system. This

explains why inductors are enclosed.

VI. Resistor: they can either go into short or open circuit conditions all of which can

be detected by measuring with a multi-tester. They can also read above their rated

values which will also amount to malfunctioning of system.

B: Volume control: It is simply potentiometers used to vary the volume of a sound

system. We have stereo and mono volume controls. The stereo goes for system with more

than one speaker while mono is used for system with only a speaker.

C: Other units (Television) are turner unit, vertical unit, horizontal unit, audio unit e.t.c

3.2.0 Television Room (Studio, Studio Control and Master Control Unit)

The Television room is the most important and powerful form of communication in

broadcasting station. It is where information is generated, processed and controlled

before they are sent into the transmitter for further processing, filtering and amplification

for millions of people to watch. The television room is divided into the following.

1) Studio Room

2) Studio Control Room (SCR)

3) Cyber control room (CCR)

4) Master Control Room (MCR)

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3:2.1 Studio Room

The studio room is an important part of any television station. It is a facility area

where lives programs and commercial are staged and recorded. Studio room of ESBS has

at least (2) cameras, recording the studio actions from different angles so that the

program director can switch or fade between shots as the creation aspect of the

programme demanded. Also in the studio room is the tele-pointer used by newscaster to

read news with the lightening director who cooperates with the camera control operator

to ensure that each scheme is correctly lit. The lightening director has control panel

which allows him/her to switch and fade the studio light. Besides, the microphone used in

a studio may be tiny unit clipped to an announcers tie or pocket or desk mounted unit or a

very long boom mounted unit which can be moved all over the studio room.

\3.2.2 Studio Control Room (SCR)

The program is put together in the studio control room which is usually alongside

the studio with some electronic equipment such as computer, monitors, video consoles,

audio console or mixers, talkback system and cable interlink. The pictures of audio/video

cabinet and console of ESBS are shown in Fig 3.0

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Fig 3.0: Audio/Video Cabinet and Console.
In the studio control room, the pictures from different cameras are mixed and

interchanged according to the director’s instruction. Here, the camera visual electrical

signals are sent into the visual (video) console while sound picked by the studio micro-

phone is transmitted to the audio mixer. The studio directors works from the studio

control room where he/she can look directly into the studio and also video on special

monitors with picture coming from each camera. The studio director is able to

communicate with the studio crew by way of headphones or talkback microphone system

and instructs the audio and camera operators on how to position their microphones and

cameras in order to get the needed shot.

3.2.3 Cyber Control Room (CCR)

The cyber control room of ESBS otherwise known as the graphical arts unit is

where run down of programmes such as weather maps and sport results are placed on the

screen using graphics, character generator and paint box. Cyber machine is used in

15
designing studio background for most live programs. The paint boxes are used for still

background while chrome is used for moving background.

Major equipment used in television room is the video console. It is an electronic

device with various video input and output. It performs the function of mixing video

signal, super-imposing them to produce different interesting and fascinating colour

backgrounds. It also performs the function of both mixer and switcher together and it is

used to control different monitors at the same time.The audio console is also an

electronics device with various input and output ports. It has the ability to mix sound

signal from different sources with display of audio gain spectrum as it rises and fall

within interval.

3.2.4 Master Control Room (MCR)

The master control room is the television room where incoming and outgoing

signals are monitored and switched when necessary to produce the quality pictures and

sound. The master control room takes in signals from the television rooms. These signals

are properly filtered, amplified and sent to the transmitting hall for proper processing.

The signals are transmitted through two coaxial cables for video and audio signals. The

master control room consists of electronic systems such as the video machine, digital

video cassette recorder machine, monitor, computer system, switcher and talk back

microphone which are used to communicate with the studio crew for any adjustment in

any area in the studio room.

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3.3 Editing Room

This is a room where television programmes, films, music or movies which have

been recorded are put together either in pieces or in order. Most programmes that are pre-

recorded in bits and pieces, either in studio or on location are finally put together in a

video tape for editing. The editing room consists of monitors, computers and different

playback machines for replay of air program.

3.4 Problems Associated With Television Room of ESBS

1) Loss of signals: This is mostly common when the coaxial cable and

Audio wires lose its continuity.

2) Machine Breakdown: Most of the playback machines are very sensitive to

voltage and atmospheric temperature. If a bad video cassette is inserted into the

machine, it can cause fault. This problem therefore made ESBS to have more than

two playback machine.

3) Loss of Colour: Colour loss usually occurs when the video console of the

playback machine is faulty.

4) Power surge: This is a sudden increase or decrease in the supply voltage from

PHCN or generator. Whenever it occurs most of the circuit’s power supplies are

affected. This is the reason why automatic voltage regulator and uninterrupted

power supply (UPS) systems are used.

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3.4.1 Personal Involvement in Television Room

Due to the professional and sensitive nature of the job, we the SIWES students were

only permitted to carry out limited activities personally while we watched other activities

been carried out and asked questioned for clarification in areas where we did not

understand. Some of the activities I was personally involved in this unit include.

1) Lying of cables and setting of equipment for transmission of programme.

2) Installation of satellite dish.

3) Mounting of cameras at their designated location and connecting all the

accessories necessary for proper operation in the studio room when live

programmed is about to take place.

4) General monitoring of programmed in the control room such as inspection of

required programme (VCD, VHS) tapes where necessary

3.5.0 Transmitter Section

Enugu state Broadcasting Service (ESBS), both the TV and Radio station use two

stages of transmission consisting of two transmitters and two transmitting antennas. This

is because the studio and master control room of both the TV and Radio is located at

different direction from the main transmitter. The first transmitter called microwaves

transmitter acts as the linking medium between the master control room and the main

transmitter.

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3.5.1 Main Transmitter

The transmitter room consists of the UHF-TV transmitter, the microwave

receivers, the 382V DC UPS (uninterrupted power supply), the 400V 3-phase stabilizer,

dehydrator (use to remove the moisture content and dust particle from the feeder cable),

31hp air condition. The 20kW UHF-TV transmitter comprises two/ double parts. The two

parts which are called alpha and beta are each made of sixteen amplifiers (packets) with

each amplifier having 700W transmitting power, each of which can be remove separately

without affecting the performance of others. The advantage of this type of power packed

over single power amplifier being that transmission will still continue even when one or

more of the packets are faulty.

3.5.2 Functional Description and Power Supply

The 20kW UHF-TV transmitter is particularly studied for common amplification and

transmission of sound and vision carrier. The RF amplifier mount cavity has high gain

and a very long life term. The main transmitter components are

1) Power splitters

2) Transmitter rack with built in isolator main transformer and power

distribution.

3) Dual drive exciter with changeover or single drive exciter.

4) RF amplifier modules.

5) Power combiners.

6) Output band-pass filter.

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The exciter modulates the video and audio signals unto the set channel frequency,

provides procreation circuit that ensure linear transmission with minimum intermediation

production.

Power splitters distribute the exciter output power to the RF amplifiers modules,

the RF broad band amplifiers modules provide linear, class AB signals, and are

compatible with digital TV standards DVB-T ATSSC.

A band-pass filter is installed before the output directional coupler for the suppression of

the out of band interference.

Twenty four (24) large diameter fans in the transmitter rack provide the extraction

of exhaust air.

The 20kW UHF –TV double parts is made up of different modules of transmitter

ports.

Front View

 Safety modules (Electric power supply line switching and high voltage

grounding)

 Drive ( pre-connector Up converter and RF vision drive)

 Control logic unit for automatic manual management of equipment

Rear View

 Main AC 400V, 3 phase + neutral

 Remote control switch and main distributor.

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3.5.3 Master Control Room and Transmitter Engine

The video and audio signals coming from the MCR are linked by underground

cables into the fibre optical system (multiplexer) in the satellite room. The multiple input

signals are combined by the multiplexer into a single composite signal that is transmitted

over the communication medium. At the end of the communication system is a single

cable which goes into the optical fibre terminator that separates the audio and video

signal. The audio signals link directly into the transmitter via a cable and the video signal

enters into the video distribution amplifier. The video distribution amplifier splits the

video signals into driver forms, one goes into the monitor, one into the vectroscope and

the last signal enters the transmitter engine for further filtering, processing and

amplification.

Fig 3.1 Diagram of Chains of Distribution from Master Control Room (MCR) to the
Transmitter Engine

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3.5.4 Transmitter Power, Antenna Gain and Transmission Lines.
All electronic communication system consists of transmitter, a receiver and a

communication medium. But a television broadcast transmitting station is composed of

three elements.

 The transmitter located in the transmitting room.

 The transmission medium which is a direct link such as coaxial cable or fiber

optical in some system.

 The antenna system located on the top of the tower is usually composed of several

individual antennal couples together to give the needed radiation patterns.

The transmitter is delivers its nominal output power (in Watts) to the feeder cable.

The coaxial feeder cable transports the power to the antenna with loss. The gain or loss of

a system is expressed in decibel (DB), is positive or negative accordingly. The RF signal

generated by the transmitter is sent into free space and is eventually picked up by the

receiver. The process of launching the signal into space and receiving it is the function of

the antenna. The antenna is a device that acts at the interface between the transmitter and

free space and between free space and the receiver. It converts the transmitter RF power

into electromagnetic signals that can propagate over a long distance and it is also the

device that picks up the electromagnetic signals and converts them into signal for the

receiver. The antenna system radiates power into air to reach the listeners. It has some

gain when coupled together. This means that the power reaching the antenna system is

multiplied by a factor depending on the number and the position of the antenna.

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Since the antenna is typically remoted from the transmitter and receiver, some means

must be used to get the power to and from the antenna and this is the work of the

transmission line of an RF connector.

3.5.5 Transmitting Antenna

This is a conductor used to transmit the modulated radio waves into space in

television transmission. It is made up of 6ft-white fibre glass reflector mounted on a

triangular shaped metallic structure of 1050ft. height (for ESBS TV). There are four of

the fiber glass reflectors mounted at an angle of 900 to each other to form a total of 3600

for propagation of waves in all direction.

3.6.0 Maintenance of Broadcasting and Communication Equipments

Generally, maintenance is mostly done on Monday morning in the television room of

ESBS and this involves physical checking of equipment and dusting of all parts of the

equipment. A test operation of all equipment is done to detect any malfunction before

commencement of transmission.

3.6.1 Transmitter Maintenance

The maintenance of the transmitter is carried out mostly during the midnight. The

transmitter must be usually inspected. The engineer or technician has to be acquainted

with normal operating condition in order to recognize and identify abnormal condition

readily available. He/she has to carry out the following.

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  Check parts for overheating especially rotating parts such as blower, motor and

circuit breakers.

 Lubricate and replace every worn out nut and bolt.

 Blow out every dust particle with the use of blower machine.

 Monitor and check the input and output signal and wave form.

 Check the transmitters for poor operation.

 Check the transmitter tower light for any burnt out bulb.

3.6.2 Effect of Lightning

Lightening effect is one of the major problems in broadcasting and

telecommunication industry. When there is lightning, the charges look for the tallest

insulator around to discharge their ions, and the antenna is always protected by insulation

in this area. If the antenna is struck by these charges, the charges will pass through it to

equipment in the transmitter and lots of equipment will be destroyed as a result of

thunderstorm. This damage may even extend to the equipments in the studio because

there is a link between the control room and the transmitter. The measures to prevent

transmitting antenna from thunderstorm include the following.

1) The antenna is sited on clay soil because clay does not have free electrons in it.

This therefore makes antenna conduct while the charges are easily barred but if

the antenna is sited on rocky area, the rock will repel the charges back to antenna

thereby increase the voltage of the transmitter.

2) Salt should be poured inside the soil around the antenna to increase the

conductivity of the soil.

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 3) Thunder arrester should be used to collect and to earth the charges.

3.7.0 Satellite Section

This section discussed the space station which is made up of the communication

satellite.

3.7.1 The Space Station

The space station is made up of communication satellite, which receives signals

from the earth station, amplifies it, down converts and sends it back to the earth station in

the form of downlink

3.7.2 Communication Satellite

The word satellite means “follower”. A body of matter that is in orbit around the

earth also follows the earth in its orbit around the sun.

Definition: A communication satellite is basically an electronic communication package

placed in orbit around the earth with the prime objective of facilitating communications

transmission from one point on earth to another.

The satellite collects the electromagnetic field, and retransmits the modulated

carriers as a downlink.

Communication satellites are usually located in the geosynchronous orbit around

the earth and are responsible for reception from the ground station and subsequent

transmission to the earth stations in several locations.

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3.7.3 Geosynchronous Orbit

The geosynchronous orbit is the orbit where communication satellites are placed.

This orbit is at a distance of about 35, 785kM (22,300 miles) above the earth’s surface at

any point on the equator. The satellite is placed in the geostationary orbit by the use of a

rocket launch vehicle. These satellite moves at the same speed on the earth thereby

appearing stationary to an observer on earth. They are normally fitted with equipment

that is responsible for transmission to various locations on earth.

3.7.4 Satellite Communication System

Communication satellites are not originators of information to be transmitted;

they are instead relay stations for other sources. If a transmitting station cannot

communicate directly with one or more receiving stations because of line of sight

restriction, then a satellite can be used. The transmitting station sends the information to

the satellite which in turn transmits it to the receiving stations. The transmitter-receiver

combination in the satellite is known as the transponder.

3.7.5 Transponder

A transponder is a wireless electronic circuit or a communication device on a

satellite that receivers, modulates, amplifies and re-transmits an uplink signal. A

transponder receives and transmits signals at a prescribed frequency range and re-

transmits the signal at different frequencies. Transponder is a combination of transmitter

and responder. Its basic functions are amplification and frequency translation. An

operational process in a transponder is depicted on Fig 3.2 below

26
Fig 3.2 Operational Processes in a Transponder

A parabolic antenna directed towards the earth receives the uplink signal. The first thing
that happens inside the transponder is that the received signal is amplified. However, it is
not possible to transmit the signal in the same frequency band as the uplink, so the signal
is down converted into the downlink frequency band. Finally the downlink signal is
amplified to an output level between 50 and 10Watts before the signal is beamed back to
the earth using a downlink parabolic antenna on the satellite. The performance of the
satellite transponders are to a large extent decided by the transmission tubes. Another
transponder feature is the gain control amplifier that has an AGC (Automatic Gain
Control) facility. The AGC keeps the output signal of the transponder at a saturated level,
even if the incoming signal on the uplink is attenuated due to rain or other problems at
the uplink station site.

3.7.6 Satellite Downlink Process.

The function of the downlink is to capture enough of the transmitted signal from

the satellite to at least attain or more preferably exceed the “threshold” of operation. The

system of the downlink is essentially the reverse uplink process. The downlink has a

receiving antenna, LNB (made up of down converter and low noise amplifier, LNA) and

receiver (made up of demodulator, de-multiplexer, and decoder e.t.c) for digitally

27
compressed signal. There would also be a sophisticated monitoring system able to

measure all parameters of the received signal i.e the spectrum analyzers.

Fig 3.3 Satellite Downlink Process

3.7.7 The Downlink Antenna (Satellite Dish)

The purpose of a satellite antenna is to collect and concentrate signals coming

from a targeted satellite while ignoring extraneous signals and noise. Downlink

equipments are downlink satellite dish/antenna, satellite receiver, monitor and spectrum

analyzer. The downlink frequency is 4GH, usually lower than the uplink frequency.

28
3.7.8 Satellite Uplink

The function of uplink is to transmit the original signal from the earth station to

the satellite in space. The uplink frequency is 6GHZ, usually higher than the downlink

frequency. The overall diagram of communication satellite in space is shown in fig. 3.4

Fig 3.4 The Diagram Of Communication Satellite in Space.

29
3.7.9 Frequency Bands Used in Communication Satellite.
A typical communication satellite has 12-24 or more transponders. Each

transponder represents an individual communication channel. Most communication

satellite operates in the microwave frequency spectrum. The microwave spectrum is

divided into frequency bands which have been allocated to satellite as well as other

communication service such as Rader. The most widely used satellite communication

bands are the C-band and the Ku-band.

C-Band

C-Band is a range of satellite used by TV channels to transmit to full size satellite

dishes. The uplink frequencies designated for the C-band are in the 5925 to 6425MHZ

(5.9-6.4GHZ) rage. The c-band uplink frequency is generally said to be 6GHZ. The

downlink frequencies are 3700 to 4200MHZ (0r 3.7-4.2GHZ). The C-band is

occasionally designated as 6GHZ/4GHZ. Most satellite communication activities take

place in the C-band.

Ku-Band

The Ku-band is a range of satellite transmission frequencies which has its uplink

frequencies in the 14.0 to 14.5GHZ range and downlink in the 11.7 to 12.2GHZ range.

This is designated as 14/12GHZ. Naturally, the electronic equipment needed to achieve

these range of higher frequencies is more expensive but it has improved communication

reliability while decreasing antenna size to smallest sizes unlike the C-band antenna.

Example of Ku-band is seen in the multi-choice decoder used in digital satellite television

(DSTV). Most new communication satellites are in the Ku-band frequencies. The reason

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for the upward shift in frequency is that, the C-band becomes over crowded which may

result in interference because of the heavy usage. The only way this interference will be

minimized is to shift all future satellite communications to higher frequencies.

3.8.0 Earth Station Subsystem of ESBS TV

The earth station communicates with satellite to carry out the designated mission. The

earth station is located with ground base intercommunications link between the earth

station and the end users. An earth station consists of five major subsystems. These are:

1) Antenna subsystem

2) Receive subsystem

3) Transmit subsystem

4) Ground communication equipment (GCE) subsystem

5) Power subsystem.

3.8.1 Antenna Subsystem

The antenna subsystem consists of the parabolic reflector, the feed horn antenna wave

guide transmission line and mounts. The parabolic reflector is a large dish-shaped

structure made of metal or screen mech. Dish antenna comes in various types and side

each with its specific characteristics and purposes. There are three sizes which are:

 Small-60 to 70cm diameter.

 Medium-90cm diameter.

 Large-1.2 to 1.5m diameter.

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3.8.2 Receiver Subsystem

The receiver subsystem consist LNB down converters and related component.

The purpose of receiver subsystem is to amplifier the down link satellite signal collected

by the LNB and converts the signal from the satellites nature C-or Ku-band to L-band.

3.8.3 Transmit Subsystem

The base band signals such as the video signals are applied to an encoder which

permits multiple signals to be carried on a single channel. The multiplexer signals are

applied to a modulator along with the carrier oscillator. This output is fed to an Up

converter which generates the carrier channel and the signal through wave guide to a high

power amplifier (HPA) and the final signal is radiated out by the antenna system

(parabolic dish).

3.8.4 Ground Communication Equipment (GCE) Subsystem

The GCE consists both the receiving and transmitting circuit which makes way

for the connection of telephone system, terrestrial microwave relay links, and computer

interface.

3.8.5 Power Supply Subsystem

The power supply subsystem furnishes all power to the other equipment. The

primary source of power is standard DC power lines. The power supply subsystem also

consists of the emergency diesel generator, batteries and inverters (UPS) to ensure

continuous operation during power failure.

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3.9.0 Radio Communication (ESBS Radio Am/Fm Station)

Student who undertakes his/her IT at ESBS is expected to have the knowledge of

both the TV and radio transmission since the organization is made up of both the two

transmission stations.

On my I.T period there at the organization, I was posted to both of the stations

with Radio station being the last. The detail of experience learnt at the Radio station of

ESBS by me is given thus.

The engineering department of ESBS radio is made up of the following sub-unit.

 Studios; signal monitoring and outside broadcasting (OB) unit.

 Transmission unit.

 Maintenance and repair unit.

3.9.1The Studio Signal Monitoring Unit.

The unit is made up of continuity studio, recording studio and master control

studio.

3.9.2 Continuity Studio

In the continuity studio are found the continuity announcer and the control

engineer who monitors or controls the activities of the continuity announcer through

several electronic machine such as mixer (console) made of several channel,

microphones, DVD/CD players, Tape recording deck, talk back machine, computer, e.t.c.

There at the studio room, I learnt how to use the above mentioned equipments in

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controlling the audio signal leaving the continuity announcers room via audio cables for

the transmission processes.

3.9.3 Master Control Studio (MCR)

Here I learnt how to monitor the continuity studio and the transmission room as

well as the recording studio. This is because all the outputs were passed through the

master control room for scrutiny before being sent out. The master control room as the

name implies is used in monitoring pre-transmission and post transmission signals.

The control panel has equipment like oscilloscopes (computer in the case of

ESBS) showing changes in the electrical current as wave in a line on the screen of a

cathode ray tube. In the master control room, I was able to access the output of the

continuity studio to be sure of signal being sent on air and what they were meant to be. In

instance where the quality of the signal is poor, CD crack, the pressure’s voice too high

or low, I signal the person in the control room through talk back machine located on the

panel for adjustment, likewise the output of the transmitters passed through the master

control room to make sure what we are sending on air is desired quality.

3.9.4 Transmission Unit

Transmission unit is made up of transmitter which is an electrical machine that

carries out the transmission of signals. Modulation takes place in the transmitter and is

the variation of carries wave in accordance with the modulating signals. Sound or radio

broadcasting in general is a process that has to do with sending of sound information in

form of signals in air with the high frequency radio waves called cameras.

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The information broadcast may be music, drama, or news originating from the studio

where the sound is first converted into electrical signal of corresponding frequency using

a crystal microphone.

Enugu state broadcasting service (ESBS) transmits only on frequency modulation

(FM) band of 96.1MHZ as the amplitude modulation (AM) band has its transmitting

antenna destroyed by a heavy wind over 10 years ago.

However, ESBS radio FM uses two stages of transmission consisting of two

transmitters and two transmitting antenna. The first transmitter which is called Mart- link

transmitter and a receiver are used as a link between the continuity studio (also master

control room) and the final transmitting room. A detached block diagram of the station

transmission process is depicted in fig 3.5

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Fig 3.5 The Block Diagram of Transmission Process of ESBS FM Radio.

3.9.5 Marti- Link Transmitter

The speech or music from the broadcasting studio is converted into tiny varying

electrical currents with the help of a crystal microphone. This is the electrical signal that

leaves the broadcasting studios through audio cables in the master control room where a

10W Marti- link transmitter is located.

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For effective and widely transmission the FM transmitting house (and hence the antenna)

of ESBS radio is located about 30kM away from the broadcasting house in an isolated

hilly area where the antenna can be least disturbed. A mean is therefore needed to link the

broadcasting house to the transmission house, in other words, a transport means is needed

to deliver the signal from the continuity/master control studio to the point of

transmission. A Marti-link transmitter, receiver and two antennas are used since a direct

link using audio cables will amount to serious loss in power and increase costs.

The transmitter has an inbuilt oscillator that generate oscillation of very high

frequency of about 96.1MHZ. it then couples the audio signal into it by a process called

modulation and it is this modulated wave that is sent into the air through the antenna.

3.9.6 Marti Link Receivers

This receives the signal sent from the 10W Marti-link transmitter with the help of

two antennas directed towards the direction of broadcasting and transmitting house and

sends it further to the main transmitter via some other processes like limiter and AF.

Amplifier.

3.9.7 Limiter

The sound recovered from the Marti-link receiver contains some noise and other

disturbance. The limiter is therefore used in filtering the signal to remove the

disturbances before it is sent to the amplifier.

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3.9.8 Amplifier.

The signals reaching the limiters are weak and there is therefore need for

amplification before they are finally sent to the transmitter.

3.9.9 Final Transmitter.

This is the unit that performs the final modulation of the signal to the designed

carries frequency (which is about 96.1 MHZ for ESBS FM station). Just as explained

earlier, this final transmitter also has an inbuilt oscillator that generates oscillations

(carries) at a fixed frequency of 96.1 MHZ. The audio signal reaching the transmitter

from the amplifiers is then coupled with carries (modulation) through antenna into space

to be picked by any radio receiver tuned at this frequency. Fig 3.6 shows the block

diagram of ESBS FM transmitter.

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Fig 3.6 The Block Diagram of ESBS FM Transmitter.

3.9.10 Levels of Transmission

Since the degree of coverage of a station depend largely on the radiating power of

the antenna (power of transmission). To cover all local government areas of the state, the

station uses a 100W transmitter.

There are two levels of transmission in radio transmission. Low level and High

level transmission.

In high level transmission, the AF signal reaching the transmitter at a low power

is amplified to a high power (with the aid of power amplifiers as in Fig. 3.6) and

subsequent transmission. FM band of the station broadcasting employ this level of

transmission. The low level transmission is employed in AM broadcasting station.

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The power compartment of the transmitter is split into 4 small units of amplified power

called packets, each of which supplies 25W of amplified powers. And each of these

packets can be removed separately without affecting the performance of the others. The

advantage of using power packets over single power amplifier unit being that

transmission will still continue even when one or more of the packets are faulty. The

picture of ESBS FM transmitter is show in fig 3.7

Fig 3.7 Diagram of ESBS FM Transmitter

3.9.11 Modulation
Modulation is the process of combining an audio frequency (AF) signal with a

radio frequency (RF) carrier wave to form a resultant wave called the modulated wave.

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Fig 3.8 Modulated wave.
Signal leaving the studio is 0f the form e(t)=Asin(2πft +φ) where A=amplitude;

f=frequency and Ф=phase

3.9.12 Amplitude Modulation (AM)

In this type of modulation, the amplitude of the carrier wave is varied in

proportion to the instantaneous amplitude of the AF signal i.e. the information or AF

signal changes the amplitude of carrier wave without changing its frequency.

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Fig 3.9 Amplitude Modulated Wave.

3.9.13 Frequency Modulation (FM)

In this type of modulation, it is only the frequency of the carrier wave that is

changed, the other parameter (amplitude and phase) are not varied i.e. the information

signal changes the frequency of the carrier wave without changing its phase or amplitude.

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Fig 3.10 Frequency Modulated Wave.

3.9.14 Personal Involvement in Radio House (FM Station)

The activity I carried out at the studio and master control room was to monitor

and control the programmes that are meant for transmission.

3.9.15 Knowledge Gain:

I had the opportunity of adjusting the knob of audio console (mixer) as well as

know the general principle involved in radio communication (transmission).

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 CHAPTER FOUR

Summary of Experience Gained, Challenges, Recommendations and Conclusion.

4.0 Summary of Experience

The SIWES program is an unforgettable and enriching experience as it availed me

the opportunity to broaden my appreciation of electrical and electronics engineering

beyond the theoretical level to its immense practical applications in various aspects of our

economy.

It also helped to deepen my understanding of several theories and practices of

electrical and electronics engineering especially in the area of communication by

exposing me to the reality and giving me a brand new perfective in the course of the

various practical processes we carried out.

Some of my experiences and knowledge gained from units I served are itemized

below.

4.1.0 Repair and Maintenance Unit

I learnt how to trouble shoot an electronic machines such as TV, radio, CD

players, fans e.t.c in order to detect faults and subsequently fix it

4.1.1 Television Room (Studio, Control/Master Control Room)

1) I learnt how to setup a television camera and set up a news studio.

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 2) I obtained a detailed understanding of the practical processes and equipment

involved in transmission of TV signals from source to destination.

3) I learnt how to adjust the knob of audio/video console (mixer) in the control room

and master control room.

4.1.2 Transmitter Unit:

I learnt the various processes that signal follows in the transmitter engine before

being sent out to the viewer/listener. The process such as modulation and amplification of

signal.

4.1.3 Radio House (FM Station)

Here I learnt the general processes involved in radio transmission or broadcast

from the continuity studio to the master control room and finally to the transmitter for

final signal amplification.

4.2 Challenges Encountered

Though the industrial training was a very educative and exciting experience, yet it

was not without its challenges. Some which are highlighted below.

1) Getting Placement: It was difficult in getting a place for my training because

some of the companies were not accepting students or in some cases where there

is space you ought to know somebody before you can get placement.

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 2) Financial Challenges: Due to high cost of transportation because of its long

distance involved and no financial assistance from companies, we had to rely

basically on our parents/guardian to meet our needs.

3) Transportation: Due to the distance involved, it was always difficult to get to

work on time because of hold up on the road and sometimes inadequate vehicles

to convey people.

4) : Language Barrier The issue that before being employed as a staff in the

establishment I did my I.T, you must be an indigene resulted in all the workers

speaking their native language (Igbo) almost all the time. This was a great

challenge to those of us who are none-indigene undertaking our I.T there as we

could not understand their message most of the time.

5) Unorganized Training Format: In most organization there is no formal or

defined procedure for learning as SIWES students are not fully recognized and

sometimes not given right placement in department where they are to obtain the

designed knowledge.

4.3 Recommendations

The following should be considered in order to sustain and improve upon the SIWES

program.

1) SIWES program should be encouraged and sustained. Potential SIWES students

should be adequately sensitized and educated on the benefits of the program The

so that they might go prepared with a positive and flexible mind set.

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 2) The SIWES coordinators and the Nigerian Government should try and make the

student’s placement for I.T paramount.

3) The authorities should ensure that supervisors visit students at their different

placements regularly to help them tackle some of the problem they are facing.

4) The Government should intensify efforts to assist students on the SIWES program

by availing them some form of remuneration that would alleviate their financial

burdens and increase their zeal to put in their best.

5) The SIWES program should not be seen by students as an opportunity to earn a

leaving but an opportunity to deepen his/her understanding of his/her course of

study as well as appreciate his/her course in relation to other courses.

4.4 Conclusion

Enugu State Broadcasting Service (ESBS) has been able to position itself as a

prime driver of broadcasting standard by its well equipped digital studios which conforms

to the

present ages demand. The establishment affords me the opportunity of gaining

meaningful insight to her operational activities in various areas such as maintenance,

repair, installing, troubleshooting and monitoring TV and Radio broadcast.

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 REFERECE

1. “SIWES Guideline”, National University Commission (NUC) Handbook, 2008. Pl-4

2. “Earth Station Technology”, A Handbook by Applications Support and Training

Manual, INTELSAT, 1999.

3. Stephen, O.M (2004) “Satellite Communication”, A lecture presented at NTA

Television College Jos, 2004. Unpublished Note

4. Odigbo E.U et al.(2003) “Effective Communication of Technical Ideas in Science and

Engineering” University of Nigeria Press Ltd.

5. Ayua A. (2009) “principle of communication engineering” Unpublished Notes.

6. ESBS TV-50 (2010) “Note on transmission and communication” Unpublished

Note.

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