CR (Community radio)
CR: A user’s guide to the
A guide to the technology and technical
parameters of community radio in India
N. Ramakrishnan
CR: A user's guide to the technology (2007)
© UNESCO (2007)
ISBN 81-89218-12-3
This publication may be produced in any media appropriately
acknowledging UNESCO
Published by :
The United Nations Educational Scientific & Cultural Organization
B-5/29, Safdarjung Enclave
New Delhi - 110019, India
Phone: +91-11-26713000
Fax: +91-11-26713001/2
E-mail: [email protected]
Author, Researcher: N.Ramakrishnan (Ideosync Media Combine)
Editorial Team: Seema Nair, Sajan Venniyoor, Gitanjali Sah
Cover & Binder Design: Inverted Commas, New Delhi
Inside page design and graphics: Mensa Computers Pvt. Ltd., New Delhi
Photo credits :
N.Ramakrishnan:Pages 4, 5, 6, 7, 13, 48, 57, 61, 73, 92-94, 96, 101,103,
104, 165-171, 204
Choy Arnaldo: Pages 14, 25, 26
Pages 11, 38, 76, 90, 100
All others images are courtesy the respective manufacturing companies
Photographs of CR groups in action appear with permission of Samudayik
Radio Mandakini Ki Awaaz and Hevalvaani Samudayik Radio, Uttarakhand
Please send in comments and your experiences with this manual to
[email protected] and:
N. Ramakrishnan
Ideosync Media Combine
177, Ashoka Enclave III
Sector 35, Faridabad - 121 003
Haryana - INDIA
Tel: +91-0129-4131883/6510156
Email: [email protected]
The author is responsible for the choice and the presentation of the facts
contained in this news piece and for the opinions expressed therein, which
are not necessarily those of UNESCO and do not commit the Organisation.
The designations employed and the presentation of materials throughout
the publication do not imply the expression of any opinion whatsoever
on the part of UNESCO concerning the legal status of any country,
territory, city or area or of its frontiers
(ii) or boundaries.
N.Ramakrishnan is a development communications professional, trainer
and author with more than a decade of experience in the development
sector. He is also a cinematographer, editor, director, and technology
enthusiast; and conducts workshops on community radio, developmental
filmmaking and low cost radio and video technology.
With extensive experience in developing community-derived and
community-oriented behaviour change materials, Ramakrishnan has worked
on a number of behaviour change communication tools, including the
National Award winning film Nirankush, on female infanticide in the Indian
state of Rajasthan; and the acclaimed Growing Up/Badhte Hum/Time of
Our Lives video module series on reproductive and sexual health for young
Ramakrishnan works with Ideosync Media Combine, a communication for
development organization based in the NCR of Delhi, India,. He is currently
engaged on several community radio and radio for development initiatives,
including a cross border radio programme series on safe migration and
HIV for Nepali, Garhwali and Kumaoni migrants.
This manual is the outcome of a number of years of practical field work, and
the inputs of a vast number of communication and audio/video professionals
that its has been my pleasure and privilege to work with over the last several
years. Their advice, tips and generosity in sharing their own experiences and
learning has been central to the compilation of the information contained in
these pages.
This manual has also been through an extensive process of review on the
Solution Exchange and CR India e-discussion lists. Mr.Arvind Kumar, Director
(Broadcasting Policy & Legislation), Ministry of Information & Broadcasting,
Govt. of India, participated in this discussion by placing the use of this manual
in the current context. The members of both lists have been more than
generous with their time, and in sharing their vast experience and
understanding of community radio technology and audio equipment for the
betterment of this manual. Their combined knowledge is a wonderfully rich
resource which I have made extensive use of in this volume.
In particular – and without in any way reducing the value of the contributions
by the other members of both lists – I would like to extend my gratitude and
thanks to the following community members who volunteered their time
and energy :
Ashish Bhatnagar, Prasar Bharati (Akashvani and Doordarshan), New Delhi
Ramnath Bhatt, VOICES, Bangalore
Benjamin Grubb, Queensland University of Technology, Brisbane, Australia
Douglas Bell, Education Development Center, Bangalore
Aaditeshwar Seth, University of Waterloo, Canada
Jayalakshmi Chittoor, Centre for Science, Development and Media Studies
(CSDMS), New Delhi
Michelle Chawla, Nomad India Network, Dahanu (Maharashtra)
Frederick Noronha, BytesForAll, Panaji (Goa)
My thanks also to Shri D.Singaravelu, Dy.Advisor (Wireless), WPC, Ministry
of Communication & Information Technology, for his key inputs on the
technical aspects of the guidelines governing CR policy in India; and to
Choy Arnaldo, who has provided several photographs in this manual
illustrating CR experiences from around the world.
A special word of thanks to UNESCO, for understanding and responding to
the need for this manual; and specifically to Seema Nair at UNESCO, and
Sajan Venniyoor and Gitanjali Sah at Solution Exchange who jointly
constituted the editorial team for this manual. I thank them all for their
enthusiasm and hard work in rearranging, clipping and pruning this manual
into its final shape.
Last – but not least – my thanks and appreciation to my colleagues at Ideosync
Media Combine, who helped organize a vast number of resources into
something that I could use to write this manual; and to the members of
Hevalvaani and Mandaakini Ki Awaaz CR groups in Uttarakhand, who
provided valuable feedback on the kind of information that would make
this manual usable and accessible to its users.
New Delhi
November 2007
Foreword................................................................................................... ix
What they said ........................................................................................ x
Introduction: Who is this manual for, and how should it be used?............ xii
Section A: Community Radio: An overview
Chapter 1: So what is radio, and how does it work? ............................... 3
Radio broadcasting: The Process – and some terms ................................. 3
Radio waves: A brief look at some important concepts ............................ 8
Linking the technology to the production .............................................. 10
Chapter 2: Technology I: Setting up a studio space ............................... 15
Section A: Siting the CR station .............................................................. 15
Section B: Defining the spaces ............................................................... 17
Section C: Important considerations while setting up the spaces ............ 20
Chapter 3: Technology II: Studio Equipment ......................................... 39
Section A: The Broadcast Studio ............................................................ 39
Section B: The Production Studio .......................................................... 49
Chapter4: Technology III: Field recording equipment ........................... 61
Why do we need field recording equipment? ........................................ 61
What are the main considerations in selecting
field recording equipment? .................................................................... 62
What should a field recording kit consist of? .......................................... 63
Chapter 5: Technology IV: Transmission equipment ............................. 69
Chapter 6: Telecommunications & other ancillary equipment .............. 77
Section A: Telecommunications & Telephony ........................................ 77
Section B: Other office equipment ......................................................... 86
Chapter 7: Planning for maintenance & management ........................... 91
Setting rules & regulations in the studio ................................................. 91
Planning for maintenance ...................................................................... 92
Maintaining the documentation & plans ................................................ 93
Maintaining inventories of equipment ................................................... 94
Assessing (and investing in) maintenance skills ...................................... 95
Assessing maintenance costs .................................................................. 95
Annual Maintenance Contracts (AMCs) ................................................. 96
Chapter 8: Assessing training requirements ......................................... 101
Assessing training needs ...................................................................... 102
Training resources ............................................................................... 104
Chapter 9: CR guidelines in India and their implications .................... 105
Section B: Detailed notes on equipment & audio concepts ................. 121
(See table of contents at beginning of Section B)
Section C: Appendices ........................................................................ 231
Appendix 1: Suggested setups for CR stations ...................................... 232
Appendix 2: Audio & Radio equipment manufacturers (Global list) ..... 245
Appendix 3: Index of advisory organizations & individuals .................. 254
Appendix 4: Audio & Radio equipment vendors in India ..................... 260
Appendix 5: Useful web-based resources ............................................ 265
Bibliography ....................................................................................... 269
Notes pages ......................................................................................... 270
The Government of India earlier this year announced its intention to establish
4000 community radio stations by 2008.
This has brought a flood of questions from prospective Community Radio
applicants/operators and in particular: what equipment do you need to set up
a community radio, and how much would it cost? While there are many solutions
that are available off the shelf, our main line of advice has been “Costs depend
on the context of the Community Radio Station you are trying to build”.
We also strive to bear in mind the Objectives of UNESCO’s programme
stressing promotion of community access and engagement, and the Action
Plan of the World Summit on the Information Society, (Tunis, 2005) which
emphasises values of inclusive and pluralist knowledge societies. It is more
to such inclusiveness and the level of participation of a community, together
with relevant programming rather than the technology, that we owe the
success of a community radio station.
Our further piece of advice therefore, is to “Begin small and grow inch-byinch with your community”.
This manual is designed to accompany you in the demystification of each
piece of equipment usually found in community radio stations; its role and
function within a wider social context; advantages and disadvantages of its
usage. For others who dare to be technically more adventurous detailed
notes on equipment are also provided.
As hands-on participatory community development specialists it is in your
interest to be aware of the different options open to you in sourcing,
maintenance and operation of the equipment that is most suited to your
individual needs. This manual is intended as a tool for such information and
we hope you will find it useful in applying this knowledge to your own local
It is through localisation not only of content, but also of technology that we
may assist in accelerating the community radio movement in India and making
the intentions of the Government a live reality.
Jocelyne Josiah
Advisor in Communication and Information for Asia
UNESCO New Delhi
What they said...
er. I
us pow n it [radio].
od i
a mir
This is us power of G
Radio is the theatre of th
mind. Steve Allen
You can make good
interesting radio, gr
eat radio even,
without an urgent qu
estion, a
burning issue at sta
Ira Glass
Radio could be the most
wonderful public
communication system
imaginable, a gigantic
system of channels – could
be, that is, if it were
capable not only of
transmitting but of
receiving, of making
listeners hear but also
speak, not of isolating them
but of connecting them.
Bertolt Brecht (1930) quoted in Lewis and Booth
Television is
radio without
ge, bu
e an
e r y o n a million
TV giv ves birth to ains.
n br
It’s a pleasure,
a gift, an honor,
to go in front of a
microphone and
Larry King
You don
don’tt work for
the radio station.
You work for the people
out there.
Wolfman Jack
Congratulations! If you’re reading this, you have taken the first steps on a
long and satisfying journey that should (we hope) culminate in the setting up
and successful operation of a community radio station: A radio station by,
for and from the people. With the Government. of India allowing community
radio stations (CRS) in India in late 2006, a new chapter has begun for those
who have been working towards creating media and technology access for
communities – and to empower ourselves with an understanding of how to
use these technologies to highlight our concerns, our ideas, and our cultural
and traditional practices.
But in the excitement of gaining access to this truly participatory, inclusive
and inexpensive mass medium, we often forget that radio is a technological
medium – and that it calls for communities and civil society organizations
working with radio to have an understanding of the technology, the
equipment, and the processes and parameters that govern the setup, operation
and successful running of a community radio station. It is all too easy to
forget about the technology while we exult in the joy of hearing our own
voices and our ideas over a speaker or radio set; but it is important to realize
that the technology of radio is what allows us to preserve these thoughts and
send them out to our listeners.
That could be your cue to say, Uh-oh, I’m not a technical person; this looks
like it’s going to lead to a lot of tech stuff - I’m not going to get all of this!
How do I begin to understand all the jargon and the science?
Relax. That would be true – if this was a manual that intended to explain the
construction of electronic circuits or the repair of complex recording and
transmission equipment. But it’s not that kind of manual: This is a manual
for the everyman, the interested community member, the hobbyist, the NGO
worker and all those of us who run for help when our TV remotes and
cellular phones misbehave. In short, this is going to be an easy introduction
to the technology of radio.
Reading this manual may not bring you to a level of understanding where
you can take all the decisions and select all the equipment by yourself –
especially since radio equipment changes and evolves all the time – but if
you read this book cover to cover, it’s probably going to give you a feel of
the wide variety of technology options, decisions and concepts that you’ll
have to keep in mind while setting up a CRS. And it’s going to help you take
informed decisions on all those things.
So, in a nutshell, what this manual hopes to present is 1. A user level understanding of how to set up and equip a CRS, and a taste
of the kind of decisions you’ll have to take while planning your CR set up;
2. An understanding of the types of equipment that a CRS requires, their
functions and the costs involved;
3. An understanding of how the various components of a radio production
and the broadcast process work together;
4. An understanding of CR related regulations, technical parameters and
the licensing procedures applicable in India;
5. Enough insight into all the ‘tech stuff’ to inspire you to learn more about
the electronics and physics part!
What it’s not going to do is make you an expert on every aspect of radio and CRS
setup – that’s beyond the scope of any single book or document, and requires
years of practical experience and learning. It’s going to place some options in front
of you and it’s going to give you further resources you can access to learn more:
Web based and print material, as well as organizations and individuals who can
advise and assist you while you learn and build your CR setup.
It is also important to stress that community radio stations work out of single
rooms with basic equipment; as well as dedicated buildings housing multiple
studios and packed with all kinds of high technology. Both can produce
brilliant, locally relevant, interesting programmes. It’s up to you to decide
what kind of a setup is most appropriate for your station, a decision you
must base on five things:
1. The kind of programmes that you plan to broadcast;
2. The amount of money at your disposal;
3. The kind of spaces that are available for you to set up a CR station in the
area you will be operating in (rented or self owned; constructed to your
requirements or an existing space reconfigured);
4. Your ability to handle the costs and effort required to maintain your
equipment, and support the costs involved in acquiring consumables
and recurring costs like the spectrum fee; and finally
5. Your ability to access trained people to operate and maintain your
equipment (and/or training resources to build a pool of trained manpower
to fulfil these functions.)
Depending on a combination of these factors, you may mix and match and
adapt the ideas that you will find in this manual to arrive at a unique solution
which will meet your requirements.
In the same spirit of selection and adaptation, we have also tried to make this
manual as adaptable to your needs as possible: To start with, we’ve included
several notes pages at the end of this manual so that you can add your own
notes and comments based on your own research and experimentation. We’ve
also included a variety of diagrams and illustrations/photographs to give
you an idea of the equipment, devices and setups referred to in the text.
We’ve also tried to include helpful notes and comments where possible,
identified by the following icons:
Warning! Things you must remember to avoid damage to
equipment or injury
Remember! Things you should keep in mind from the
information immediately preceding the icon.
Maintenance related information that you should remember
to keep your equipment in good working order.
Cross references to other parts of the manual. This symbol may
also refer you to the Detailed notes on equipment section (Section
B) that follows the main manual. This includes detailed
explanations of several concepts and types of equipment, to allow
you to understand equipment specifications better.
The appendices at the end of this manual give you lists of equipment vendors,
lists of advisers and organizations already working on CR and suggested
equipment setups on which you can base your own assessment of the
equipment combinations you require. All these lists will need revision as time
goes by: New equipment and equipment suppliers turn up all the time, so it is
probably a good idea to jot down information on any new vendor or piece of
equipment that you come across. All the costs are in Indian Rupees, and have
been converted from US Dollar rates at 1 USD = INR 40, the rate current at
the time of publication of this manual. (But the exchange rates and prices
change all the time too, so do check on this before you take any final decisions!)
Last, but not least, remember that this manual is not an encyclopaedia – and it’s
not trying to be one. This is a ready resource for the interested user, which you can
also use as training material. It is impossible to give a detailed understanding of
everything that is included in this manual in a single volume. But if this manual
leaves you feeling a little more confident about your understanding of the technology
of community radio, we’ll consider its job done.
We welcome your comments on the manual, so that we can
constantly update and revise this document. Please write in to the addresses
given on the first flyleaf of the book.
Once again, welcome to the world of community radio! We hope this manual
plays a part in improving your understanding of the medium and the
technology involved in running a community radio station.
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Section A
Community Radio : An Overview
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Chapter 1
To many of us, the first time we listen to the radio can be a magical experience.
The prospect of using a device that seems to be an illimitable source of so
many different kinds of music and programmes is a stunning concept, and
many of us struggle to come to terms with it.
One of the trainees at a workshop I conducted, who came from a small
village in a remote part of the country, told me that the first time he saw and
heard a radio, he spent a lot of time debating whether he should open it up
and release all the people inside it. He didn't - but as he will attest to, the
experience is one to which we grow quickly accustomed - even addicted.
Few of us stop to ponder about the process by which the sound we are
hearing is captured, joined, corrected and sent out to the little box in front of
us. How does a programme get made and go on air, anyway? To understand
this, it's important to have an overview of the entire process of radio
broadcasting. We'll start by looking at the broad picture, and as we go
further along in this manual, we'll have a look at each of the processes and
equipment involved in greater detail.
Radio broadcasting: The processes - and some terms
The process of making and broadcasting radio programmes combines
teamwork, creativity, punctuality and technology. It often involves a number
of people working in tandem and with reference to each other; and it's an
intricate process where every part of the chain has to work correctly for the
programme to be of good quality and for it to reach the listener on time.
From a holistic point of view, radio broadcasting includes five discrete
1. Research and pre-production (ideation on the programme, and preparing
for the production)
2. Production (Recording or gathering the sounds that will be included in
the programme)
3. Post-production (Editing, or selecting the best portions of the recorded
sound, and assembling them together in a logical and coherent fashion;
and finalizing the programme)
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4. Transmission/Broadcast (Sending the programme out over the airwaves,
so that your listeners can listen to it on their radio sets)
5. Feedback (Getting your listeners' opinions and inputs on the programme
that was broadcast, so that future programmes can be improved.)
Let's have a closer look at what exactly each of these steps involves:
1. Research and pre-production : As with most things in life, the process of
radio broadcasting begins with an idea - and research. The idea can be
based on your observations (say, problems with the water supply in your
area) or a recent event (say, someone in your area winning a dance contest);
or on the basis of a need felt by the listener group or 'audience' that you are
addressing (say, you receive a request to make a magazine programme on
local events). The research (often called formative research, because it
helps 'form' the programme) involves the process of reading any background
material that is available on the idea, along with meeting people within the
community who know more about the issues that need to be included in the
programme. Once you have gathered all this information, you start identifying
the specific people who you would like to interview or record for the
programme, as well as the other sounds that you will include in the
Members of a community radio group discuss programme
ideas with members of their community
programme to give listeners a feel of the places and people who are presented
in the programme. The last step in this process, of course, is deciding the
logistics of the production - that is, the setting up of appointments, deciding
when to record your interviews and sounds, and deciding on and arranging
for the equipment that will be required.
As we shall see, this is the least technological of the four steps, as it primarily
requires only your notes, paper, pen - well, a computer if you have access to one a telephone (or other means to contact people)…and time. At the end of the preproduction process, one should ideally have:
A complete outline script for the programme (if it's a fictional programme,
like a radio drama, then this will include the final dialogues for all the
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characters; if it's a documentary or magazine programme, this will include
a reasonably detailed outline of what you expect the interviews to be like,
along with references to the sounds you will be recording);
A run down sheet, which is a production schedule, and gives a day by
day and hour by hour definition of when, where and what you will be
A time frame within which you expect to complete the recording and the
final programme. (This last may often not be completely in your hands,
especially if you are broadcasting on a regular basis - in which case, the
day and time each programme needs to go on air, every week, is really
how your schedules are decided.)
2. Production : This is the process of actually recording the voices and
sounds that you will need to make the programme - and this is where the
technical part of the broadcasting process really begins. We use a variety of
devices and material to record or store the sound we are gathering, so that
we can arrange it in the way we like later on.
For more on recorders and microphones, see Chapter 4: Field Recording
Equipment on Page 63
The recording process follows the schedule and script that were developed
during the first step. During this process, we ensure that the sounds we are
gathering are recorded at good quality - that is, following the technical
parameters that we need to store the sound in a way that mimics the original
sounds as closely as possible - and in a way which allows us to use and
discard portions of it. We also keep checking to ensure that our recordings
are relevant to the script for the programme.
A programme recording in process
At the end of the production process, typically, one should have:
A completed set of audio recordings and source materials (including
archival material, if required, and sound effects);
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A field log sheet, which gives details on the audio recorded on each cassette
tape/disk used at the field recording stage. A good field log sheet will give
you a preliminary idea of the recordings you have managed to obtain.
Notes on how to rewrite the script, based on your outline script and on
your assessment of which recordings are good enough to be included in
the final programme.
3. Post-production : Post production starts with the process of listening to
the recordings we made during the production phase, and selecting the
portions that we would like to keep in the final programme. (The usual though not entirely recommended - practice is to record as much material as
possible within the time and resources that are at our disposal, so that we
have the luxury of selecting the best sections.) This process, called logging,
should result in a list of the relevant sections that you will refer to while
editing, which is the term for the process of selecting and ordering our
sections of sounds. Editing is the main part of the post production process,
because this is where the raw material that we have gathered is shaped into
the logical and orderly form suggested by the script we have written.
For more on editing equipment, see Chapter 3/Section II: The Production
Studio on Page 57
When the editing is complete, the music (if any) selected and the arrangement
finalized, we 'mix' the sound. Mixing involves the adjustment of the loudness
of the various sounds we have incorporated, so that the programme is
clearly audible, comfortable to hear, and feels seamless. The last step of the
post production process is the mastering of the programme, where we store
the final edited and mixed version of the programme in a way that allows us
to broadcast or transmit it.
A Volunteer at a CR station edits a programme
4. Broadcast/Transmission : The final step of the radio broadcast process
involves using the transmission equipment to put the programme 'on air'.
Essentially, this means combining the sound of the final mastered programme
with a radio signal and broadcasting it (sending it) through an antenna that
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allows the combined signal to reach across space to your listeners' radio
sets, where they can hear it.
For more on transmission equipment, see Chapter 5: Transmission Equipment
on Page 69
The process of transmission is nearly instantaneous, which means the
listeners can hear the programme almost exactly at the same time as it plays
out over the transmitter. It also involves a precise technological process of
controlling and refining the radio signal that is broadcast, so that listeners
can listen to it at a specific setting on their radios, which is how one identifies
a radio station. (90.4 MHz, say, or 102.8 MHz).
5. Feedback : Our work doesn't stop once the programme goes out over the
airwaves, of course - we also need to understand what our listeners think
about the programme and whether they understood it or not. When you are
standing face to face with someone, it is relatively easy to judge whether the
other person understands what you are saying (and what he or she thinks
about your programme) from their expressions, their responses and their
body language. But when the listener is unseen, as happens when using
electronic media like radio or television, we have to evolve processes that let
us obtain regular feedback. This usually involves mechanisms like a postal
or email address that listeners can write to; or a phone number or website
where listeners can leave their comments. It also means you have to look
regularly into these comments and inputs, and revise your programmes
accordingly. The radio station can also increase listener inputs and
interactivity by creating phone in shows where callers can call a 'live' number
and be heard as part of the broadcast.
For more on phone in equipment, see Chapter 3/Section I: The Broadcast
Studio on Page 46
Listeners' letters programmes, where selected letters received are read out
over the air, and request programmes, which offer listeners the opportunity
to request music or specific types of programming, are also an important
way to incorporate feedback.
A CR group volunteer records a listener's feedback
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Radio waves: A brief look at some important concepts
Before we move on, it's important that we understand some basic
concepts about radio - and radio waves in particular - so that some of
the terms we will be using as we move further make sense. (Some of you
may remember this from your physics classes in school!)
We've all seen ripples form in a pool of water when we toss in a pebble:
The ripples start at the point where the stone hits the water, and spread
out in concentric circles from that point outwards. Simply put, the energy
the flying pebble possessed at the moment it hit the water surface has
been converted into the up and down movement of the water particles,
which have now formed WAVES. So a 'wave' is an up-and-down or
side-to-side movement of the particles in a medium, which we usually
illustrate like this:
Fig 1-1. Simple sine wave
Radio waves are also similar to the ripples we see, except that they are
not mechanical (in the sense of the water actually rising and falling):
They are electromagnetic, which means they are actually rises and falls
in the strength of a electrical-magnetic field around the point where the
wave originates. (Visible light is also an electromagnetic wave - we don't
really see anything oscillating or rising and falling, but we can perceive
the light from an electric bulb perfectly well. In exactly the same way,
when radio waves are emitted, we don't see any physical movement of
any medium, but we can build electronic devices that can measure
these waves and interpret them for us.)
Radio waves are emitted naturally by radiant sources like the sun and by
radioactive minerals like uranium as they decay. But we can also build
artificial sources of radio waves - exciters or transmitters - that we can
control and use for our purposes.
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There are three properties of a radio wave that we will be most concerned
with in our work with radio:
1. Amplitude : This is the difference between the highest and the lowest
portion of a wave, and is a measure of the strength of the wave. The
larger the amplitude, the higher the energy of the wave, and the greater
the distance the radio wave will travel.
Fig 1-2. Amplitude
2. Frequency & wavelength : Frequency refers to the number of waves
that pass through a given point in space every second, like this:
Fig 1-3. Frequency
Frequency is measured in Hertz (Hz); and where radio is concerned,
more often in KHz or MHz, which are measures equivalent to 1000 Hz
and 1,000,000 Hz respectively. (Now you know what FM 104.7 means
- the 104.7 refers to the frequency of the station, 104.7 MHz, which is
where we need to tune our radio sets to receive the station's signal.)
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Wavelength refers to the distance between two successive waves, as
shown here:
Fig 1-4. Wavelength
If you'll think about it a bit, frequency and wavelength have an inverse
relationship, which means the greater the frequency of a wave, the
shorter the wavelength; and vice versa.
Linking the technology to the production
Back to figuring out where the technology part overlaps the stages of making
a radio programme, then. Let's understand where the technology plays a
part within each of these five processes we just saw:
1. Research & Pre-production: As we have seen, this is not a particularly
technology intensive phase. An understanding of computers - especially the ability
to write documents, and do research on the internet - could be the primary
'technological' requirement in this phase, as is one's ability to use a telephone to
make arrangements, talk to people and set up the production phase.
For more on office computer equipment, see Chapter 6: Telecommunication
& Other Ancillary Equipment on Page 86
2. Production: The very first part of the radio broadcasting system is the
conversion of the sound we want to preserve into electrical energy, so that
it can be stored (recorded). This is achieved with a microphone, a device
that converts - or transduces - sound energy into electrical energy.
For more on microphones, see Section B: Microphones on Page 198
Once the sound is converted into electrical energy, we can not only store it
and recreate the original sound from it a later time, we can make changes to
it in a variety of ways: The audio signal, as it is now called, can be amplified,
or made louder; it can be filtered to remove unnecessary portions of it - and
most importantly for us, it can be edited and joined to other audio signal
For more on recorders, see Section B: Field Recorders on Page 184
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CR volunteers learn to edit audio on a computerized editing system.
The microphone is usually connected to a device that stores the audio
signal in a retrievable form. These devices, known as recorders, range from
small portable units to very large and highly accurate models.
The electrical signal may be stored through a second process of transduction,
in the form of analog or digital data on a magnetic medium (tapes, hard
disks), digital data on electronic solid state memories (compact flash and
secure digital cards), digital data on an optical medium (CDs, DVDs, Blu-Ray
or HD-DVD disks), or even as a combination of both (minidisks or MDs).
3. Post production: The post production phase is still more technology
intensive: Not only do we now have the audio signals recorded during the
production phase (in one or more of several media), we may want to record
more sounds to add to what we have already recorded: That means we have
more work for our microphones and recorders. We may also use a variety of
already recorded sounds from other source equipment - CD players, DVD
players, cassette decks - that will also provide us more audio signals.
For more on CD players, see Section B: Compact Disc Players on Page 141
For more on cassette decks, see Section B: Cassette Tapes & Cassette Recorders
on Page 134
Once all this is gathered together, and our selection of audio signals made,
we will edit the programme on an editing console or a computer using
suitable software that lets us pick, order and mix the audio signals.
For more on editing consoles, see Chapter 3/Section II: The Production
Studio on Page 57
If we are using modern digital equipment to edit, the process may involve
converting the audio signals once more from the format they were recorded
in into digital data, which can then be manipulated on a computer.
For more on digital audio, see Section B: Analog & Digital Audio on Page 124
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The final mix or master can then be removed from the editing console or the
computer in whatever format we choose, and on our choice of media for
broadcast. We may also use a variety of signal processors - mixers, filters,
equalizers, limiters - at any point in this process to make corrections to the
quality of the audio.
For more on mixers, see Chapter 3/Section I: The Broadcast Studio on Page 44
and Chapter 3/Section II: The Production Studio on Page 54
For more on compressor/limiters consoles, see Section B: Compressor/Limiters
on Page 149
A recorder connected to a portable digital
editing console for the transfer of recorded
material. The transferred audio will then be
edited during post production.
4. Transmission/Broadcast: Perhaps the most purely technological step of
the entire broadcast process, transmission involves the combination of the
final audio signal of our programme along with a radio wave of highly
specific and identifiable characteristics; and the transmission or broadcast
of the combined radio signal. The three primary items of equipment required
to do this are a playback source to play back the final audio signal/programme
(say, a cassette deck or a CD player), a transmitter to combine the audio
signal with an internally generated radio wave; and an antenna that lets us
radiate the combined radio signal into the air.
For more on transmission equipment, see Chapter 5: Transmission Equipment
on Page 69
At the listener's end, this step requires the use of a radio receiver set - more
often shortened simply to 'radio' - to catch or receive the signal we have sent
out. The radio receiver allows the listener to tune the set to receive the
specific wave that we have broadcast, and extract the audio signal from it.
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The extracted audio signal, once again in the form of electrical energy, is
then subjected to a transduction process in a loudspeaker or a headphone
- devices that change the electrical energy back into sound, so that we can
listen to it.
Listeners in the community listen to a radio programme
5. Feedback: Strictly speaking, simple feedback processes don't need any
technology at all - the simplest feedback process is to ask listeners to write
letters to the station! The technology part becomes important if we ask
listeners to email or phone in their comments (in which case we need an
internet connection and a computer); a telephone line or mobile connection
(possibly with a recording system attached so that we can receive and store
comments that are phoned in); and if we're ambitious, an adapter that lets us
connect callers directly to the studio for a 'live' phone in programme where
they can be heard or recorded as part of the programme.
So that, then, is a summary of the way the technology, the creativity and the
teamwork that go into producing a radio programme go together.
Ready for more? Plunge on!
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CR volunteers from Radio Tambuli in the Phillipines learn about
radio recording equipment. Learning about radio and transmission
requires a sense of application and interest, rather than a
technical education or a background in engineering.
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Chapter 2
In an ideal world, members of every community would be able to build their
own CR stations to suit their own unique and specific requirements. But it’s
not an ideal world, and CR stations often have to adapt to whatever spaces
are available to it – usually a rented or community donated pre-built space
that may not entirely meet the station’s needs.
This makes understanding the station’s design and infrastructure doubly
important, because it means we have to be clear about each of the adaptations
we may have to make – why we need to do it, and how best to do it in order
to make it meet our requirements. Let’s start by looking at some basic issues
we need to address while setting up a community rardio station.
Section A: Siting the CR station
There are four primary criteria for selecting a site for your CR station:
1. Local geography and terrain;
2. The physical distribution of the community your station will be
broadcasting to;
3. The strength of the radio signal you will be transmitting;
4. Local noise levels
Of these four considerations, the primary consideration is easy accessibility
by the members of your community: The very essence of a CR station is that
members of the community should be able to participate in the process of
making programmes. So it won't do to have the station in a place where only
a few of your listeners will be able to access it. Many CR stations work out of
spaces close to the village panchayat or community center. Others are set
up near local crossroads or market places. Think about all the members of
your community when you decide a site for the station. Ideally it should be
a place which all sections of the community can access: Young and old,
men and women, able bodied and physically challenged.
Having said that, we also have to ensure that there isn't too much noise
around the CR station itself. Your recording areas and working areas may
need to be comparatively noise free to ensure good audio quality. A noisy
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marketplace, for instance, may force you to adopt much more extensive
measures to isolate yourself from the noise than usual.
In most cases, the antenna/mast and the station are located in close proximity
to each other for a variety of technical considerations. Since FM radio
transmission is line of sight, the transmission can only reach areas that can
electronically 'see' the transmitting antenna. This means we must choose a
site that does not have too many natural or man made obstacles in the path
of the radio signal - that is, it would be preferable to not choose a site where
a hill, mountain or high-rise building could prevent some of our potential
listeners from hearing the station's broadcast.
Fig 2-1. Radio shadow area caused by obstructions near antenna
The line of sight principle, however, can present some direct benefits as
well: CR stations generally have transmitters of limited output, as they are
meant to service smaller areas - but selecting a good site for the station can
maximize your transmission range. Just as standing on a tall hill can give
you a commanding view of the surrounding area, placing your antenna at a
high vantage point can increase your effective range, and let you broadcast
to a larger audience.
Remember that these are just a few points you need to consider while selecting
the site for your CRS: There's always a trade off between all these criteria,
and a site that may be excellent from the point of view of one of these criteria
may fail miserably on another. You will have to weigh your options and
select a site which combines as many of these qualities as possible. Also
keep in mind that the spaces and sites a community is able to create or
develop for a CRS are often more a matter of convenience and ready availability
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than any of these considerations - though it would be nice if the community
as a whole can be sensitized to these issues so that its members can weigh
possible options before taking a decision.
Section B: Defining the spaces
There are three types of spaces that a community radio station generally needs:
1. A broadcast studio: This is the primary studio space for the station, the
place where the programme audio is broadcast from and the programme
presenter (or compere) sits. This space is often used as the 'live' studio, from
where audio is played out to the transmitter, and where one or two person
interviews can be conducted by an interviewer.
For more on equipment for a broadcast studio, see Chapter 3/Section I:
The Broadcast Studio on Page 39
2. A production studio: This is the space where recordings can be done,
and programmes edited and refined for later broadcast. The production
studio is usually equipped with a sound booth or recording floor, where
sound can be recorded in carefully controlled conditions.
For more on equipment for a production studio, see Chapter 3/Section II:
The Production Studio on Page 49
3. Office space: Somewhere where we can meet visitors who visit the station,
and where the people working at the CR station can work together on
production related or administrative tasks.
For more on office and telecommunication equipment see Chapter 6:
Telecommunication & Other Ancillary Equipment on Page 77
A small CR setup may actually have a single space that fulfills all these
functions, and that's perfectly all right. The most common approach for
middle level CR stations is to have a single space setup that combines the
functions and necessities of both studio spaces - including a small recording
floor - with a separate office cum meeting space.
If you have more funds and access to more space, you might like to define
clearly demarcated spaces for all three; and there's really no limit to how
large and well equipped each of these spaces can be.
Thus a simple setup for a single room CR station could be like like the one
shown in Fig 2-2 (below).
The single room acts as both broadcast and production studio, or multipurpose studio, and is also used to store the studio materials and equipment.
Realistically, this space should be at least 12 feet long and 12 feet wide: Any
smaller, and it would really be cramped!
A two or three room CR station setup (Fig 2-3) on the other hand, gives us
a little more flexibility to arrange our spaces. It could still have a single studio
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space that combines the production and broadcast units, but could include
a separate space in which to meet people and run the administrative functions
of the station.
Fig 2-2. Simple single room CR setup
Fig 2-3. Simple three room CR setup
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A still more complex CR station setup could resemble something like this:
Fig 2-4. Larger CR setup A
In this kind of setup, the main office and reception lead to the studio spaces, but
can be kept quite separate in operation. More importantly, it means the production
studio can carry on with its work of preparing features and 'canned' (pre-recorded)
programmes for broadcast while programme hosts continue playing out
programmes and doing the live programmes from the broadcast studio.
Manager’s Office
Broadcast Studio
Fig 2-5. Larger CR setup B
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Note that the diagrams given here are suggestions based on existing
CR setups - they are not meant for you to copy literally while setting
up your own CR station! Use these as a reference to conceptualize
your own setups, which will probably have to work with a different
layout. It's often a good idea to start with whatever spaces are available
and expand slowly rather than try and set up a sprawling multi-room
set up right away. The idea, after all, is to get programming on the air
first, rather than see the station as an end in itself! As your community's
programming needs increase and your volunteer base and staff
increase, you can expand and equip your station spaces bit by bit.
This will not only allow you keep your initial costs low, it will also
allow you to think about each section of the station as you set it up.
Section C: Important considerations while setting up the spaces
Besides deciding the broad separation of your station and studio spaces,
there are some important additional considerations to keep in mind. Thinking
about these in advance helps to make operation and utilization of the station
facilities and studios easier, even while it helps us keep everything orderly
and easy to maintain.
1. Dust free atmosphere
The primary concern with all studio spaces is keeping them dust free and
clean. Dust and grime are the worst enemies of sensitive broadcast and
production equipment - and a major portion of the defects and breakdowns
that happen in studios could be avoided with simple dust proofing and
preventive maintenance.
For more information on maintenance see Chapter 7: Planning for
Maintenance & Management on Page 91
The doors leading to the studio spaces should fit well, and should be kept
closed (if not locked) whenever possible. You may have to equip some or
all of the doors with rubber gaskets in order to make them dust proof.
Since the studio spaces are likely to be entered and used frequently by
members of the community, it's probably also a good idea to build a work
ethic and a system where everyone can be inspired to treat the station
spaces as their own, and keep them neat and clean in much the way they
would their own homes. (Strategically placed signs all around the office
and within the studio may play a useful role here - inspire people to help
keep dust out!)
Dust free also means leaving all street shoes outside - a shoe rack for this
purpose is probably a good idea - with people in the studios either in socks
or barefoot. Some stations like to keep separate sets of slippers that are used
exclusively within the studio space.
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Spaces that are used for CR studios are often not designed for a radio station
type setup, so they often have inconvenient doorways and windows. If you
are faced with multiple entrances and exits, it is wise to plan your space in
a way that allows you to use one of the doors as the primary access point.
Similarly, windows can be bricked up or otherwise built over to close the
space or - and this is usually much nicer - sealed with double pane glass, so
that dust stays out even while the light can still come in. Double glazing also
plays a dual role for acoustic treatment (see below).
Try to keep the space utilization logical and easily cleanable: Don't
design nooks and crannies that are hard to reach, because that is a
recipe for dirt and disaster.
2. Air conditioning
Air conditioning is by no means mandatory or even necessary for a CRS: If
your CRS is built around low cost cassette recorder based equipment, or
hardy solid state memory devices, it may be totally unnecessary to aircondition the studios. Simple precautions like having an insulated terrace,
or housing your CRS in old-fashioned double walled or thick-walled highceilinged buildings may be an equally effective solution to keeping equipment
cool and protected. If your station is situated in the hills, or by in a coastal
area, the weather conditions may be temperate enough to dispense with air
However, depending on the local weather conditions and the kind of
equipment that you have invested in, air-conditioning on some scale may
have to be considered. If we seal all the windows in order to keep the
studio(s) dust free, then air circulation and ventilation inside the studio spaces
can be a problem. So let's just say that if the outside temperature and dust
conditions warrant it, and if you can afford it, it may be wise to invest in air
conditioning units for the studio spaces, both in the interests of keeping the
spaces cool and so that there is some filtration of the air inside. (More
complex setups could include an air filtration unit, but that would be a
luxury for most CR stations.)
Where they are required, the best ACs for studio use are split air conditioners,
where the blower unit is in the studio, but the condenser and the fan unit,
which make most of the noise, are safely outside the studio. A professional
and expensive setup would probably dispense with individual AC units
altogether, and set up a central ducted AC system, with a cooling tower on
the terrace or in the grounds outside the station - but that is a prospect that
should only be considered if you have a lot of funds at your disposal, and a
very large space with a number of rooms and studios.
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Having said that, air conditioning, while attractive in the hot and dusty
conditions that are common across much of South Asia, has its own downside
- and it can be a serious downside:
1. ACs require a regular mains power supply - if your station is in a power
poor area, or has regular power cuts or 'brown-outs', it could render an
investment in ACs pointless.
2. ACs consume a lot of power and are expensive to run. If your wiring is
not up to the mark, and you cannot afford a big power bill, ACs are a bad
idea. The wiring will have to be of good enough grade to take the load an
AC places on it, often 1500 - 2000 watts or more.
3. ACs need maintenance too - It's not enough to simply install an AC and
use it whenever you want. You have to plan for a regular maintenance
schedule for the unit, and keep it in good running order, which adds to
your maintenance related expenses and responsibilities.
Making an estimate of your AC requirements
The cooling capacity of ACs are rated in BTUs (British Thermal Units) or
more usually in tons (1 ton = 12000 BTU per hour). The ton measure
refers to the volume of air that can efficiently be cooled by the AC, and
1 ton, 1.5 ton and 2 ton ACs are most common.
Divide the square feet area of your room by 600 to arrive at the basic
tonnage capacity required.
z Add 0.5 tonnes for every 10 people occupying the room at the same
z Similarly add 0.5 tonnes for every 1500 watts of appliances or lighting
present in the room (A computer would consume about 300 watts
and a regular bulb, 40 to 60 watts).
Calculate the volume of your space on a similar basis for a rough estimate
of the AC capacity that you need.
3. Acoustic treatment
When we record sound, it's always a good idea to record the sound as
cleanly as possible - that is, we try to record the sound as faithfully as possible,
with no unnecessary background noise and as little echo or reverberation
as possible. By reverberation - or reverb, as it's more commonly known - we
mean the hollow sound that you hear when you speak or make a noise in an
empty room: The sound bounces off the walls all around you, and reaches
your ears a fraction after the original sound reaches you, giving it the
'hollowness' or echoing quality. (Anybody who has ever whistled or
hummed a few snatches of a song in a bathroom knows this as the
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'bathroom effect': The hard tiled surfaces in a bathroom emphasize the
effect quite a bit.) As human beings, we are able to discount the reflected
sound in our brains, but machines cannot do this - and the sound a
microphone 'hears' in a room with a lot of reverb can quite ruin the recording.
We increase the clarity of the sound in our studios by acoustically treating
the space: Simply put, this means we prevent outside sounds from getting
into the space (sound proofing), and we find ways to keep the reverberation
of our studio space down.
There's always a debate about the acoustic treatment part of studio set up:
How much of a priority should it be for a community radio setup? There is
no easy answer to this question, except to say that it depends on your
choice of spaces and the availability of funds. Personally, I would say the
cost or size of your setup should not be an excuse for poor audio quality or
production values, so you should try and make the best use of local expertise,
your research and your creativity. A CR setup can afford to make more
compromises and can afford to deal with less stringent recording needs
than a commercial station; but a sense of application can achieve a lot, as
we will see.
a. Sound proofing: The first step to acoustic treatment is the isolation of the
studio from outside noises. And the first step to achieving that is to set up
your station and studio space in a quiet locality as far away from busy
thoroughfares as possible, while remaining within the community. (This is
usually easier in a rural area than in a town or an urban area, but if you look
hard enough, you should be able to find a space that is less exposed to
outside sounds.)
The other way to soundproof your studio is to have multiple surfaces with
air trapped between them.. For example, it's usually a good idea to have a
set of double doors at the studio entrance, if that is feasible. (At the very least,
a thick, well fitting door with rubber gaskets around the door edges should
be possible, with some help from a good carpenter.) The air trapped between
the two doors in a double door system (a 'sound lock') keeps outside sounds
from traveling through. Studio doors should preferably be fitted with a small
glass panel - like a porthole - at eye level, so that one can peer in before
actually entering, in case a recording or broadcast is taking place.
It helps greatly to have thick outside walls - 9 inch thick load bearing walls
are great - and if the studio isn't part of a wall-to-wall construction setup
where the next building or house physically shares the same wall, that's
great as well. Studio windows that open to the outside should ideally be
sealed and double glazed. This means we have to install two window panes
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of glass that are at least 5 mm thick, with about 5 - 8 cm of air in between,
like this:
Glass Pane
Half Inch
Air Space
Fig 2-6. Double glass window cross section
Note that the two glass panes are angled slightly with reference to each
other - this is so that any sound that enters the outer pane doesn't end up
being reflected repeatedly between the two panes, causing them to rattle or
buzz. It's also a good idea to ensure that the channels the glass panes rest in
and the frames holding them in place are padded with thermocol or a thin
strip of rubber.
Properly used and worked on, outside windows on the studio spaces
are not an issue at all - in fact, once you've cut off the intrusion of
external noise, it may excite attention about your work from passersby who can watch your studio in action, especially if your studio
windows face a street. Internal windows opening into other rooms in
the station are equally interesting if designed well, as it lets other
people in the station remain involved in what's happening in the
studios and lets visitors peek in as well.
Remember that sounds slips through the smallest gaps - so pay
attention to small crevices and ventilator spaces. All of those are
potential sources of unwanted outside sound!
b. Cutting down the reverberation: Now that we've cut out the outside
sound, it's time to explore how to cut down the reverberation in our studio
space. Reverberation treatment is especially vital for the spaces within the
station where the microphones will actually be used - the recording booth
or stage, for example.
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A professional grade studio, if you have the funds for it, would use
fibreboard, coirboard or gypsum panels, along with glasswool. Some studios
use a variety of angled wooden surfaces attached to the walls to control and
manage the sound reflections. Floors and ceilings in a professional studio
may also be built of absorbent materials like cork, mounted on a shock
absorbing frame supported on a dampening cushion of springs or rubber
runners. This kind of acoustic treatment needs to be installed by an expert,
and is usually quite expensive, being charged on a square foot basis.
However, a little understanding of how sound waves are reflected by surfaces,
along with a sense of invention can achieve a lot: A number of community radio
stations use simple low cost techniques to reduce the reverb in the studio.
To start with, it helps to have rooms that don't have continuous walls that
exactly parallel each other, because parallel walls create the most echoes. If
one of the walls has a staggered construction, with sections that are slightly
ahead or behind the other, this can cut down the reverb quite a bit. A simple
way to reduce the reflection is to attach something to the walls that reduces
the reflection of sound from them. The easiest and simplest way of doing this
is to acquire a large number of egg trays, the papier mache trays that eggs
are supplied in. If you have enough of these, you can physically paste them
over the entire wall, edge to edge, with any strong glue. The indented surfaces
and the soft material of the trays absorb and dampen the reflections to a very
great extent. (Make sure you treat the trays with a strong pesticide to keep
out cockroaches and other bugs).
Radio Muye, Suriname (Caribbean) – note the creative
use of rattan panels in the studio for acoustic treatment
Alternative low cost techniques are to paste foam sheet - 1.5" or 2" thick
foam sheet is best - across the entire wall surface, and cover it with cloth; or
to hang thick double panel drapes - velvet or any other fabric with a thick
pile work best - from floor to ceiling, with plenty of folds and ruffles in the
fabric to create a varied surface. Remember to put a carpet or dhurrie on the
floor, as thick as you can arrange; and to cover the ceiling with acoustic
material as well - floors and ceilings reflect sound too!
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It is worth exploring other low cost construction materials that are
used commonly in your area to see whether we can use them for
acoustic treatment: Many low cost studios successfully use materials
like panels of dried hay and porous clay attached to the walls; or
even rattan and bamboo screens made out of woven strips of cane or
A studio in Radio Toco, Trinidad & Tobago (Caribbean).
This one uses cloth and padding for the walls.
c. The recording floor/stage - control room partition: When we have a
single room setup, which combines the functions of both studios, there is
usually no separate recording space at all: Interviews, recordings and
broadcasts all happen within the same space. If at all there is a separate
recording space in this kind of a setup, it is usually if the form of a small
booth. This booth may be as small as a closet or cubicle. It generally has a
small door on one side and may accommodate one or two people.
On the other hand, when we have the luxury of a separate production
studio or a larger dual purpose studio, the studio space can be sub-divided
more clearly into a recording floor and a control room, as shown in the
three room studio diagram shown in Fig 2-5. In this case, by recording
floor, we mean the acoustically treated area where the microphones are
actually placed, and where guests or performers actually speak, sing or play
their instruments. Ideally this space should accommodate at least 3 - 4
people at a time, and should be paid greater attention from an acoustic
treatment point of view.
The control room, then, is the space where the producer or sound recordist
sits with his equipment and from where he/she guides the recording process.
In such setups, the partition between the recording floor and the control
room is of great importance, as it also needs to be factored in when planning
the acoustic treatment of the recording floor. The partition itself could be of
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solid brick and mortar, if you want to make it permanent. Alternatively, it
could be constructed of a wood frame and plywood, with thermocol or
glasswool in the gap between the two sides, for better sound insulation. The
door to the recording floor can then be built into the partition with good
quality plywood, and equipped with rubber gaskets to provide a good seal.
Fig 2-7. Double paned and one tilted glass pane partition
The greatest attention, though, has to be given to the window in the partition
between the two spaces: It is vitally important for the sound recordist or
producer to signal the people inside the studio during the recording process,
and this window is used for that purpose. It is often quite large, covering a
substantial portion of the partition, to allow one to see the entire recording
floor and - like the external windows in the studio (if any) - needs to be
double glazed, with non parallel panes and rubber or silicone mounted
glass panels, to avoid sounds from the control room entering the recording
space. It's a good idea to get a few packets of silica gel, a substance that
absorbs moisture, and place it between the two glass panels when you fit
them in place: This will absorb any moisture that would otherwise condense
on the inside of the glass if the weather grows colder.
4. Furniture
Once our spaces are broadly defined, it's time to think about the kind of
furniture that we'll need to utilize and operate in these spaces conveniently
and comfortably. And the key words to remember here are reconfigurable
and hard-wearing.
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It may also help to have an accurate idea of the equipment you are going to
install - especially the dimensions of mixers or monitors - before acquiring
any furniture or asking a carpenter to make them.
It is best to think in terms of furniture that could be mixed and matched in a
variety of ways so that we can adapt our setup to different needs. At the same
time, we need furniture that doesn't get damaged or scratched easily with
use, as we would like to keep our studios and offices looking good for
visitors even if they are constantly utilized all through the year.
The office space is comparatively easy to kit out, with a couple of desk spaces
(desks with drawers are to be preferred), some comfortable working chairs, a
filing cabinet (optional, a shelf or a cupboard will be fine) and wall space
where we can hang some pin boards and whiteboards if we need them.
The studios need more attention, especially the broadcast studio and the
control room. Traditionally, professional studios use a curved half moon
shaped (or broad vee-shaped) desk with the compere or recordist sitting in
the inner curve. This kind of a desk allows the compere/recordist to access
different pieces of equipment on all sides with a minimum of movement, an
important consideration when he or she may be talking into a microphone
even while he/she is operating the mixer, CD player or studio computer. But
depending on the space you have and the kind of equipment you are using,
there is absolutely no reason why any desk shape that fits cannot be used.
Just remember that:
(a) The desk should give you some working space along with any equipment
on it, so that you don't keep knocking expensive equipment off it every
time you move;
(b) Your studio chairs should be sturdy, should not squeak, and should be
comfortable enough to be occupied for extended periods of time;
(c) For control room desks, the desk and chair should be oriented in a way
that lets the producer/recordist look comfortably into the recording
floor space through the window without having to move or get up.
(d) The furniture should give you access to the back panels of the equipment
easily to be able to connect and disconnect cables, and so that you can
perform maintenance related tasks.
A readymade studio desk with space for mixer,
equipment and interviewer.
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Recording floors are generally equipped with a small 'talk' table, where the
interviewer sits with the interviewee(s). This is removable, of course, should
we decide to use the space for radio drama, when moving room will be
It's also a good idea to equip the studios with plenty of shelf space, open
and with doors, to place pieces of equipment, cables, manuals, and related
stuff. Expensive equipment may need to be stored in a more secure metal
cabinet, or at least a shelf that can be locked. Equipment, especially if you
have higher end pre-amplifiers and patch boards, may require the making
or purchase of standardized equipment racks that allow you to fit the
equipment rack style one above the other. These racks are generally made
to standard heights in multiples of 44 mm (44mm, 88 mm and so on) and
483 mm/19" widths. The pieces of equipment designed to fit in them
subscribe to the same standard - like this:
44 mm
88 mm
483 mm
Fig 2-9. Standard rack mount
Remember that furniture should not be a limitation: Almost any
furniture you can access can be used imaginatively to furnish your
station. A good carpenter can also help you design furniture that fits
the dimensions of your spaces precisely (something that may not
always be possible with readymade furniture).
5. Electricals
Needless to say, setting up a community radio station means having adequate
access to electricity. It also means having to deal with a whole lot of cables
and connecting wires - microphones to mixers, recorders to mixers, broadcast
studio to transmitter, and so on - running between equipment and from
room to room. So it's wise to give this some thought in advance.
While it would be an asset to have someone who has an advanced knowledge
of electrical systems and wiring as part of the team, it's not very difficult to
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grasp the basic electrical setup that we will be required to deal with in a
community radio station. Given that we are dealing with expensive and
sensitive electronic equipment in a CRS, the value of a stable and risk free
electrical supply cannot be overemphasized.
To start with, it's a good idea to see that there are adequate electrical points
and outlets in each room, especially the rooms in which much of the
equipment is run. Points should generally be of the 3 pin line-neutral-ground
type, and electrical switches and points should preferably be from a reputed
manufacturer and be certified by a standards organization like BIS. This
ensures that the dimensions of the sockets conform to international standards
and that loose plugs and switch contacts (which could cause sparking) do
not result. Beware of counterfeit goods, which are plentifully available - so
don't just go blindly by the brand.
Wiring is the second concern: always check that high grade wiring - BIS
marked is highly preferable, as is fire retardant wiring - exists throughout
the station. (You may consider getting the wiring done anew if it is of poor
grade or undependable). Check that the distribution of power supply across
the station is even, especially where multiple rooms are concerned, and that
specific wire sets do not take the brunt of the load. 22/7 grade wiring is
acceptable for most uses, with 22/4 grade wiring preferred for heavy load
points. It is good practice to equip heavy load electrical points with the
larger 3 pin sockets (also called Power points or 15A sockets), which accept
the corresponding larger three pin plugs. Lesser load points can utilize the
smaller 3 pin (5A) sockets and plugs. You can decide where you need to
connect what equipment on the basis of the power consumption of each
piece of equipment.
While on this subject, you may also like to ascertain whether the supply you
have is three phase or single phase, with the former much to be preferred.
Three phase connections are more usually available in urban or semi-urban
settings, but offer the advantage of being able to distribute the loads you
place on the supply across the three phases. (Besides, power tends to be
available in one of the phases even in the event of a power cut, which means
we can always make arrangements to reroute our supply from the active
phase, if this is required.) Single phase, while being perfectly usable, does
not permit us these advantages.
The incoming supply should ideally be routed through an isolator, which
allows us to disconnect the entire wiring system from the main supply at any
moment) or a large load MCB (miniature circuit breaker, a spring loaded
switch system that trips or shuts off the supply if the load exceeds a certain
value or if there is a short circuit of any kind). An ELCB (or Earth Leakage
Circuit Breaker) is also a wise choice, as it is a device that automatically cuts
off the power if there is a short circuit, or if there is an accidental contact - like
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A typical three phase electrical isolator unit.
The unit allows the connection of three phase wires
and the neutral wire.
someone coming in contact with a naked wire, for instance. Each point (or
set of points and switches, as the case may be) should then be connected to
individual MCBs of an appropriate rating, to enable us to cut off supply to
individual problem areas for maintenance. The entire combination of ELCBs,
isolators and MCBs should be mounted in a safely sheltered but accessible
circuit box somewhere near the entrance of the station: Circuit boxes are
available in several readymade sizes in any large electrical market and contain
a metal rail system on which individual components can be mounted.
Also check the approved load available from the a/c (alternating current)
mains supply: The original paperwork for the electricity connection should
contain this information. If not, you can examine the record at the local
electricity office. This should usually be given in KW (Kilo Watts, multiples
of a 1000 Watts). Compare this with an estimate of the total consumption of
the equipment you will be installing. Try and ensure that your 'load' never
crosses 2/3rds of the total approved load. (For example, if you have an
approved load of 5 KW, try to see that the sum total of all appliances, even
the ones that aren't on all the time, doesn't exceed 3.5 KW. You can exceed
this self-imposed limit, of course, up to the total rating, but it's a good idea to
have some headroom and not strain your wiring too much).
If you feel your load may exceed this or approach your approved load, see
if it might make sense to increase the approved load officially and get a
greater electrical supply. You will need to apply to the local branch of the
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Calculating appropriate ratings for your main power board
To select the correct rating for an individual MCB, first ascertain the
consumption of the equipment or fixtures that you will be connecting to
it: Most equipment manuals will tell you the consumption in Watts, and
items like bulbs and fans are usually marked with Wattage figures. Use
the formula:
W/V = A
where W is the consumption in Watts, V is the voltage of the system in
Volts (usually 220 Volts in India) and A is the current drawn in Amperes,
to calculate the corresponding current draw through the MCB. MCBs
are marked with the maximum current draw in amperes that they will
accept before tripping, with 6A, 10A, 15 A, 20A and 32 A being quite
common. Select an MCB that exceeds the Amperage of the fixtures and
equipment you intend to connect to that specific MCB: Keep an eye on
the future, and select one that can accommodate a couple of extra
pieces of equipment if need be. ACs and heavy draw equipment will
need higher capacity MCBs, while all the lights and a couple of fans in
a room may need a single 6A MCB.
Sum up the Amperage of all the equipment and fixtures on all the
individual MCBs to arrive at the appropriate rating for the master isolator,
MCB and/or ELCB (40 A and 63 A are the most common types, and
should be fine for most setups). MCB and ELCB installation may require
some electrical expertise, so consider this before starting any
electricity department for this. Please note that rentals for electrical supply
are based on KW slabs and that - depending on your location - there may be:
(a) a limit on the maximum approved capacity that you can obtain;
(b) a distinction between residential and commercial connections, with
sharply higher rentals for the latter; which may make a difference to your
operational budget;
(c) a lengthy application and approval process for the upgradation.
Finally, where electricals are concerned, we have to plan for backup supply:
Transmission and production work cannot be interrupted if your primary
energy supply fails for some reason. It is therefore wise to invest in a battery
based backup system like an inverter, which will at least support the key
equipment that cannot be shut down - especially the transmitter. Inverters are
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also available in various capacities and ratings - the 650 VA, 1250 VA and
1500 VA are the most common. VA is analogous to Wattage, a term we are
already familiar with.
Inverters can be acquired in single battery or multiple battery configurations
for extra storage. They are charged from the mains electrical supply, so an
important consideration, again, is whether there is enough continuous main
electricity supply to keep the batteries charged against power cuts. It is also
wise to remember that the storage capacity is linked to the cost of the unit, and
that the battery units - usually 25 or 27 plate automotive or tubular batteries need to be replaced roughly every two years. (Most of these batteries are of the
lead-acid type and need a topping up with distilled water and/or acid at
regular intervals. Maintenance free batteries, which need no topping up, are
also available, but are more expensive.)
The more expensive - but more independent - backup is an electrical
generator set, with a motor which runs on kerosene, diesel or petrol.
Available in a variety of ratings from 650 VA to several KVA - the larger ones
are run on diesel - they allow you to operate in areas with no power supply
at all, or during extended power cuts, but require a continuous fuel supply
and regular maintenance. The noise they make - even the sound insulated
ones make some noise - and the exhaust gases can also be a concern.
For more on generators see Section B: Generators on Page 229
It's also a good idea to economize by using more energy efficient lighting
fixtures (compact fluorescent lamps or CFLs). instead of standard tubelights and tungsten incandescent bulbs, for instance), natural ventilation
systems (better insulated walls for heat and cold protection instead of coolers,
fans and heaters) and alternative energy supply systems.
A typical CFL bulb. CFLs consume very
small quantities of electricity to provide as
much or more light than equivalent
incandescent (tungsten) bulbs.
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Alternative energy systems like solar power (which converts sunshine into
electrical energy) or wind power (which uses the wind to move turbines
which generate electricity) can be a great cost saving in the long run - and
are eco-friendly as well. Though the initial installation costs are often very
high, if you can invest in these systems, they are more than likely to pay for
themselves within a few years. In places where mains power is very intermittent
or suffers frequent breakdowns, these can be very viable systems to consider,
as they allow your station to operate without any interruptions of service.
A solar panel array. Typically, a smaller setup would
need only a few panels (or a single medium sized panel)
to fulfill some of its energy needs.
A good compromise with alternative energy systems is to use them to
power only certain sections of the station - just the lights, say, or the
transmitter and playout system - so that you can keep the load on the
alternate supply low, and incur a lower initial cost. Keep in mind,
though, that this may involve revisions of your wiring, though, to allow
the alternate energy system to supply only select pieces of equipment.
The last, but not the least, thing we need to remember is to ground or earth
the entire electrical supply and wiring of the station.
Practically, this means providing a safe route for the absorption of electricity
leaking in the system, as well as a creating a zero potential against which
reference electrical voltages in the system may be read. As we shall see later
in the manual, this is of special significance for the antenna tower, which is
often prone to lightning strikes. But where the station and studios are
concerned, grounding is important for two reasons:
a. To allow the ELCB to work, since the ELCB breaks the circuit when it senses
the sudden flow of current into the earth through the accidental contact;
b. To prevent leaking currents from damaging sensitive electronic equipment
(the shock you sometimes feel from a television or the metal surfaces of
any electric/electronic device is usually due to poor grounding); and
c. Poor grounding often leads to a hum that can be heard over the audio
cables in the studio, caused by the cyclical nature of the a/c mains supply.
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This is often accompanied by electromagnetic interference from the
Earth's magnetic field and transmission lines, which can also be addressed
by good grounding.
Sub panel
Service entrance
3- wire branch
Fig 2-10. Grounding equipment is an important consideration for CR stations.
Most modern electronic systems are susceptible to faults caused by poor grounding.
Typically, in the absence of a formally wired ground, grounding can be achieved
by simply running a wire connected to the ground points of all the power
outlets and connecting it to any buried water pipeline made of metal (especially
the galvanized iron or GI main water supply lines found in most places.)
A more through professional grounding is to be much preferred, however,
and involves the connection of the ground wire to a buried copper
conductor plate. The size of the plate is worked out on the basis of the total
estimated load on the supply and the plate is buried at a depth which
guarantees enough moisture to ensure good conductivity. This is often
improved by burying the plate at that depth in a bed of charcoal and salt,
which makes for better conductivity; and by leaving a channel or pipe
buried alongside to allow the periodic addition of water to keep up the
moisture levels.
Again, the importance of good grounding cannot be over-emphasized, as
the safety of very costly electronic equipment in the station is dependent
on this.
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1. Routing Equipment wires and cabling
While designing the spaces and studio setups, it is also important to decide
where and how you will route the numerous cables that connect the
equipment together. Many of these wires and cables will actually connect
different spaces together and we must think about how to organize and
route them to avoid tangles and provide for easy upkeep and maintenance
and to ensure that the cables are not accidentally damaged during general
use, by rats or other vermin.
For more on cables and connectors see Section B: Connectors (Power) on Page 163
and Section B: Connectors (Audio & Telecom) on Page 166
The first requirement is cable ties, which are flexible binders made of nylon,
and available in electrical and computer stores. There are reusable and single
use varieties. Cable ties can be used to gather sets of related cables and tie them
together; many cable ties have a space for you to attach the tie - and thereby the
gathered cables held by the tie - to the wall or to the back or underside of furniture,
which keeps things from getting messy and allows easy cleaning. In a pinch,
these can be substituted with twists of wire cut to size or stout twine.
A selection of cable ties. The tip is looped around the
cables that need to be tied together and through the box
at the other end of the tie, which locks the loop in place
The second option is to fit plastic cable channels or cable trays to walls, just
above the skirting, through which cables can be routed to keep them from
coiling all over the floors. Cable trays have perforations around their entire
length, and a sliding plastic cover, so that we can add and remove cables at
will with very little effort.
Where cables pass from one room to another - between the recording floor
and the control room, say - we must make special provisions, especially if
acoustic treatment of one of the spaces must be respected: Cables must be
routed through prepared channels or spaces designed in the partitions,
preferably with a system of baffles or a rubber diaphragm around the cables
to make an airtight seal.
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Professional studios and auditoria are designed with these cable routing
exigencies in mind, and include under-floor channels and concealed wall
panel fittings for connections and wires. If these are feasible in your spaces,
they are excellent methods to keep cables out of the way.
Never let equipment and mains power supply wires overlap
cables carrying audio between equipment. The electrical
supplies may cause interference.
A short note on flexibility
While planning and designing your station, always think about how
you can rearrange your setup to meet future needs: Accommodate new
equipment, for instance; or even move the entire setup to a new location.
All too often, CR stations have to upgrade or replace equipment, in
which case a lack of planning means you are stuck with furniture or
spaces which will now not go with the new equipment.
Keep the setups as modular and easy to dismantle as possible, to allow
quick swaps and switches to be made. Some items, like soundproofing
or partitions may be harder to change or shift - but that's unavoidable.
The more you plan for this in advance, the easier it will be to make
changes without seriously disrupting the station's activities.
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A radio programme being broadcast by
Radio Madanpokhara in Nepal. The studio
dimensions are small, but the space has
been utlilized creatively.
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Chapter 3
In the previous section, we discussed the division of the station's studio
work between the production studio and the broadcast studio. Continuing
on the same theme, let's have a look at the kinds of equipment that go into
the working of each of these studios.
There are many items which may be common to both studio setups: A two
studio setup would need one each of these pieces of equipment, but a
single studio setup would (obviously) require only one.
A second consideration is that modern computerized systems can often use
different kinds of software to perform functions that would otherwise require
a wide variety of studio equipment: For example, there are now different
softwares available for editing, mixing, and mastering audio which can all
run on a single computer. This may help you avoid acquiring some of the
studio equipment outlined in this chapter.
For more on editing/mixing software, see Section B:Computer Software on Page 159
Relying on a single computer for all your studio functions could
hinder your production and broadcast process if the computer fails
or requires maintenance!
These descriptions do not include details of the cables and connectors
required in the two studios, as that varies from equipment manufacturer to
equipment manufacturer.
For more on cables and connectors see Section B: Connectors (Power) on Page 163
and Section B: Connectors (Audio & Telecom) on Page 166
Section I: The Broadcast studio
The broadcast studio typically has an equipment setup something like
Fig 3-1.
Let's look at each piece of equipment step by step, to understand its function:
1. Microphones: Typically, the broadcast studio should have at least two
high quality voice mics - one for the compere/host/presenter, and one for
the guest. (A third would be good value if it is affordable, allowing a second
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Fig 3-1. Schematic diagram of a broadcast Studio setup
guest to be 'miked' separately (and thereby, his/her audio levels controlled
independently) as well as giving the studio a spare mic.
For more on microphones see Section B: Microphones on Page 198
The mics are typically not powerfully directional, as the studio already has
controlled acoustics, and the speakers are quite close to the mics. In some
cases, there may be a single mic which has a pickup on both sides, which is
then shared by the people on either side of it.
Shure SM 58 dynamic microphone
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The mics are also usually mounted on adjustable stands - in the case of the
compere's mic, often on a swinging armature that allows for very precise
adjustment of the mic position. This is so that so that the speakers do not
need to hold the mics in hand, and also so that the mic stays at a constant
distance. Speakers tend to have different speaking voices, and tend to be of
different heights, so ease of stand adjustability is an important consideration.
Good studio mics include the Shure SM 58, the Behringer TSM 87 and the
Rode NT-1A. Very high end mics include the Neumann U87 and the
Sennheiser MD 421. Indian mics include those manufactured by Ahuja
Radio, which supplies a variety of mics for different purposes. Nowadays, a
number of very economical microphones made in China are also available
in the market quite easily.
A Neumann U 87 condensor studio
microphone. Note the suspension shock
mount that holds the microphone and
prevents accidental movements of the
mic from causing a rumble in the audio.
Stands are available from a variety of suppliers, and in a pinch, even locally
manufactured stands will do, as many of the mics come with appropriate
grips that fit on top of the stands. Sometimes, but not often, mic manufacturers
provide stands specific to their mics.
It is important to select mics according to the function they must
perform, and so that they meet the appropriate quality standards that
are required for radio transmission. Select mics that have a reputation
for sturdiness; and which will not fail at key times.
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2. CD players: The current standard for playback sound sources - especially
for music - is the CD player (though DVDs and their most recent cousins,
the Blu-Ray disc and HD DVD, are the recent rage in the video world.) Two
CD players would be very useful for a broadcast studio, allowing prerecorded materials to be smoothly mixed with each other without gaps in
A mid range CD player from Denon, with a matched
amplifier unit. Mid range home music CD units are often a
good option for CR stations.
Studio CD players should have large displays so that they can be read from
a distance, and should preferably be controllable from the mixer, which
makes them easy to use (though this is not vital). Most importantly, they
should allow you to connect them to a professional grade mixer unit with a
balanced connector. They are one of the workhorses of any station setup.
Good studio CD player units are available from Denon, Sony, Tascam and
For more on CD players see Section B: Compact Disc Players on Page 141
3. Studio cassette deck: The cassette deck, which plays audio cassettes, is
still a staple of many radio setups, since a lot of recorded material - especially
music - is still available on cassette. Usually, any good home cassette deck especially those from Denon, Sony or Pioneer - can perform this function,
but a professional deck provides the advantage of balanced outputs for
connection to a mixer. A dual tape deck, which allows you to use it as a dual
cassette source for mix purposes is an added benefit. The Tascam pro units
are of good grade and take heavy studio use.
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PIC- 3.4
The Tascam 322 dual cassette deck, a popular studio deck.
Note the flanged edges that allow it to be mounted in a rack mount.
For more on studio cassette decks see Section B: Cassette Tapes & Cassette
Recorders on Page 134
For more on balanced connectors see Section B: Balanced & Unbalanced
Connectors on Page 131
4. Recorder unit(s): There is actually a wide variety of studio recorder units
now available to choose from. Till a few years ago the recorders of choice and still popular in many places - were the Digital Audio Tape (DAT) recorder
(which records digital audio on magnetic tape at very high quality) and the
MiniDisc (MD) recorder (which used small magneto-optical disks somewhat
like small CDs, and also records broadcast quality audio). Today, flash
memory based recorders recording on solid state memory like SD (Secure
Digital) cards and CF (Compact Flash) cards are rapidly becoming the norm.
Two popular units, equally at home in a studio or in the field because they
are so compact, are the Marantz PMD 670 and the Edirol R-09. (There is a
Marantz PMD 660 as well, which is an even smaller version of the PMD
670.) A number of studios have also moved to purely computerized units
where the audio is recorded digitally directly on the computer's hard disk.
Marantz PMD 670 solid state recorder.
The recorder records on Compact Flash (CF) cards.
For more on Flash recorders see Section B: Flash Recorders on Page 187
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5. Mixer : A good mixer is the heart of the studio, allowing you to combine
a variety of inputs and manage the audio levels of the various sources and
mics. Each of the sources is connected to a separate channel for independent
control, each of which has a sliding fader that allows you to raise or lower
the level of the audio signal feeding through that channel.
A Mackie 4 channel mixer unit.
Note the four white channel faders
at the bottom left of the mixer.
The number of sources and mics you have in the studio usually decides the
number of channels you need on the mixer - but 4 to 8 channels should be
fine for most mid level stations. Prime considerations are the quality of the
sliders (the moving resistors of the fader units); and the options for controlling
all the other studio equipment - decks, CD players and mics - from the
mixer itself. Good broadcast mixers are available from Behringer, Mackie,
Sony, Soundcraft and Tascam. (In case a broadcast mixer with such controls
is not available, a production mixer may be substituted instead, with the
other sources and controls operated manually.)
For more on production mixers see this chapter's Section II on Page 54
6. Headphones and monitors: The usual rule is to have a pair of headphones
for each speaker in the studio. The headphones are used to monitor the audio
going on air and to preview a new source before its sound is actually mixed in.
Using headphones is especially important in the broadcast studio,
because speakers would feed back sound into the mics, creating a loud
whine or howl called acoustic feedback noise or 'howlround'. (Some
studios use speakers and a switching system where the on air audio is
heard over the monitor speakers, which cut off the minute any of the
mics become active.)
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A pair of Sennheiser high quality headphones.
Note the padded ear cups designed to fit snugly
on and around the wearer's ears.
Good headphones are available from Behringer, Sennheiser and Sony.
Good studio monitors are available from Behringer, Sony, KRK, Denon,
and Tannoy, with the last three being very expensive pro studio options.
For more on Headphones see Section B: Loudspeakers & Studio Monitors on
Page 190
7. Distribution amplifier: The Distribution Amplifier is another important
piece of broadcast studio equipment. It boosts and amplifies audio from all
the sources - audio players, mics - and feeds them to the recordings units
and to other studios if necessary.
For more on Amplifiers see Section B: Amplifiers on Page 128
A Behringer 4-headphone audio amplifier.
The unit is used specifically to distribute sound to
upto 4 headphones with no loss of signal.
8. Pre-amplifiers and amplifier units: Several source units may have very
low signal outputs which need to be amplified by pre-amplifier units that
boost the signal to a level comparable o the remainder of the sources. Also,
the outputs going to the headphones, the transmitter or - more usually - the
studio monitor speakers may need to be boosted by an amplifier unit.
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Whether these units are required or not depends on the precise configuration
of your studio setup.
For more on Amplifiers see Section B: Amplifiers on Page 128
9. Telephone hybrid or caller input: One of the best ways to get your
listeners involved in the programme is to give them an opportunity to call in
during the programme, so that they can also participate in the programme.
To get your callers on air, we require a telephone hybrid unit - there's
usually a hybrid unit available to connect almost any type of telephone to
the mixer unit, but it's important to first think about how many telephone
lines you may have for callers to call in on: Large professional stations have
dozens of lines for callers, but a smaller CRS may have only one, which
considerably simplifies the job of selecting a hybrid unit. Some stations get
around the need for having a multi line hybrid by connecting their office
EPABX intercom system to their mixer, and using their dual or multi-line
capabilities to enhance their call-in facility.
A Sonifex telephone hybrid unit
A simple way to connect callers to the studio setup is to use a phone
line connected to a speaker phone unit: Incoming calls can be played
over the speaker phone, with a mic placed close to the speaker
phone to pick up this sound and feed it to the mixer unit. With this
technique, it is important to avoid audio feedback, which could
cause a whining noise in the audio.
For more on telephone lines, see Chapter 6: Telecommunication & Other
Ancillary Equipment on Page 81
For more on Telephone Hybrids, see Section B: Telephone Hybrids on Page 220
10. The On-Air light: In order to effectively signal that the studio is in use and
broadcasting ('live'), the usual system is to have a red 'On Air' light inside
and outside the studio, that can be activated when work is going on. The
inside light then tells guests that the broadcast is taking place, and the outside
light tells people outside the office that the studio is busy. High grade on-air
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lights are activated automatically when the mics are live, and are connected
to the mixer unit.
The On-Air light can also be a simple switch operated light that can
be turned on just before broadcast begins or when the stusio is in
use. It just takes a bit of discipline to build this into the standard
operating procedure for anyone working in the studio.
11. Computerized playout system: When we have a variety of live and prerecorded programming being broadcast, it's often a little difficult to cue the
programmes manually in a seamless and uninterrupted fashion. With
computer systems becoming cheaper by the day, a number of small radio
stations have increasingly begun to rely on computer based playout systems,
which automatically play programmes in the correct sequence without human
intervention. In some ways, this is a luxury for small station, but the potential
savings of time and effort are enormous, as this would avoid having a variety
of playback systems in the studio: The programmes, whether they are on
cassette, CD or any other medium, are transferred onto the computer first,
which then becomes the only 'source' unit in the studio. Professional playout
systems like Enco often require specific hardware to work. There are also
free alternatives like Zara Radio and Campcaster.
Several simple software meant to play back audio on a computer in
a particular sequence can be substituted as basic playout systems:
Just complete your programmes, compile them into a playlist using
free software like WinAmp, and press 'play'!
For more on playout systems, see Section B: Digital Playout Systems on Page 173
12. Broadcast recording devices (Audio Loggers): As part of the monitoring
and grievance redressal mechanism, many governments and adjudicating
bodies make the recording and storage of all the programmes broadcast over
a given period of time preceding any given date mandatory. In India, it is
mandatory to record and store each programme for a 3 month period from
the date it is broadcast: This is so that the programme may be produced before
the adjudicating committee if someone files a complaint about the content.
For more on CR broadcast regulations in India, see Chapter 9: CR Guidelines
in India & their Implications on Page 105
This means, naturally, that we have to record the programmes on a continual
basis, and have enough storage capacity to store three months worth of
programmes at any given time. This is not a very great problem if your
station only broadcasts one or two hours in a day - which would add up to
90 days x 2 hours = 180 hours of programmes. But a station broadcasting
8 hours every day would have to store 8 x 90 = 720 hours worth or
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The amount of programming you have to store to comply with the regulations
really decides what kind of equipment you will store the broadcasts on: If it
is comparatively little, you may decide to record the programmes on cassette
tapes - it may take just a couple of cassettes to record two hours of
programming a day. The cassette recorder can be connected to the broadcast
chain in parallel with the transmitter, so that it receives the same signal that
will finally go out over the antenna.
If the programming is greater than that in quantity, it is wise to set up a
dedicated computer with a large hard disk based storage capacity to record
the programmes in a suitable format. If space on the computer's internal
hard disk is limited, the recordings can be regularly transferred to CD, DVD
or an external high capacity hard disk from the computer's internal hard
disk. (With memory and hard disk prices coming down so sharply over the
last couple of years, it is now relatively inexpensive to install a suitably large
hard disk within the system itself.) The programmes so recorded must be
clearly labeled with the programme name and the date of broadcast, which
should also be marked on any external media that are used - CDs or DVDs
for example - so that there is a clear record of the broadcast content.
13. Satellite receiver: A new addition to the bank of source units is the
satellite radio receiver, which receives radio signals directly from a satellite,
like a DTH (Direct to Home) TV system. There are two or three satellite radio
services providing a variety of music and programming available in South
Asia, with the most prominent being the Worldspace Radio system. If you
feel you can use the programming to pad out and fill in certain programming
needs, it may be useful to acquire a satellite radio receiver, and work out a
rebroadcast deal with the service provider. The upside is the availability of
plentiful and CD quality programming. The downside is that the programming
may not be relevant to your audience; may be mostly music based; and that
your station will have no control over what's coming in and being rebroadcast.
A Hitachi Worldspace satellite radio receiver unit.
The line out socket can be connected to the mixer.
14. Optional: Other playback source units (DAT, LP players, spool players)
As noted before, CD players, solid state recorder/players and computerized
playout and playback systems have made rapid strides in recent years, and
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have all but replaced older warhorses like the vinyl record or LP player; the
spool (or reel-to-reel) player/recorder; and even the comparatively recent
DAT recorder/player. If you feel that any of your source materials may still
be in any of these formats, you should consider whether you need to acquire
any of this equipment for your station.
Since most modern audio systems are digital, it makes sense to transfer
older recordings on tape or LP records into a digital format that can be stored
and played back on a computer or flash recorder unit in the long run.
Section II: The Production studio
The first thing to remember is that the basic setup of a production studio is
not very dissimilar to a broadcast studio (and, in fact, that's the idea, because
it gives us the flexibility of using it as a backup broadcast studio!) But the
choices we make of the numerous options of each type of equipment may
sometimes be a little different.
The primary difference is that it is not directly connected to the transmission
system, and that it is generally equipped with equipment that allows you to
Fig 3-2. Schematic outline of a production studio setup
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record and edit programmes for later broadcast. The second difference is as we have seen - that the production studio is usually equipped with a
formal control room and recording floor spaces.
The production studio typically has an equipment setup something
like the one shown in Fig 3-2.
Once again, let's look at each piece of equipment step by step, to understand
its function:
1. Microphones: Like the broadcast studio, microphones are an integral
part of the production studio. They will usually be set up in the recording
floor area, and the preference in production studios is often for mics that
have a bigger pickup area, usually all around the mic itself, as we often use
the production floor for discussions involving three or more people; or for
radio drama that may mean several voices talking at once.
Unlike the broadcast studio mics, though, the mics in the production studio
may not necessarily be on stands - often they are placed on the 'talk' table
placed in the production floor, equidistant from all the speakers, or
suspended from above in the middle of the recording floor, so as to enable
people to stand or sit around the microphone. However, depending on
what you are producing, there may be a variety of specialized mics used
individually or simultaneously - including highly specialized mics that may
be used to record individual musical instruments. But good mics, remember,
are expensive - and while the temptation to equip yourself with a number of
mics is always there, you must consider what selection of mics is affordable
within your budget - and what kind of recordings you will be doing most of
the time. (Obviously it makes no sense to buy an expensive professional mic
that is designed to record a percussion instrument well if we will actually be
recording panel discussions and human voice most of the time!)
The Samson C-01 condensor mic.
This type of mic is especially useful where
you have more than one performer around
the mic, as in radio drama.
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To our previous recommendation of the the Shure SM 58, the Behringer TSM
87 and the Rode NT-1A - and the Neumann U87 and the Sennheiser MD 421
- we might add the AKG C 414, the AKG C 3000 and the Samson C01.
For more on microphones, see Section B: Microphones on Page 198
2. CD players: Since prerecorded programs mean that you may be mixing a
number of different sources into the final programme, a good broadcast CD
player is an asset to the production studio. (However, this could be substituted
with a more affordable home CD player as well, as reading the display of the
unit from a distance is not a primary concern here. A home CD player would
not have a balanced professional output, but that can be worked around if
you are on a tight budget.)
Good studio CD player units are available from Denon, Sony, Tascam and
Pioneer. Good combo drives (CD writer + DVD-ROM) or DVD-Burners
(Superdrive) are made by Sony, Liteon, Samsung and LG.
An HP internal combo drive unit that plays DVDs and can read and write CDs
A useful solution is to have a good quality DVD writer, CD recorder
or CD player built into the computerized editing and post production
unit (see below), which will allow you to 'rip' tracks from CDs directly
in digital format, thereby preserving their quality.
For more on CD players see Section B: Compact Disc Players on Page 141
3. Studio cassette deck: Once again, a good cassette deck is vital to the
production studio. Cassettes are still the primary way to store pre-recorded
materials in many portions of the country, especially the rural areas; and
cassette players are therefore still in abundant use. CR setups that intend to
distribute copies of their programmes to the listening public - and especially
those that also have outreach projects where programmes are 'narrowcast'
(played off portable cassette decks to small listening groups) - may pay
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special attention to this need, and install more than one, to allow quick
dubbing of programmes. As noted before, the Tascam pro units are of good
grade and take heavy studio use.
A Tascam studio cassette deck. Note the VU meters at the top right
which help you adjust audio levels while recording.
Smaller CRS with tighter budgets may also skip having a computerized
(digital) setup altogether and use two cassette decks in the production
studio - with or without a mixer - for cut-to-cut (start and stop) editing.
This is the simplest and most basic way to edit - by dubbing the
portions we require section by section onto a second tape.
For more on studio cassette decks see Section B: Cassette Tapes & Cassette
Recorders on Page 134
4. Recorder/audio storage unit(s): Besides the studio cassette deck, you
must decide what your final programmes will usually be stored on - that is,
in what format. If they will be stored on CDs or DVDs, the CD-burner or
DVD-burner unit which you will include as part of your computer editing
system will do fine. On the other hand, you may decide to store or write your
final programmes to DAT (in which case you will need a good studio DAT
recorder from Tascam, Denon or Sony), or MD (in which case you will need
a good MD recorder from Sony or Sharp). Studio MD models are hardly
available anymore, but Sony Hi-MD field recorders - Hi-MD is the updated
MD format - are still available at some outlets.
For more on MiniDisc recorders see Section B: MiniDiscs & MiniDisc Recorders
on Page 204
Finally, you may also decide to store and write final programmes to the
editing system's hard disk drive (HDD) itself, in which case you will probably
need several high-capacity HDDs in your system, to store a lot of audio.
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PIC- 3.14
A large capacity external hard disk unit is a useful way
to back up your files and your complete programmes.
Such disk storage units may connect to the computer's
USB port or Firewire port.
It is usually good practice to store the recorded 'raw audio' and the final
version of the programmes on an external HDD of very high capacity: 750GB
and higher external storage units are now quite common. Keeping these
backups on an external HDD ensures that your DAW's internal memory is
always available, and also that your finished programmes are always safe if
your DAW fails for some reason.
Remember that storage technology changes every day, with newer
audio formats and higher storage capacities emerging all the time!
A comparison of various audio storage media
Hi-MD/MD disc
300 MB/1 GB
(26 mins/
125 mins)
Hi MD can record and
playback in MD mode,
but not vice versa.
Compact Disc
700 MB/80
CD-RW may not be
read in all CD players
Digital Versatile
4.7 GB
Writable DVDs may not
be played back in all
DVD players. Most
DVD recorders can also
record on CDs
Blue Ray disc
Some Blu-Ray
recorder/players may
also play back DVDs.
Not compatible with
HD-DVD, though
some newer players
can play both formats.
25 GB/50GB
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15 GB/30 GB
Magnetic storage Current
(magnetic platters highest: 1.5 TB
inside HD casing)
Some HD-DVD players
will also play back
DVDs. Not compatible
with Blu-Ray, though
some newer players
will play both formats
Can store all digital
audio and video
formats. Highest
capacity. Only needs
appropriate operating
system and software to
play back contents. Can
only be used with a
computer. (Some newer
home video/audio
recorders have HDDs
built in for their higher
storage capacity).
5. Mixer : Once again, a good mixer is the heart of the studio, allowing you
to combine a variety of inputs and manage the audio levels of the various
sources and mics. Each of the sources is connected to a separate channel
for independent control, so the number of sources and mics you have in the
studio usually decides the number of channels you need on the mixer - but
a 4 - 6 channel mixer should be fine for most mid level stations. Prime
considerations are the equalizer controls (which let you control the tone
and quality of the audio); the pan controls (which allow you to mix in
stereo); the gain controls (which let you boost the inputs and match them to
each other; and the sliders/faders.
The Behringer UB 502 2-channel mixer. Decide the number
of channels and controls that you will require on your mixer
on the basis of the equipment you will connect to it.
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Experienced recordists and sound engineers would also like the ability to
group sets of inputs together to be controlled by a master fader. Good
mixers, as mentioned before, are available from Behringer, Mackie, Sony,
Soundcraft and Tascam.
Resist the temptation to acquire huge commercial or pro studio mixers
with 24 or 60 channels - you probably won't need them, and they
are fabulously expensive!
For more on mixers see Section B: Mixers & Mixing Desks on Page 207
5. Headphones and monitors: Production studio monitors usually need
to be of better quality than those in the broadcast studio, because one
tends to monitor the audio in the latter more over headphones. Good
quality monitor speakers from Behringer, Sony, KRK, Denon, and Tannoy
- especially the last three - can be very expensive, and it's okay to settle for
a lower grade of monitor speaker as long it doesn't buzz or crackle at
relatively higher volumes, and gives you an output that sounds reasonably
close to the original sound.
Listen to a lot of speakers and choose them according to your budget
and your own ability to distinguish between their quality. (In many
cases, where the production studio is equipped with a computerized
production and editing system, CR stations use good quality computer
speakers from Cambridge Soundworks, Logitech or Creative as the
studio monitor.)
A Creative Labs 2.1 computer speaker set with
subwoofer. Good quality computer speakers can often
be used as audio monitors in low cost CRS setups.
It is also wise to have three or four headphones - and the corresponding
outputs from the mixer, which may require a separate headphone amplifier
- in the control room; and two or three headphones in the recording floor
area, to allow singers or performers to hear a beat track or instrumentals
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while they are singing. Headphones may also be used for the talk back
system (see below.)
Remember that most of the programmes a CR station makes are likely
to be heard in noisy situations on relatively inexpensive transistor
sets - so even though it is always nice to make a programme that has
very high production standards, very fine sounds and subtle mixing
are probably never going to be a priority.
For more on headphones & studio monitors see Section B: Loudspeakers &
Studio Monitors on Page 190
For more on headphone amplifiers, see Section B: Amplifiers on Page 128
6. Distribution amplifier: Ideally, the production studio needs a distribution
amplifier as well, to feed the main output to the recording units (this may not
be necessary if the entire process is oriented around a computerized editing
system) and to the broadcast studio.
For more on Amplifiers see Section B: Amplifiers on Page 128
7. Pre-amplifiers and amplifier units: Once again, consider amplifier units if
there are several source units, many of which may have very low signal
outputs which need to be amplified by pre-amplifier units. Also, the outputs
going to the headphones, and the studio monitor speakers may need to be
boosted by an amplifier unit. (Some studio monitor speakers may have their
own amplification systems built in, in which case they are likely to be very
expensive indeed!). Whether these units are required at all - and if they are,
what kind are required - is dependent on the precise combination of
equipment in your studio.
M-Audio ‘Audio Buddy’ pre-amplifier,
a low cost unit with two mic inputs
For more on Amplifiers see Section B: Amplifiers on Page 128
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8. Telephone hybrid or caller input: It's also a good idea to have a telephone
hybrid system that feeds into the mixer unit in the production studio - this
allows you to pre-record telephone calls and edit them if necessary, an
undeniable advantage over the live call. However, many CRS prefer to equip
only their broadcast studios with telephone hybrids, as the immediacy of a
live call is often seen as more vital to audience participation than a recorded
and pre-edited phone call.
For more on telephone hybrids, see Section B: Telephone Hybrids on Page 220
9. The On-Air light: Production studios are also well advised to install an On
Air light, with lights in the control room, outside the studio door and in the
recording floor area, in order to advise guests in the studio and workers in
the office outside that the studio is recording.
10. The computerized editing system or Digital Audio Workstation (DAW):
Increasingly, production studios - and this applies to small CR setups
as well - are oriented around a Digital Audio Workstation, which acts
as a hard disk based recording system as well as an editing setup.
When we say computerized editing system, we mean, of course, a
computer equipped with the hardware to speedily and accurately
process audio data, and store and retrieve several fairly long (30 minute
and more) programmes simultaneously; and equipped with the software
to access, play back and edit audio data. Very well equipped DAWs are
no longer the preserve of expensive professional studios. A very good
system that is more than adequate for any high grade work by a CRS
can actually be assembled from components obtained from any
reasonably equipped computer parts market, by someone with a fair
knowledge of computers.
Modern audio workstations use software like Adobe Audition that let us
perform audio edits and sound manipulation. Freeware and open source options
have brought these costs down sharply of late.
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The primary considerations for a DAW are:
Processor speed
Hard disk capacity
Good motherboard with plenty of inputs and outputs
High quality sound card, ideally with a 'breakout box' that lets you connect
balanced outputs from the mixer
A good quality monitor (as large as is reasonable: 17 inch is good, 15" will
do in a pinch)
As much Random Access Memory (RAM) as can be afforded (512 MB
Audio editing software (proprietary or open source, freeware or paid,
there are many excellent options)
Ability to connect a variety of field recorders directly to the DAW for
transfer of audio
For more on computer hardware and software, see Section B: Computer
Hardware on Page 152 and Section B: Computer Software on Page 159
13. Talkback system: Since the production studio must interact with the
people in the control room while recordings are going on - and it's not
always feasible to keep opening and closing the access door in the partition
between them - it's advisable to arrange a talkback system between the two
spaces. This is usually setup with a dedicated 'talkback' box that is connected
to a small mic near the mixer console on the control room side, and a small
speaker or a headphone set on the recording floor side, so that the recordist
or producer can give instructions to the people inside the recording floor
area. (On the control room side, the recordist may use a headset unit that
combines headphones with a small microphone before one's mouth,)
The Mackie Big Knob talkback unit allows you to 'talk back' to the people inside the
recording areas, as well as choose between multiple audio inputs.
Many mixer units include a talkback section built in, which may help
you avoid the need for a separate talkback setup.
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14. Optional 1: Patch-board or jackbox: If there are lots of different pieces
of equipment in the production studio, some recordists prefer to have a
patchboard installed. This is essentially a unit with lots of audio jack sockets
to which all the inputs and outputs of the equipment in the studio are
wired. Instead of keeping them all connected with a jungle of cables, the
recordist can now connect only the pieces of equipment he or she actually
wants to use, with short connector leads. It's a good way to keep away
from the nightmare of a tangle of cables, and from the need to plug and
unplug connectors if there are limited inputs and outputs on the mixer
or DAW.
An 8 jack modular patch panel from Hosa.
More such modules can be added to this one to expand the
patch bay as the equipment increases.
For more on patchboards, see Section B: Patchbays on Page 121
15. Optional 2: Additional players and recorders: Since pre-recorded
programmes may draw on a variety of different audio sources for their content
- features and documentaries, especially, may tap into old archival recordings
- it may be wise to have a spool recorder, a turntable/LP player and other
player units as part of the production studio equipment. These, however,
are comparatively infrequently used, so you may decide to have a single set
that is shared between the broadcast and production studios - not a problem
at all if you have a single studio setup - or dispense with them altogether, and
arrange to rent or borrow them if required.
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A brief note on the equipment suggested in this chapter
In this chapter, we have looked at ideal setups, and the types of
equipment that are typically required by a well-equipped CRS. These
suggestions must be adapted to your requirements: Feel free to mix and
match, get double duty from single units of equipment, and avoid certain
pieces of equipment wholesale.
Make the effort of finding out what other CR setups are using, as this will
give you ideas on how you can develop your own setup.
Above all, plan for the future and plan to add equipment bit by bit as
you go along: Starting with a very basic setup will still allow you to make
quality programmes. It's the mind and the ear behind the equipment
that make good programmes, not the equipment itself.
Don't get caught up in technolust and want a piece of equipment just
because another CRS has it, or because you have a fixed idea of what a
studio should be equipped with: Your decisions should be ruled by
logic, rationale, an eye on your budget and common sense.
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Chapter 4
Now that we've had a good look at the kind of equipment we need to equip
our studios with, it's time to examine what kind of field recording equipment
a community radio station needs.
Why do we need field recording equipment?
The simple answer to that is: Because we cannot gather all the audio we
need for a programme within the confines of a community radio station or
the studio. Sure, the studio may be connected to the outside world with
telephones and other communication equipment; but the fact remains that
some audio can only be recorded 'on location' or 'in the field', as it's called.
For instance, there may be people who cannot come to the studio to be
recorded, or to participate in a discussion, but who may be important to the
content of a programme. (A busy government officer, say, or a villager in a
remote area, who has no means to travel to the studio.)
A field recording in progress by volunteers at Mandaakini
Ki Awaaz Samudayik Radio in Uttarakhand.
There may also be audio which can only be recorded at the place where the
sound is actually produced: Natural sounds like birdsong, or the sound of a
waterfall, say; or the sounds made by a wedding procession.
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What are the main considerations in selecting field recording
Since field recording equipment - unlike our carefully protected and shielded
studio equipment - is exposed to dust, humidity, and extremes of
temperature, it is important to consider the following factors while selecting
field recording equipment:
1. Ruggedness: Any equipment we move around with should be able to
take some basic knocks and bumps without malfunctioning: Climbing in
and out of vehicles, travelling in crowded buses, and hiking some distances
on foot are par for the course for CRS volunteers, and the equipment should
be able to take that. (Note that this does not include rough handling or
dropping the equipment - that's just plain carelessness, and there's no excuse
for that.) You'll find that modern solid state recorders, in particular, fulfill this
condition well, as they have very few moving parts.
The portable Marantz PMD 660 flash recorder. Designed
for field use, the recorder is able to handle large
variations in humidity and temeperature.
2. Resistance to humidity and dust: Many pieces of electronic equipment
are so sensitive that they cannot withstand shifts in temperature - interior to
exterior, for example, or from sunshine to shade. Others get easily fouled by
the fine dust that pervades Indian cities and rural areas, and need multiple
cleanings of their heads and other moving parts to stay in working order.
Such pieces of equipment cannot be part of our field recording kit. While
some maintenance is unavoidable, the ideal field equipment will not mind
a bit of dust, and have a large operating temperature range.
For more on maintenance and protection of equipment, see Chapter 7: Planning
for Maintenance & Management on Page 91
3. Adaptability and portability: While we are in the field, we do not have
the luxury of carrying large varieties of equipment to suit different situations.
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The recording equipment we carry has to give adequate or good results in
all the situations and recording conditions we are likely to encounter. (This
means the microphone has to be good for delicate as well as harsh sounds,
voices as well as music, able to work in noisy conditions and in quiet.)
Similarly, this will be equipment we will be carrying on our persons most of
the time, so it has to be reasonably light, or we will be weighed down and
tired out by just the effort of carrying it around.
4. Availability of spares and ancillaries: While most modern electronic
equipment is too complex for us to expect that there will be people capable
of repairing faults wherever we go, always plan on acquiring field recording
equipment for which supplies are available easily in the areas you work in.
For example, choose equipment that uses standard AA, AAA or D cells over
fancy proprietary batteries that may not be easily available: The standard
batteries are usually available somewhere close by no matter where you are.
Similarly, if the availability of recording media is an issue for you, it makes
better sense to choose an audio cassette based recording device than a
MiniDisc or DAT recorder. (Of course, this is not always a problem - MDs and
DATs, for example, are highly reusable media, and can be erased and reused
several times, thereby increasing the gap before fresh supplies are needed.)
For more on maintenance and protection of equipment, see Chapter 7: Planning
for Maintenance & Management on Page 91
What should a field recording kit consist of?
The components of a field recording kit are really very individual to the
setting of the CRS and the preferences of the field reporters; but there are
some broad components which we should include:
1. Microphones(s) & accessories: Ideally, the field recording kit should have a
couple of microphones, one with a wider pickup, that can be used to record a
group of people or a sound effect; and one that is highly directional and has a
narrow area of pickup, for noisy situations or to isolate particular sounds. But
this is usually a luxury, so it is more likely that you will have one multipurpose
rugged microphone that will give you acceptable results in most conditions.
A basic digital audio recording kit. Note the case within
which the recorder is carried to protect it from dust.
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The mic should have a good grip, to allow it to be comfortably handheld;
and should be accompanied by a foam or fiber windshield that prevents
wind from hitting it and causing a rumbling noise. Most field mics use
standard AA or AAA batteries. A balanced output is to be greatly preferred,
as that assists us to get clean recordings even in areas with high
electromagnetic disturbances.
Microphone cables matching the connectors, naturally, will also be part of
the kit - unless the microphone connects to the recorder wirelessly. Cables
should be of good quality and purchased readymade or made by someone
who knows how to do it, to avoid problems in the field.
It's usually a good idea to carry one or more spare microphone cables as
part of the kit, so that some spares are available if the main cable is
damaged for some reason. The spare cables could also be of different
lengths, to allow us to use the mic at varying distances from the recorder 2 metre, 5 meter and 10 metre lengths should be fine. (But it is wise to
remember that not all mics give a good quality signal over cables longer
than 5 metres.)
For more on microphones, see Section B: Microphones on Page 198
2. Recorder unit: The field recorder should - besides being rugged and
hard wearing - be easy to use and set up. A unit with very complex prerecording processes will invariably cause you to miss important recordings
which you otherwise should have managed to catch. It should have balanced
inputs, for the reason stated above; but also allow you to connect a variety
of different types of mics to it: Standard inputs could include professional
(XLR and large ¼" phono) and semi-professional (RCA, mini 1/8" phono)
inputs, if possible.
For more on connectors, see Section B: Connectors (Audio & Telecom) on Page 166
A headphone socket, to allow us to monitor what we are recording, is vital,
as is the ease of changing used media for fresh media: There is nothing more
irritating than having to struggle to insert a fresh cassette or MD in the middle
of an interview. Ideally, you should not have to change the recording medium
at all during a field recording trip.
The recorder should also run off batteries; and have a low power draw,
allowing us to use fewer batteries in the field. To have easily replaceable
standard batteries is a distinct plus.
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The Zoom H2 Handy recorder. With a small form factor
and built in stereo mics, this recorder works on two AA
cells and records on SD flash memory.
A large and clear display screen, that lets you observe all the important
parameters - battery life, the amount of recording media left, the audio
level and the track number (if applicable) is a great plus.
A digital recorder, which allows us to sort and classify recordings as we go,
as well as save time during the transfer process to our editing systems, is also
a wise investment, especially if we have a DAW based editing process: It's
usually possible to transfer the recording into the computer very quickly
from a digital recorder. This is not possible if we use an analog recorder with
a DAW, where the transfer process will be as long as the time it takes to
physically play back each recording (i.e. 5 hours of recording = 5 hours of
transfer time.)
For more on field recorders, see Section B: Field Recorders on Page 184
For more on digital recorders, see Section B: Flash Recorders on Page 187
3. Recording media: In case the recorder needs replaceable media for
recording, there should be adequate supplies of blank media to cover all the
recording planned for the day. (Estimating how much media is required is
an acquired skill.) A good rule of thumb is to estimate the total recording
time anticipated, estimate the blank media accordingly, and then add enough
to cover a recording 1/3 rd longer than anticipated.
The cost of the media is a consideration, of course, with cheaper media
often being kinder to you operating budget. But do factor in the reusability of
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the media as well - an MD which costs a lot more, but can be reused fifty
times may actually prove more economical in the long run than a very low
cost medium like the audio cassette, which is cheaper, but can only be used
only a few times before the recording quality starts to drop.
Secure Digital (SD) and Compact Flash (CF) memory are
solid state and have no moving parts. Very small cards can
now give several hours of broadcast quality recording.
Don't be stingy while carrying spare media - better to have a few
unused cassettes and MDs at the end of the day than to travel miles
to find that you've run out of media and have to miss out on the best
interview of the day.
Modern flash based solid state recorders have much to commend them in
this respect - memory is rapidly becoming cheaper, and vast amounts of
recording can be made on one relatively inexpensive and reusable memory
For more on flash recorders, see Section B: Flash Recorders on Page 187
4. Power supply: Most good field recorders come with an a/c mains power
adapter, but also run off batteries. The dual supply system allows you a
longer recording time in the field, as we can plug in wherever we have
access to mains power supplies. It's a good idea to carry at least one totally
fresh set of spare batteries for the recorder and for the mic (if it is powered).
It is ideal to carry appropriately sized Nickel Cadmium (NiCD), NiMH
(Nickel Metal Hydride) or LiIon (lithium Ion) rechargeable batteries that
are compatible with our equipment, along with charger units for each
variety, so that we can recharge batteries along the way where possible.
Many pieces of equipment come with internal rechargeable batteries in the
first place, that are charged by the accompanying a/c adaptors.
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A family of alkaline cells from Maplin. It is important to identify and
carry the correct batteries for your equipment when in the field.
As a rule, rechargeable batteries have a longer life than standard dry cells. If
rechargeables are not a part of your kit, try using lithium or alkaline cells
(Energizer, GP or Duracell) - these are long life dry cells, but can be quite
expensive on a recurring basis.
All rechargeable batteries have a finite life, measured by the number
of time they can undergo charges and recharges. (Each charge and
discharge is called a 'charging cycle', and a given battery may be
rated as good for a 1000 recharge cycles, or 20000 recharge cycles.)
NiCd and NiMH rechargeable batteries are especially prone to losing
their capacity to hold a charge after some time, a phenomenon called
the 'memory effect'.
5. Headphones: A good pair of headphones to monitor the recording is an
important part of the kit. Some recorder units come with a pair of high
quality in-ear earphones, but a pair of over-ear headphones with comfortable
padded earcups, and a long enough lead are to be preferred over this. Noise
canceling headphones, which allow you to cut out environment noise, are
also of great help, if you can afford them.
Yamaha's RHC headphones are low cost and affordable
while remaining hifi enough for professional use.
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A good pair of headphones, remember, can help you spot audio problems
while you are still in a position to do something about them - so get the best
pair you can afford.
For more on headphones see Section B: Loudspeakers & Studio Monitors
on Page 190
6. Carrying cases and covers: Field recording equipment should always be
carried in their carrying cases: There are a variety of cases, hard and soft,
available for each piece of equipment, with many cases designed to allow
operation of the equipment with the case still on. (This is especially true of
the soft rexine or plastic carry cases that go with many field recorders.) The
cases protect from jars and scratches, as well as dust; and most have straps
and belts that allow you to sling the equipment around your waist or over
your shoulder for easy carrying.
If standard cases are unavailable or too expensive, it's easy to stitch cloth
cases with straps for the various pieces of equipment. A stout kit bag or hard
case for the entire kit is also a good idea, both in terms of transporting the
equipment safely, and in terms of keeping the kit organized.
7. Optional 1: Cleaning kit: A cleaning kit containing cotton swabs, surgical
alcohol or cleaning fluid and an antistatic duster is a vital addition to your
field recording kit if you are using a cassette recorder in the field, as they
require frequent cleaning of the heads and pinch rollers. This is much less
important with latter day digital recorders, where there are no magnetic
heads that are exposed or even user accessible. A clean duster cloth is a
good idea anyway.
8. Optional 2: Boom rod/fishpole: Many microphones can be fitted onto a
long extensible rod called a boom rod, so that they can be held closer to a
subject or sound source from a position several feet away. (This can be an
important consideration while recording natural sounds in inaccessible
places, for example.) There are also flexible versions of this called fishpoles.
Depending on the kind of situations you record in, you might like to make
one a standard part of your kit, or have one available for use as needed:
They are especially useful in news situations, where a crowd of reporters
may be jostling to use their recorders simultaneously!
9. Optional 3: Accessories pouch: Some field reporters like to be prepared
for any eventuality and carry a simple repair kit - soldering iron, solder
wire, flux, miniature screw drivers, cutter and pliers - as well as marking
chalk, rubber bands, cable ties and spare connectors. This is a good idea,
especially if you make the effort to learn how to do these basic repairs on the
fly - it has saved more than one field recording trips from disaster!
For more on repairs and maintenance see Chapter 7: Planning for Maintenance
& Management on Page 91
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Chapter 5
The transmission process, as we have seen, is more or less the final step in
getting the audio from our studio - live and pre-recorded - out to listeners.
Let's pick up the process at the point the final audio signal leaves the broadcast
mixer, and see how it carries on from there:
Fig 5-1. Schematic diagram of the transmission and reception process
1. The Compressor/Limiter: The incoming signal from the broadcast studio
to the transmitter is (if we've done everything right so far) already somewhat
controlled and corrected from the audio level point of view. But this still
needs to be processed in order to keep it within a stricter range, so that the
transmitter isn't overloaded by a signal that it cannot handle. That's where
the compressor/limiter comes in: It controls the signal and keeps it within the
range the transmitter can handle, so that the broadcast radio signal is
distortion free, and so that the sensitive components of the transmitter are
not damaged.
For more on Compressor/Limiters, see Section B: Compressor/Limiters on Page 149
2. The Studio Transmitter link (STL): The studios and the CR station are
usually located in a place where people from the community can access the
station easily. But that's not necessarily the best place to put the antenna,
which has to be at a vantage point which overlooks the largest possible area
for broadcast. And since the transmitter is usually placed in close physical
proximity to the antenna, this means we have to find a way to get the audio
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signal from the station/studio to the transmitter. This connection is called the
studio transmitter link or STL. It can be a physical (wired) connection, using a
tough armoured cable that can withstand the vagaries of weather and direct
sunlight; or it can be an all weather microwave radio link that connects the two.
There are two key considerations where STLs are concerned: If it is a cabled
connection, then there is the matter of cable loss: The reduction in signal
strength due to the resistance offered by the cable itself. This can often be
quite sharp, and may play a large part in the deciding what strength your
transmitter has to be. The lower this loss, the better the cable - and the higher
its cost. But it is generally wise to keep the studio to transmitter and the
transmitter to antenna distance as short as possible: Many agencies advise
keeping the studio to transmitter distance under 50 metres.
50 meters
Fig 5-2. Keeping the STL cable as short as possible is a vital consideration.
It is a good idea to install the antenna mast on the roof of the studio building itself
in order to keep the distance to a minimum, and gain the added height offered by
the building itself.
Wireless STLs, though not specifically banned under the guidelines governing
CR broadcasting in India, invite a whole different set of issues: The microwave
link will be treated by the Dept. of Telecommunications as a separate radio
link, requiring a license from the Wireless Planning and Coordination (WPC)
committee of the Dept. of Telecommunications. It will also involve a separate
spectrum fee, which can be quite high. This is, of course, in addition to the cost
of the link equipment itself, which is likely to add a few lakh rupees in the first
3. The Transmitter: The transmitter is the central component in the
transmission process, and is a device that performs two functions: It generates
a radio frequency wave that carries the audio signal (and is hence called the
carrier wave); and it combines the audio signal that we input into it with the
radio wave it generates (a process called modulation). The combined signal
is very specific and precise, and is fed to the antenna.
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A NICOM USA 30W FM transmitter. Note the LCD screen on the front which reads out
the frequency setting of the transmitter.
The transmitter needs to be set up by an expert who can set it to a precise
frequency, and test whether it is working well. During testing, the transmitter
may be connected to a test or dummy load, instead of the antenna, to
simulate transmission.
The transmitter must never be run without either a dummy load or
the antenna connected to its output, as that can damage the unit.
Depending on the size and complexity of the unit, it may have a digital
display that shows the current frequency and the strength of the outgoing
signal. There is usually a built in system that allows you to set the frequency
of the carrier wave it generates to a specific value. (This is usually in steps of
1000 kHz, meaning we can set the unit to (say) 102.1, 102.2 or 102.3 MHz,
with the 0.1 MHz differences corresponding to the 100 kHz steps. Practically,
of course, stations are only allotted frequencies separated by at least 200
kHz on each side - that is, 92.0 MHz, 92.2. MHz, 92.4 MHz and so on-to
prevent accidental transmission overlaps ('interference') that could disturb
transmissions over the two neighbouring frequencies.)
Small and medium range stereo and mono FM transmitters are manufactured
by West Bengal Electronics Corporation (WEBEL), and Bharat Electronics
(BEL), as well as several foreign companies like Itel and Veronica. Several
other makes and varieties are available, including kits from organizations
like the California, USA, based Free Radio Berkeley. With a moderate
knowledge of electronics, one can build transmitters from pre-fabricated kits
and from the basic electronic components on the basis of circuit designs
available on the internet and elsewhere.
It is illegal to make or own an unlicensed transmitter under Indian
law. Indian regulations currently allow only transmitters meeting a
set of stringent international broadcast specifications. If your
transmitter is manufactured by a non-standard manufacturer - or you
have assembled it yourself! - you can only use it if it is officially
certified by a Bureau of Indian Standards recognized physical
laboratory that can test its adherence to these parameters. The
transmitter is expected to conform to the requisite International
Telecommunication Union - Radio Communication (ITU-R) standards.
For a list of NABL certified labs, go to:
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Stereo or mono transmitter?
One of the important decisions to be taken by every CR station is whether
the transmission should be in mono, or in stereo. FM radio technology
inherently allows the transmission of CD quality stereo audio, so this is
a decision that needs some thought.
For more on mono and stereo audio, see Section B: Stereo & Mono on Page 217
In order to take an informed decision, we should consider the following
1. To get the full value out of stereo transmission, listeners require a
stereo receiver as well to listen to the programming.Most potential
listeners for an average CR station in this country are likely to be
using low cost transistor receivers - where the absence of a second
speaker makes stereo transmission pointless anyway.
2. Stereo transmission means mixing the audio in stereo to utilize its
full effect. Stereo mixing is a comparatively difficult skill to learn,
and needs considerable more practice than mixing in mono.
3. Stereo transmitters are more expensive than mono transmitters.
4. Stereo transmitters have a shorter transmission range than a
mono transmitter of the same power rating. (i.e. A 30W stereo
transmitter has a smaller range than a 30W mono transmitter.)
Of course, any decision we take on this matter also has to take into
account future developments in our transmission area technological developments like plentiful availability of cheap stereo
receivers, for example, or FM enabled cell phones. So be careful
and think ahead!
4. The Antenna: The antenna is a device made of metal, which radiates or
sends out the modulated radio signal into the air all around it. Antennas, like
microphones, can be directional (with much of the radiated energy sent in
one primary direction); or, more usually, omni directional, with the energy
being radiated evenly in all directions.
Siting or deciding the location of the antenna for best reception is an
important consideration, with high vantage points overlooking the maximum
possible area greatly preferred. This is why the antenna is usually fixed to a
tall mast or tower that is carefully anchored to prevent it from falling over the height gives it a greater vantage point.
For more on regulations regarding transmission power and antenna tower
height, see Chapter 9: CR Guidelines in India & their Implications on Page 105
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A simple homemade dipole
antenna. This unit is mounted
on a large bore metal post.
The antenna tower or mast can be of many varieties: The more complex
ones are self supporting tower designs on three or four stilt legs, with
built in ladders which can be used to access the antenna mounted at
the top.
Self Supporting Tower
Fig 5-3. A basic self supporting tower design.
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The simpler ones, which cost much less, are the antenna masts. Such masts
are usually supported against wind by anchoring wires or guy ropes, in
which case they are often referred to as guyed masts. (Of course, in a pinch,
even a long bamboo pole that is suitably braced upright on a building's roof
could provide a more than adequate height for the antenna - especially in a
plains area.)
A guyed antenna mast, on the other hand, is quite easy to manufacture: All
it requires is a good fabricator (iron worker) who has basic welding tools.
You will require:
1. Angle iron (22 x 22 x 5 grade is quite adequate) in 10 or 15 foot sections;
2. Cross strut metal sections to provide the bracing between the three angles;
3. Nuts and bolts to attach the sections to each other, along with fish plate
style punched metal sections.
The sections are manufactured by connecting the three metal angles in a
triangular pattern, with equal sized cross-struts welded to the inner side of the
angles. If constructed in 10 or 15 foot sections, these can be handled easily,
and attached to each other with nuts and bolts holding the sections together.
Iron Angle
Dipole Antenna
Iron Angles
Metal Cross
Guy Wires
Fig 5-4. A simple guyed antenna mast design. The inset shows how the 3 angles
used are interlinked and braced.
Care should be taken that there are no large physical obstacles mountains, hills or tall buildings - near the antenna that may block
the radio signal emanating from it.
Grounding of the antenna is a very important consideration, as a tall metal
tower is an open invitation to lightning strikes. The grounding of the antenna
is distinct from the grounding we have already seen for the station electricals:
This grounding is built to divert the millions of volts of energy from lightning
into the ground, to protect the transmitter and other equipment in the studio
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from being jolted. If the electric charge gets back to them through the cables
and link, they will all be destroyed and lakhs of rupees worth of equipment
could be ruined.
Lightning Conductors
Ground Level
Grounding Cable
Copper Plate
Salt & Charcoal Bed
Fig 5-5. Grounding the antenna mast is vital, especially
in hilly areas and storm prone areas.
The modulated radio wave emanating from the antenna can be received by
radio sets at all the locations within a finite range of the antenna. The strength
of the radio signal drops off with distance: Typically, for a 30 watt transmitter
(which should give 100 Watt ERP with a correctly matched antenna), this is
about 10 - 12 kms in the plains and 4 - 8 kms in the hills. The range refers to
a distance of adequate reception: Any radio set within that range will pick up
a strong signal that can be heard without the audio fading in and out, or with
breaks in the signal.
A note on the regulation of FM transmission
In the modern world, we are surrounding by a plethora of radio signals
used for telecommunications and data transfer, not to mention multiple
radio and television broadcasts running simultaneously. It would lead
to total chaos if anyone could broadcast any signal at any time: Think of
ten stations in a given area all broadcasting at the same frequency! This
is why there is a process of registration and allotment of frequencies.
The transmission process in India is stringently regulated by official
processes and government bodies.
Non-standard transmission equipment can also lead to spillovers of the
signal into areas beyond the allotted frequency, and that that can also
cause reception issues at the listener's end.
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A live CR broadcast in progress. There is no way to rectify
mistakes in production before a live programme is transmitted - so
such programmes call for concentration, coordination and skill from
the presenters and the producer.
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Chapter 6
While setting up and running a CR station, it is also important to plan the
ways in which the station will connect to the world outside. Technology can
play a major role in the way the community interacts and participates in the
day-to-day functioning of the CRS.
Besides the transmitter and the broadcasting equipment itself, there are three
primary technologies through which the CR station can be connected to the
community and the world:
1. Telephones;
2. Facsimile or fax;
3. The internet (and email)
Section A: Telecommunications & telephony
1. Telephones
There are several types of telephone connections available nowadays:
(Wired) Landline, cellular (mobile) and WLL phones. In some areas we
may have access to all the three varieties, and in others to only one of the
three. Some sections of the country still remain unconnected even today
- but we can be hopeful that this will be remedied before long given the
rate at which the telecom networks are expanding.
a. Wired landline telephones: The oldest kind of telephone connection,
the wired landline connection involves the physical laying of a
copper wire telephone cable to the place where the connection is
installed. All the lines from all the phones in a given area are
connected to local telephone pillars or boxes; and thereby, to a
telephone exchange, through which they are connected to each
other, and to phones in distant areas.
The biggest drawback of landline phones is the wire (or 'telephone
pair') that actually covers the distance between the closest exchange or
pillar, and the place where the telephone instrument is installed: Being
a physical connection, it is subject to vagaries of weather; and also
often gets snapped by strong winds, passing vehicles or even animals.
In a remote area, a broken connection can take a long time to repair or
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A modern landline phone instrument. The landline phone is
increasingly losing out to the anywhere-anytime
convenience of cellular telephony.
replace, which means the station's connectivity is compromised in the
meantime. It is relatively easy for fixed line connection - especially in
tropical weather conditions - to develop a disturbing crackle or noise
that can make voices sound unclear.
b. Wireless in Local Loop (WLL) phones: A modern variation of the fixed
line phone connection, WLL phones get over the problem of damaged
pairs by using radio technology to connect the instrument to receiver/
transmitter units mounted on masts or towers in each area. The WLL
instrument is usually characterized by a small antenna that projects out
of the back of the instrument; and most units need a power source of
some kind (usually a battery, or mains power through an electrical
adaptor.) WLL phones can also be moved within a building as required,
unlike fixed line phones where the entire wire may have to be uprooted
and re-laid. Most phone companies also allow WLL instruments to operate
within a limited range of the installed premises.
A WLL phone instrument. The antenna on the right
side of the instrument links the phone to the
closest transmitter/receiver unit.
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c. Cellular Telephones: Like WLL phones, cellular phones use radio
technology to connect the instrument to a transmitter/receiver mounted
on a mast or tower close by. But unlike WLL phones, cellular phones
are mobile - a factor also governed by the extremely small size of the
instruments - with the signal reaching you wherever you are.
A Personal Digital Assistant (PDA) cellular phone
instrument from HTC. Increasingly, internet enabled
cellphones like this one are becoming all-in-one
communication and entertainment devices.
Types of wireless telephone networks
WLL and cellular networks usually work on one of two popular
standards: GSM (Global Standard for Mobile communications, more
common among cellular networks) and CDMA (Code Division Multiple
Access, available for both WLL and cellular networks).
GSM networks are more widespread globally, being an older technology.
But CDMA networks offer higher rates of data transfer, as well as
greater potential connectivity to internet and audio/video/multimedia
services. Both types of networks are constantly being upgraded and
new research being done to improve service quality - so both now offer
a variety of value added services and higher speed connectivity,
collectively now known as 3G (third generation) services.
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2. Facsimile (Fax)
The facsimile or fax machine is a device that allows you to scan documents
and send them to a similar device over a standard telephone line, where the
document can be printed out. Even though they are increasingly becoming
obsolete in a world where the internet and email prevail (see below) they are
still useful devices - a variety of organizations are still not totally computerized,
and rely on fax machines for document transfers.
Fax machines need electricity to run; and also need a clear line for
transmission or reception. If the line is damaged or unclear in any fashion,
the received image tends to be distorted or incomplete.
A fax unit from HP. Though email is now rapidly replacing the fax
machine, the device is still favoured by many government offices
and by smaller organizations in the field.
Fax machines are of many varieties, notably those which store numbers in
a memory, and those with timers that can automatically send pre-scheduled
faxes at a specified time. Another important consideration is whether the fax
machine uses thermal paper (more common) or regular paper (less common,
also more expensive.)
Thermal paper holds images only for a few days before the image
starts fading. If you use a thermal paper fax, photocopy the fax as
soon as possible.
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Which type of phone and how many lines?
Which type of phone you select for your CR station is governed by what
is available in your area most conveniently; and by how you want to
equip the office, studio and staff.
Where phones for the office are concerned, you may want a line each
for each of the following:
1. The office line: This connection will be for administration, research
and other functions. If you have a large setup, with a number of rooms,
this line may be connected to an EPABX, a device that allows you to
connect multiple instruments to the same telephone line or lines. (The
multiple instruments can then also connect to each other - forming an
intercom system - with the outside line accessible from any of the
2. The studio line: This line is for callers to call the studio for phone-in
programmes and to participate in programme activities. The line is
connected to a telephone hybrid unit, a device that lets you relay the
sound coming over the telephone line into the mixer unit, and use it as
an audio source. The caller's voice can then be incorporated into the
programme, and - if the line is connected to the production studio recorded for later editing. Phone hybrids can thus be used for:
Conducting interviews with people who cannot be accessed directly
for a recording
Calls in by listeners who would like to request songs or programmes,
or respond to questions
'Live' broadcasts by reporters in the field (including events)
3. Feedback and listener response: To let listeners call in with their
opinions regarding the programmes the station is broadcasting, you
might also consider having a separate line connected to an answering
machine, a device to record incoming calls. Answering machines are
available as standalone units which automatically record incoming calls
on cassettes or (more lately) solid state memories. Software is also
available to let you connect a phone line to a computer, in which case
the computer records the calls directly onto its hard disk.
4. Fax line: If use is likely to be heavy, it makes sense to have a dedicated
line for the fax machine. On the other hand, if you will be using the fax
only sporadically, it could share the main office line, with the fax machine
switched on or off as required.
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Fig 6-1. A typical distribution of telephone lines in a middle level CR station.
Smaller CR stations often get multiple duty out of a single incoming line.
It's really up to you to choose which type of connection is best for
your situation. It is a wise idea to not have WLL phones or cell
phones for the studio line, as having a wireless unit close to audio
equipment can mean disturbances in the audio that is being
broadcast or recorded. (This is why all studio staff are generally
advised to switch their cellular phones off when in the studio.) WLL
phones are also usually not connectible to fax machines, so this
should be a consideration when investing in a WLL phone for the
Any phone units or extensions installed in the studios should also
have the facility to mute the unit - keep it from ringing - so that it
doesn't actually sound when audio is being recorded or broadcast
from the studio. Many specialized phone instruments are available
for this purpose, with blinking lights indicating incoming calls
instead of the standard ringtone.
If your radio station is constantly receiving more calls that one phone
line can accommodate, it is a good idea to invest in more phone
lines for the studio - there is nothing more frustrating for a listener
than to be invited to call in and get an engaged tone. More than one
line, while not a perfect solution, increases the chances that a caller
will get through. Combined with a hunting phone system, which
searches for the free line out of the ones connected to it, this can
provide a much better connectivity experience for your listeners.
(Multiple lines may also need multi-line telephone hybrids to connect
to the mixer system, and this can be very expensive!)
For more on telephone hybrid units, see Section B: Telephone Hybrids on Page 220
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Finally, you may like to consider the value added services available
with a given choice of telephone line - WLL connections and cellular
connections also offer you the ability to see incoming callers' numbers
(caller ID) and send SMSs (Short Messaging Service, short text messages
that can be transmitted to another phone working on the WLL or cellular
system.) SMS, in particular, is increasingly being used by stations to ask
listeners to make requests, vote for songs and/or send in their opinions.
When calculating approximate costs of operation, remember
that fixed line and WLL phone connections generally charge a
flat per month rental, along with a usage charge that is linked to
the number of calls made. Cellular phone connections are either
postpaid (with a rental and call charge structure like the one
described above) or prepaid (where a predetermined amount
is deposited in advance in exchange for a fixed amount of
calling time.)
3. Internet & email
Most modern offices are connected to the internet, a worldwide network of
computers and data relay systems that allows access to information stored on
the network. The internet is a huge resource, with billions of websites - collections
of electronic web pages - providing a variety of information on organizations,
people, and events (and increasingly audio and video clips as well.)
Its ability to transcend geographical boundaries allows the creation of global
electronic groups which can hold discussions on issues and information of
common interest. It also allows individuals and organizations the ability to
publicize themselves, their work and their ideas at relatively low cost. Most
importantly, its value as a repository of information transcends traditional
encyclopaediae, making it a hugely important component in research.
Connecting to the internet requires computers equipped with browser
software, specialized software that can interpret data available on the internet
in electronic language designed for fast and efficient data transfer over the
world wide web, as it often called.
Most modern computer systems come pre-equipped with browser
software: Internet Explorer is usually included as part of the Windows
operating system, with free software like Mozilla Firefox, and Opera
also widely available.
Websites follow a naming convention that uses http:// or www followed by
a name and a .com/.org/.net suffix that identifies them uniquely. This must
be entered in the browser window to access the page or site.
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But perhaps the single greatest use of the internet is the ability it gives us to
send electronic mail or email - electronic messages that travel over the
internet almost instantaneously. Email communication is rapidly becoming
the modern communication standard, especially since it now allows us to
attach electronic computer files to mail messages. Many websites provide
free email services, where you register to get a unique email address
([email protected], for example) where others can send email to you. Many
organizations tend to set up their own websites and their own coordinated
email addresses that include the organization's name.
Internet connections are usually provided by an Internet Service Provider
(ISP), who sells you a predetermined amount of connection time or data
transfer against a set fee. As charges drop, many ISPs now provide an
unlimited data and time connection against a per month flat fee. The ISP
runs a computer called an internet server that can be connected to your
computer in a number of ways:
a. Through a regular phone connection: Several ISPs are also telephone
service providers and offer combination packages that combine internet access
with phone calling. The fixed line phone cable, WLL instrument or cellular
phone is connected to the computer, which then sends and receives data
over the telephone connection. Many such ISPs offer a facility where the
telephone continues to remain active even while the internet connection is
on, though this is more common with DSL and ADSL connections (see below).
LAN Cable
Telephone Line
CR Station
LAN Card
Fig 6-2. The computers in a CR station can connect to the internet in a variety of ways.
Wireless Wi-Fi connections are rapidly becoming popular in offices.
b. Through a dedicated internet connection: Many ISPs also provide
connections that are meant specifically for high speed internet data transfer.
These could include internet over LAN, where the connection is provided
over the type of cable that is used to connect Large Area computer networks
(LANs); ISDN (Integrated Services Digital Network), a high quality copper
wire telephone line usually provided for internet connections by telecom
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service providers; and DSL (Digital Subscriber Line) or ADSL (Asymmetric Digital
Subscriber Line), which also uses a physical copper wire connection, but offers
very high data transfer rates. ISPs providing DSL or ADSL line often bundle
packages that include phone instruments and phone calling, as the DSL/ADSL
line is capable of easily handling both phone and internet traffic simultaneously.
Depending on what type of internet connection is being used, the computer
either needs a device called a modem (short for modulator-demodulator), which
converts the computer's digital data into analog audio signals which are then
transmitted over the network to the internet server; or a network or LAN card, a
piece of equipment that allows computers to connect to each other. Discuss this
with your ISP before acquiring an internet connection: They will let you know
what the specifications and equipment you require will be.
More internet based communication opportunities
As the internet plays an increasingly larger role in our lives, it is also
leading radio stations to leverage new technologies. Most popular among
these technologies are:
1. Blogs or web-logs: These are online internet diaries maintained by
individuals or members of a team or organizations, which offer an
opportunity to share personal observations, experiences and memories.
Many websites and ISPs offer visitors or users space on their internet
servers to host blogs, which can then be accessed by anyone visiting a
specific website. The newest variant of the blog is the audio blog or
video blog, which offer the author of the blog facilities to present audio
and video recordings respectively as part of the 'diary'. Almost any
audio recording once converted to digital form can be used for this
purpose. Popular blog sites include, and
2. Podcasts: Named after the popular Apple iPod music player, a podcast
is an audio programme hosted on a website, which can be downloaded
to one's computer or digital music player and heard by the listener.
Though a good internet connection is called for - podcast files can be
large in size for longer programmes - the advantage over broadcasting
programmes is huge, as it allows one to listen to the programme at
leisure. Many long-running prodcast series are now available over the
internet, and many international media organizations like the BBC now
regularly make their programming available as podcasts. Try http:// to hear some
interesting podcast radio documentaries.
3. Streaming audio and internet radio: With comparatively inexpensive
software and a good internet connection, it is now possible to schedule
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and play programmes over the internet to listeners who connect to your
website or server. The audio - although in lower quality than broadcast
level audio - can even be customized according to the listener's
preferences, in terms of selecting which programmes to hear, or the
order in which the programmes are played back. At the receivers' end,
all that is required is a computer with some commonly available
streaming multimedia players like Windows Media Player or Real Audio
player; a good internet connection and a pair of speakers or headphones
over which the audio can be heard. A large number of internet radio
stations are now active, and may be accessed over the internet.
For CR stations, podcasts and internet radio present an additional
opportunity to air programmes and expand their listenership beyond
the local audience, as well as listen to other programmes from groups
working in other geographical areas. Since both these technologies are
license-free (or unregulated) and give the listener the ability to control
their media consumption, they are seen as important changes in the
traditional scheduled broadcast model in a globalizing world that now
works across political boundaries and time zones.
Section B: Other office equipment
As we have seen in the previous section, the office requires a variety of
telecommunications equipment for its functioning. In addition to all this and as indicated by what we have already discussed - we must consider the
following equipment for the office:
1. Computers (for administration & research): In today's world, computers
are not only at the heart of broadcast systems, they are an ubiquitous part of
the office as well. You should consider a at least one computer for the office more than one, if you can find the funds for them! - as everything from
documents to records to financial matters are now maintained on computers.
A modern branded desktop computer system from Lenovo.
While branded desktops often carry extended warranties,
assembled PCs often let you match components of your choice.
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Office computers need to be of far simpler specifications than the DAWs we
saw in a previous chapter, as they type of data they are expected to handle
is primarily text and numeric. But they do need to be equipped with
accessories that allow them to connect to the internet (modems) and/or to
other computers (network or LAN cards). Of course, if you intend to use
them for more demanding applications - like transferring audio programmes
over the internet, or playing back audio or multimedia from internet sources
- then the specifications will need to be higher. But a computer like this
should usually be more than enough:
A basic configuration for an office computer
Intel Pentium-4 3 GHz or Intel Core 2 Duo Processor 1.83 or higher
(or) AMD Athlon 3000 dual core processor
120 GB hard disk drive (160 GB preferred)
512 MB RAM (1 GB preferred)
15" LCD or CRT monitor
56K modem
10/100 Ethernet (LAN) card or Wireless network card (if you have a
wireless router)
ATX cabinet with 300W SMPS power supply
Appropriate motherboard for processor above (integrated audio and
video are fine)
At least 4 USB ports+serial port+Firewire port preferred
Standard 101 keyboard and 3 button mouse
750 VA Uninterruptible Power Source (UPS)
You can buy pre-designed branded computers, or have one assembled to
your specifications from components by an assembler. Discuss computers
with your local computer supplier or with someone knowledgeable regarding
computers and networks so that you can get a system appropriate for your
For more on computer hardware and software, see Section B: Computer
Hardware on Page 152 and Computer Software (for Radio) on Page 159
2. Network hubs/Routers: If you have multiple computers in the office, it is
usually advisable to connect them together so that they can transfer files and
data between them. The connection is usually achieved with a network hub
or router switch. If each of the computers is equipped with a network card,
and the network cards connected to the hub, the computers will be able to
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share data. Some router equipment allows you to connect the internet
connection to the router itself, so that it can be shared by all the office
computers - though it must be remembered that the more the number of
computers sharing the internet connection, the slower the data transfer speed
that each experiences will be.
A Linksys WiFi (802.11g) wireless router.
Such a router allows WiFi enabled laptops and desktops to
connect remotely to it within a given range.
Nowadays, routers and network hubs are also available in wireless versions,
based around the 802.11 standard. This standard, known popularly as
WiFi, allows computers equipped with the appropriate wireless network
cards to connect to the router without cables. However, in a radio station,
using wireless equipment of this sort could conceivably interfere with the
audio studio's operations, so such equipment must be used with some care.
3. UPS: Every computer that you have in the office requires its own
Uninterruptible Power Supply (UPS), a battery based unit that doubles as a
device to correct variations in incoming AC mains voltages, as well as provide
emergency power during a power failure. Depending on its capacity and
the number and type of batteries attached to it, the UPS may provide enough
time to shut down the system, or run it during an extended power cut.
UPS batteries need to be replaced at regular intervals, as batteries
have finite ability to retain a charge - in regular use, this should be
about every two or three years.
For more on UPS systems, see Section B: Uninterrupted Power Supply
on Page 224
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A note on the equipment mentioned in this chapter
It is important also to remember that though computerized offices are to
be preferred, there is absolutely no reason why a CR station office cannot
work with much more basic equipment - typewriters and manual records.
A number of CR stations worldwide continue to operate effectively in
this fashion, and do a very good job of it.
Remember that equipment is not the be all and end all of a CR station and certainly not for the station office, even if it is important for the
studio and production work. What is important is getting the work done
and the broadcast running steadily - and within the limitations of the
budget that you have.
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An internet browsing programme being broadcast live by a CR
station . The programme is interactive: Listeners call in with
queries, which are then answered over the air by the show’s
hosts. The hosts find the answers to the queries on the internet.
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Chapter 7
Since most CR stations run on stringent budgets and aim at serving the
community with a not-for-profit motive, it becomes very important that its
plans for the upkeep and maintenance of its equipment are up to the mark.
If done regularly and well, maintenance should:
1. Prevent breakdowns before they happen;
2. Avoid unnecessary operational hassles and expenditure;
3. Ensure that the broadcast and production process is never interrupted,
and that a good quality transmission goes out all the time.
Setting rules and regulations in the studio
Maintenance starts before the breakdown happens! So start by creating
some simple rules for studio access and use - and enforce them strictly.
These include:
1. Cleanliness: Dust and dirt should not be allowed into the studio areas - that
means no shoes or dirty clothes, or even food or drink in the studio areas. No
pets should be allowed into the studio area either - animal hair is just as bad as
dust! Ensure that the studio area is swept and mopped every day.
2. Trained personnel only: Put in place systems that allow for consistent
capacity building of volunteers and producers on how to handle the
equipment, and - as far as possible - allow only them to actually work in the
studios. All too often damage occurs because someone is just fiddling with
the equipment without really knowing how to use it. Of course, fiddling with
equipment is part of learning how to use it as well - so the trick is working out
a balance. (Strategic signs placed all around the office and within the studio
may play a useful role in inspiring people to fiddle responsibly!)
3. Report problems as they happen: Instruct staff and volunteers and staff to
report any problem, however small, as soon as they experience it. This will
avoid the problem snowballing into a much greater issue. Computerized
equipment, in particular, often signal when things are going wrong with a
number of error messages. Instruct staff to note error messages whenever
they appear so that the problem can be diagnosed.
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Members of a CR group learn how to repair their field
cassette player units. Field units need servicing on a
regular basis to keep them in peak operating condition.
Never force equipment to work - if a CD tray is stuck in the eject
position and doesn't go back in, don't manhandle it into going back
in! Your haste may damage an expensive piece of equipment and
make it unusable!
Planning for maintenance
It is a good idea to incorporate a regular inspection process for all equipment
into the management process - that way, equipment testing is done on a
regular basis and possible trouble spotted early. Also, since radio and
broadcast equipment is costly to repair - and given that repair facilities may
not always be easy to access in your area - planning in advance for possible
repairs allows you to manage the expenses in a way that is more convenient
to you.
Planning includes:
1. Scheduling a system of equipment checks, and designating the people to
carry them out;
2. Maintaining a log of equipment trouble faced and repairs carried out;
3. Maintaining a filing and documentation system where original equipment
warranties and manuals are stored for reference;
4. Keeping a database of repair facilities and tech support persons accessible
for ready reference;
5. Incorporating a maintenance budget into the yearly or monthly operational
budget for the station;
6. Scheduling a regular training process that teaches station staff how to
work on the equipment.
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Maintaining the documentation and plans
It is very important to maintain an orderly system to file and keep accessible
all the plans for the station - layouts, wiring diagrams and equipment manuals.
If these are kept handy, then a number of problems can be sorted out very
quickly when they arise.
Besides the fact that reading the equipment manuals allows the staff to learn
the functions and correct operation of the equipment, manuals often have
detailed instructions on procedures to be followed if the equipment gives
trouble. Consult them first in case you are finding issues with any equipment
- sometimes it can be as easy as switching the equipment off and then
turning it back on!
Maintaining records and documentation for equipment especially field equipment, which is often away from the
station - is vital to keeping the technology in good order.
The wiring layout of the station - electricals and audio cables - will help you
understand where a possible break or interruption may be happening. If
you don't keep this filed away and accessible, as people change and time
passes, the original layout will be forgotten and then you may have to
painstakingly rip the floor and walls up to rediscover where the cables go.
Update these diagrams and plans as you make alterations, corrections or
upgrades - that way you always have a current picture of the setup.
Warranties, especially, are very important documents - within the warranty
period, most equipment manufacturers will not charge labour or parts costs
to fix equipment. File these away carefully, and see that they are duly
completed when you acquire the equipment.
Warranties are not always available if you acquire equipment from
the unofficial market (often called the 'grey' market). So if you buy a
really expensive piece of equipment in the grey market, you may
save some money up front by buying it without a bill or at a discount
from an unauthorized dealer - but be aware that equipment failure
could cost you much more in repairs.
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It is also a good idea to evolve and file your own training manuals and
documents so that they can be accessed easily by staff - often manuals may
give too many details regarding the equipment, and a simplified version
may be useful to have for staff to use or train new volunteers with.
Maintaining inventories of equipment
It is also good practice to maintain an inventory or equipment list for all the
equipment in the station, and to affix labels that correspond to the entry in
the list to each piece of equipment. That way, it will be easy to find the details
of any individual piece of equipment almost instantaneously by just referring
to the appropriate entry in the list. The inventory should carry details like:
1. Name and model of the equipment
2. Serial number or unique ID
3. Function
4. Date of manufacture
5. Date of purchase
6. Name and contact address of the dealer
7. Warranty period
8. Situation (where is it located/installed)
9. Comments (a column where you can record remarks regarding the
equipment, including complaints and repairs)
Many of these details will have to be gathered from the papers that accompany
the equipment when it is acquired: Bills of sale, warranties, and so on.
Some of the details - serial number, model and so on - may be read off the
labels or printing that is usually affixed to the rear side of the equipment.
Serial numbers, in particular, are very important during repairs, as
this will be how you identify the equipment that has gone back to the
repair shops: The repair shop may have many similar units with it at
a given time. The serial number is also mentioned on the warranty, as
it identifies the unit uniquely.
The serial number of the equipment is usually mentioned on a label
on the side, back or underside of the equipment. Note that the
label also gives information regarding power ratings.
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Assessing (and investing in) maintenance skills building
It is also a good idea to see whether what the maintenance skills of various
staff and community members is - there may be people among them who
are adept at electric and electronic repair work, or who may even have
experience in repairing some of the equipment. Maintain a list or resource
directory of the people you identify.
Be careful while doing such an assessment - everyone enjoys being a source
of information, and a lot of people like being tech gurus, but may actually
not have much skill at all. If someone who only pretends to have experience
sets about doing a repair job, you may end up with more problems that you
started out with!
It is good to have some basic ability to repair equipment and clean and
maintain it - and that includes the ability to make running repairs that keep
the equipment functioning while more formal repair assistance can be called
for - but too much experimentation can be detrimental to the equipment:
Some parts can simply not be jury rigged, and being able to recognize
where something can be done and where one should not take the risk is a
very important ability.
It may also be a good idea to send staff out to equipment manufacturers'
facilities and maintenance centers to learn some basic repair skills for the
various kinds of equipment. Many manufacturers hold workshops and
preventive maintenance courses for their equipment, which you may be
able to access.
Assessing maintenance costs
When you run a CR station, the costs involved in repair and maintenance
often run beyond the simple costs of repair and spare parts: Many CR stations
are situated far away from the repair centers which can fix their equipment.
Repair and maintenance costs may therefore have to include:
1. Spare parts: This includes the cost of any replacement parts that may be
required to fix the equipment. Within the warranty period, this is generally
not a concern, but outside warranty, it is definitely a cost. Note that warranties
generally do not cover physical breakage, only normal wear-and-tear related
2. Labour: The charges related to the time spent by the technician in fixing
the equipment. Some suppliers will charge this as a flat fee as they already
have an assessment of the average time it takes to fix common problems.
These are also often covered by the warranty during the warranty period.
3. Travel & boarding: If the repair center is far away, you may also have to
pay the repair technician's travel to and from your station, as well as the
costs involved in putting him up if repairs take more than one day or travel
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exigencies require him or her to stay overnight. This can add up to quite a
lot, especially if the service center has rules regarding the kind of travel
facilities that they require. Additionally, the service person may not be carrying
all the spare parts required for a given repair job, as it is often impossible to
prepared for every eventuality - and this may require more than one trip as
a result.
You can save yourself some bother by noting error messages carefully
and reporting the problem faithfully and in detail when requesting
repairs: This may help the technician identify the possible problems
and come prepared with the appropriate tools and parts.
Even within the warranty period, travel and boarding for on-site repairs are
unlikely to be covered by the service center unless expressly mentioned in
the bill of sale or warranty. You may be able to convince the supplier to
include this as a facility when you acquire the equipment, so try and bargain
for it!
4. Courier & postage: Sometimes you may have to package and ship
equipment to the manufacturer or supplier in order to get it fixed. This will
require special packing, and shipping by courier, so that the equipment
arrives safely and without further damage at its destination. A good courier
company may charge you steeply for this service, especially since many
pieces of equipment are heavy, and shipping is charged on a weight basis or
a volume basis.
A CR volunteer discusses repair instructions over the
phone as he checks an electrical point. Doing some
basic preparatory work before calling in a technician
can save time and money.
Annual Maintenance Contracts
Beyond the warranty period, many suppliers and repair centers offer Annual
Maintenance Contracts or AMCs for the upkeep of the equipment. This
usually involves a flat fee per annum for the equipment covered, which
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takes into account all the costs mentioned above. Under the AMC, the
repair center usually does not charge you for every repair that they execute,
as they will be paid the fee whether problems crop up or not: It is their
responsibility to fix the problem, whatever it is, once the AMC is drawn up
and agreed upon.
AMCs can often be negotiated, and it is up to you to work out the best deal
for your station - try and get one or two preventive maintenance visits in a
year included within the terms, and check for loopholes that force you to
pay for specific portions of the repair and maintenance despite paying the
annual fee.
A good AMC contract should cover all the possible costs involved in keeping
the equipment running in good order, and also include a timeframe within
which problems will be fixed.
Many repair centers stop taking an active interest in your equipment
once they have been paid the AMC fee - after which they put your
work on hold while they attend to other paying customers. A punitive
clause that forces time bound responses from the service provider is
a good way to keep things in order!
General maintenance tips - A ready reckoner
1. Read the Instruction manuals - All the safety and operating
instructions should be read before equipment is operated.
2. Keep the Instruction manuals - The safety and operating instructions
must be kept for future reference.
3. Heed Warnings - All warnings on equipment and in the operating
instructions should be obeyed.
4. Follow Instructions - All operating and use instructions should be
5. Cleaning - Unplug equipment from the wall power outlet before
cleaning. Do not use liquid cleaners or aerosol cleaners. Use a soft,
damp cloth for cleaning the exterior of equipment.
6. Attachments - Do not use attachments not recommended by the
equipment manufacturer, as they may be hazardous.
7. Water and Moisture - Do not use equipment near water - for
example, near a bath tub, wash bowl, kitchen sink, or laundry tub;
in a wet basement; or near a pool or any similar wet or damp place.
8. Stability - Do not place equipment on an unstable surface. The
equipment may fall, causing serious injury to yourself or others,
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and serious damage to the equipment. Preferably all broadcast
equipment should be mounted in a rack or stand, recommended
by the supplier or sold with the equipment.
9. Equipment should be moved and carried with care. Rough
handling, quick stops, excessive force, and moving over uneven
surfaces may cause the equipment to be dropped or damaged.
10. Ventilation - Slots and openings in equipment cabinets are provided
for ventilation and to ensure reliable operation of the equipment
and to protect it from overheating. These openings must not be
blocked or covered when the equipment is in operation, though
you may be tempted to cover the equipment with a cloth or plastic
sheet to protect it from dust. The openings should never be blocked
by placing the equipment on a bed, sofa, rug or other soft surface.
Equipment should not be placed in a built-in installation, such as a
bookcase or rack, unless proper ventilation is provided or the
manufacturer's instructions have been obeyed.
11. Power Sources - This product should be operated only from the
type of power source indicated on the marking label. If you are not
sure of the type of power supply you need for the equipment, consult
the supplier or local power company. For products intended to
operate from battery power or other sources, refer to the operating
12. Power-Cord Protection - Power-supply cords should be routed so
that they are not likely to be walked on or pinched by items placed
upon or against them, paying particular attention to cords at plugs,
convenience receptacles and the point where they exit from the
13. Outdoor Antenna Grounding - If an outside antenna or cable system
is connected to the equipment, be sure the antenna or cable system
is grounded so as to provide some protection against voltage surges
and built- up static charges.
14. Lightning - For added protection for your equipment during a
lightning storm, or when it is left unattended and unused for long
periods of time, unplug it from the wall outlet and disconnect any
antenna or cable system. This will prevent damage to the equipment
due to lightning and power-line surges.
15. Power Lines - An outside antenna system should not be located
near overhead power lines or other electric light or power circuits,
or where it can fall into such power lines or circuits. When installing
an outside antenna system, extreme care should be taken to keep
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from touching such power lines or circuits, as contact with them
can seriously injure or kill you.
16. Overloading - Do not overload wall sockets or extension cords, as
this can result in fire or electric shock.
17. Object and Liquid Entry - Never push objects of any kind into
equipment through openings as they may touch dangerous voltage
points or short-out parts that could result in damaged equipment,
fire or electric shock. Never spill liquid of any kind on the equipment.
18. Servicing - Do not attempt to service equipment yourself unless you
are qualified to do so. Opening or removing covers may expose
you to dangerous voltages or other hazards. Refer all servicing to
qualified service personnel.
19. Damage Requiring Service - Unplug this product from the wall
outlet and refer servicing to qualified service personnel under the
following conditions:
a) When the power-supply cord or plug is damaged.
b) If liquid has been spilled, or objects have fallen into the equipment.
c) If the equipment has been exposed to rain or water.
d) If the equipment does not operate normally by following the
operating instructions.
e) If the equipment has been dropped or damaged in any way.
f) When the equipment exhibits a distinct change in performance
- this indicates a need for service.
20. Adjust only those controls that are covered by the operating
instructions. Improper adjustment of other controls may result in
damage and will often require extensive work by a qualified
technician to restore the equipment to its normal operation.
21. Replacement Parts - When replacement parts are required be sure
the service technician has used replacement parts specified by the
manufacturer or that have the same characteristics as the original
part. Unauthorised substitutions may result in fire, electric shock or
other hazards.
22. Safety Check - Upon completion of any service or repairs to this
product, ask the service technician to perform safety checks to
determine that the equipment is in proper operating condition.
23. Wall or Ceiling Mounting - The equipment should be mounted to a
wall or ceiling only as recommended by the manufacturer.
24. Heat - The equipment should be situated away from heat sources
such as radiators, heat registers, stoves or other products (including
amplifiers) that produce heat.
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Keeping your audio recordings and reference materials neatly
arranged and categorised is a very important part of the
maintenance process. Libraries such as this one make locating
archived programmes and raw recordings an easy process.
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Chapter 8
Now that we've had a look at the responsibilities involved in maintaining
equipment in good order, it's time to ask ourselves an important question: What
are the technology related training requirements required for our CR station?
(Of course, your station staff may require a variety of inputs and capacity
building measures in terms of running/managing a station, mobilizing the
local community whom the station addresses, and developing a feedback
mechanism that allows the incorporation of listeners' opinions into the stations'
programming. But for the moment, we will confine ourselves to the question
of technology related training, as that is the primary focus of this manual.)
The first step to assessing your technological training requirements is, of
course, to ask yourself what level the various members of your team are at
(with reference to their ability to interact with technology):
1. Absolute novice (no idea regarding equipment, operation or repair)
2. Trainee (Has some understanding of practical usage of equipment, but
must be accompanied by more experienced people)
3. Operating level (can operate equipment comfortably and competently);
4. Expert operating level (can operate equipment and can fix common
operating issues and make fine adjustments to the equipment if required)
5. Basic Repair level (can fix most simple problems in equipment easily)
6. Advanced repair level (can handle advanced electronic repair equipment
and has an excellent understanding of circuits, circuit diagrams, soldering,
and electronic theory.)
A technical training in progress. CR volunteers learn how
to install and setup software on their editing system.
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Assessing training needs
Technical training can also be of different types: How to operate various
kinds of equipment of software; how to make common repairs on studio or
field equipment; or even electrical repairs and maintenance To assess the
type of technical training that you and your team require, you will first have
to answer the following questions:
1. Are there any community members who have any knowledge of
electronics, electricals and/or equipment repair that we can access
readily? (If so, what kind of skills do they have, and will they be willing to
volunteer their expertise to the CR station?)
2. What kind of equipment are we going to install in the CR station? Will the
station staff need any training to operate this equipment? Will this
equipment have any simple components or pieces that we can maintain
on our own within the staff?
3. Are there any equipment repair shops or service centers nearby which
can undertake some of the simple maintenance responsibilities? If yes,
can this service center/repair shop train some of the CR staff in basic
4. What kind of advisers and training facilities can we access outside the
immediate community? (Are there any courses or service trainings offered
by equipment suppliers which are relevant to our setup and equipment?)
5. Can we work out a training process with whoever installs the equipment
and sets up the studio for us? What kind of trainings can these be?
(Installation/Operation/maintenance/simple repairs/complex repairs?)
How many such trainings can be arranged - and where?
6. What are the points to consider when we budget for trainings to address
these needs?
7. Can we hire a specialist repair and maintenance technician to run the
repair and maintenance process, or will this have to be an additional
responsibility for management or an identified member within the staff?
8. Will we undertake the training of fresh volunteers and technical staff
ourselves, or will we access outside resource persons or organizations
for this? (That is: Will we become technical master trainers ourselves, or
will we just learn what needs to be done and outsource the training
It is important to remember that it is almost impossible to become experts at
everything - being a service technician requires several years of training and
an expert understanding of electronics, for instance.
It is also wise to recognize that your training requirements will be different at
different points in time; and that training is likely to be a continuous part of
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the process of running a CR station: At the beginning, you may have to
access training from outside the immediate community; and you might like
to get the kind of training that lets you get the station off the ground and
running quickly - an important consideration given that CR guidelines in
India state that the station must be broadcasting within three months of
obtaining the Grant of Permission agreement. (Given that you are unlikely to
actually acquire equipment and set up the studios before your application
crosses the first set of clearances from the various ministries - see the guidelines
in next chapter - this actually doesn't leave you with very much time for the
set of trainings!)
CR volunteers from Mandakini Ki Awaaz CR in Uttarkhand
conduct an internal training for other members of the group.
Technical and production training must be a continuous process.
Later in the process, you may establish a sustained programme that lets the
senior members of the team take on some of the training processes themselves,
as they will now be reasonably familiar with the equipment and operation.
Building an internal training process also has the advantage of being low
cost, from the station's perspective - outside trainers may charge you for
their expertise - and sustainable, as skills acquired by staff can be passed on
and preserved even if they leave.
It is important, therefore, to create a combination training plan that keeps in
mind the available skills and the requirements of the CR station in the long
term, in this fashion:
1. Initial training: The training of the core personnel/volunteers and
producers of the CR station just before it commences operations;
2. On-going training: The continual training process of staff as new members
join and old ones leave; and as equipment, technologies and content
production techniques change.
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Training resources
Many training resources in the form of manuals and guides (like the one you
are reading, for instance) or online internet based articles are readily
accessible if you are willing to do some research . Several organizations also
run online training courses on various aspects of content production and
equipment handling.
For a basic list of online web based resources on radio and community radio
technology, see Appendix 5: Useful Web-based Resources on Page 265
Several organizations and individuals also provide training in radio, radio
programming, radio technology and station setup. Some of them can provide
an entire package of services that can help your team develop a CR station
from scratch, and assist you through to your first few months on air.
For a list of organizations and individuals with experience in working on
community radio, radio programming, station setup and equipment setup,
see Appendix 3: Index of Advisory Organizations & Individuals on Page 254
It may be a good idea to discuss the trainings that staff from other CR stations
have attended or been a part of, including the kind of advisers and trainers
that they have had in the past. This may give you a few clues regarding
where you can access training, and who from. Last but not least, it will
probably give you an idea of whether the training the other station's staff
received was any good - because it should reflect in the way that station runs
its operations and produces programmes!
A CR group volunteer conducts a demonstration at a
local school. Planning ahead often means grooming
young people who can bring energy, dynamism and
hard work to the station.
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Chapter 9
In this chapter, we'll see the entire CR guidelines issued by the Govt. of
India when it permitted the setting up of CR stations in November 2006.
While a large portion of the guidelines are not related specifically to the
technology of community radio, there are a few clauses that do specify
certain parameters that have to be followed. Use this entire text as a reference
for the guidelines and for the application procedure. The sections that
have technological implications have notes inserted to explain and clarify
what the implications are.
Policy Guidelines for setting up Community Radio Stations in
In December 2002, the Government of India approved a policy for the grant
of licenses for setting up of Community Radio Stations to well established
educational institutions including IITs/IIMs.
The matter has been reconsidered and the Government has now decided to
broad base the policy by bringing 'Non-profit' organisations like civil society
and voluntary organisations etc under its ambit in order to allow greater
participation by the civil society on issues relating to development & social
change. The detailed policy guidelines in this regard is given below:
1. Basic Principles
An organisation desirous of operating a Community Radio Station (CRS)
must be able to satisfy and adhere to the following principles:
a) It should be explicitly constituted as a 'non-profit' organisation and should
have a proven record of at least three years of service to the local
b) The CRS to be operated by it should be designed to serve a specific
well-defined local community.
c) It should have an ownership and management structure that is reflective
of the community that the CRS seeks to serve.
d) Programmes for broadcast should be relevant to the educational,
developmental, social and cultural needs of the community.
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e) It must be a Legal Entity i.e. it should be registered (under the registration
of Societies Act or any other such act relevant to the purpose).
2. Eligibility Criteria
(i) The following types of organisations shall be eligible to apply for
Community Radio licences:
a) Community based organisations, which satisfy the basic principles
listed at para 1 above. These would include civil society and
voluntary organisations, State Agriculture Universities (SAUs), ICAR
institutions, Krishi Vigyan Kendras, Registered Societies and
Autonomous Bodies and Public Trusts registered under Societies
Act or any other such act relevant for the purpose. Registration at
the time of application should at least be three years old.
b) Educational institutions
(ii) The following shall not be eligible to run a CRS:
a) Individuals;
b) Political Parties and their affiliate organisations; [including students,
women's, trade unions and such other wings affiliated to these
c) Organisations operating with a motive to earn profit;
d) Organisations expressly banned by the Union and State
3. Selection Process & Processing of the applications
(a) Applications shall be invited by the Ministry of I&B once every year
through a national advertisement for establishment of Community
Radio Stations. However, eligible organisations and educational
institutions can apply during the intervening period between the
two advertisements also. The applicants shall be required to apply
in the prescribed application form along with a processing fee of
Rs.2500/- and the applications shall be processed in the following
i) Universities, Deemed Universities and Government run
educational institutions will have a single window clearance by
putting up cases before an inter-ministerial committee chaired by
Secretary (I&B) for approval. No separate clearance from MHA &
MHRD shall be necessary. Once the WPC Wing of the Ministry of
Communication & IT earmarks a frequency at the place requested
by the institution, a Letter of Intent (LOI) shall be issued.
ii) In case of all other applicants, including private educational
institutions, LOI shall be issued subject to receiving clearance
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from Ministries of Home Affairs, Defence & HRD (in case of
private educational institutions) and frequency allocation by
WPC wing of Ministry of Communication & IT.
The application for permission to set up a CRS is available on the Govt. of India's
Ministry of Information & Broadcasting's website (
CRSmainpg.htm). This is the CR related link, and contains detailed FAQs and
guidelines, as well as the status of applications pending with the Ministry.
The application requires the attachment of a variety of background documents that
prove the authenticity of your organization and its work within the community the
CRS will address. It also requires the completion of some proposed site related
data, and the attachment of a map on which you are expected to mark the site of the
CR station and antenna mast/tower. This can be a simple map, even hand drawn,
that gives a broad idea of the surrounding area and the location of your CRS.
The application must be filed with the office of the Under Secretary (FM) at the
Ministry for Information & Broadcasting.
(b) A time schedule for obtaining clearances as below shall be prescribed:
i) Within one month of receipt of the application in the prescribed
form, the Ministry of I&B shall process the application and either
communicate to the applicant deficiencies, if any, or will send the
copies of the application to the other Ministries for clearance as
prescribed in para 3(a)(i) and 3(a)(ii) above, as the case may be.
ii) The Ministries concerned shall communicate their clearance within
three months of receipt of the application. However, in the event
of the failure of the concerned ministry to grant the clearance
within the stipulated period of three months, the case shall be
referred to the Committee constituted under the Chairmanship of
Secretary (I&B) for a decision for issue of LOI.
The process of verification of the applicant's antecedents and background is
conducted through an Intelligence Bureau (IB) enquiry ordered by the Ministry
for Home Affairs, and through the local police department. This usually involves
a visit by an IB person, who may inspect your records and ask for various
background details regarding your operation, current projects and the details
included in your application form.
Subsequently, the authorized representative of the applying organization will
also be invited to make a presentation to a Community Radio screening committee
at the Information & Broadcasting Ministry's offices in New Delhi. The presentation
should give the background on the organization and the reasons for applying for
a CR license. This is usually followed by an interview/question-and-answer
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session where you may be asked detailed questions regarding your application
and the need for a CR station in your area for the proposed community. The
panel for the screening committee is composed of civil society representatives as
well as government representatives.
iii) In the event of more than one applicant for a single frequency at a
given place, the successful applicant will be selected for issue of LOI
from amongst the applicants by the Committee constituted under the
Chairmanship of Secretary (I&B) on the basis of their standing in the
community, the commitment shown, the objectives enunciated and
resources likely to be mobilized by the applicant organisation as well
as its credentials and number of years of community service rendered
by the organisation.
iv) Within one month of the issue of the Letter of Intent (LOI) the eligible
applicant will be required to apply, in the prescribed format and with the
requisite fee, to the WPC Wing of the Ministry of Communication & IT,
Sanchar Bhawan, New Delhi for frequency allocation & SACFA clearance.
One of the primary questions that CRS applicants need to ask themselves is when do we actually buy the equipment we need and set up the physical station
premises? The answer to that is: When you receive the Letter of Intent, because
once you receive this, your application is on reasonably safe ground. There is still
the chance that the WPC and SACFA clearance may not be forthcoming - see
below - but this is primarily a greater issue for CR stations in urban areas. To buy
equipment before the LoI is a distinct risk.
It also makes sense to start setting up your equipment and station at this point,
because officially, you are just 6 - 8 months from here to going to air: You are
expected to commence broadcast within 3 months of receiving the Grant of
Permission Agreement that follows WPC and SACFA clearance. That's usually
too short a period to set up, test and start using transmission equipment. Buying
equipment at the LoI stage gives you the time to do this properly.
Of course, this discussion assumes that activities like mobilizing the community
and establishing a volunteer based staff for the CRS are already complete or
ongoing - that is something you definitely will not be able to complete even if you
start those activities when you receive the LoI!
v) A time frame of six months from the date of application is prescribed for
issue of SACFA clearance. In the event of non-receipt of such clearance
from the Ministry of Communication & IT within the stipulated period of
six months, the case will be referred to the Committee constituted under
the Chairmanship of Secretary (I&B) for a decision.
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of Communications is the National Radio Regulatory Authority responsible for
Frequency Spectrum Management, including licensing and caters to the needs of
all wireless users (Government and Private) in the country. It exercises the statutory
functions of the Central Government and issues licenses to establish, maintain
and operate wireless stations. WPC is divided into major sections like Licensing
and Regulation (LR), New Technology Group (NTG) and Standing Advisory
Committee on Radio Frequency Allocation (SACFA). SACFA makes the
recommendations on major frequency allocation issues, formulation of the
frequency allocation plan, making recommendations on the various issues related
to International Telecom Union (ITU), sorting out of problems referred to the
committee by various wireless users, and issuing siting clearance of all wireless
installations in the country.
Based on WPC records, official policy and existing stations and plans for future
expansion, these bodies decide whether your application for a transmitter of a
particular strength and a mast of a particular height can be permitted - especially
in cases where more than one CRS may be set up to address different communities
within overlapping or congruous geographical areas. WPC also decides whether
your transmitter meets specifications as per the ITU-R broadcast guidelines and is
responsible for the allocation of your station's frequency.
It may be wise to remember that the WPC can also decide to reduce the power
of your station in order to prevent overlaps with other stations nearby, and to
refuse frequency allocation altogether if too many stations have been set up
already in your proposed geographical area of work. (This issue is set to become
extremely acute in the near future in urban and peri-urban areas, where commercial
and campus FM radio stations have already been allocated a number of stations
and frequencies, leaving little space for new CR stations.)
SACFA clearance applications can ONLY be filed online on the WPC website The process involves registering yourself as a user and
logging in with your user identity and password; completing the form (which
includes details regarding the fee that has to be paid by Demand Draft to WPC,
so it's a good idea to make the DD before you sit down to apply!); getting an
online application number; and submitting a hard copy of the completed
application along with the fee demand draft to WPC. Details are given on the
WPC website itself, including a step-by-step guide for applying parties. The
website can also be used to track the status of your application at any given point
in time.
The SACFA clearance application also involves the submission of a second map
of the geographical area where the proposed station will be located, clearly
indicating the station's own location within this area. The primary consideration
for this map is that there should be latitude and longitude markings on it that help
to identify the precise position of the CRS. While a Survey of India map is ideal for
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this purpose, it is likely to be expensive and may not be easy to access for
everyone. The WPC is therefore willing to accept even commercially available
maps in the 1:100,000 or better (1:50000) scale - the more the detail, the better
- with latitude and longitude marked on the map by a qualified geographer or
WPC is also responsible for deciding the spectrum usage fee for each station, a fee
levied by the Govt. of India for the right to use specific bands of the radio
spectrum for broadcasting. While there has been much debate on this with
regard to CR stations, this is a necessary reality that you will have to plan for: A
100 Watt ERP transmission system in the plains area, with a reach of 5 - 12 kms
is likely to pay an annual fee of Rs.19700 to the DoT for spectrum usage.
Remember that just because the guidelines mention 100W ERP transmission with a possibility of 250W ERP setups in certain geographical conditions - and a
30 metre mast, it doesn't necessarily mean you have to apply for the maximum
possible: If your coverage area crosses the 25 km range, the annual spectrum fee
becomes approximately Rs.36000!
vi) On receipt of SACFA clearance (a copy of which shall be submitted
by the applicant), the LOI holder shall furnish a bank guarantee in
the prescribed format for a sum of Rs.25, 000/-. Thereupon, the LOI
holder will be invited to sign a Grant of Permission Agreement
(GOPA) by Ministry of I&B, which will enable him to seek Wireless
Operating License (WOL) from the WPC Wing of the Ministry of
Communication & IT. The Community Radio Station can be made
operational only after the receipt of WOL from the Ministry of
Communication & IT.
vii) Within three months of receipt of all clearances i.e signing of GOPA,
the Permission Holder shall set up the Community Radio Station
and shall intimate the date of commissioning of the Community
Radio Station to the Ministry of I&B.
viii) Failure to comply with time schedule prescribed above shall make
the LOI/GOPA holder liable for cancellation of its LOI/GOPA and
forfeiture of the Bank Guarantee.
4. Grant of Permission Agreement conditions
The Grant of Permission Agreement period shall be for five years.
The Grant of Permission Agreement and the Permission letter will be
iii) No permission fee shall be levied on the Permission Holder.
However, the Permission Holder will be required to pay the
spectrum usage fee to WPC wing of Ministry of Communication
& IT.
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iv) In case the Permission Holder does not commence his broadcasting
operations within three months of the receipt of all clearances or
shuts down broadcasting activity for more than 3 months after
commencement of operation, its Permission is liable to be cancelled
and the frequency allotted to the next eligible applicant.
An applicant/organisation shall not be granted more than one
Permission for CRS operation at one or more places.
vi) The LOI Holder shall furnish a bank guarantee for a sum of Rs.25,000/(Rupees twenty five thousand) only to ensure timely performance of
the Permission Agreement.
vii) If the Permission Holder fails to commission service within the
stipulated period, he shall forfeit the amount of bank guarantee to
the Government and the Government would be free to cancel the
Permission issued to him.
5. Content regulation & monitoring
i) The programmes should be of immediate relevance to the community.
The emphasis should be on developmental, agricultural, health,
educational, environmental, social welfare, community development
and cultural programmes. The programming should reflect the special
interests and needs of the local community.
ii) At least 50% of content shall be generated with the participation of
the local community, for which the station has been set up.
iii) Programmes should preferably be in the local language and dialect(s).
iv) The Permission Holder shall have to adhere to the provisions of the
Programme and Advertising Code as prescribed for All India Radio.
The Permission Holder shall preserve all programmes broadcast by
the CRS for three months from the date of broadcast.
As discussed previously in the manual, this clause refers to the mandatory
requirement that every CRS preserve recordings of its broadcasts over the 3
months preceding any given day of operation.
This means we have to record our broadcasts on a continual basis, with recordings
older than 3 months junked or erased simultaneously to make space for new
Thus, if today is the 1st of June, at this point in time, we will have to be in
possession of broadcast recordings from the 1st of March onwards, so that we
have three complete months of programmes - March, April and May - on file.
Tomorrow, on the 2nd June, we can erase programmes recorded on the 1st of
March, as the three month clause means we need to have recordings starting on
the 2nd of March.
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The three month archiving system is mandated in order for the government - or
any mandated authority vested with the power of investigating complaints against
the programming generated by the CR station - to be able to call for and listen to
a copy of the programme in question. (If programmes are not preserved, they
would be broadcast and would then be lost forever, making such a process of
investigation and adjudication impossible.) The implications for the CRS of this
clause are that it has to set up an efficient archiving system that records the on air
broadcast and preserves it on a storage medium that will not call for too much
physical space.
At its simplest, the on-air programming can be recorded on cassette tape, clearly
marked with day and date, and stored in a 'library' - which essentially needs to be
no more than a cupboard that can store a reasonably large number of tapes. (At
60 minutes per tape, make an estimation of the number of tapes that will mean:
Even two hours of programming a day means 2 hours/2 tapes x 30 days x 3
months = 180 tapes!)
Modern digital audio - if the CRS can afford it - can make this process less
cumbersome, as digital storage essentially means recording on air programming
directly onto a hard disk. Compression technology allows us to store good quality
audio in relatively little space, and hard disks are becoming cheaper every day.
So a single 500 Gigabyte hard disk should comfortably store nearly
500 x 1000 = 500000 minutes of broadcast quality programming: More than
8000 hours of programming!
Of course, the thing to remember with such a dedicated archiving computer is that
there should be provisions to regularly back up the material that it is recording, so
that a single system failure does not wipe out a large quantity of programming. This
is especially significant assuming that you want to go beyond the three month
regulation and store programming on an ongoing basis. (This is not required under
the guidelines, but is good practice as a CRS, since you may reuse programming
later, and be able to share it with other CR stations, with or without compensation.)
It is therefore a good idea to equip such a system with a DVD writer, so that
accumulated programming can be written to DVDs at intervals, and preserved
off-system. DVDs don't take up much space in their slim cases, and if treated well,
can be a long term storage method.
vi) The Permission Holder shall not broadcast any programmes, which
relate to news and current affairs and are otherwise political in nature.
vii) The Permission Holder shall ensure that nothing is included in the
programmes broadcast which:
a. Offends against good taste or decency;
b. Contains criticism of friendly countries;
c. Contains attack on religions or communities or visuals or words
contemptuous of religious groups or which either promote or result
in promoting communal discontent or disharmony;
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d. Contains anything obscene, defamatory, deliberate, false and
suggestive innuendoes and half truths;
e. Is likely to encourage or incite violence or contains anything against
maintenance of law and order or which promote-anti-national
Contains anything amounting to contempt of court or anything
affecting the integrity of the Nation;
g. Contains aspersions against the dignity of the President/Vice
President and the Judiciary;
h. Criticises, maligns or slanders any individual in person or certain
groups, segments of social, public and moral life of the country;
Encourages superstition or blind belief;
Denigrates women;
k. Denigrates children.
l. May present/depict/suggest as desirable the use of drugs including
alcohol, narcotics and tobacco or may stereotype, incite, vilify or
perpetuate hatred against or attempt to demean any person or group
on the basis of ethnicity, nationality, race, gender, sexual preference,
religion, age or physical or mental disability.
viii) The Permission Holder shall ensure that due care is taken with
respect to religious programmes with a view to avoid:
a) Exploitation of religious susceptibilities; and
b) Committing offence to the religious views and beliefs of those
belonging to a particular religion or religious denomination.
6. Imposition of penalty/revocation of Permission Agreement
In case there is any violation of conditions cited in 5(i) to 5(viii),
Government may suo motto or on basis of complaints take
cognisance and place the matter before the Inter-ministerial
Committees on Programme and Advertising Codes for
recommending appropriate penalties. On the recommendation of
the Committee a decision to impose penalties shall be taken.
However, before the imposition of a penalty the Permission Holder
shall be given an opportunity to represent its case.
The penalty shall comprise of:
(a) Temporary suspension of Permission for operating the CRS for a
period up to one month in the case of the first violation
(b) Temporary suspension of Permission for operating the CRS for a
period up to three months in the case of the second violation
depending on the gravity of violation.
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(c) Revocation of the Permission for any subsequent violation.
Besides, the Permission Holder and its principal members shall
be liable for all actions under IPC, CrPC and other laws.
(iii) In case of revocation of Permission, the Permission Holder will not
be eligible to apply directly or indirectly for a fresh permission in
future for a period of five years.
"Provided the penalty imposed as per above provision shall be
without prejudice to any penal action under applicable laws
including the Indian Telegraph Act 1885 and Indian Wireless
Telegraphy Act 1933, as modified from time to time."
(iv) In the event of suspension of permission as mentioned in para 6 (ii)
(a) & (b), the permission holder will continue to discharge its
obligations under the Grant of Permission Agreement during the
suspension period also.
7. Transmitter Power and Range
CRS shall be expected to cover a range of 5-10 km. For this, a
transmitter having maximum Effective Radiated Power (ERP) of 100
W would be adequate. However, in case of a proven need where the
applicant organisation is able to establish that it needs to serve a
larger area or the terrain so warrants, higher transmitter wattage with
maximum ERP up to 250 Watts can be considered on a case-to-case
basis, subject to availability of frequency and such other clearances
as necessary from the Ministry of Communication & IT. Requests for
higher transmitter power above 100 Watts and upto 250 Watts shall
also be subject to approval by the Committee constituted under the
Chairmanship of Secretary, Ministry of Information & Broadcasting.
The strength of a transmitter, like the power in an electrical circuit, is measured
in Watts. Essentially, this refers to the amount of electrical energy that it converts
to radio wave (or electromagnetic) energy. Thus, a 30 Watt transmitter would
consume a little more than 30 Watts of electricity - there is some internal loss in
the system, and the conversion is not 100% efficient - and give an output of
roughly 30 Watts worth of electromagnetic energy.
However, it is important to remember that just the transmitter's output does not
tell us the station's output strength, because the actual strength - or Effective
Radiated Power, ERP - is a combination of the transmitter's strength and the
amount this is magnified by the antenna we use. (The magnification is called
'gain', and this is a natural property of the antenna based on the materials it is
constructed out of and its physical structure and shape. It is also directional in
nature, with the gain - and therefore the ERP - varying at different points with
reference to the antenna.)
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Essentially, this means that the sum total of the two - the net strength of our
station, as it were - must be a maximum of 100 Watts, with 250 Watts allowed
in geographically difficult areas. Practically, this means if we select the correct
combination of transmitter and antenna, our actual transmitter strength can be as
low as 30 Watts, since gains of 3x (3 times the transmitter strength) are easily
achievable through many antennae.
At the same time, we must factor in losses of signal strength caused by the cables
connecting the studio to the transmitter, and the transmitter the antenna, which
can also be an important consideration, especially if the transmitter has to be
located at a little distance from the studio.
As noted earlier, please be aware that these are merely wattages and limits
specified by the Govt. guidelines - whether you actually are allowed a transmitter
of a specific output, or a mast of a particular height is dependent on WPC and
SACFA clearance, as seen above.
ii) The maximum height of antenna permitted above the ground for the
CRS shall not exceed 30 meters. However, minimum height of
Antenna above ground should be at least 15 meters to prevent
possibility of biological hazards of RF radiation.
As discussed earlier in the manual, keeping the antenna high off the ground not
only prevents it from being accidentally obstructed, but also gives the antenna a
vantage point from which it can broadcast over a larger area.
This clause states that the metal pole or antenna tower on which the antenna is
mounted for this purpose - the antenna unit itself is only a couple of feet long in
most cases - can be a maximum of 30 metres high. It also states that the antenna
must be at least 15 metres off the ground to safeguard against any radiation
hazards caused by the electromagnetic energy emanating from it.
What you must remember is that this in no way restricts you from installing the
antenna on a hillock or mountain overlooking your potential broadcast area as
long as this falls within the space where your listener community resides, and
considerations of equipment and studio location allow this (see the section on
Studio Transmitter Links). Thus, even with the height restriction this clause imposes,
you can actually get a much larger broadcast area if you can exploit some natural
formations in your geographical area.
It is also a good idea to take advantage of building height if possible: If you install
a 15 metre antenna on a 15 metre building, remember that you are actually
getting the advantage of a 30 metre height with half the actual mast length.
iii) Universities, Deemed Universities and other educational institutions
shall be permitted to locate their transmitters and antennae only within
their main campuses
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iv) For NGOs and others, the transmitter and antenna shall be located
within the geographical area of the community they seek to serve.
The geographical area (including the names of villages/institution
etc) should be clearly spelt out along with the location of the transmitter
and antenna in the application form.
Taking off from the point above, this clause specifies that you cannot install your
antenna mast or tower on any convenient location just because it affords you a
bigger broadcast area: It has to be in an area that falls within the space occupied
by your potential listener community. In hilly regions, of course, the population
may be sparse, and distributed up and down valleys or both sides of a hill or
mountain. In such cases, we have relatively greater flexibility to decide the best
placement of the antenna tower, as the definition of what constitutes the listener
community's geographical area is rather hard to define exactly.
8. Funding & Sustenance
Applicants will be eligible to seek funding from multilateral aid
agencies. Applicants seeking foreign funds for setting up the CRS will
have to obtain FCRA clearance under Foreign Contribution Regulation
Act, 1976.
Please remember that this means if you access funding from a donor agency to
purchase equipment and/or set up your CR station, the wording of the policy
suggests that funding can only be obtained through UN agencies or international
aid agencies that are not part of the bilateral government-to-government aid
Also, this means that accessing funds - whether in cash or in equipment form - is
governed by Foreign Currency Regulation Act norms. If your organization does
not have permanent registration with the FCRA authorities, it may have to apply
for 'prior permission' clearance for the funds or in kind assistance that it hopes to
access. This process takes time, and must be factored in when planning the
station setup and/or equipment purchases. Consult a good chartered accountant
to figure out this process if you think you need help on this.
Note that United Nations funding is not governed by FCRA regulations.
Transmission of sponsored programmes shall not be permitted
except programmes sponsored by Central & State Governments and
other organisations to broadcast public interest information. In
addition, limited advertising and announcements relating to local
events, local businesses and services and employment opportunities
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shall be allowed. The maximum duration of such limited
advertising will be restricted to 5 (Five) minutes per hour of
iii) Revenue generated from advertisement and announcements as
per Para 8 (ii) shall be utilized only for the operational expenses
and capital expenditure of the CRS. After meeting the full financial
needs of the CRS, surplus may, with prior written permission of
the Ministry of Information & Broadcasting, be ploughed into
the primary activity of the organization i.e. for education in case
of educational institutions and for furthering the primary
objectives for which the NGO concerned was established.
9. Other Terms & Conditions
The basic objective of the Community Radio broadcasting would
be to serve the cause of the community in the service area of the
Permission Holder by involving members of the community in
the broadcast of their programmes. For this purpose community
shall mean people living in the zone of the coverage of the
broadcasting service of the Permission Holder. Each applicant
will have to specify the geographical community or the
community of interest it wants to cover.
The Permission Holder shall provide the services of his CRS on
free-to-air basis.
Though the Permission Holder will operate the service under
these guidelines and as per the terms and conditions of the
Grant of Permission Agreement signed, the permission shall
be subject to the condition that as and when any regulatory
authority to regulate and monitor the broadcast services in the
country is constituted, the permission holder will adhere to the
norms, rules and regulations prescribed by such authority from
time to time.
iv) The Permission Holder shall provide such information to the
Government on such intervals, as may be required. In this
connection, the Permission Holder is required to preserve
recording of programmes broadcast during the previous three
months failing which Permission Agreement is liable to be revoked.
See notes on Clause 5 (V)
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The Government or its authorized representative shall have the right
to inspect the broadcast facilities of the Permission Holder and collect
such information as considered necessary in public and community
vi) The Government reserves the right to take over the entire services
and networks of the Permission Holder or revoke/terminate/suspend
the Permission in the interest of national security or in the event of
national emergency/ war or low intensity conflict or under similar
type of situations.
vii) All foreign personnel likely to be deployed by way of appointment,
contract, consultancy etc by the Permission Holder for installation,
maintenance and operation of the Permission Holder's services shall
be required to obtain prior security clearance from Government of
viii) The Government reserves the right to modify, at any time, the terms
and conditions if it is necessary to do so, in public interest or for the
proper conduct of broadcasting or for security considerations.
ix) Notwithstanding anything contained anywhere else in the Grant of
Permission Agreement, the Government shall have the power to
direct the permission holder to broadcast any special message as
may be considered desirable to meet any contingency arising out of
natural emergency, or public interest or natural disaster and the like,
and the Permission holder shall be obliged to comply with such
The permission holder shall be required to submit their audited
annual accounts to the Government in respect of the organization/
division running the CRS. The accounts shall clearly show the income
and expenditure incurred and the Assets and Liabilities in respect of
the CRS.
xi) A Permission Agreement will be subject to such other conditions as
may be determined by the Government.
xii) The Government shall make special arrangements for monitoring
and enforcement of the ceiling on advertisements, particularly in
those areas where private FM radio stations have been granted
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Section B
Detailed notes on equipment
& audio concepts
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PART B: Detailed notes on equipment & audio concepts
Analog & Digital Audio ...................................................................... 124
Amplifiers .......................................................................................... 128
Balanced and Unbalanced Connections ............................................ 131
Cassette Tapes & Cassette Recorders .................................................. 134
Compact Discs ................................................................................... 138
Compact Disc Players ........................................................................ 141
Compact Disc Writers (CD Writers) .................................................... 145
Compressor / Limiters ........................................................................ 149
Computer Hardware .......................................................................... 152
Computer Software (For Radio) ........................................................... 159
Connectors (Power) ........................................................................... 163
Connectors (Audio & Telecom) .......................................................... 166
Decibels ............................................................................................. 172
Digital Playout Systems ...................................................................... 173
(Audio) Effects .................................................................................... 175
Electromagnetic Spectrum .................................................................. 177
Equalizers .......................................................................................... 179
(Acoustic) Feedback ........................................................................... 182
Field Recorders .................................................................................. 184
Flash Recorders ................................................................................. 187
Loudspeakers & Studio Monitors ....................................................... 190
Magnetic Recording ........................................................................... 193
Meters & Audio Level Measurement .................................................. 195
Microphones ..................................................................................... 198
Minidiscs & Minidisc Recorders ......................................................... 204
Mixers & Mixing Desks ...................................................................... 207
Modulation ........................................................................................ 209
Patchbays .......................................................................................... 212
Signal to Noise Ratio .......................................................................... 214
Sound & Audio .................................................................................. 215
Stereo & Mono .................................................................................. 217
Telephone Hybrids ............................................................................ 220
Transmitters ....................................................................................... 222
Uninterrupted Power Supply (UPS) .................................................... 224
Generators ......................................................................................... 229
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Sound travels as a series of waves - that is, as a continuous rise and fall in the
pressure of the air at a given point in space. When we speak, our vocal
chords vibrate at various frequencies, creating corresponding vibrations in
the air around them. These vibrations - waves - are then transmitted by the
particles that make up air, and the vibrations are passed along till they reach
someone else's ears…or a microphone that is designed to pick up these
For more on microphones, see Section B: Microphones on Page 198
Analog Audio
The microphone, in turn, converts these vibrations into an electrical signal,
that rises and falls in exact correspondence with the rises and falls in the
sound wave that is reaching the microphone. If the signal is then recorded
on magnetic tape, what we have thus far is a process where a continuous
wave or signal - even if it is changing from sound energy to electrical energy
and stored as an arrangement of magnetic particles - is being preserved
throughout the entire process. Since in each case, we have a signal that is
analogous to the original sound wave that was produced, such signals are
called analog signals.
Volt +
Changing voltage
signal in response
Input Signal
Volt –
Fig 1: An analog signal produced by a microphone in response to a
continuously changing sound
Digital audio
As technology progressed, however, new ways to store information became
available. One such technology was digital storage, where information of
any kind - visual, audio, or a combination of both - could be stored as a
series of numbers, which together represented the original information. The
information was stored usually in combinations of ones and zeros, a system
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of mathematics called binary numbers. (In fact, the fact that the storage was
in the form of numeral digits was why it began to be called digital storage in
the first place!)
Digital signals and storage offer us vast advantages over the older analog
1. Digital signals can be stored more economically than analog signals
can. An LP or long playing record could store about a half hour's worth
of music per side. Today, a small digital music player the size of a
matchbox can store ten times as much.
2. Digital signals can also be manipulated more easily than analog signals,
both in terms of clearing out unwanted components, and in terms of
making changes to the signals.
3. Digital signals can also be copied and duplicated more easily: There is
no deterioration of the signal across copies, unlike what used to happen
with analog storage methods. This also applies to transmission of the
signal through cables or broadcast, where analog signals invariably pick
up some noise, but digital signals do not by virtue of the way the
information is carried in both cases.
Where audio was concerned, this presents a plethora of options, with high
quality audio becoming easily accessible to everyone: The first item of digital
audio to make it to the market was the compact disc or CD, which stores
digital data on a spinning disc of plastic encased metal.
For more on compact discs, see Section B: Compact Discs on Page 138 and
Section B: CD Writers on Page 145
Increasingly, audio recording - professional or for personal use, large radio
station or community radio station - relies on digital audio equipment.
Computers store information digitally, as do CDs, VCDs and DVDs. However,
there is a downside to using digital technology; and that has to do with the
way analog sound is converted to a digital signal by the digital sound
equipment we use.
A/D conversion
We have already seen that a sound, when it originates, is a continuously
rising and falling wave, and hence analog in nature. To convert analog
sound into a digital signal, there has to be a process where we convert the
characteristics of the sound wave into a set of equivalent numbers that
describes the wave. This process is called Analog to Digital (or A/D)
conversion, and the first step in this is called sampling.
Sampling is essentially the process of dividing the original wave up into a
series of smaller slices. Obviously, it is easier to describe each slice more
accurately than one can describe the wave as a whole. And if we then have
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Volt +
Each dot represents
a 'snapshot' or
sample of the wave
Volt –
Fig 2: Analog to Digital sampling
a description of the value of each slice (as an equivalent number), and a
description of that number's position in the overall list of numbers describing
the wave, it is fairly straightforward to reconstruct the original wave from
these descriptions.
The figure above shows the original wave, and slices we have made. We
can reconstruct the wave by joining the samples (dots) that we have created.
The reconstructed wave is not totally an accurate copy - it is more jagged
than the original. This is the negative side of digital technology. A/D conversion
is essentially a matter of approximation: The slices only give you an idea of
what the original analog signal was like. However, this is becoming rapidly
less of a drawback, as modern technology is using higher and higher
sampling rates to make finer and finer slices of the original signal. If we can
make the samples/slices much finer, the wave we can reconstruct from this
information becomes closer and closer in shape to the original analog wave.
It is generally accepted that if the sampling rate is twice the highest frequency
wave in the audio signal, the results of sampling will be indistinguishable to
the human ear from the original analog sound wave. This is why digital
audio on CDs are sampled at 44100 Hertz (or 44100 samples per second,
44.1 KiloHertz or KHz) - because the highest frequency detectable by the
human ear is 20000 Hz, and this is more than twice that. Digital video
recordings record sound at 48000 Hz, so their audio is a little higher in
quality. FM stations often sample the audio at 32 KHz, as the higher
frequencies - 16000 Hz and above - often get lost in the broadcast process,
and we need to be concerned with recording and reproducing audio only
upto that limit.
Data/Bit Rate
The other factor that controls the quality and accuracy of the digital signal is
the amount of information we can store about each of the samples/slices:
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The more information we store about each sample, the greater the accuracy
in reconstructing the original wave. In digital storage, each 1 or 0 that we use
is called a bit of information. CDs usually use 16 bit sampling - that is, 16 bits
to describe each sample. More recent pro audio equipment uses 24, 32, 48
or 96 bit sampling, leading to ever more accurate storage and retrieval.
D/A Conversion
Once the audio is stored in a digital format, we need equipment and
techniques to convert it back into the original analog sound as well. The CD
players, DVD players and MP3 music players that we see all around us
today - including the music players built into many mobile phones - perform
just this function: They convert the digital signal back into the analog signal,
a process known as D/A conversion. This is the exact reverse of the sampling
As noted previously, both the sampling and the D/A conversion process
involve some loss of audio information. Some people can be sensitive to
this loss, and can 'feel' the difference between the digital version and the
analog version of the same audio recording. But increasingly, as digital
audio equipment improves, even low cost consumer grade equipment can
give you a high enough grade of storage and reproduction to satisfy the vast
majority of listeners.
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The first step in recording and storing audio - and in sending it over cables
or any other kind of link between pieces of equipment - is to convert the
sound waves into electrical energy.
The electrical signal that is generated by transduction devices like
microphones is actually a very tiny current - so small, in fact, that you will not
even notice it is there if it weren't for the sensitive instruments and devices
we use to monitor, interpret and store it. In order to be able to effectively
store and manipulate the sound, we need to be able to raise and lower its
level - that is, make the electrical signal stronger or weaker, and thereby the
sound louder or softer.
This is achieved with a device called the amplifier. The word 'amplify'
means to increase; and this, indeed, is the primary function of an amplifier:
To increase the magnitude or size of the signal.
Gain is a measure of the amount by which an amplifier increases the size of
the electrical signal. It is measured as the ratio between the strength of the
output signal to the strength of the input signal. (A gain of 2, for example,
shows that the output signal is twice as strong as the input signal.)
The level or strength of an audio signal is measured in deciBels (dB); and
looked at another way, a gain of 2 can also be seen as an increase of 3
decibels (3dB).
Fig 3: How an amplifier increases the level of an input signal.
Types of amplifiers
Amplifiers are one of the most essential components in a variety of audio
processing situations, which makes them of special significance when we
discuss their use in radio broadcasting.
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1. Power amplifiers
Power amplifiers are used whenever we need to raise the strength of the
signal high enough to drive a speaker: The larger the speaker, the larger the
output required of the power amplifier…and consequently the greater the
gain required of the power amplifier. Power amplifiers are often used in live
sound situations - concerts, for instance - because the speakers required for
the sound to reach a large gathering are very large.
Power amplifiers may or may not have controls of their own, though they
commonly have a knob that allows you to control the gain (output). They
also usually have connectors for a pair of speakers, and may accept a variety
of connector types depending on the specific use they are meant for.
In the radio studio, the power amplifier is usually used to feed the studio
monitor speakers. Most often, it is controlled from the mixing desk itself,
with the faders of the mixer used to adjust the input (and thereby the output)
of the amplifier.
2. Distribution amplifiers
The distribution amplifier (DA) is a type of amplifier used to keep the strength
of the signal constant across a large number of outputs when a single
source must feed multiple devices. Just as the pressure of water in a water
pipe decreases if it is connected to too many taps, the strength of a signal in
the system will fall if the same signal must be given to multiple outputs.
In the radio studio, there are usually a number of different pieces of equipment
- and they may all need to be fed the output from a single mixer. (The same
mixer may also give an output for the production studio, if the mixer in
question is in the broadcast studio - and indeed, even to the voice booth or
recording floor.) This means the signal will be greatly diminished if we just
split it up electronically and try to feed it to all these devices. This is where
the distribution amplifier comes in: The mixer output is fed to the DA, which
boosts the strength of the input signal, and feeds it to a number of outputs and thereby solving our problem of lowered signal strength.
In the radio studio, DAs typically have stereo inputs and a number of stereo
outputs - often 8 outputs or more - which can then be connected to stereo
recording devices and the transmission system. A low cost option would be
to keep the entire system mono, and have a DA that has mono inputs and
outputs; but these are comparatively rare as an option, since there is very
little difference in price for such a setup.
3. Headphone amplifiers
A headphone amplifier is a specialized type of distribution amplifier that is
used to connect more than one headphone to the same output.
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When a programme is being made, or a transmission is taking place, more
than one person will often need to listen to the audio output at the same
time. Connecting multiple headphones to the same headphone socket would
lead to the same situation we saw above: A weak signal that cannot be heard
properly over any of the headphones. A headphone amplifier solves this by
keeping the output to each pair of headphones constant.
Headphone amplifiers are often used in on air studios and on recording
floors where each of the guests/speakers may be required to have a pair of
For more on headphones, see Section B: Loudspeakers & Studio Monitors
on Page 190
4. Pre-amplifiers
Pre-amplifiers are used to boost the tiny output signals that emerge from
many audio devices: Microphones, for instance, have outputs that are hardly
a few microvolts strong. Pre-amplifiers boost these outputs to a level where
they can be fed to other audio devices.
For more on microphones, see Section B: Microphones on Page 198
In many field recorders and mixers, the pre-amplifier is built into the input
into which the microphone's output will be connected. It is important for the
pre-amplifier to be of good quality, since it boosts the microphone's signal
by a large amount (meaning it will also magnify any distortions by a large
factor); and because it is the first electronic signal processing unit in the
chain (and is therefore responsible for the quality of the signal that will be fed
to all parts of the chain of electronics that follows it). A good microphone
connected to a bad pre-amplifier can ruin any advantage and quality gained
by the quality of the microphone.
It must be noted that among pre-amplifiers, the ones used for LP players
(phonographs or turntables) are a specific subtype that cannot be connected
to any other variety of equipment.
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One of the issues with transferring weak audio signals over wires is that the
signals can be affected by any electromagnetic disturbances in the area. The
powerful electromagnetic noise generated by overhead electrical cables, a
nearby transformer field or even the Earth's own magnetic field can result in
annoying distortions of the audio, or crackle, noise or hum in the circuit.
Engineers have found a number of ways to protect the signal from these
disturbances, and chief among them is the concept of balanced and
unbalanced connectors.
Balanced connectors
Balanced connectors constitute a system that allows us to filter out unwanted
noise from the useful components of the signal.
The balanced connector system is composed of three wires: The hot and
cold wires, which both carry the signal; and a common screen wire. The
key to the entire system is that the hot and cold wires carry the same signal,
but with the polarity reversed or 'out of phase' - that is, with the peaks and
the troughs of the wave reversed, like this:
– A+n
Fig 4: A balanced connector system.
As the figure shows us, the combination of the out of phase signals, and the
fact that noise gets added to both wires equally allows us to output a signal
that is twice as strong (2A) as the basic input audio (A), even while we
manage to cancel out the noise (n).
Balanced connectors are found on all professional equipment - including
semi professional equipment nowadays. For the system to work properly,
the origin and receiving systems must both be balanced.
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Unbalanced connectors
Unbalanced connectors use a two wire system where the inner (hot)
conductor wire is surrounded by an outer wire, which is often in the form of
a mesh or shield that is designed to absorb unwanted electrical disturbances.
But since the system is not designed for a cancellation process like the
balanced system is, the noise cannot be filtered out of the system.
Owing to the effectives of the noise canceling system, balanced cables can
be as long as 500 metres or more with no loss in the quality of the signal they
carry. Unbalanced cables, on the other hand, have to be much shorter to
keep the amount of noise they pick up to a moderate level. This is why
balanced cables and connections are used in professional equipment, and
unbalanced in consumer equipment, since the latter tends to require much
shorter lengths of cable.
Balanced connections are also designed to carry a much higher signal level
(usually +4 dBm) than unbalanced connections (usually - 7.8dBm). There
are a number of equipment combinations and setups where we are required
to connect balanced and unbalanced equipment; and when a balanced
Fig 5 : Balanced connection wiring
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input is connected to unbalanced equipment, we must be careful while
amplifying the signal, since it is already at a level much higher than what the
unbalanced system was designed for . Conversely, an unbalanced connector
connected to a balanced input will actually be feeding it a signal that is too
low for what it is designed for.
In such situations, the solution is to use a piece of equipment called a
balancing amplifier, that converts balanced inputs to unbalanced and vice
versa. The illustrations in this section show a variety of balanced and
unbalanced connectors, and how the wires are connected.
For more on connectors, see Section B: Connectors (Audio & Telecom) on
Page 166
Fig 6 : Unbalanced connector wiring
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Almost everyone, even in the relatively remote parts of the country, has
heard audio played off a cassette player at some point in time. The cassette
recorder has been the standard for small radio stations around the world for
a long time; and though MiniDisc recorders and solid state flash memory
recorders have increasingly begun to replace them, they still remain a useful
part of the CR station's equipment list.
The cassette recorder is an analog audio recording system, and uses a
recording system which we refer to as magnetic recording. There are two
parts to any audio magnetic recording system:
the tape it uses as the storage medium.
the recorder, which also acts as the playback device
The Tape
Cassette tapes - and their predecessors, the spool or reel tape - are a typical
example of the media used in magnetic audio recording systems. The three
main features of the cassette tape are the tape box, the tape ribbon and the
plastic cassette.
The box is a plastic case, usually with a hinged top that you open to remove
the tape. The lid is often of clear plastic so that you can insert labels identifying
the tape, which can then be read without opening the box.
A typical audio cassette, also known as a compact
cassette. The tape ribbon is contained in a
transparent plastic shell.
The tape (often also referred to as the ribbon) is essentially a long strip of
plastic coated with a layer of magnetic particles. If you expose these magnetic
particles to a magnetic field, they are permanently magnetized by the field
until they are exposed to a fresh field. This is the property that magnetic
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recording utilizes to store the recording on the tape. This ability gives magnetic
tape two of its most appealing features:
Firstly you can record audio instantly and the tape will "remember" what
was recorded for playback.
Secondly you can erase the tape and record something else on it.
For more on magnetic recording, see Section B: Magnetic Recording on Page 193
Tape Type & Length
Cassettes are available in of various lengths. The ones most commonly sold
in shops are 60-minute or 90-minute cassettes. A 90-minute cassette has
135 meters of tape inside it, which runs at 1 7/8th inches per second in the
Cassettes are also usually available in three types of coatings. In increasing
order of audio quality, these are:
Ferric oxide, where the magnetic particles are actually particles of an
iron compound called ferric oxide. This is the most common type, and
the kind most cassette recorders can record on
Chrome, where particles of chromium dioxide are mixed in with the
ferric oxide
Metal tape, which uses particles of pure metal rather than an oxide
Metal tapes can be played back on all cassette players, but can only be
recorded on recorders which have a special setting for metal tapes. Most
professional cassette recorders will have a small switch that lets you shift
between 'Normal' (Ferric Oxide), 'Chrome' and 'Metal' settings
The Cassette
The cassette is a fairly simple protective covering and case for the tape.
In cassettes, the tape is usually attached to and wound around two plastic
cores, two rollers and the plastic outer shell that protects the tape. (In spool
tapes, the tape ribbon is loose, and is physically wound around the core of
a plastic spool by the user.) There is also a small felt pad that keeps the tape
pressed against the the record/playback head in the tape player.
The cassette also has two protective tabs on top. When these tabs are
broken off, you can no longer record on the tape. Use a pen or something
similar to gently break the tabs when necessary. If you have broken these
tabs, but want to record onto the cassette again, you can cover the holes you
have made by covering the tab slots with two small pieces of sticky tape. Be
sure that the tape is securely stuck down, so that it cannot come loose while
inside the cassette recorder.
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Things to remember when using cassette tapes and recorders
The relatively poor quality compared to CD and reel-to-reel, and lack of editing
facility, mean many broadcasters believe cassettes are not appropriate for
regular use. Nevertheless, the cassette tape's small size and the almost universal
access to cassette tape decks in studios make it a very useful medium.
Because the tape is contained inside the cassette, compact cassettes are very
robust. However to protect your recordings, you should handle tapes with care.
Keep cassettes in their cases when not in use.
Keep tapes away from magnetic fields. The tape is a magnetic medium,
so exposing the tape to a strong magnetic field will affect the stored
sound. In the studio, computer screens and loudspeakers often have
strong magnetic fields. So leaving tapes near the computer, or on top of
a loudspeaker, is not good practice.
Always label the cassettes you are using. A fresh blank tape usually
includes a labelling sheet. People finding unlabelled cassettes lying
around in the studio may record over them, and you may lose important
sound that you will never be able to record again. Another reason is that
you may lose your cassette and it will take time to listen to a whole lot of
unmarked or poorly marked tapes to find the sound you need. Ensure
that labels and stickers identifying tapes are not loose or peeling off. The
labels can cause the tape to get stuck in the tape deck and will damage
the machine.
Most tape decks have an unbalanced stereo output, although some more
expensive broadcast tape decks have a balanced stereo output. RCA
connectors are usually used for the unbalanced output. The left and right
channels are usually colour coded, with red indicating right, and white left.
These outputs are connected to the tape channel inputs on the mixing desk.
In some instances these can be passed through a balancing amplifier before
being connected to the mixer. In some studios they may also be connected
to the studio patch panel.
Most cassette recorders and decks also have a stereo input for recording.
Again this is most often through unbalanced RCA connectors or phono
connectors. The tape deck is usually fed with audio directly from the
recording bus of the mixing desk, or via a distribution amplifier connected
to the recording bus. Some broadcast tape decks have a control input that
allows the tape-deck to be controlled from the mixer.
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Cleaning & Maintenance of cassette recorders
On the whole, however, tape recorders needs very little
maintenance. The most important thing to remember is to clean
tape heads and the compartment.
The tape heads should ideally be cleaned after every five hours
of use. To clean the heads, take a cotton wool earbud and
cleaning alcohol such as surgical spirits. Both earbuds and
surgical spirit are available from most pharmacies. After shave
lotion will work in an emergency.
Dip the earbud into the spirit so that it is moist but not dripping
wet. Then gently rub the earbud over the heads in the tape deck.
Avoid touching the plastic and rubber parts of the device with
the spirit.
The main dirt that collects in the compartment will be dust and
fluff. It is difficult to avoid getting dust in the compartment, but
you can minimise the problem by keeping the compartment
closed when not in use and by regularly cleaning the studio.
If you see any bits of fluff or other dirt, gently pull them out using
a pair of tweezers.
Most tape decks come with a noise reduction system to minimise
unwanted noise during recording and playback. Dolby Noise
Reduction is the most common system. Using the Dolby system
properly will improve tape sound quality. For the best results, a
recording made using a noise reduction system must be played
back using the same system. If your station chooses to use noise
reduction, then all the tape decks in the station need to be set to
use the same noise reduction system.
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The compact disc is a digital audio medium. The disc stores stereo 16-bit
audio sampled at 44.1 KHz. As an industry specification developed when
CDs were invented, CDs can record 74 minutes 33 seconds of audio at this
quality, although many newer CDs store up to 80 minutes. In terns of the
amount of digital data that can be stored on a CD, this translates to 650
Megabytes (MBs) of information (700 MB for newer CDs).
Prerecorded audio CDs contain audio items such as songs organised into
tracks, with each track identified by a track number. However, CDs can also
contain digital data of other kinds, in which case they may be seen as files,
much as you can see them on a computer's hard disk. If the CD contain
audio in other digital audio formats like mp3 or wav, this audio data will not
be seen as tracks, but as data files.
A CD is only 120mm (millimetres) in diameter and about 1.2 mm thick. Most
of a CD consists of a piece of clear polycarbonate plastic. During
manufacturing, this plastic is impressed with microscopic bumps, arranged
as a single, continuous, extremely long spiral track of data. These bumps
mark the binary numbers, that is, the 1's and 0's (bits), which make up the
digital audio on the disc. In the case of a data CD that is used in a computer,
the bumps mark the bits that make up the data files stored on the CD. In all
other respects it works in exactly the same way.
Once the clear piece of polycarbonate is formed, it is covered with a
thin, reflective aluminium layer. A thin acrylic layer is then sprayed over
the aluminium to protect it. The label and artwork is then printed on
the acrylic.
Fig 7 : Cross Section of a CD
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The data track on the CD spirals outwards from the centre to the edge. The
data tracks are extremely small and are measured in microns. A micron is a
millionth of a metre. The data track is about 0.5 microns wide, and the gap
separating one track from the next is only 1.6 microns wide. The bumps that
make up the track are each only 0.5 microns wide, a minimum of 0.83
microns long and 125 nanometers high. (A nanometer is a billionth of a
meter.) The microscopic sizes of the bumps make the spiral track on a CD
extremely long. If you could lift the data track off a CD and stretch it out into
a straight line, it would be 0.5 microns wide and over 5.5km long!
Reading the CD data
To read something this small requires an extremely accurate disc-reading
mechanism. A CD player uses a low power laser to read the data track from
the disc. A laser (Light Amplification by Stimulated Emission of Radiation) is
a beam of intense light of a specific wavelength which can be focused and
controlled very precisely. A motor unit spins the disc in the player and a
sensitive tracking system keeps the laser beam focused on the spiral data
track. The laser shines through the polycarbonate layer onto the aluminium
backed data track. The shiny aluminium layer reflects the laser light back off
the surface of the disc. The light is either reflected straight off the aluminium,
or is deflected off a bump in the data track. The CD player detects these
differences. It registers the light deflected off a bump as a 1, and light that is
not deflected (the reflected light) as a 0. In this way, the CD player creates the
stream of digital information that can be converted into an audio signal. The
digital information on the CD is coded to ensure that as long as the CD is
well looked after, it will work perfectly.
The CD also contains other digital data, called sub-code. The sub-code
contains a Table of Contents that organises the data on the CD. The subcode also contains information about the tracks on the CD, such as the
number of tracks and their duration. The sub-code makes it possible to find
different tracks on the CD easily, and allows the CD player to display things
such as the elapsed and remaining playback time of a track.
Writable CDs
CD-Rs (compact disc-recordable) and CD-RWs (compact disc-rewritable)
are increasing finding their way into many radio studios as the technology is
becoming more affordable and easier to use. Some community stations
have CD-Writers, and many are using them to distribute programming. This
is especially important where CR stations share programming.
CD-Rs - writable CDs that can only be written once - can be read by almost
any conventional CD player. CD-RWs - rewritable CDs that can be erased
and reused several times - may not be read by some CD players (though this
is changing rapidly). This is because CD-Rs are often "finalised" when they
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are written - that is, a Table of Contents is written into the sub-code
when it is written. It may be worth investigating if your choice of CD
player can play "unfinalised" CD-Rs, as this feature may become more
useful in the future.
For more on writing CDs, see Section B: CD Writers on Page 145
Caring for CDs
The CD is a very delicate system, using the deflections of light off
microscopic bumps to read audio. The CD is coded with a variety
of error-correcting techniques to make it more reliable, but unless
you look after your CDs, and handle them properly, they will be
damaged and start "skipping" or not play at all. Being an optical
based system, the usual problem is scratches and chips on the
clear polycarbonate layer which prevent the laser from reading
the data properly.
To take a disc from its case, press down on the centre of the
case and lift the disc out, holding it carefully by the edges.
Fingermarks and dust should be carefully wiped off the disc's
recorded surface (the silvered side) with a soft cloth. CDs do
not have any grooves that can collect dirt and dust, so gently
wiping the disc with a soft cloth should remove most dirt. To
clean the disc, wipe in a straight line from the centre to the
edge. Wiping in a circular motion will scratch a large part of
the spiral data track and will cause the disc to "skip".
Never use chemicals such as record sprays, anti-static sprays,
benzene, methylated spirits or thinners to clean CD's. Such
chemicals can do irreparable damage to the disc's plastic
Return discs to their cases after playing to avoid scratches that
could cause the disc to "skip".
Do not bend the disc.
Do not leave the discs in the sun, or in areas of high temperature
or humidity. Long periods in high temperatures can cause the
disc to warp.
Do not stick labels on the label side of the CD. If you need to
write on the label side of the CD, write very gently with a
permanent felt-tipped or other soft-tipped marker. Do not use a
hard-tipped pencil or ballpoint pen. Never mark or write on
the recorded side of the disc.
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A Compact Disc player is used to play CDs. The machine consists of a very
sensitive reading mechanism that reads digital information from a CD. The
CD player also contains digital-to-analog conversion circuits. These digitalto-analog conversion circuits convert the digital data stored on the CD into
an analog audio signal that can be fed into a mixer or amplified for a
For many community radio stations, CDs are the main source of audio other
than the microphone. As a result, there is an enormous demand on the
broadcast CD player. These machines are often in continuous use for up to
18 hours a day, and are opened and closed thousands of times each month.
A radio station environment demands ruggedness, reliability, and instant
cueing from audio source equipment. This is why studio CD players are
built differently, and have controls and other features that are different to
those found on a domestic CD player. However, if you are familiar with
domestic CD players, then a few minutes with the manual of a broadcast CD
player will teach you all of the extra features.
For more on compact discs, see Section B: Compact Discs on Page 138
Playing CDs in a player
The basic operation of a CD player is straightforward. It involves putting a
CD in the machine, choosing the track you want to play, and then pressing
the play button to start playback. The CD is usually placed in a tray that
slides out of the body of the player. In some players there may be a slot for
the CD instead of a tray. Consult the user manual for your particular CD
player for specific instructions on its features and operation.
An open/close button opens the CD player's disc tray. Press it to open the
tray and insert the CD.
Always place the CD in the disc tray with the label facing upwards. CDs can
only be played on one side, and putting a CD in the wrong way round will
cause the CD player to "freeze up" as it tries to read the CD. It will eventually
give up trying, and you will be able to open the tray and take out the CD, but
this wastes precious time. When the CD is in the tray correctly, press the
open/close button again to close the tray.
Many broadcast CD players disable the open/close button if a CD is playing
in the machine. This stops presenters from accidentally ejecting the
wrong CD.
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Do not EVER push the tray closed, as this will damage the motor
that opens the tray. Damaging the motor may cause the player
to refuse to open or close at all. Avoid using special shaped CDs
(heart shaped CDs, octagonal CDs etc.). Trying to play them
may damage your CD player.
Choosing and playing tracks
Choosing tracks on the CD involves pressing the TRACK or SEARCH buttons.
Some CD players use a jog wheel instead of a button to select tracks. A jog
wheel is a control that is turned instead of pushed like a button. Turning it
clockwise (to the right) will increase the track number. Turning it anticlockwise (to the left) will decrease the track number.
Once you've selected a track, press the PLAY button to play that track. One
of the marks of a good quality broadcast CD player is that when you press
play, the machine starts playback instantly. There is no delay. These CD
players "cue" the track when it is selected. This means the tracking mechanism
in the machine immediately reads the sub-code on the disc and positions
the read laser at the start of the track that is to be played ready for playback.
These players often have a CUE button instead of a pause button, or an
AUTO CUE control. This control flashes for the short time it takes the player
to find the track. It then stays lit once the track is cued.
Some CD players may take a few seconds to start playback and do not start
instantly once you've pressed PLAY. This short amount of time is taken by the
CD player to look for the track you've chosen. To minimise the "dead air"
created while the player locates the track, you can cue the player as follows:
Use the track controls to select the track you want, and then press PAUSE.
Make sure the pause indicator is showing, or that the elapsed time is
shown as zero.
When you are ready, press PLAY - and the track will play instantly.
Controlling CD players from an on-air mixer
Broadcast CD Players often use fader start, allowing them to be controlled
from the studio mixing desk. In this case, the start button or the on-off buttons
on the mixing desk can be used to play and pause the CD player. The
mixing desk and the CD player have to be capable of using this feature if you
want to use fader start.
Elapsed time and remaining time
The term elapsed time means the amount of time that has passed since the
beginning of the track that is playing. The term remaining time means the
amount of time left before the track comes to an end. Normally, the CD
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player's display shows elapsed time. That is, it counts up the seconds and
minutes that have passed from the time the track started playing. A CD
player used in a broadcast studio should also be able to display the remaining
time, or the time left before the end of the track. This is an essential feature as
it allows presenters to see how much time is left on a track, so that they can
prepare the next item. Presenters don't want to be surprised when the track
comes to an end. They must be prepared for the end of the track so that there
is no dead air time while they set up the next item. You can choose whether
elapsed time or remaining time is shown on the CD player's display by
pressing a button marked TIME or DISPLAY.
One track at a time
Another important feature of broadcast CD players is that they should be
able to play tracks one at time. Domestic players play tracks continuously
from the beginning of the CD to the end. It is very rare that a station will play
an entire CD from beginning to end. Normally stations play only one track
from a CD and then an item from a different source - another CD player, or
the MD, or a microphone. It makes your job much easier if you don't have
to worry about stopping the CD player while starting the next item. This is
why it is important that the CD player is capable of playing one track and
then pausing itself. A button labelled SINGLE/CONT, or the AUTO CUE
control, normally controls this. Pressing this button will put the player in
single play mode - that is, it will play one track and then pause. Pressing the
same button again make the machine continue with the next track. The play
mode will be shown on the display.
Other functions
A LOOP function allows a part of a track to be looped - that is to be played
over and over. The REPEAT function allows a track, or the whole CD, to be
played repeatedly. A PROGRAMME PLAY function allows the running order
of tracks on a CD to be programmed.
After the mixer and the microphones, the CD player is possibly the most
important item in a community radio studio. So it is important to choose the
right CD players for your station.
As we've said, your CD players need to be rugged and reliable. They must
be chosen for their ability to play even dirty or scratched CDs. There are
dramatic differences between CD players. There are many factors that are
not easy to judge without experience. The experience of fellow broadcasters
is valuable here. Ask around before buying CD players and see what other
stations have to say.
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Cleaning and maintaining CD players
Maintaining the CD player involves keeping the unit clean both
externally and internally.
The lens used to focus the laser beam that reads the CD and the
optical sensor that picks up the reflections off the CD can gather
dirt and dust. Using a Cleaning CD approved by the player's
manufacturer once a month should prevent this from becoming
a problem.
Also, keeping the CD tray closed and your CDs clean (no sticky
fingerprints and dust) will help prevent dirt getting into the
Connectors and connections for the player
Typically, broadcast CD players have two stereo outputs, one balanced and
one unbalanced. These usually use male XLR connectors for the balanced
output, and RCA connectors for the unbalanced output. (Note that consumer
grade CD players are often used in CR stations, and tend to have only the
RCA outputs.) For RCA connectors, the left and right channels are usually
colour coded, with red indicating right and white indicating left.
Most professional CD players also have digital outputs. These may be marked
OPTICAL or S/PDIF (Sony-Philips Digital Interconnect Format). Using these
outputs, the CD player feeds the digital information from the CD directly to
a digital mixer or the digital input of a digital recording device, such as a
computer, minidisc or DAT recorder. This avoids any loss of quality that
may result from D/A conversion. Optical ouputs need a special optical
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Today, writable CD drives (CD-Writers or CD-Burners) are standard
equipment in most new computers. A CD-Writer allows you to take audio or
data files from your computer and place them on CD. CDs containing audio
can be played in a CD player, or if the CDs contain data, they can be used in
a computer.
CD-Writers are relatively inexpensive, as are the blank CDs they use.
CDs have rapidly begun to replace cassette tapes and floppy discs as the
medium of choice for storing recordings and data.
Pre-recorded CDs are mass-produced through a complicated manufacturing
process which is not practical to use unless producing hundreds, thousands
or millions of CD copies. However as CDs became the standard medium for
audio, the demand for a simple CD recording technique grew. At the same
time, computer users needed a medium that could store more data than
floppy discs. In response to this demand, electronics manufacturers
introduced the CD-R and the CD-Writer.
For more on compact discs, see Section B: Compact Discs on Page 138
CD-R stands for CD-ROM Recordable. A new CD-R does not have
microscopic 'bumps' on its surface. That is, it contains no digital data. The
CD-R is coated with a special chemical film coated with a light sensitive dye
into which the 'bumps' can be burned using a CD Writer. When the disc is
blank, the dye is translucent and light can shine through it and reflect off the
metal surface. But when the dye layer is heated, it darkens so that light can't
pass through it.
By darkening particular points along the CD track, and leaving other areas of
dye translucent, you can create a digital pattern that a standard CD player
can read. The light from the player's laser beam will only bounce back to the
sensor when the dye is left translucent, in the same way that it will only
bounce back from the flat areas of a conventional CD.
A CD-Writer is used to burn this digital pattern onto a blank CD-R. A CD
Writer has two lasers: a standard read laser (like a normal CD player), and a
write laser. The write laser is more powerful than the read laser and is
intense enough to darken the dye material on the CD-R. The weaker read
laser does not affect the dye. This means that information on the disc will not
be affected by the read laser.
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Advantages & Disadvantages of CD-Rs
The main advantage of CD-R discs is that they work in almost all CD players
and computer CD-ROM drives. CD-Rs are also the cheapest media available.
They are even cheaper than most high-quality cassette tapes.
The only drawback of CD-R is that once you've burned in the digital pattern,
it can't be erased or re-written. It is possible to leave out some areas on the
disc for later writing, but this creates a multi-session CD. A multi-session CD
can not be read properly in a standard CD Player and some older
CD-ROM drives.
To overcome the problem that the CD-R cannot be erased or rewritten, a
new format was introduced in the mid-90s, called CD-RW (or CD-ROM
Rewritable). The laser of a CD-RW writer, called a CD-Rewriter, can both
burn bumps into the media and also melt the media back into its original
state. In place of the dye layer in the CD-R, a CD-RW disc contains a chemical
compound that can change its form when heated to certain temperatures.
When the compound is heated above its melting temperature, to around
600 degrees Celsius, it becomes a liquid. At around 200 degrees Celsius, it
turns into a solid.
The solid form of the compound is translucent (light can show through it),
while the liquid is dark. On a new, blank CD-RW disc, all of the material in
the writable area is in the solid form, so light will shine through this layer to
the reflective metal above and bounce back to the light sensor. To write
information on the disc, the CD-Burner uses its write laser, which is powerful
enough to heat the compound to its melting temperature. As with CD-Rs,
the weaker read laser does not change the state of the material in the
recording layer.
Advantages & Disadvantages of CD-RWs
Due to the very flexibility of the medium, CD-RW discs do not reflect as
much light as the other CD formats and cannot be read by many older CD
players and drives. So these are not a good choice for music CDs. However,
most new drives and players, including all CD-Rewriters, can work with all
the different CD formats. For the most part, they are used to back-up
computer files.
CD-Rewriters can write to both CD-R and CD-RW discs, whereas CD-R drives
can't write to CD-RW discs. CD-RW discs are, however, about twice the
price of CD-Rs. CD-Rs and CD-RWs are written using light and for this reason
should be kept away from strong direct light, as this can corrupt the
information stored on the disc.
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Read & write speed
CD-Writers can read and create CDs at different speeds: This is usually
expressed as a combination of two figures, a read speed and a write speed.
Both are written as a multiplication factor (1x or 4x or 8x and so on).
At 1x (1 times) writing speed, the CD spins at about the same rate as it does
when the player is reading it. This means it would take you about 60 minutes
to record 60 minutes of music. At 2x speed, it would take you about half an
hour to record 60 minutes, and so on. Current CD-Writers operate at 24x
writing speed or faster. Faster writing speeds need a faster connection between
the computer and the writer; and a blank disc that is designed to record
information at higher speed.
Like the CD writer, the CD-Rewriter also works at different speeds. In fact, the
device is usually specified by its write speed, its rewrite speed and its read
speed. (For example a CD-Rewriter would be specified as 16 x 8 x 32. This
means it can write CDs at 16x speed; it can re-write CDs at 8x speed, and can
read data from a CD at 32x speed.) The speed for re-writing is often slower
than the write speed, as rewriting needs the extra step of first erasing the
existing data on the CD.
Internal or external CD writers?
Most often the CD-Writer or Rewriter is part of a computer, and the information
written to the CD comes from a file stored on the computer. The CD-Writer
can be fitted into the case of the computer (an internal writer) or can be an
external unit that connects to the computer via the USB, Firewire or PC Card
Internal CD-Writers are relatively easy to install, and are about twice as fast
and half the price of external writers. However external writers do have
some advantages:
Installing an external writer is much easier and you don't have to open
up your computer's case.
External writers are portable. This means that the writer is not tied to a
particular computer and can be connected to any of the computers at
your station. It is also a good solution if you want to use the CD-Writer
with a laptop computer.
External drives are usually compatible with different types of computers.
(Remember, though, that an external writer is likely to be about 50% more
expensive than an internal one; so you should factor that in when making
your choice.)
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CD burning software
Using a CD-Writer attached to your computer requires CD writing software.
Basic CD writing software will be supplied with the CD-Writer. The software
allows you to decide what type of CD to make (audio or data) and choose
the files you want to write to the CD. Programmes such as Nero Burning
Rom, Adaptec Easy CD Creator and Toast (for Apple Macintosh computers)
are very popular. In many cases, the software is supplied along with the
writer device itself - but these versions may be limited in function.
Writing a CD places large demands on your computer and things can go
wrong. Do not be surprised if some of the CDs you are burning don't come
out right. CD-Rs cannot be overwritten. This means that when an error
occurs while writing the disc, you have to throw away the whole disc. If you
continually have problems burning CDs, try to reduce the write speed. The
most common problem when writing CDs is called a buffer underrun. This
happens when the computer is unable to send data to the CD-Writer fast
enough. Reduction of the write speed can overcome this problem.
Not all CD-Writers are part of a computer. There are a number of standalone CD recorders available for both domestic and professional use. Often,
these have two drives that allow you to record music tracks directly from
one CD to another.
Remember that copying pre-recorded CDs raises very serious
copyright issues. Breaking copyright laws can lead to legal action
that could cost you a lot of money.
These stand-alone recorders can also have audio inputs, allowing them to
record incoming signals, much like a cassette or minidisc recorder. These
writers are usually fast and accurate, but typically can only be used to create
music CDs. Professional models are also very expensive when compared to
computer-based writers.
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A compressor limiter (compressor) is a device used in most community
radio station transmission systems. It is used to process the signal that comes
from the broadcast studio before it is transmitted. The compressor/limiter
keeps the level of your station's signal constant and at the best possible
volume, both for your listeners and to compete with other stations.
In broadcast terms, we say the compressor is used to control the dynamic
range of the station's sound. Dynamic range is the range between the loudest
and quietest sounds that are broadcast. Reducing the dynamic range of the
signal by using a compressor is called compression. The effect of
compression is to make your station sound louder and clearer on air.
The limiter, on the other hand, sharply controls the audio output level at a
predetermined level. This is often a much more harsh adjustment to the
sound, and must be used with caution, as it can make your audio sound
very bad if done improperly.
More usually, we use devices that combine both functions, allowing you to
compress the signal to a certain extent, and limit it sharply after a certain
point. Such devices are called compressor/limiters.
Fig 8 : A schematic view of how a compressor/limiter functions
Not all compressors work exactly as shown above. For example, some
compressors monitor both the input and the output audio. Also, there is
computer software to carry out the role of the compressor. However the
underlying principle remains the same.
The compressor control panel generally has two meters:
„ one meter indicates the amount of gain reduction or compression
„ the other meter usually shows the signal level of the compressor's audio output.
The threshold control is used to set the signal level at which you want the
compressor to begin reducing the level of the signal. The ratio control
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controls the change of output level for a given change in input. (For example
a compression ratio of 2:1 means that for a 2dB (dB = decibel) increase in
input signal level, the output signal will only increase by 1dB.)
The speed at which the gain is reduced in response to an increase in input
signal level is called the attack time. This is usually specified in milliseconds,
and is set using the attack control.
The speed at which the gain is restored to its original level after the input is
removed is called the release time. This is set using the release control.
You need to listen to your signal very carefully in order to set these parameters.
If the attack time is set too fast, the compressor will respond to even the
shortest peaks (loudest sounds), causing the level to change very quickly.
For example, the beats in a dance track often cause short peaks in the signal.
If the attack time of the compressor is so short that it responds to the individual
beats, the compressor will reduce the signal level on each beat, and produce
a very unnatural sound. On the other hand if the attack time is too slow, the
compressor's output may exceed the desired maximum before the
compressor acts on the signal.
Too fast a release time causes "breathing" as the gain changes rapidly. If the release
time is too short, quiet sections of music will be lost as the compressor will still be
reducing the gain, even though the loud input signal is no longer there.
Many compressors have an auto (automatic) switch for the attack and release
time. When the auto switch is on, the attack and release times are set
dynamically, based on the input. This is often the best for CR stations, as the
system is self adjusting to the needs of different kinds of audio and
Some compressor/limiter units have an additional gain knob that can be
used to match the final output gain to any of a variety of equipment. The
output level resulting from using the gain control can be monitored on the
output level meter.
Some compressors also have a stereo link button, which links the two channels
of the compressor together so that both channels process their signals in the
same way. If your compressor doesn't have a stereo link button, you will have
to set controls for each channel to exactly the same level.
Pressing the bypass button bypasses the compression circuitry, and allows
you to quickly compare the compressed and uncompressed output.
The compressor has a variety of possible settings. Small adjustments to
any of them can make a considerable difference to your station's on-air
sound. It is a good idea to document the compressor settings that work
best for your station and compressor. Keep this record available for
reference. Also, once the compressor has been set for your station, put
a guard or protective covering on the front panel to prevent anyone
from accidentally changing the settings.
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The compressor settings you choose will depend very much
on your preferred sound. However, many stations have been
happy using:
z a threshold level of 0 dB
z compression ratio of between 1.5:1 and 4:1
Set the output gain so that the output level meter reads the ideal
input signal level for subsequent equipment (often 0 dB).
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Computers have become a vital tool in modern communication, both for
office work and for the production of high quality audio and video with a
considerable decrease in effort. Computers and digital technology have
developed hand in hand over the last few decades, as digital storage was
initially a system conceived for computer data.
There are two vital components to any computing system:
The hardware. This is the wiring, electronic circuits, disc drives, monitors,
keyboards and so on that make up the physical machine we call a
The software. This is the term used to describe the programmes that we
use on the computer.
Hardware and software must work together if we are to get anything useful
done with a computer.
For more on computer software, see Section B: Computer Software
(for Radio) on Page 159
Your choice of computer hardware will differ according to your needs and
according to the kind of software you are planning to use on your computer.
In general, however, all computers share certain basic hardware:
Fig 9: A schematic view of the average computer's innards.
The CPU tower or cabinet
All computers need a case to house all the electronic components. Cases
can come in a variety of colours and shapes, but all of them have the same
purpose - that is, to hold and protect the electronic components. Modern
CPU towers are usually of the ATX or Micro-ATX variety, which means they
automatically switch the power off when the computer is shut down. It is a
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good idea to assess how large a case you need based on the number of
peripheral systems (CD-ROM drives, CD-writers etc.) that you plan to install
internally - these are usually accessed through configurable slots in the front
of the system, and smaller cabinets have fewer slots.
The computer's power supply is normally supplied with the case. This power
supply, called an SMPS (Switched Mode Power Supply), is basically an AC
to DC convertor; and can come in a variety of ratings: 200 Watt, 300 Watt
and 450 Watt are most common.
Plan ahead and get a more powerful SMPS than you need if you
intend to add more components later on to the system. (But remember
that it will still consume its rated power whether you actually install
those components or not!)
The SMPS usually has a fan fitted on it which is visible at the back of the
cabinet: This is because the power conversion process generates a lot of
heat which needs to be vented.
The motherboard is a large circuit board into which all the other components
are plugged: The motherboard supplies power to all the components and
connects them together, transporting data from one component to the other.
The motherboard is mounted in the computer's case, and has slots and
connectors for the other components
Motherboards vary in terms of speed and features. More expensive boards
tend to be faster, more reliable and support more features and advanced
components. It is important to match a motherboard to the processor unit
that you install, as many of the features can be interdependent: A fast processor
can be hampered by a poor motherboard, or a fast motherboard can be
underused by a slow processor.
Processor and peripheral manufacturers usually specify the best
motherboard solutions for their equipment, so it's always worth having
a look at those while deciding your configuration.
Last but not least, it is always worth considering how futureproof your
motherboard is in terms of plugging newer peripherals into it: You may like
to increase the RAM or plug a different card into one of the slots later on, and
you should explore whether this will be possible at a later date.
The Central Processing Unit (CPU)
The CPU can be thought of as the brain of the computer. It is the part of the
computer that does the actual computing, and co-ordinates the actions of
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the whole system. Software programs are written to give the CPU a set of
instructions. The CPU will follow the instructions to accomplish a specific
task. The two principal CPU manufacturers globally are Intel Corporation
and Advanced Micro Devices (AMD).
Like all other components, the CPU is connected to the motherboard. It is
easy to spot on the motherboard, as it usually the largest microchip on the
board. This is why it is often called the chip for short. The CPU is covered by
a cooling fan, as modern CPUs are very powerful and compact, and generate
a lot of heat.
Computers are often differentiated by the type and speed of their CPU. For
example, in terms of type, people may refer to a computer as a Pentium III
or Pentium IV or as an AMD Dual Core Turion.: This means that the
computer has a Intel Pentium III or IV series processor or an AMD Dual Core
Turion processor installed.
The processor name also usually has a number and a frequency attached like Pentium IV 2.4 GHz, for instance. The 2.4 GHz refers to the speed of the
CPU and indicates that it can operate at a speed of 2.4 GHz (or 2400 MHz).
This means it is actually capable of doing 2400 million operations per
second, which should indicate just how fast modern computers are.
The newest type of processors actually carry two processor chips in one
casing - 4 and 8 chip versions are also beginning to make an appearance,
but are still very expensive. These types of processors are called Dual Core
processors, and are quickly becoming the modern standard for computer
Random Access Memory (RAM)
The CPU has to process digital data to carry out instructions. This data has
to be stored so that the CPU can quickly retrieve the data, process it and
save it again for further processing. This storage space used to hold the
data that the computer is working with at any time is referred to as the
computer's memory. Memory is like the CPU's scrap paper - somewhere
to write down notes and calculations as it works. It is referred to as Random
Access Memory (RAM). RAM is storage space that is available for shortterm storage of data.
RAM relies on a constant presence of electrical charges, and operates
only when the computer is turned on. Data written to RAM vanishes
when the system is powered off.
Computers are also differentiated by the amount of RAM they contain. The
more RAM in the computer, the faster it works, but this is only applicable up
to a point: For a slow processor or motherboard, increasing the RAM cannot
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push performance beyond a point. Most computers currently should come
equipped with at least 512 Megabytes (512 million bytes of data) of RAM,
though increasingly, advanced software has meant more should be preferred
if it is possible. Computers can often take upto 4 Gigabytes of RAM in all,
though this is dependent on the motherboard.
The computer has another kind of storage called Read Only Memory (ROM).
ROM contains data that is permanently etched onto a chip, and typically
stores the commands necessary for a computer to boot up, or start.
Secondary storage devices: Hard disks (HDDs). Floppies and CD
In addition to RAM and ROM, computers have secondary storage devices
such as floppy discs, hard drives, and CD-ROMs. These devices are
responsible for long-term storage of data and software programmes. They
can hold much more data than RAM and ROM, and are much less expensive.
They are also much slower than the primary storage devices. Data stored in
memory can be accessed by the CPU in nanoseconds (a nanosecond is a
billionth of a second), while data on a hard drive is accessible in microseconds
(a thousandth of a second). This means your hard drive is about a thousand
times slower than RAM.
Most modern computers have hard discs capable of storing 120 gigabytes
or more of data, with 250 and 500 GB becoming rapidly more common.
(A gigabyte or GB equals a thousand megabytes.)
Floppy disc drives use an external storage medium called a floppy disc,
which is a small 3.5" square plastic case that contains a magnetic surface.
Though comparatively less used nowadays, they are still found on many
older systems, especially in small towns and more remote areas.
The graphics/video card and the monitor
The video card and monitor allow us to communicate with the computer by
seeing what it is actually doing to the data we are giving it. We need to give
the computer instructions and data before it can do anything. We then need
to see the results of the instructions displayed in a way that we can understand.
The monitor, or screen, works much like a television screen. Like a television,
the computer monitor needs a video signal to display a picture. The video
card creates this signal by interpreting the data the computer processes. The
video card connects to the motherboard and converts the computer's digital
output into text or pictures for display on the computer monitor.
Demanding video applications like video editing may require
specialized video cards that carry their own memory and execute
this process quickly.
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Monitors come in several varieties: Cathode Ray Tube (or CRT) monitors are
most common - and cheaper - and work exactly the way your TV does. They
come in flat screen and normal screen varieties, with flat screen to be
preferred because the picture doesn't distort as much at the edges. The
other type of monitor is the LCD or Liquid Crystal Display, which are thinner
and lighter, but are somewhat poorer in colour rendition.
Monitors are usually 15" or 17" in diagonal screen size - the latter consumes
more power - but larger monitors (21", 25") are also available for specific
Keyboard & Mouse
The keyboard and the mouse provide us with a way to input data into the
computer, and interact with it. By typing on the keyboard - which is almost
exactly like a typewriter keyboard - and pointing and clicking with a mouse,
we are able to give instructions to the computer. The instructions are
converted to digital data.
Keyboards are usually in English, though specific language keyboards are
also available. In many cases, the same keyboard is adapted to type letters of
various other languages, a function that is guided by the availability of the
font (or typeface file) for that language on the computer.
Mice are available in two button and three button versions, with various
functions being accessed by each of the two or three buttons - most functions
can be achieved with two. Many modern mice also carry scroll wheels, a
small wheel on top which you can use to quickly move up and down on a
page displayed on the screen. Older mice have a trackball based design
where a small rubber ball at the bottom moves as you move the mouse.
Newer mice have an optical input system where a laser reads the surface
the mouse is moving on to understand which direction it is moving in (and
are hence known as optical mice.)
Sound or Audio cards
Adding a sound card to a computer makes it possible for the computer to
play and record sound.
The card converts audio signals into a digital format that can be processed
by the computer. The card also converts digital audio stored on a computer
into a format that can be sent to other equipment such as loudspeakers and
the mixing desk.
Sound cards vary enormously in quality and features. In the radio studio the
primary purpose of a computer is to play and manipulate sound. Therefore,
there are more demands on the studio sound card than on a standard office
or home computer. The right choice of sound card used in a studio computer
is vital. As the studio sound card tends to be more sophisticated than others,
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it is also often more expensive. Even basic sound cards today give very good
quality audio; but if you intend to connect professional grade microphones
directly to the computer, a sound card that has balanced and unbalanced
connectors - on the card itself or on an attached break out box - may be a
good choice.
For more on balanced and unbalanced connectors, see Section B: Balanced
and Unbalanced Connections on Page 131
Modems and LAN cards
Computer communications are becoming a part of everyday life. More and
more people are using the internet and e-mail as a resource and as a means
of communication. By connecting our computer to a phone line or a network
connection, we are able to communicate with other computer users.
A modem makes it possible for a computer to communicate through phone
lines. Modem is an acronym for Modulator/Demodulator. Modems translate
digital computer information into analog signals used over phone lines.
They can also work in reverse and translate the analog signal from a phone
line into a digital signal used by a computer.
Modems are distinguished by the number of bits per second (Bps) of
information that they can transmit. Nowadays, commonly used modems
operate at 33 600 and 56 000 bits per second. However, older modems that
work at lower speeds are still used in some places.
Like CD-writers, modems can also be internal or external, though it is more
usual to find the internal ones today. They need to be connected to the
telephone socket using a telephone cord, more usually known as an
RJ-11 connector.
For more on RJ-11 conenctors, see Section B: Connectors (Audio & Telecom)
on Page 166
If you have more than one computer in your station, you will probably want
to share files and resources such as printers amongst them. To achieve this
your computer needs networking hardware. This hardware is a network
interface card (NIC), often just called a network card or Large Area Network
(LAN) card. Most new computers are supplied with a network card. The
network card allows the computer to talk with other computers on the network
(that is transmit and receive data).
Modems and network cards are more important for the office systems
than for any computers based DAWs that you may be installing:
Most of the outputs from a DAW are likely to be through the mixer or
on a CD, so networking the system is not a priority.
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If you have more than two computers that you want to connect together,
you may need a network hub to which you connect all of your computers.
The hub switches information between the computers.
Other peripheral hardware
In addition to the hardware already listed, there is a wide variety of external
hardware, often referred to as peripheral devices (or peripherals) that can be
connected to a computer. The more common devices are CD-Writers used
to make audio and data CDs; printers for printing information onto paper,
and scanners to convert text or pictures on paper into a digital format for the
computer. Many stations today use CD-Writers and store and distribute
programmes they have produced.
It is also useful to have a printer for printing out text reports, letters and other
information. Printers can be colour or black and white; and can be inkjet or
bubblejet printers; or laser printers. Laser printers tend to be more expensive,
but their toner (ink) cartridges tend to last a long time. Inkjet printers are
intended for lighter work. They may cost less initially, but often have
expensive ink cartridges that over time can cost more than the printer itself.
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As we saw in the hardware section, there are two parts to any computer
system: The hardware, and the software. Software is the term used to describe
the programmes (or sections of computer code) that we use on the computer.
The programme is a set of instructions that instructs the computer in how to
execute a given task: This could be typing a word on the screen, or
manipulating audio or anything that that you want the computer to do. Both
hardware and software are very important, and we need the right hardware
and software if we want to get anything useful done with a computer.
Different software for different uses
There are different software programmes or packages that perform different
functions. For example to type and edit a script, or a letter, you need a word
processing programme such as Microsoft Word or Open Office Writer.
For accounts, budgets and spreadsheets, there is a wide variety of software
you can use to make accounting easier, like Microsoft Excel, or OpenOffice
Calc. Graphic designers use software packages for design and layout, like
Adobe InDesign, or CoreDraw! or OpenOffice Draw. We also use internet
browsing software such as Mozilla Firefox or Internet Explorer for accessing
the Internet; and e-mail software such as Outlook Express or Mozilla
Thunderbird for sending and receiving e-mail.
Proprietary, Freeware, Shareware and Open Source
Software can be proprietary (meaning it has to be purchased before use);
freeware (meaning it is free to access and install); or shareware (where you
can install it, but should pay for it if you continue to use it beyond a fixed
amount of time). When software is purchased, you are basically licensing a
copy of the software for use; and this license may limit the number of
computers you can install the software on.
Over the last several years there has also been a worldwide movement to
create and use software where anyone can access the basic code and make
changes to suit their own purposes. This is called the Open Source movement,
and it has resulted in a large variety of freely available and customizable
software that perform nearly all the functions that proprietary software was
once invariably required for - including audio editing and manipulation.
Many open source software packages today are available for download
directly from the Internet - but be careful while doing this, because people
pirate or make illegal copies of proprietary software as well. This is not only
illegal, it is unfair to all those who make a living by writing the software.
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To go into all the kinds of software used on computers for various tasks is more
than can be covered in this manual. So we'll focus first on the important software
that we may use on a computer used for radio and audio related work.
1. Operating Systems (OSs)
The operating system controls all of the computer's hardware and provides a
base upon which other software can be used. The operating system manages
the hardware for the user, and provides onscreen images that you can
understand when you are working on the computer. On PC based computers,
the popular OSs are Microsoft Windows (Windows XP SP2 is common, with
Windows Vista now preinstalled on many computers), as well as many variants
of the GNU/Linux open source OS (including variants like Red Hat, Fedora
and Ubuntu, some of which must be paid for). On Apple Macintosh
computers, often used for professional audio and video work, the current OS
used is Apple OS 10.5, also popularly known as Tiger.
Many computers still use older variants of Windows, such as Windows 95,
Windows 98 or Windows 2000 or ME. It's usually a good idea to get as new
an edition of the OS you select as possible, as it will have updated controls
and software for the hardware that you install on the system.
Some OSs are written specifically to facilitate multimedia and audio work on
a computer. One such freely downloadable OS is Ubuntu Linux Studio,
which comes bundled with audio processing and editing applications that
work seamlessly in tandem with each other.
2. Audio editing and processing software
Audio editing and processing software is used to record, input, adjust, trim
and refine audio from a variety of sources to make a programme. In the radio
production studio, software programmes such as ProTools, Cakewalk Pro,
Peak, Nuendo, and Audition are the common proprietary software choices.
The open source preferred choice is usually SourceForge's Audacity. Other
possible choices are Solition II, Audioblast and Reaper.
A screen capture of Nero Wave Editor, a simple audio
editing software bundled with the Nero Ultra
CD burning tools package.
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These programmes let us mix and edit sounds, add sound effects, and
generate digital audio files that can be sent to another computer for playout
in the studio, or for writing onto a CD-R. Advanced audio editing programmes
often demand more advanced sound hardware, and the soundcards used
in audio production computers are usually more sophisticated than those
on a standard computer. But CR stations often have less demanding
requirements than professional studios, which require very high grade
adjustments to music recordings for film and CD production. So simpler
software and hardware can often be used, without the tremendous variety of
functions that are often available in pro software.
As audio editing is usually graphical based - the software displays pictures
of the sound waves you are working with - this often makes it easier to work
with the sound, as opposed to the laborious manual work one had to do in
studios once upon a time. Software can emulate most of the expensive
hardware that audio studios once used to be equipped with, because the
software can now manipulate the audio in exactly the same way - an important
consideration in making radio more accessible to communities.
Most audio editing softwares also let you save the final version of the audio
in a variety of audio file formats: MP3, WAV, AIFF, and so on.
3. Playout software
Stations that use computers in the broadcast studio will use playout software.
Playout software provides a way for presenters to quickly access audio files
stored on the computer and then to play them on the air. Programmes such
as Netia, On the Air, Wavecart, Radiohost and many others have been
especially designed for use in the radio studio.
There are free and open source counterparts like ZaraRadio that can be
used for playout as well; and many small radio stations use simple audio
player software like WinAmp to queue audio for playing.
Using playout software may require more sophisticated sound and
computer hardware, as well as considerably higher expense.
4. CD burning software
As noted in the section on CD writers, there are specialized softwares that
can help you with the process of organizing and burning your files onto
CDs for archiving or for playout. These include versions of Nero Burning
ROM, Alcohol, Toast (for Macintosh), or CD Burner XP. Most will give you
advanced functionality like leaving the disc unfinalized, or making a CD-R
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5. Audio playback software
Most Windows OS based computers come equipped with a version of
Windows Media Player, a playback software which you can use to play
audio. But a variety of software is available to play audio on a computer:
These range from WinAmp and Realplayer to Quicktime Player and
Jet Audio.
Your choice of software depends on the scale you want to work at, how
much you want to automate the process - and what kind of a budget you
have. There may be differences in functionality between many of these
softwares - but then again, you may not need much of the pro functionality
or controls to achieve many of the things you require as a CR station.
Your choice of software depends on the scale you want to work at,
how much you want to automate the process - and what kind of a
budget you have. There may be differences in functionality between
many of these softwares - but then again, you may not need much of
the pro functionality or controls to achieve many of the things you
require as a CR station.
Don't invest blindly in expensive software without exploring
availability, support, usability, and functionality.
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While all radio equipment runs on electricity – DC or AC – the cables that
connect all these varieties of equipment to their power sources are often
different from each other – and so are the connectors at each end of the
power cable. In most cases, the connectors will be of one of the following
two types :
1. The standard power plug
The standard plug is the most common power connector, and is usually used
to plug into AC mains supply sockets. AC mains power is of a very high voltage
– 220 Volts in India – and can damage your equipment and cause fatal electric
shocks if care is not paid to the way the plug is wired and plugged in.
Power plugs of this type come in two varieties: A larger variety with thicker
cylindrical pins for heavier loads (often called a power plug or 15 Amp
plug), and a smaller variety with thinner cylindrical pins (often called 5 Amp
plugs) for lighter loads. Each of them requires a corresponding socket, as the
pin spacing is different in each case – but modern socket fittings generally
feature sockets which accept both varieties of plugs.
Socket and plug fittings vary from country to country, as do the
operating voltages of equipment. As most equipment used in a radio
station is manufactured outside India, it is vital to check whether the
plug supplied with the equipment will fit into sockets here: If it doesn’t,
it may be necessary to obtain adapter plugs that allow us to connect
it to Indian standard sockets. If the operating voltage is also different –
equipment from the United States operates at 110 Volts instead of
220 Volts, for example – then a power adapter may also be required
to step down the voltage.
Plugs need to be wired as per existing international and domestic conventions
for electrical wiring. This is done according to a colour coding system that
identifies the correct wires to be connected to the phase, neutral and earth
points of the socket.
The black wire connects to the pin on the left as seen from the back of
the plug. This pin is most often labelled Neutral, Black or just N.
The red wire connects to the pin on the right as seen from the back of the
plug. This pin is often labelled Live, Red, L or Phase.
The green earth wire connects to the top pin of the plug. The earth pin
is often labelled Earth or marked with the earth symbol.
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Fig 10: Standard wiring for a 3 pin plug in India.
Not all pieces of equipment use the earth wire, and you will have to
read the wiring instructions to see whether or not ‘earthing’ is needed.
Where there is a choice, always try to use a 3 pin plug instead of a
two pin plug for the earth protection the third pin gives you.
Wiring a power plug correctly
Though it appears very simple – and it actually is, once you learn how
to do it properly – there are some basic procedures that must be followed
when wiring a plug.
The first thing is to note that the earth, live and neutral wires of a power
cable each have their own colour coded insulating plastic or rubber
coating. Together they are then surrounded by a second rubber or
plastic coating (mostly white, grey or black) which keeps all three wires
To wire the plug, you will first have to remove a section of this outer
coating, enough to expose the three individual wires, but without
stripping the inner wires’ own coatings. Also, when you do this, make
sure you leave enough of the outer insulation jutting into the plug.
The earth, live and neutral wires are often stuck together. You may have to
separate them by pulling them apart. When you do this, make sure the
insulation (the blue, yellow / green and brown coating) surrounding the
copper wire remains intact. Also, make sure that the three separated sections
are just long enough to fit comfortably into the pins. Depending on the
plug, you may have to leave the green wire a little longer and clip the other
two wires slightly shorter so that they fit comfortably into the pins.
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Then remove a very short section of the green, red and black coatings
to expose the copper wire within. Expose just enough so that the
exposed copper portion fits into the holes in the three pins: If you
expose too much, there is a risk that two of the wires may short circuit.
Each of the wires may have several finer strands or filaments of copper
wire. Twist these strands together so that they stay together. Then insert
them into the holes on the pins.
Screw the screws that will hold the copper wire in the pins down firmly,
making sure that they are holding the copper wire down. Tug gently on
the wires once the screws are in to check. If the screws are not firm, or
the pins wobble in their casings, or the screws that seal the plug casing
are loose, change the plug at once.
2. The Kettle plug or IEC connector
The IEC connector is often called a “kettle plug”, as they are often used on
kettles. They are used to supply power to many pieces of studio equipment,
and to computers. The formal name for this type of connector is the IEC320/
C-14 (male) and the IEC320/C-13 (female). The former usually receives the
power, and the latter supplies the power. Commonly, the male connector
will be found on the equipment body, and the female connector will be
found on the end of the cable that is attached to it.
In most cases, equipment that uses IEC plugs and connectors are supplied
with sealed molded plugs that do not have any joints and cannot be rewired
by you. In these cases, if a plug shorts out ot malfunctions, the better option
is to simply purchase the entire connector, with the wire/cable and the
A female IEC or kettle plug connector
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There are a variety of connectors that are used to join pieces or groups of
equipment together so that they can communicate with each other, and so
that an audio signal may be passed among them. In some cases, this variety
is the result of efforts by equipment manufacturers to develop proprietary
connectors designed to fit only their own equipment. In other cases, newer
connectors have been developed over time that have begun to coexist with
older connectors.
1. The XLR connector
The three pin XLR connector is probably the most common ‘pro’ connector
that one encounters on broadcast grade audio equipment. Typically, it has
three pins, with Pin 1 used for the shield (or wire mesh) of the armoured
cable, Pin 2 for the phase or ‘hot’ signal, and pin 3 for the cold (or reversed
phase) signal. The three pin arrangement – four and five are also possible,
though less common – make this the connector of choice for balanced
For more on balanced connections, see Section B: Balanced & Unbalanced
Connections on Page 131
Since the XLR connector design includes a locking tab that clicks into place
when attached - and which must be pressed to release the connector - it is a
particularly safe connector. It is impossible to line the connector up the
wrong way, or misconnect it.
By convention, the male XLR connector – with the pins – carries the signals
out, and the female connector, with the sockets, takes in the signal.
A male and a female XLR connector. Note the tab on top
that must be pressed to disconnect the connector.
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2. ¼" phono plug and jack
The ¼" phono plug comes in two varieties: Two contact or three contact.
The three contact point version, with the two visible black bands, is also
known as the TRS or Tip-Ring-Sleeve connector. The three contact points
can be used for a stereo connection (tip = left, ring = right, sleeve =
ground); or for balanced connections (Tip = hot, ring = cold, sleeve =
shield). The two contact jacks only have a tip and a sleeve; and are used for
mono or unbalanced connections.
A pair of ¼" phono jacks. Both are mono connectors, as
indicated by the single black band.
3. 1/8" TRS plug or mini-phono plug and jack
The 1/8" phono plug – also known as the mini-phono plug – is the small
cousin of the ¼" connector. On professional equipment, this is found only
on portable equipment – notably field recorders – or on mid-range
soundcards. They are, however, more common on consumer grade and
home audio equipment.
The mini-phono jack is also available in two and three contact versions,
though the latter is much more common. The three contact version is also
the TRS variety (see above) and is most commonly used for unbalanced
stereo connections.
A 1/8" mini phono jack. This one is a stereo TRS connector,
as shown by the two black bands near the tip.
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The small size and the (usually) flimsy construction means there are high
failure rates with 1/8" connectors, and that they need constant checking
when used in ‘pro’ work.
4. RCA jack and connector
The name RCA comes from the Recording Corporation of America (RCA)
which was the first to develop this connector for their audio equipment. The
RCA is an unbalanced connector, with the jack having a central pin
surrounded by a flanged edge which acts as the other contact.
A pair of RCA jacks. Together, they make a stereo pair,
with one carrying the L signal and the other the R signal.
Designed for domestic use, it may nevertheless be found on some studio
equipment. The connector is prone to usage related wear and tear, as the
outer ring often spreads due to careless handling and is then unable to make
a clean connection.
5. D-Type connectors
The D-type multi-pin connector is available in male or female versions, and
is often used where large amounts of data needs to be handled.
The connectors range from 15 pin to 50 pin. They are common on digital
equipment and are also often used on studio mixers.
A D-type connector.
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6. BNC connectors
The BNC connector is most often found on RF transmission equipment, and
has a locking ring system that is similar to those found on a lightbulb. The
TNC connector is also quite common, and is a screw type version of the
BNC connector. A third variant, the N-Type connector is a larger version of
the TNC connector. It is able to handle considerably higher RF powers, and
is commonly found on transmission and RF test equipment.
Network, computer and telecom connectors
1. RJ-11 (telephone) connector
The RJ-11 clip connector is used for telephone connections. It is a small
four-pin type connector; and is often found on modem and hybrid units.
The plastic clip snaps into place, and must be pressed to withdraw the
connector from its socket. The connector requires a special crimping tool to
be attached to the telephone cable.
An RJ-11 connector. Note the clip on top which
snaps into place when it is inserted in its socket.
2. RJ-45 network connector
The RJ-45 connector is a larger version of the RJ-11. It has eight pins and is
used for data network cables such as ISDN cables and computer network
cables. Standard computer network cards and network hubs have sockets
for this connector, often known as an Ethernet or LAN (Large Area Network)
connector. This connector needs to be crimped in place within the connector
with a crimping tool as well.
An RJ-45 LAN connector. The 8 wires of the LAN
cable need to be crimped in place.
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3. USB connectors
USB or Universal Serial Bus connectors are found on computers and some
audio devices like MDs and flash recorders. USB devices may be chained to
each other to form a chain as long as 128 devices, all of which can be active
simultaneously. Nowadays, USB is also used to power some devices like
microphones: USB mics are often used on computers.
USB connectors may be classified on the basis of their data transfer standard
(USB 1.0 and USB 2.0) or on the basis of their size (mini-USB and standard
USB). Mini USB is often found on portable digital equipment and digital
cameras. Standard USB is usually found on computers.
USB 1.0 offers data transfers at about 11 MBps (or Megabits per second).
USB 2.0, the newer standard, can transfer at a thumping 480 MBps!
Regular size and mini-USB connectors, both male
A Female USB connector
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4. Firewire connectors (IEEE 1394)
Originally developed exclusively for high speed digital audio and video
transfer, Firewire or IEEE 1394 standard connectors come in two variants:
Firewire 400 (capable of 400 MBps transfers) and the newer FireWire 800
(capable of a mind-boggling 800 MBps transfer speed.).
This connector comes in a larger and smaller variety as well.
A standard (left) and a mini firewire (right) connector
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When we work with audio equipment, it is important to keep track of the
overall levels of the audio we are working with for two reasons:
1. So that we can compare the relative levels of various sounds and
recordings, in order to adjust them relative to each other; and
2. So that we can keep the audio levels at a level where the equipment’s
circuitry can handle it.
In order to do this, however, it was important to develop a system of sound
units which could mimic the human ear’s way of distinguishing. The units
which were developed became known as the Bel and the deciBel (dB). The
Bel was named after Alexander Graham Bell, the inventor of the telephone.
A deciBel is one tenth of a Bel, and is the more commonly used of the two
measures, as the Bel is a very large unit.
As a measure, the Bel and decibel are logarithmic. Logarithms are an arithmetic
system where large numbers can be expressed as a system of smaller
numbers, and where the progression of numbers is not linear in nature.
(Our hearing is actually logarithmic in nature: A sound that we perceive as
twice as loud is actually nearly four times as loud in absolute pressure terms,
so it is easier to perceive this in relative terms. Additionally, ‘loudness’ is a
very subjective quantity.)
What is important is to grasp that dB always represents a ratio of two
quantities, and not a quantity itself. This can be the ratio of two powers,
voltages, currents or sound intensities. Most often it is a ratio of power
quantities. As we have seen, it is immaterial whether we talk about an audio
signal in terms of the actual pressure wave that we hear or the change in
electrical voltage that a microphone converts it into. Thus, if 0 dB is specified
as some reference value then any number of dB above or below that zero
reference can be used to describe a given quantity.
The standard dB term used for expressing input and output voltage is
dBu. 0 dBu corresponds to a voltage of 0.775 volts. Another dB unit that
is often used is the dBv, which is equivalent to the dBu. An older dB unit
that is used is the dBm. 0 dBm is 1 milliwatt. dBm has no direct relationship
to voltage.
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The advent of computers has not only made the process of editing and
manipulating audio easier, it has also made the process of storing and
accessing large quantities of audio data very convenient. Where radio was
once a purely ‘live’ medium, today we can select and playback a huge
variety of programming with the click of a few buttons.
At its most basic, a digital playout system is a computer set up to playback
audio for broadcast. Most computers are capable of playing back audio
with an appropriately installed sound card and audio playback software.
What distinguishes a digital playout system from other such computers is
the software used to organize, sort and search through the audio stored in its
hard disk – and to ‘queue’ the audio so that it plays back in a specific
sequence and without a pause.
For more on sound cards, see Section B: Computer Hardware on Page 152
For more on audio playback software, see Section B: Computer Software
(for Radio) on Page 159
A large part of using a playout system is creating the sound files the system
uses. For this, the audio must first be stored as digital audio files on the playout
computer. If the original audio is on an analog medium like audio cassette or
LP record, it will first have to be digitized or captured, and then transferred
onto the playout system. On the other hand, if the audio is already on a digital
medium like a CD, it will need to be ripped using a ripping software. Ripping
is essentially a process of converting the audio from its original digital format
to an audio format that is compatible with the playout software.
Most playout softwares are compatible with MP3 format files!
For more on digitization, see Section B: Analog & Digital Audio on Page 124
All the audio that will be broadcast (‘played out’) from the playout system
has to be in the form of audio files on the playout computer – jingles, ads,
programmes, music, teasers, everything. Since digitization may be a time
consuming process, this generally means that one must have separate
systems for the production work and the playout, because the playout system
cannot be utilized for any other work while the broadcast is going on. If you
do decide to share a single system for production and playout, remember
that you must have large amounts of hard disk space and that you must plan
in advance to share your time across these two functions.
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Organising and managing the sound files in the playout system is the most
demanding part of using the system. If sound files are not named according
to a common convention and properly organized, the playout system
becomes completely chaotic and it becomes impossible to find specific
sound files. It is essential that everyone who uses the system knows how the
sound files are organised. Since a number of people – community reporters,
station manager, community volunteers – may be operating the system, this
process must be set up when the system is first installed. Usually, the computer
is set up with a folder where music sound files are saved, a folder for ads and
jingles, a folder for finished productions such as interviews, one for sound
effects and so on. Some systems already have folders for storing different
items but will still rely on the user to label the item or save it in the right place.
Folder systems and file naming conventions are sometimes dependent
on the specific playout software being used.
Playout systems make the presenter’s job much easier. At the same time, the
station will need extra computer skills to maintain the playout system, and
this can make the technical department’s work more difficult. These skills
can be difficult to learn and so it is important to have a good relationship
with your supplier to talk through problems as they arise.
Digital automation systems – the next step
The digital automation systems are the next higher step beyond the audio
playout systems, allowing us to automate the entire task of broadcasting
programmes according to a pre-decided schedule. Once specific time slots
have been set for various programmes to air, and for the programmes to be
interrupted at specific points by advertisements, public service
announcements and programme promos, the digital automation system
allows us to simply line these up for several days in advance, for the
programmes to play out completely without human interference.
Naturally for this system to work to its true potential, this means having a full
time team to manage and organize the audio on the system, not to mention
full time teams working on generating the programming and the advertising
(especially if the programming team is also producing the advertisements on
behalf of the advsertisers). It also means an enormous level of coordination
and cooperation between these teams in terms of getting the relevant audio
ready several days in advance of the play date.
Given the scale of operation of a CR station, automation must be
used with care. Extensive automation also means having a full time
infotech team that can manage and maintain the computers involved
at all times. This is only a viable option if your station is doing more
than 8 hours of broadcasts a day.
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Audio effects can be of two kinds: The ones that are actually recorded from
a source – a car passing, say, or a baby crying – and the kind that are
generated artificially to change the audio quality of a recording or emphasize
something (a whistle or bloop or thweep, for instance).
Properly used, effects can add a whole new dimension to recorded sound.
Effects can make advertisements more appealing; dramas more dramatic;
and jingles ear catching. Nearly all computer-based digital-editing systems
now come equipped with a toolbox of effects – but it is often simplest to
record the kind of sounds we want, unless we want something quite unnatural
which can only be created artificially.
Of the many effects that one might use in radio work, the most common and
popular are as follows:
1. Reverberation
Reverberation (or reverb) is the natural reflection of sound from walls and
structures around us, which give a voice its ‘presence’ in an enclosed space.
These reflections reach us so quickly after the original sound is made that
we don’t consciously perceive them as being separate from the main sound
– but we can and do notice when they aren’t there. (This is why a padded
room or an acoustically treated studio floor, where reverb has been
deliberately reduced through various techniques, sounds ‘dead’ to us, as if
our voice has been swallowed up by the room.)
For audio recording purposes, we always try to record ‘clean’ sound – that
is, sound without reverberations in a controlled studio environment. Later,
during post-production, we add the ‘reflections’ electronically, to the exact
degree that we require. Doing this well is an art, and calls for sharp ears and
an understanding of what real reverb sounds like. Done properly, it can
create the impression of a real room of a specific dimension.
2. Echo
When the reflection of the original sound reaches us after a distinct delay,
we perceive the reflected sound as an echo. In electronic terms, we can add
echo the same way we add reverb, but by increasing the return time.
3. Delay
Along with echo and reverb, we can also electronically create multiple
reflections, and alter the duration and volume at which each of these echoes
return after the original sound. This is achieved by using the delay effect
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controls. If the delay effect is used in combination with the pan control (see
below), this can create spatial effects in stereo.
4. Modulation
Modulating the delay time creates modulation effects. If we use a low
frequency oscillator to generate a signal that varies the delay time in
accordance with the frequency of the oscillator signal we can create a chorus
effect, like two or more voices singing the same part, but with slight differences
in timing and tuning.
Using different length delays and different modulating frequencies can also
create effects like:
Phasing: Very short delay time and mixing the delayed sound with the
original creates a slightly flatter and ‘treated’ effect;
Flanging: A longer delay and feedback creates the effect that we hear when
a guitar string is stretched sharply in the middle of a note;
Vibrato: When only the delayed sound is used, with a slight change in
pitch, to create a wavering sound that is more tremulous than the original.
5. Pitch shifting
Pitch is a measure of the overall combination of frequencies in a sound or
voice. (Hence: "She has a high-pitched voice" – that is, a voice where the
shrill notes and higher frequencies predominate.) Before the advent of
modern effects processors, pitch shifting was achieved by speeding up or
slowing down the recording during playback – the former increased the
pitch, and the latter decreased it. Unfortunately this technique also changed
the overall length of the audio. Modern effects processors can pitch shift
the sound – make it shriller or more bassy – without changing the speed of
the audio.
6. Time stretching
Another sound effect that is possible with modern effects processors is the
time stretch, where the length of the audio can be changed without affecting
the pitch of the audio. (See Pitch shifting above.)
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Radio waves are a form of electromagnetic radiation: Electromagnetic
radiation is the transmission of energy in the form of waves that have electrical
and magnetic components. Where scientists once thought magnetism and
electricity were entirely unlinked phenomena, research over the last few
centuries proved beyond a doubt that not only were the two linked, in many
cases they were simply different expressions of the same energy.
The most familiar forms of electromagnetic radiation are radio waves and
visible light waves. They differ primarily only in the frequency and wavelength
of the radiation.
All electromagnetic waves travel through empty space at the same velocity
(speed) – namely the speed of light. The speed of light (often denoted by the
symbol ‘c’) is 2,99,792,458 metres per second. For most calculations the
approximate value of 3,00,000 km/s is used. This is true whether we are
talking about radio waves or visible light.
Fig 11. The Electromagnetic Spectrum
Mathematically, electromagnetic waves are represented by sine waves.
The sine wave is a graphical representation of wave phenomena. As we
have seen earlier, the wavelength and frequency of any electromagnetic
wave are related to one another inversely; that is, when one increases, the
other decreases.
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We can now quantify this as an equation as:
Wavelength = Speed of light / frequency
Different forms of electromagnetic radiation are characterized by their
wavelength and frequency. When electromagnetic waves are ordered by
frequency or wavelength, this ordered array is called the electromagnetic
spectrum. The electromagnetic spectrum represents all electromagnetic
signals, from very low frequency (long wavelength) to very high frequency
(low wavelength). Note that even visible light, the electromagnetic radiation
that our eyes have evolved to perceive, is itself composed of a variety of
frequencies of light: The colours of the rainbow that we see when sunlight is
refracted or broken up by a glass prism are the different frequencies of light
that together make up (white) sunlight.
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Many of us are already familiar with the treble and bass controls on our
home stereos, that let us control whether the sound is higher or deeper
in pitch.
For more on pitch, see Section B: (Audio) Effects on Page 175
Consumer grade equalization controls
The tone and bass controls are the most basic equalisers, allowing you to
change the overall mix of frequencies in the audio to suit our listening
experience, the listening area we are hearing the audio in - or to emphasize
specific instruments or voices in the audio. Essentially, they act as a sort of
electronic filter, allowing you to turn up certain frequencies in the audio,
and turn down others.
A slightly more advanced version of the treble and bass knobs is the graphic
equalizer, which is often found as a set of sliders on hi-fi consumer equipment.
Each slider controls a specific band of frequencies, with the entire range
from 50 Hz to 20000 Hz divided among 6 or 8 sliders. These are better than
simple tone knobs or controls.
Professional grade equalizer controls
The equalizer controls on professional equipment are a lot more precise
than the band equalisers found on home and consumer grade equipment.
(Band equalizers are so named because they are not very precise, affecting
a large group of frequencies together rather than a single frequency or a
small range of frequencies.)
On studio mixers, one typically sees an equalization section that includes
HI, MID and LO knobs, as well as an EQ button. Pressing the button activates
the equalization section, and using the three knobs turns up or turns down
the gain for the three equalization/filtration units.
The LO knob is a high-pass filter, which means it only low frequencies.
The HI knob is a low-pass filter, which means it cuts or boosts only high
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Fig 12. Effect of a low cut/hi pass filter
Fig 13. Effect of a hi cut/low pass filter
The MID knob is a bandpass equalizer. It typically affects frequencies between
500 Hz and 5000 Hz (the frequencies most commonly falling within the
human vocal range). On many mixers the MID equalizer is also tunable, in
that the centre frequency can be changed: This is the frequency in the exact
middle of the range that this knob controls. This form of EQ is also known as
a sweep equaliser.
Parametric equalization
The parametric EQ is very like the sweep equalizer in that it controls a band
of frequencies. In addition, it has a third control that allows the width of the
band to be adjusted. This is referred to as the ‘Q’ of the control: A higher Q
means a wider band of frequencies is being controlled, and a lower Q
means a smaller band of frequencies is being controlled.
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Software based equalization
Many audio editing and processing software now include equalization
sections where you can perform the same function, sometimes in an even
more precise way. Often these softwares have graphical representations of
the equalization controls, to make them comfortable for those used to
hardware mixers.
Don’t use equalization when recording audio unless there is no other
way. Most of the time, audio is poor only because our microphone
position or recording area is not up to scratch. Use equalization only
at the post-production stage – and in moderate amounts.
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Acoustic Feedback is most often experienced as the nasty screeching you
sometimes hear coming out of speakers at a concert, or when someone is
talking over a public address system. It is a high pitched sound that rises
quickly to a shriek – and is not only unpleasant to hear, it can be downright
dangerous for your equipment. Feedback is also known as howlround.
Feedback is produced when an unwanted sound output (or audio signal)
from a loudspeaker or audio device is fed back to an earlier part of the
sound reproduction system. The unwanted audio signal is picked up and
amplified (made louder) by the electronic circuits in the system. The amplified
sound is then output again over the speakers, and is picked up again by the
inputs (microphone), making a closed loop. The system then quickly becomes
overloaded, and this is heard as a nasty screeching sound through the
Typically, feedback happens when the speakers in a public address system
are placed behind the microphone, giving the speaker output a chance to
go back to the input and be amplified. To stop feedback, you have to break
the feedback loop. In the example described above, you will have to move
the mic to a place where sound coming from the speakers is not picked up
by the mic. Or you can move the loudspeakers so that their output cannot
reach the mic. Moving either the speakers or the mic will break the feedback
loop, and the system will work properly.
Fig 14. Poor speaker placement leading to ‘howlround’ – the speakers should have been
placed between the mic and the audience.
Avoid situations that will lead to acoustic feedback for two reasons:
Firstly, it always affects your sound output. The noise is horrible and it will
make your sound unlistenable. Even a small amount of feedback can cause
echoes or boosting or cutting of certain frequencies.
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Secondly the very high signal levels associated with feedback can destroy or
damage loudspeakers and other equipment that are part of the feedback loop.
Acoustic feedback is not acceptable at all in the broadcast studio. To make
sure feedback from the mic to the loudspeakers doesn’t happen, broadcast
studios have special switching units. These units, often incorporated into
the mixer, turn off the studio loudspeakers whenever a microphone is turned
on. The same switching unit also normally triggers the RAG lights or On-air
lights. These are indicator lights placed inside and outside the studio to
show that a microphone is switched on, and that someone is ON AIR. It is
good practice never to enter or leave the studio when the on-air light is on.
Another kind of in-studio feedback relates to recording equipment. For
example, let us assume a recording device is being used to record a signal
from the recording output of a mixing desk. If the recorder’s output is added
to the mix on the mixer’s recording bus, and you lift the fader of the channel
feeding the recorder, feedback will occur. The audio is feeding back into the
system, and the same kind of noise will result.
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The term field recorder refers to any portable recording device that allows
reporters to go into the field with the means to capture sound. Because there
are so many different kinds of field recorders you can buy, it is impossible to
enumerate every type that is available in the market. But we can quickly list
the most popular varieties.
1. Cassette recorders
Cassette recorders are the most common field recording devices available
in many places even today. The cassettes that we use in them are readily
available almost everywhere, and are quite cheap. They are relatively rugged,
easy to repair – cassette recorders are plentiful enough for even the average
electronics repairmen to fix the common problems – and are relatively
cheap. Good cassette field recorder models are the Sony Recording Walkman
series, and (a little more expensive, but with far more controls for professional
grade work) the Sony TCD-5M recorders.
For more on cassette recorders, see Section B: Cassette Tapes & Cassette
Recorders on Page 134
2. Minidisc recorders
The minidisc or MD was originally invented by Sony as a replacement for its
cassette walkman players – that is, as a handy portable recorder that could
carry high quality audio. It never found acceptance in the home consumer
market, as it was an expensive device. Instead, it became popular with
filmmakers and journalists as a way to record high quality digital stereo
audio. MDs have been the staple recorder for a number of CR stations
across the globe for some time. The newer Sony HiMD models – an upgraded
version with higher capacity media and the ability to record PCM WAV
uncompressed audio – are still quite popular. The recorders are priced
quite reasonably for the quality of recording; and the HiMD recorders offer
the additional option of digital USB transfers for editing on a DAW, making
them an attractive option.
For more on MD recorders, see Section B: Minidiscs & Minidisc Recorders on
Page 204
3. Flash recorders
The most recent type of field recorder – and by far the ones gaining greatest
ground today - are the solid state flash recorders that record on Compact
Flash (CF) media or Secure Digital (SD) cards. As digital memory has improved
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in tandem with the increasing roles computers play in our lives, flash recorders
– which use the same kind of solid state memory used in computer BIOS
memory – have also improved by leaps and bounds. The most recent versions
– like Zoom’s H-2 recorder or the Edirol R-09 – are very high quality
instruments, with the ability to record several hours of high quality audio on
media that are rapidly becoming cheaper by the day. (SD cards are available
in 8 GB versions today, enough for over 10 hours of non stop recording in
uncompressed WAV format; and CF cards are available in as high a capacity
as 64GB.)
For more on flash recorders, see Section B: Flash Recorders on Page 187
Conducting a field recording
A field recording normally involves the following steps:
1. Connect the microphone to the recorder. The microphone cable
usually has a female XLR or connector at the microphone end, or it may
be built into the recorder. The recorder end of the cable could use a
variety of input connectors, including male XLRs and ¼" mini-phono
plugs. Make these connections gently and correctly, and never force
the connectors to go in. Remember to press down the tab on XLR
connectors. Field recorders are often made of lightweight materials, and
force may crack the case or break the connector mount.
2. Connect headphones to the recorder. Smaller field recorders come
with earbud style headphones. Pro models often need to be matched
with full size headphones. Gently push the ¼" plug or minijack plug
into the jack for the headphones. If your full size headphones need a
plug adapter to make them fit, be sure to attach this first.
3. Insert the media. Follow the operating instructions of your recorder
and gently insert a recordable tape, MD, flash memory chip (or other
appropriate blank medium) into the recorder. Always ensure that the
inserted medium is fresh/blank. If there is already a recording on it,
ensure that you will not accidentally erase it while doing the new
4. Switch on the recorder and check your levels. Start by conducting a
short test recording to check your recording levels. Switch on and hold
the microphone in the position that you expect to work with it. Say a few
words, and ask your guest to speak as well. Keep your eyes on the audio
level meter. (Some recorders may require you to put them in REC-PAUSE
mode to do this.) Change the record levels on the recorder, or adjust the
mic position till you are happy with the levels. Check audio quality on
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the headphones as well, so that you know there are no unnecessary
crackles or loose connections.
5. Make the recording. Different recorders require you to press different
combinations of buttons to start the recording process. Confirm the
exact process to start and stop recordings before you commence your
6. Complete your recording, and label your media or identify it in
some fashion. Many reporters/recordists use sticky notes or insert labels
that can be written on to identify tapes/MDs/CDs. It’s a good idea to also
keep a notebook or pad close to hand to note good takes and pre-select
sections of recordings at this stage itself.
7. Pack your equipment in their cases. Carry a checklist to ensure that
all the bits and pieces have been packed up and not left on location.
Coil all the cables neatly and stow them so that the connectors do not
get accidentally damaged. Make a note of any equipment that has been
malfunctioning. Pack your used media separately.
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Till a few years ago, the first choice of field recorders for CR stations used to
be cassette recorders and minidisc recorders. But with computers and
cheaper memory becoming rapidly available – and therefore increasingly
becoming a part of even smaller stations – the stage was set for a new type of
device that could give very high quality digital recordings, and yet be very
compact and rugged.
This new type of recorder was the device that is now popularly called the
flash recorder, as it records on various types of flash or solid state memory.
Many of us are familiar with flash memory in the form of the thumb or USB
drives that have increasingly replaced the use of floppy discs over the last
few years.
Flash memory
Flash memory is a comparatively new type of data storage system, and is a
considerable improvement on hard disk and tape based digital storage
systems (like that used in the Digital Audio Tape, DAT) as it has no moving
parts. It uses an electronic chip that is essentially the same as the BIOS
memory in your computer. Each of the chips contains thousands of electronic
transistors, tiny ‘gates’ that allow electrons and charges to move from one
part of the chip to the other.
In flash memory - more correctly known as EEPROM memory - the data
is stored as a change in the conducting parameters of the electronic
chip itself: That is, as a property of these individual transistor ‘gates’. To
change the state of each gate takes an electronic input – but the best
part is that though it takes power to change the state of the transistor,
once the power is withdrawn, the state of the transistor remains static.
This means the chip does not forget the information once the power is
withdrawn. This type of memory is also known as non-volatile memory
i.e. memory that does not vanish when the power source shuts down.
(Contrast this with the fact that computer RAM, which also stores
information while the computer is on and running, ‘forgets’ all the data
when the computer is shut down – this is called volatile memory, and
means that a computer has to automatically write all the data in the
RAM onto the hard disk for later retrieval before it shuts down.) Since
the amount of power required to operate with flash memory is also very
small, and since writing information to flash memory involves no moving
mechanical parts, this also means a very small power source can go a
long way.
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Types of flash memory
Flash memory is available in an incredible variety of shapes, sizes and
capacities: You see MMC cards in mobile phones, SD and Micro SD cards
in cameras, and CF cards in a variety of instruments. For audio, the two most
common recording media are SD (Secure Digital) cards and CF (Compact
Flash) cards, with the former rapidly outdistancing the latter.
1. Secure Digital cards (SD)
SD cards are available in capacities ranging from 16MB to 4 GB (though
commonly the maximum used in many recorders is 2 GB, which gives
approximately 3.5 hours of uncompressed professional grade audio).
By convention, they are small blue chips about twice the size of your thumb
nail, with the golden electronic contacts exposed at one end.
SD cards have a small notch at one corner: This helps you identify how to
orient and insert them into the slot that is provided for them on audio recorders
and cameras.
2. Compact Flash cards (CF)
CF cards are an earlier development in flash memory, and are slightly bulkier,
being about the width and breadth of a box of matches – but the extra
dimensions also mean a staggering amount of information can be stored on
them. The most recent types of CF can store as much as 64 GB of data,
though 4 GB and 8 GB are more commonly used in audio recorders.
CF cards are also thicker than SD cards – which actually means a couple of
millimetres, so don’t go imagining something very thick! – and have a series of
slots across one edge: This is for the connector, which usually has 50 pins.
Flash recorders
Given the type of memory it uses, the flash recorder has several things to
recommend it over other types of recorders:
1. It is noiseless
2. It has no moving parts, and therefore fails less
3. It allows faster access to your data, and in a non-linear way (more like a
computer does)
4. It is lighter and smaller
5. It consumes very little power
6. It can be connected directly to a computer via USB for direct digital file
transfers with a minimum of fuss and complexity
All these together make the average flash recorder very small, compact,
rugged and battery conserving – all very important factors for field
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Selecting a flash recorder
Flash recorders range from the basic dictaphone varieties (with an inbuilt
mic, meant mainly to record voice for notes and in field dictation, like
the Samsung Voice Pen or the Olympus DS-2200); to the higher end
dictaphone units (still meant for dictation, but often with provision for
external mics, like the Sony ICD-B 500 or the ICD-MX20); the middle
end professional units (like the Edirol R-09 or the M-Audio Microtrack
24/96); and the high end professional units (like the Marantz PMD 670
and 660 or the Tascam HD-P2, with XLR inputs and advanced controls).
There are flash recorders today to suit every pocket and budget, so you
will have to consider the key features one by one when you purchase a
flash recorder. Important considerations include:
1. What is the maximum memory it can take? (in case you upgrade it
2. What kind of VU meters does it have?
3. What kind of batteries does it use, and how many?
4. What kind of memory does it take (SD cards are rapidly becoming
cheaper than CF)
5. What kind of connectors does it have? (XLR or mini phono?)
6. Can it be powered externally if required? (Most middle and high
end recorders come with power adapter provisions)
7. Does it have an internal mic and a built in speaker? (Depending on
the kind of field recordings you do, you may want to operate without
an additional mic, or even listen to the audio without headphones.)
8. What kind of audio file formats can it record in, and at what sampling
rates? (Higher end units offer WAV and MP3 recordings at a variety
of settings – lower end units may not offer uncompressed audio at
all, as they may have smaller memories. This is especially true of the
Dictaphone varieties, which have non-removable memories, and
which are optimized for long recordings in the field rather than high
quality audio).
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In a sound studio, we don’t just listen to sound – we monitor it, with attention
and focus, so that we can perceive small distortions, issues with diction, or
small changes in tonality. Naturally, this is a process that calls for a high
quality pair of speakers, so we can hear the audio that’s coming off the mic
or off our recording system.
From a mechanical/electronic point of view, the speaker is the exact reverse
of the microphone – it is a transducer that converts the electrical audio
signal into physical movements of a surface which then generates pressure
(sound) waves that we can hear with our ears. A good speaker, like a good
microphone, should conduct this conversion process with a minimum of
distortion or change in audio quality.
For more on microphones, see Section B: Microphones on Page 198
The electrical signal from a mic or a recorder is too weak, of course, to drive
a large surface back and forth, so speakers are generally used in conjunction
with an amplifier, which can boost the signal to a strength where it can
‘drive’ the speaker.
For more on amplifiers see Section B: Amplifiers on Page 128
The speaker consists of three main sections: drivers, a cross over network
and an enclosure (the speaker box).
Fig 15. Cross section of a speaker unit
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The input wires for the speaker carry the audio signal to the driver unit,
which is essentially a cone of stiff cardboard (in consumer end speakers)
and Kevlar plastic (in higher end speakers). The narrow end of the cone is
connected to a coil of wire (the voice coil) that is wrapped around a
permanent magnet. The amplified audio signal is fed to this coil, which then
acts as an electromagnet, and alternately is repulsed by the other magnet
and attracted by it. These movements are dependent on the frequency and
strength of the electrical (audio) signal fed to it, which – of course –
corresponds to the frequency and strength of the original audio.
The movements of the voice coil are transferred to the cone, to which it is
attached; and the vibrations of the cone make the air in front of it vibrate as
well, which is what we perceive as sound.
Woofers and tweeters
We have already seen that the audio signal must be amplified in order to drive
the speaker cone back and forth. It stands to reason that if the cone is large, the
amplification must correspondingly be greater. Most good speakers, therefore,
use a combination of two driver units, a smaller cone handling higher
frequencies (tweeter) and a larger cone (woofer) handling low frequencies.
Such speakers need a crossover circuit to channel specific frequencies to
the two driver units
The enclosure
Usually, the drivers and all the related circuitry, including the surface on
which they are mounted, are encased in a heavy box or enclosure, often
made of wood. This not only serves to keep all the components together, it
also keeps them all in the correct position relative to each other. Additionally,
since the drivers are moving quite fast, and set up powerful vibrations, the
enclosure is heavy in order to be able to absorb the vibrations.
Enclosures are carefully designed and calibrated to provide the best sound
experience: The hollow space serves as a resonator – that means the column
of the air inside it vibrates at the same rate as the sound produced by the
speaker drivers, increasing the sound output. This is also supported by the
design of the vents surrounding the main driver cones, which are designed
to direct the backward reflections to the front.
Passive & Active monitors
Most studio monitors are passive monitors: That is, they are connected to
power amplifiers, that in turn are connected to the mixer. The levels of the
audio signal reaching such monitors are generally controlled from the mixer
itself. Some monitors, however, have power amplifiers built in. Such monitors
are called active speakers, and they’re considerably more expensive.
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With passive monitors, there is a possibility that we will overdrive the speaker
drivers – that is, give them a signal input that is beyond their capacity,
thereby damaging them. With active monitors this is not a worry, since the
amplifier and the driver are a matched set. (Having matched amplifiers often
makes active speakers sound better as well!)
Speaker cones must be protected from dust and direct sunlight – and
most of all from curious pokes by people!
Headphones & Earphones
Headphones are small paired speaker units
fitted in a plastic or leather casing which is
designed to be worn over the user's head. (The
headphone's smaller cousin, the earphone, has
two small speaker units enclosed in small plastic
holders designed to fit within your ears.)
Headphones can be used in both studio and
outdoor situations. In studio situations,
headphones are often used to prevent acoustic
feedback when there are live microphones
around. In field situations, headphones prevent
extraneous ambient noise from disturbing your concentration on the
audio that is being recorded.
The primary sections of a headphone unit are:
1. The Head strap/headband: An elasticized band that holds both
speaker units together and allows the user to fit them over his or her
2. The Ear cups: Made of plastic or leather, the ear cups enclose the
speaker units and have a covering of soft felt, vinyl or leather that
allows the speakers to fit snugly over or against the user’s ears.
3. The Lead: Headphones are generally designed to monitor stereo
audio. This is why there are two speaker units, and the input cables
are paired: A main stereo cable usually splits into two independent
left and right wires that feed each speaker unit.
4. The Jack/connector: Headphones and earphones are generally
equipped with stereo connectors, usually 1/4th inch or 1/8th inch
miniphono stereo jacks, as headphones are inherently intended to
be monitor stereo audio. (Correspondingly, most smaller field recorder
units are equipped with miniphono sockets, and most pro field
recorders with regular phono sockets: The assumption is that pro
recorders will be used with full scale headphones, and smaller
recorders with earphones.)
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Magnetic recording is an analog recording process, and works on the
principle of electromagnetism. Magnetism and electricity are linked
phenomena, which means that an electrical current passing through a
conductor like a wire or a piece of metal generates a magnetic force that is in
proportion to the strength of the current. (Similarly, if a conductor is placed
in a moving magnetic field, an electric current is generated within the
In magnetic recorders – typical examples are the cassette and the spool
recorder - the input electrical signal from the microphone (or any other
audio signal source) is fed to a recording head, which is essentially a soft
iron core with a wire coil wrapped around it. A motor unit moves a rubber
or plastic capstan and pinch roller system that grips the tape surface and
moves it under the head at a constant pace (usually 4.76 cm/second). As the
input current varies according to the changes in the audio, so does the
magnetic force generated in the iron core of the head. This varying magnetic
force is recorded onto the tape as a rearrangement of the magnetic particles
on the tape surface.
Fig 16. Recording on a magnetic tape organizes the magnetic particles on the tape in
response to the input signal
When the recorded tape is then played back, the tape is moved across a
second head – the playback head – where the reverse process takes place:
The magnetic field generated by the particles on the tape generate a
corresponding current in the iron core of the head, which is drawn off by the
wire coil and can then be amplified and played back over speakers, recreating
the original sound. In professional magnetic recorders, the recording and
playback heads are often separate, but in most consumer grade equipment,
the same head performs both functions.
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Fig 17. The magnetic recording head
The primary issue with the media - tapes, floppy discs - used in
magnetic recording is that they can be easily damaged by heat, or
any stray elecromagnetic fields in the vicinity.
Tapes and floppies can be damaged if they are left near computer
screens, speaker sets, any powerful magnets - or even, sometimes, if
they are locked up in a metal drawer or almirah!
Additionally, the tape base is actually an emulsion containing magnetic
particles; and this often attracts mildew and fungus if the tapes are not
used or aired out a bit on a regular basis.
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Almost all audio equipment used in a radio station has an audio level meter
of one kind or the other. Maintaining audio levels is important: The circuitry
in every audio equipment has a capacity beyond which it will not be able to
handle the voltages and currents involved. If we feed the equipment a signal
beyond its capacity, at best the audio will be distorted – and at worst, it will
damage the equipment. Similarly, if the audio levels are too low, then the
system’s own noise will drown out the usable signal.
For more on Signal to Noise Ratio, see Section B: Signal to Noise Ratio on Page 214
Audio meters are also necessary so that we can match levels across pieces
of equipment, keeping the quality of the audio high.
Different pieces of equipment carry different types of meters, and it is vital to
know how to use each of these to gauge the audio levels properly:
1. The VU meter
The VU or Volume Unit meter is the most common analog meter type for
audio equipment. Typically, it has a graded meter with markings ranging from
around -20 VU to +3 VU. Till 0 VU, the meter is generally marked in green or
black, and beyond this, it is usually marked in red. A needle moves across the
meter to indicate the level of the audio that is being input into the equipment.
0 VU indicates the maximum distortion free level that the equipment can
handle. In practice, there is some scope for going beyond this: It is okay
if most of the programme is around 0 VU, with the occasional peak
reaching + 2 VU.
For more on dBu units, see Section B: Decibels on Page 172
Fig 18. The VU meter
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Lining up VU meters
VU meters on various pieces of equipment are often used to align the
equipment to a reference signal. For this, we use a source that plays back
a 1000 Hz (1 KHz) test tone at 0 dBu, and feed the source to all the
equipment that needs to be aligned.
The faders on the equipment to be aligned are then set to a standard
reference point (usually -10) and the channel gain turned up or down till
the VU meters on all the pieces of equipment reach -4 VU.
When all the equipment that we are using has been so aligned, it is good
practice to mark the gain setting at which this alignment has been achieved
on each of them – this way we can be sure that all the equipment is
reflecting the correct levels.
2. The PPM meter
In some equipment, it is more important to measure the highest levels of the
audio signal – the peak. Since the VU meter needle is in constant movement,
and doesn’t stop at the peaks, it is hard to note the peaks of the signal.
This is why some pieces of equipment – especially the master broadcast
mixer in large studios – are equipped with PPM meters or Peak Programme
Meters, which are designed and graduated specifically to measure the peak
levels of the programme.
Fig 19. The PPM meter
In the PPM meter, the graduations are generally marked from 1 to 7. The
reference 0 dBu is equivalent to the 4 mark. The signal should be controlled
to not exceed the 6 mark
3. Digital meters (LCD or LED)
Modern digital audio equipment often carry a third type of meter called a
digital meter. These are often a part of the Light Emitting Diode (LED) display
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on the casing of the machine; or are carried as part of the remainder of the
display on a Liquid Crystal Display (LCD) display built into the unit.
Unlike the analog VU and PPM meters, digital meters give no headroom –
that is, we cannot exceed the 0 mark on these meters. If we do, distortion of
the sound will almost certainly result.
Fig 20. The digital meter
Many sound recordists today tend to use the -12 dBu mark on the meter in
the same way as the 0 dBU reference on the older analog meters: That way,
the audio can exceed the reference level somewhat without still reaching
the 0 dBu mark, giving the same headroom as the analog meters. If we
record using this standard, it is wise to keep the softest sounds around -18
dBU to – 20 dBu, and the loudest sounds around – 6 dBu. When we finally
mix and master the sound, we can bring the whole programme further up
towards the 0 dBu mark.
LCD digital meters are composed of a series of dots or black boxes
that appear and disappear in response to the input signal. The only
permanent markings are two dots marked towards the right end of
the meter, and corresponding roughly to the 4 and 1 marks. Try and
keep recording levels on or around the first dot, with the peaks touching
the second dot (to the right) only occasionally.
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A microphone is a transducer, a device that converts one form of energy to
another. In the case of the microphone, the acoustic energy of sounds as
they travel through air get converted to a corresponding electrical signal
whose voltage varies in direct correspondence to the original sound waves.
This electrical signal can then be fed to a recording device or other audio
devices so that it can be stored for later playback.
Microphones are popularly referred to as mics (pronounced mikes). Today,
there are several varieties available, with specific functions and purposes.
We can understand how a mic works by looking at the simplest type of mic
there is: The dynamic or moving coil microphone.
Fig 21. The moving coil microphone
At its very basic, the dynamic microphone is made up of a thin plastic or metal
film attached to a fine coil of wire. The film – known as a diaphragm – is
usually stretched across the open end of the microphone, and the coil hangs
below it, suspended between the North and South poles of a powerful magnet.
When someone speaks in front of the diaphragm, their voices reach the
diaphragm as a series of pressure waves – changes in the pressure of the air
between their mouths and the diaphragm. The pressure waves make the
diaphragm vibrate back and forth, moving the attached wire coil across the
magnet. When the wire moves in the magnetic field, a small current is generated
in the wire. This phenomenon is called electromagnetic induction.
The important thing is that the current varies in direct proportion to the
movement of the diaphragm-coil combination – and since that is dependent
on the strength and frequency of the original sound waves striking the
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diaphragm, the current is actual in direct correspondence to the original sound.
This small signal, only a few microvolts strong, can then be drawn off and
amplified by a pre-amplifier, so that we can record or manipulate it further.
For more on pre-amplifiers, see Section B: Amplifiers on Page 128
I. Mics classified by construction
1. Dynamic mics
Dynamic mics are of the moving coil or the ribbon type. The dynamic coil
type is decribed in the example above. The ribbon mic also works on the
principle of electromagnetic induction, but the transduction in this case
takes place because of the vibrations caused in a thin aluminium ribbon
suspended in a magnetic field.
Dynamics mics are especially good for field recordings, as they require no
external source of power.
Examples: Shure SM 57 and 58
2. Condensor or capacitor mics
Just as dynamic mics make use of the principle of electromagnetic induction,
capacitor mics make use of the principle of capacitance.
Capacitors – also known as condensers - are electrical components where
two metal plates are separated by an insulating material. If a voltage is applied
across the two plates, the two plates get charged. If the distance between the
two plates now changes, the voltage across the two plates will change
In capacitor mics, one plate of the capacitor is fixed, while the other plate
acts as the diaphragm, and can move freely in response to the sound energy
striking it. The change in the voltage caused by the movement of the free
plate – and the consequent change in the distance between the two plates –
is read as the audio signal.
Capacitor mics need a power supply to keep the capacitor charged. This
may either be supplied by an internal battery fitted in the mic; or through a
power supply provided through the same wires which carry the audio signal
away from the mic. If the latter system is used, the power supply is known
as a Phantom power supply. This is usually a 48V supply; and mics which
require such a supply usually include P48 within the mic name.
Capacitor mics are highly sensitive, and give very accurate sound
reproduction. This is why they are used extensively for broadcast.
Examples: Rode NT-1A, Sennheiser MKH 416 P48
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3. Electret condenser mics
Electret condenser mics are a variety of condenser mic where the capacitor
plates are permanently charged instead of requiring a continuous electrical
charge to maintain their voltage.
As they do not require a power supply, this means these mics can be very small
in size, allowing them to be used as built-in mics in several types of devices.
However, their audio quality is also poorer than powered condenser mics.
Electret condenser mics are usually found as the built in mics on consumer
grade home audio and portable audio equipment, especially smaller twoin-one cassette recorders.
4. Carbon mics
Carbon mics are one of the oldest types of mics, and are used in old style
telephone handsets. They can only handle a frequency response of about
300 Hz to 3000 Hz, making them useless for broadcast audio.
5. Piezoelectric mics
The modern replacement for the carbon mic in telephone and mobile phone
handsets, these mics make use of the piezeoletric effect - the ability of
certain crystals to generate a small voltage when distorted mechanically in a
particular direction – to generate an audio signal. Their frequency response,
though better than carbon mics, is still not perfectly suited for broadcast –
but is often adequate for phone in programmes and on-location reporting in
the absence of other equipment.
II. Microphones classified by directionality
Microphones can also be classified on the basis of their directionality – that
is their ability to pick up sound from specific directions around the mic. This
is generally represented on a polar diagram, a 360 degree chart that shows
the pick up pattern of the mic.
The polar pattern or diagram generally shows the pick up of the mic at
various frequencies. Naturally, a mic that has the same or similar pick up
pattern at every frequency is to be much preferred.
Thus, on the basis of their pick-up pattern, mics are classified as
omnidirectional (where the mic picks up sound from all around it); or
directional (where the mic only picks up sound from specific directions).
Directional microphones can be subclassified into several types, based on
how directional they are. Among these, the most common variety is the
simple cardioid mic, so called because its pick up is mildly directional, and
looks roughly like a heart shape.
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Fig 22. Omnidirectional polar pattern
Fig 23. Basic cardioid mic polar pattern
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Most cardioid mics tend to pick up sound best in the direction that they
point to directly, with the highest rejection of sound being at the sides. There
are variations of the cardioid mic which are even more directional, and
whose pick up is limited to a very narrow area in front of the mic. These mics
are known as supercardiod and hypercardioid mics.
Fig 24. Hypercardioid polar pattern
Hypercardiod mics often use additional accessories like a slotted interference
tube to heighten the directional effect. The long tube attached to the front
gives them an elongated appearance that suggests their other name: Tube or
shotgun microphones, since they often look like gun barrels.
The last kind of directional mic is the figure of eight or bidirectional
microphone, which is only sensitive to sound coming from the two sides of
the microphone.
The figure of eight microphone is usually only used for situations where one
mic may be used between guest and presenter, or where two singers share
a mic.
Nowadays, many manufacturers use advanced electronics to make
mics that have switchable polar patterns. This lets the mic be used as
cardioid, bidirectional or omnidirectional mic depending on the
situation. (For example: The Sennheiser MKH 800)
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Fig 25. Figure of Eight Polar pattern
The proximity effect
An important consideration when using bidirectional and cardioid mics is their
response when the source of sound is very close to the mic. This causes the boost
of low frequencies in the mic’s pickup, an effect called the proximity effect.
Used well by an expert and trained presented, this can result in a full and
throaty larger-than-life radio voice. But used poorly, this can mean muddied
and dull audio.
Guarding against pop
Many sounds used as part of normal speech are plosive – that is, the
sounds involve the expulsion of gusts of air from the mouth. When
these sounds are made in front of a mic, the gusts of air can strike the
mic diaphragm, and cause a rumble that can distort the audio. (The
letters P and B, in particular are responsible for this.) The effect is called
pop or popping noise.
This effect may be reduced with voice training (which teaches the
presenter to say the plosive sounds without large pops of air); and by
using a pop filter in front of the mic. Pop filters are fine screens of fabric
or metal mounted on a small stand which may be attached in front of
the mic. The mesh breaks up the blast of air, and prevents it from hitting
the sensitive portions of the mic, thereby reducing the pop.
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The Minidisc (MD) format was introduced in 1992, by Sony. MDs were
intended to replace cassette tape as a new portable digital audio playback and
recording system. This meant it had to be small and able to withstand vibrations
and rough treatment outside the safety of the home or studio. Unfortunately
it never quite reached the same level of popularity as the compact cassette –
though its quality and compactness made it the de facto standard for
community radio and journalists till the advent of flash based recorders.
For more on flash recorders, see Section B: Flash Recorders on Page 187
The Minidisc
The Minidisc or MD is actually a small silvered disc contained in a plastic
case. In some ways it looks like a computer floppy disc, only much smaller.
The disc stores up to 16 bit, 44.1 KHz sampled digital audio through a
process called magneto-optical storage, which combines some aspects of
magnetic recording with the optical storage processes used in CDs. This
also makes MDs erasable and reusable with no loss of quality, which
contributes greatly to their use in the field.
For more on sampling, see Section B: Analog & Digital Audio on Page 124
For more on magnetic recording, see Section B: Magnetic Recording on Page 193
For more on CDs, see Section B: Compact Discs on Page 138
Being a digital storage medium, MDs can store audio as tracks, which means
we can search through them in a non-linear fashion: We can skip tracks we
don’t want to hear, and jump straight through to the recordings made at the
end. Information regarding the tracks is stored – like CDs – in a table of
contents file that is updated each time we record or erase a track.
A standard MD disc. The shutter moves aside
during recording to let the recorder access
the actual disc surface.
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MDs can record in both stereo and mono. At its basic short play (SP) setting, a
normal MD recorder can store up to 74 minutes of stereo audio on a single 300
MB capacity disc. This is doubled to 148 minutes if we record in mono. Audio
is recorded on standard MDs in a digital compression mode called ATRAC.
This means that audio from a standard MD cannot be heard on a computer
without special software that can play back ATRAC compressed audio
For more on stereo and mono audio, see Section B: Stereo & Mono on Page 217
In recent times, a higher capacity 1 GB disc has become available which is
meant specifically for use with the new generation HiMD recorders (see
MD & HiMD, below).
MD recorders
MD recorders are available in both studio models and portable field
recording units, though the latter are in more common use. Most of the field
units are very compact, having dimesnsions not much larger than the disc
itself. Nearly all of the models – primarily from Sony, Sharp and Tascam –
have menu based operations, with many of the settings and features accessible
only through a customizable computer-type menu.
MD recorders were built to be used in tough field situations, and have
acquitted themselves well in a variety of conditions with minimal care. Most
accept a mini-phono jack based external microphone, and contain an internal
rechargeable battery. Some can accept an additional external battery – usually
AA size – in an attachable external case.
MD and Hi-MD
To remedy the compression that was placed on the audio in MD recorders,
Sony came up with a variant of the MD called the Hi-MD a few yars ago. HiMD recorders allow one the choice of recording in Hi-SP, Hi-LP or
uncompressed PCM WAV formats: All three modes record audio in a
proprietary Sony file format called OMG, which is then converted to
uncompressed WAV when transferred to a computer. (HiMD recorders can
also record in the older MD mode, in which case the PCM WAV option is
not available.)
Hi-MD recorders can play older MD discs; but discs recorded on the
HiMDs in PCM WAV cannot be played back on the older recorders.
Hi-MD recorders also offer the option of avoiding D/A conversion when
transferring or dubbing the audio onto another recorder: Where regular
MDs could do this only through the line out jacks (that needed a miniphono plug and cable to be plugged in), HiMD recorders allow transfer of
the audio as a digital file through the USB port built in to the recorder.
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This is highly useful, as it avoids D/A conversion related losses, and saves
transfer time.
For more on D/A conversion, see Section B: Analog & Digital Audio on Page 124
HiMDs recording in PCM WAV format give about 27 minutes of recording
on the standard MD disc, which is 300 MB in capacity. Newer 1 GB Hi-MD
discs allow one to record approximately 124 minutes of uncompressed
audio on a single disc.
Hi-MD is a recording mode, and is not related to the disc itself.
Any MD disc can be formatted to Hi-MD mode and used in a Hi-MD
Taking care of MD discs
Do not touch the disc by opening the shutter on the cartridge. The
shutter and disc will be damaged if the shutter is forced open.
Do not place MDs in direct sunlight, areas of high temperature,
or high humidity.
If dust gets into the MD cartridge, wipe it with a soft DRY cloth. Do not
use any liquids to clean MDs.
When putting a label on a MD, make sure it is fixed to the correct
position for labels on the disc. If the label is not properly fixed it may
roll up or come loose and could cause the cartridge to get stuck in
the MD player.
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At first sight, the mixer is a daunting sight. Even a comparatively small mixer
with only 4 channels on it seems to have way too many buttons and faders
for one to understand them all. But if one looks a little closely, one will
realize that the mixer is actually divided into sections, and that each plays its
own specific part in the overall process of controlling and managing audio.
Whether in the studio or the field, the mixer is the heart of the system.
At its most basic, the mixer is used to mix audio – that is, combine different
sources, adjust their individual and relative levels, and give us one combined
output which can then be fed to a recorder or a transmitter. Each source is
connected to a different channel, so that it can be controlled independently;
and all the channels feed the master channel, which controls the final output.
Fig 26. A basic mixer shown in schematic form
Note that in this diagram, the sliders or faders on each channel – which we
use to control the level of the input – are set to different points. Depending
on how loudly or softly the person in front of the mic is speaking, the fader
is moved up (boost) or down (cut). Levels may be seen on most mixers on
VU meters. There may be one or several meters, which may show individual
input levels or the final programme output level.
In this case, the three input channels form one mixing bus: One pathway
down which the combined audio will go before it reaches the master fader.
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Larger mixers with more channels may have more than one mixing bus,
letting us gang or group channels. This lets us select the inputs that will be sent
to a particular output. For example, during a live programme, which is being
transmitted directly from the studio, we may have two speakers and a music
source like a CD playing underneath their voices. For the live transmission,
we may have all three sources being channeled to a programme (mixing) bus,
from where the output goes to the transmitter. But we may want only the
voices to be recorded to a recording system - without the music - for archive which case we might also direct the two mic channels to a
second (recording) mixing bus, which sends its output to a recorder unit.
Many mixers will also feature some stereo and some mono channels, to
allow us to connect stereo sources and mono sources separately to the
mixer. Channels may also feature a PAN-POT knob, which allows us to
‘pan’ the input audio left or right when we are mixing stereo audio.
Mixers may also have an equalization section, where there may be an EQ
button along with LO, MID and HI knobs to control the relative mix of
frequencies in the input audio.
For more on equalization, see Section B: Equalizers on Page 179
Other features to remember when selecting a mixer
The illustration given on the previous page illustrates a 3 channel mixer.
In practice one should get a mixer with as many channels as one can
afford. This will allow you to add more pieces of equipment to the
studio without upgrading the mixer.
Additionally, many mixers come with A/B switches on each channel,
allowing you to keep more than one piece of equipment connected to
the same channel, but use the appropriate one as required.
Ideally, the mixer you select should offer more than one mixing bus,
allowing different mixes of signals to be sent to different equipment.
A broadcast mixer would also have stereo channels. These allow you
to control the left and right signals from a piece of stereo source equipment
with one fader.
Broadcast mixers should also be capable of controlling the operation of
source equipment: To start a CD player from the mixer itself, from example.
This is sometimes called fader start. Fader start means you must also
have playback and recording equipment that accept fader starts.
Mixer design and circuitry is a very specialized part of audio
equipment design. A good mixer with dependable and distortion
free circuitry is a very complex item, and very expensive. The mixer
is often the most expensive single piece of equipment in the studio.
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Modulation, at its most basic, means the combination of different waves.
This is a very important concept for radio transmission, because the whole
principle of broadcasting is based on the concept of modulating the audio
that we would like to broadcast.
Human ears are capable of hearing sounds between 20 Hz and 20000 Hz.
The average human voice ranges between 500 Hz and 5000 Hz, which is
directly in the middle of this hearing band. Our ears are tuned to listen
primarily to other human voices.
Now, let’s assume that we want to record and transmit a voice that is about
3000 Hz in frequency. A wave with a frequency of 3 KHz has a wavelength
of about 100000 metres. It is a principle of physics that we need an antenna
at least a quarter of the wavelength to effectively transmit the wave. This
means we need an antenna 25 km long to transmit our 3 KHz signal – which
is impractical, to say the least! The only way around this is to find a way to
raise the frequency of the audio in a way that allows us to use a more
conveniently sized antenna system. And this where modulation comes in.
For more on frequency and wavelength, see Chapter 1: So What is Radio &
How does it work? on Page 8
For more on antennas, see Chapter 5: Transmission Equipment on Page 72
We use modulation to ‘add’ the audio signal that we want to broadcast to a
high frequency (radio frequency) electromagnetic wave. The combined wave
then acquires the properties of both component waves. The audio signal
‘piggybacks’ on the radio wave, which is then called a carrier wave.
Fig 27: The modulation chain during transmission
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In radio broadcasting, modulation can occur in one of two ways:
The amplitude of the carrier wave can be modulated to carry the audio
signal. This technique is called amplitude modulation (AM).
The frequency of the carrier wave can be modulated to carry the audio
signal. This technique is called frequency modulation (FM).
Amplitude Modulation
Amplitude Modulation is the older form of modulation for radio. Depending
on the wavelength of the carrier wave, AM can be classified as Long Wave
(LW), Medium Wave (MW) and Short Wave (SW). Today, MW is the most
common form of AM transmission – All India Radio’s Akashvani and Vividh
Bharati stations broadcast on MW. Most MW stations broadcast on
frequencies between 535 KHz and 1605 KHz which correspond to
wavelengths of 560 to 187 metres. AM stations are usually spaced about
100 KHz apart.
In AM, audio information is combined with a carrier wave by varying the
amplitude of the carrier wave above and below its unmodulated value: The
changes in amplitude reflect the variations of the audio signal.
Fig 28: Amplitude Modulation
The biggest advantage of AM is that relatively modest output powers can
reach very long distances, often hundreds of kilometres. Shortwave (SW)
broadcasts can go even further – thousands of kilometers – and reflections
off the electrically charged ionosphere of the Earth’s atmosphere can increase
that distance further.
AM broadcasts can carry audio information ranging from about 200 Hz to about
5 KHz. This means the broadcasts are fine for voice, but often make music sound
scratchy, since many instruments have frequency ranges higher than 5 KHz.
The ionosphere layer of the atmosphere is more diffuse when the
sun’s radiation is striking it directly. It is denser on the night side of the
planet, when it is in shadow. Ionospheric reflection of SW broadcasts,
correspondingly, improves at night time.
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Frequency Modulation
Frequency Modulation involves modulating the audio signal with a Very
High Frequency (VHF) radio carrier wave in a way that the resultant wave
retains the amplitude of the carrier wave, but has a frequency that varies
according to the audio signal.
Fig 29: Frequency Modulation
This form of modulation makes broadcasts less susceptible to interference
from storms and stray electrical and magnetic influences – but it also means
a more limited transmission range for the same output power.
FM transmission is line of sight, meaning the broadcast antenna has to be
electronically visible to the receiving antenna. This is why FM stations are
typically local stations, and why FM is the modulation technique of choice
for CR stations.
Placing FM antennas at high vantage points can increase this range, as can
increasing the transmitter strength - but there may be physical limitations to
doing this, especially with reference to the technical guidelines covering
community radio stations in India.
For more technical parameters for CR in India, see Chapter 9: Community
Radio Guidelines in India and their Implications on Page 105
Commercial radio broadcasting is globally assigned frequencies between
88 and 108 MHz, at 200 KHz intervals. The extra bandwidth (200 KHz on
each side of the base frequency) means FM can carry higher quality audio
(20 Hz to 16000 Hz), as well as stereo signals. For digital audio, FM is
generally rated as being able to carry nearly CD quality audio, at about
96 Kbps/44.1 KHz sampling.
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A patchbay, also called a jackfield, is one of the most useful items in a
studio. Anypne who has ever connected and disconnected any audio
equipment - especially a modern multi-component hi-fi system - will agree
that it can be a really painful process, especially if it has to be done multiple
times in a day.
We make the process of connecting and disconnecting inputs and outputs
to each other easier by using a patchbay, which is essentially a series of
electric contacts enclosed in a single housing. Different pieces of equipment
are permanently wired to one or more of the contacts (two contacts if we
want to keep the stereo inputs and outputs separate, one contact if we're
only working with mono). As per our requirements, we can then connect
any combination of contacts with short patch leads, which are short
connectors designed to connect patchbay contacts.
The most commonly available patchbays normally have 2 rows of 26 sockets,
with each socket on the top row paired with the socket below it. The top row
of sockets is for source equipment; the bottom row is for inputs to the mixer
or other recording or transmission equipment. For a small CR station, it may
be advisable to invest in modular patchbays, which are available in 4 + 4
sections: This means we can add more contacts as we require them and our
studio expands.
Fig 30: A schematic of a small patchbay
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This diagram shows a small patchbay, labeled as per the inputs and outputs
connected to it.
The top row of jacks are outputs, and are labelled as follows:
CD L and CD1 R: These are the Left and Right outputs from the CD Player
PGM L and PGM R: These are the broadcast mixer's Left and Right programme
DAW L and DAW R: These are the Left and Right outputs from the Digital
Audio Workstation in the production studio.
The bottom row of jacks are inputs, and are labelled as follows:
CH 1 L and CH 1 R: These are inputs to the Left and Right inputs of Channel
1 on the mixer.
CH 2 L and CH 2 R: These are inputs to the Left and Right inputs of Channel
1 on the mixer.
TX L and TX R: These connect to the Left and Right inputs of the compressor
Thus, while the CD Left and Right outputs on the top row might generally be
connected to the Ch1 L and Ch1 R inputs on the bottom row (that is, the
stereo inputs on Channel 1 of the mixer), in an emergency - when we need
to maintain or service the mixer, say - we can connect the CD player outputs
directly to the transmitter input, as illustrated.
A patch cord must always run from an output to an input: That is,
opposite ends must be connected on different rows. This is very
important - a small mistake in plugging together circuits can severely
damage equipment!
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All through this manual, we have used the word signal whenever we have
wanted to indicate an electrical current that carries information. To this, we
will now add the word noise, which can then be defined as electrical currents
which carry no useful information.
Every electronic circuit that carries a signal inherently has some internal
noise. These are basically stray electric currents that are generated by the
machinery itself. In audio terms, you hear this noise as a hiss or as a crackle
or background pop under the main audio. (If we cut off the audio feed and
simply boost the output of the equipment to a monitor, the static noise we
hear is the internal noise generated by the equipment.)
One of the reasons we keep the signal level as high as we can - without
reaching the distortion or overload point, of course - is so that the signal
(useful) audio can be distinguished clearly against whatever background
noise the system generates: If the signal level is too low, it will be drowned
out by the system noise.
Given the variety of audio equipment available, and the number of
manufacturers, it would obviously be good to have an objective measure of
this difference between the signal level and the noise levels of the system.
This is why the signal to noise ratio was evolved as an evaluative reference:
To develop standards for the level of noise in a system. A high signal to noise
ratio means there is always a large separation between the signal and the
background noise. A low signal to noise ratio means a small separation
between the two, and therefore the risk that the signal and the noise may not
be clearly distinguished from each other.
Signal to Noise ratio - often denoted as S/N ratio in short - is measured in
decibels (dB). Thus, if the maximum signal level the equipment can handle
without distortion is 80 db, and the level of the inherent system noise is
20dB, the S/N ratio for that equipment is 80 - 20 = 60 dB. (In practice, of
course, the measurement is not as simple as this!)
The better the components and the grade of manufacture of an
equipment, the lesser the internal noise that it generates - and the
higher its S/N ratio. Given two pieces of equivalent equipment, the
piece with the higher S/N ratios will be distinctly more expensive!
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Sound is the effect perceived by the brain when vibrations travelling through
the air stimulate the ears. These vibrations are conveyed through the air as
changes in the pressure of the air.
Anything that vibrates and is in contact with the air can create sound pressure
waves. These vibrations disturb air molecules causing waves of alternating
high and low pressure. The ear is a sensitive transducer that responds to the
changes in pressure. The pressure waves strike a sensitive membrane of
tissue inside our ears called the eardrum - which, as its name suggests, is
like a drum skin. The eardrum vibrates when the waves strike it, and pass the
vibrations on through three small bones to the inner ear. The inner ear
contains two chambers full of fluid, which are lined with fine hairs and
particles of calcium. When the vibrations reach these hairs, they are converted
into electrical signals which are passed on through nerves to the part of the
brain which processes these signals into the sensation we know as sound.
Sounds that we hear as being louder are caused by greater changes in air
pressure, which means the eardrum vibrates to a greater degree back and
forth (higher amplitude). Softer (or quieter) sounds are caused by lesser
changes in air pressure, which means the eardrum vibrates to a lesser degree
back and forth (lower amplitude). Loudness is a subjective measure and the
same sound may be perceived differently by different individuals.
For more on properties of sound waves, see Chapter 1: So What is Radio,
and How does it work? on Page 8
When we say human beings can hear sound in the range 20 Hz to 20000
Hz, we are saying the pressure wave changes at a rate between 20 times a
second and 20000 times a second. Looked at in another way, this is the
definition of sound, since only pressure waves between these two limits will
result in the sensation we call sound.
Sound waves travel through air at a speed of 344 metres per second
(1238.4km/h). This is measured at sea level at a temperature of 15 ºC.
The speed of sound is independent of frequency.
Audio is the word used to signify the electrical equivalent of a sound wave,
which we create through a process of electro-acoustic transduction.
The audio signal, as we should correctly call it, takes the form of a changing
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electronic voltage in the circuit, that rises and falls in exact correspondence
with the changes in the original pressure wave.
For more on transduction and microphones, see Section B: Microphones
on Page 198
We convert sound to audio in order to be able to manipulate and/or store it
for later playback. A microphone is used to convert sound to audio, whereas
a loudspeaker or headphone is used to convert the recorded audio back
into sound so that we ca hear it with our ears.
Most of the equipment in the radio studio works with audio signals rather
than directly with sound - so most of the equipment should correctly be
termed audio devices.
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When we hear a sound, we tend to forget that we are actually hearing it with
both our ears. The purpose of two ears placed on opposite sides of our
heads is not, as widely assumed, for redundancy - 'one ear will continue
working if something happens to the other one!' - but in order to give us a
sense of spatial separation between different sounds.
We are able to create this spatial separation because of an interesting
phenomenon called phase difference. Sound, as we know, travels as a
series of waves, with higher pressure sections alternating with lower pressure
sections. When a sound is generated by a source on one side of us, it
reaches the ear closer to it by a shorter path, and the ear farther from it by a
longer path. What this results in is that though both ears hear the same set of
waves, there is a miniscule difference in the time it takes for specific parts of
the wave to reach each ear. Our brains use this to calculate the angularity of
the sound - that is, its position in front of us - and its distance from us. (This
allows us to create a mental picture of the soundscape in front of us that is
quite independent of what we see - this is why we can still tell the direction
of the sound when our eyes are closed!)
This is what stereo means - the ability to create a spatial perspective to
sounds we hear. When working with audio, we can create this effect artificially
by recording audio on two separate channels, and feeding the respective
channels to two separate speakers. By distributing signals between the two
channels, we can make the sound appear to emanate purely from one
speaker; from both to equal extents; or both, but with a slightly greater
emphasis on one of the speakers.
The effect is to create the phase difference we perceive when hearing naturally
with our ears. Naturally, to use this effect best, the ideal listening position should
be at a position exactly between and equidistant from each of the speakers.
If on the other hand, we used a single speaker - or fed the same signal to both
speakers - we would not be able to get this sense of spatial separation. When
we have only one channel of audio, we call the signal a mono signal.
Stereo & Mono connectors
As we need two channels of audio for stereo, we have to keep both channels
separated from each other when conveying the signal from one piece of
equipment to another. This is why all stereo equipment has two connectors,
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Fig 31: Stereo perception of sound. The various instruments sound as
if they are spread out in front of the listener even though we actually
only have two sound sources - the two speaker units.
usually labeled Left (or L) and Right (or R). Often the connectors are also
colour coded, with red connectors for the right channel, and white or black
for the left channel. It is important to make these connections properly, so
that the stereo image does not accidentally get mixed up.
Stereo connectors can be clearly indetified just by looking at them. RCA
stereo connectors, for example, come in a colour coded pair. Stereo phono
jacks are always of the TRS variety (Tip-Ring-Sleeve) with the three contacts
defined by two black bands near the tip of the jack.
Mono connectors usually use a single connector, or a phono jack with a
single black band near the tip. It is usually possible to make or purchase
cables that will let you feed a stereo output to a mono input, or a mono
output to both stereo inputs.
Mics: Mono and stereo
Unless you are using a stereo microphone - which actually combines two
microphones in a single body, and gives two discrete outputs - all mics are
mono, and give a single channel output. The stereo image that you see in
the final programme that is broadcast is built during the post production
process. This is what the Pan-Pot knob on the mixer is used for - to distribute
the so und between both audio channels.
For more on the Pan-Pot knob, see Section B: Mixers & Mixing Desks on Page 207
Remember, mixing in stereo or working with stereo sound automatically
assumes that the listener has equipment that will allow him or her to recreate
the spatial separation that you are building. If all your stereo programmes
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will be heard on small single speaker transistor radios, it is pointless to
spend time, money and effort on doing stereo programmes in the first place.
Mixing audio in stereo is not only more time consuming, it requires
more powerful equipment - in the sense of higher end computers
and speakers. Digital stereo audio also means larger audio file sizes
than mono. Finally, stereo transmitters give a smaller transmission
range than mono transmitters of the same power output rating.
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A telephone hybrid makes it possible to talk to callers on-air - that is, it allows
people calling the studio 'live' to participate in a discussion with the presenter
over the phone that goes out as part of the transmission. Essentially, this
means the caller's voice is added to the mixer's output; and that the studio
sound - the presenter's voice - reaches the caller over the phone line.
Having a telephone hybrid system allows you to create greater interaction
with your listeners, and involve them in the programmes the station generates
in a much more active way.
What the hybrid does
There are two important considerations when connecting a phone line to
our audio systems:
1. The telephone system works on the basis of a continuous power voltage
supplied to the telephone instrument - we have to see to it that this does
not interact with our audio systems in any way, as this can cause damage
to our equipment (not to mention a nasty hum in the audio!)
2. The telephone carries both received audio (caller's voice) and sent audio
(presenter's voice) over the same wires. We need to use a system where
these two audio feeds can be handled independently and sent independently
of each other to their respective destinations: The caller's voice to the
mixed mixer programme output, and the presenter's voice to the caller
over the phone - but keeping both audio feeds at a balanced level.
To Mixer
Tel Line
Fig 32: A schematic view of the telephone hybrid
For this the hybrid uses three types of circuitry:
1. A difference amplifier that performs the task of separating the caller's
voice and sending this to the mixer;
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2. An isolation element , which is actually a transformer that prevents the
telephone line power supply from being transferred into your audio
3. A balancing network that balances the level of the presenter's voice
against the voice of the caller, and helps the difference amplifier subtract
the send audio. If the balancing network is not very accurate, then the
subtraction operation will not completely remove the send audio, and
the audio may be distorted.
The separation is noted in the hybrid specs as a negative figure in decibels:
The higher this number, the better the hybrid - and the more expensive it is
likely to be.
The signal that is sent from the mixing desk to the hybrid send input is called
a mix minus or cleanfeed signal. This is because it contains all the on-air
audio that you want the caller to hear, less the output of the phone hybrid
(which is the caller's voice itself.)
Most broadcast mixers already have a dedicated channel for the phone
hybrid to be plugged in, and have a dedicated mix minus already set for this
channel. If it doesn't, you will have to direct all the sources except the hybrid
output into one auxiliary mix bus, and use the output of this mix bus as the
mix minus to feed back to the phone line.
Using the hybrid
Most hybrids are rather straightforward to use - they may handle one line or
multiple lines, with lights that generally come on to indicate which line the
incoming call is on. Once things are set up, operation is as easy as pressing
the correct line button to connect the line to the audio feed. Most hybrids
also allow you to connect a standard telephone instrument to them in order
to make calls.
A good multiline hybrid should allow you to queue callers, and
switch between them easily.
In the case of some older (analog) hybrids, there is generally a null adjustment
that lets you tune the circuit for best audio quality. Modern digital hybrids
are excellent at signal separation, and do not need such tuning at all.
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The transmission system is the final step in getting a broadcast signal on air
and out to its listeners. And the heart of the transmission system is the
transmitter, the combination of circuits that turns an audio signal into a
frequency or amplitude modulated radio wave that can be broadcast.
Let's take a good look at the FM transmission system to understand what a
transmitter unit does.
Processed Audio
MPX Signal
RF Power
HI power
RF signal
RF signal
MPX Signal
Fig 33: Schematic view of FM transmission system
The process starts with the final programme output from the studio or playout
system. For our discussion here, and because FM has the capability to
handle stereo broadcasts, we will assume this is a stereo signal with left and
right channels.
The final programme is by now, hopefully, mixed and the levels corrected
properly already. But this is fed to a compressor/limiter unit anyway to
ensure that the signal is properly corrected to transmission parameters.
This unit applies compression and limiting to prevent the transmitter from
being overdriven, and to control the dynamic range of the audio.
For more on Compressor/Limiters, see Section B: Compressor/Limiters on
Page 149
The processed audio signal is then fed to a stereo encoder. The encoder
combines the two channels of audio - left and right - and also generates a
19 KHz pilot tone that is used by receivers to detect a stereo broadcast.
The output is said to be multiplexed, as it now consists of several elements.
(This often shortened to MPX, a labeling that you may find marked on the
outputs of encoders.)
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The multiplexed signal is now forwarded to the exciter unit, which generates
the radio frequency carrier wave. (As we have seen, for FM, this carrier
must be between 88 MHz and 108 MhZ in frequency.) The exciter also
modulates the carrier with the encoder's MPX signal, thereby creating a low
power radio frequency (RF) signal that can be transmitted by an FM antenna.
Exciters generally have an inherent power output of 30 - 50 Watts. For most
community radio stations - and especially those in India - this may be more
than enough as per the guidelines and the signal gain one is likely to get
from an appropriately matched antenna.
For more on transmitter strength parameters, see Chapter 9: CR Guidelines in
India and their Implications on Page 105
If more power than the exciter's inherent power is required, then one or
more power amplifiers may be added between the exciter unit and the
antenna, to boost the strength of the signal. (Commercial broadcasters often
boost the signal to several kilowatts.)
The final modulated and boosted signal is then sent to the transmitting
antenna unit, which radiates the modulated multiplex signal into space.
AM antennae are designed to be a quarter the wavelength of the station's
broadcast wavelength, which - given the high wavelengths used for AM
broadcast - mean the antenna unit and the tower on which it is mounted on
can often be very large.
FM antennae, on the other hand, can be much smaller. The high frequencies
used for FM transmission mean the wavelengths are considerably smaller,
and antennae can be about half the wavelength of the station's carrier
frequency. Typically, this means an antenna of 2 metres’ width or less. The
most common antenna used is a dipole antenna, which is omnidirectional,
and radiates equally in all directions.
When the multiplexed and modulated signal reaches the antenna what
happens is this: The RF signal flowing into the antenna creates a
corresponding change in the electromagnetic field around the antenna,
which moves away from the antenna at the speed of light. Since the RF signal
flowing into the antenna is changing constantly in response to the audio
signal, the electromagnetic field being radiated is also changing constantly.
The antenna on at the listener's end picks up this varying electromagnetic
field and the radio receiver's circuitry extracts the original audio from it
through a series of RF filtration circuits. The extracted audio can then be
amplified and played back over the transistor's speaker.
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All of the studio and transmission equipment at your radio station requires
a source of electrical power to work. This is usually supplied by the AC
mains power supply provided by the local power company, which in India
is usually run by the government. (Though power distribution in some areas
has been privatized.)
However, many stations are located in areas where mains power supply is
unreliable. Unless you have back-up, a mains power failure will interrupt
your broadcast. This is a serious problem - remember, your listeners will
also be affected by the electricity failure, and will want to rely on their radio
station to keep them informed about it!
This is the purpose of an uninterrupted power supply (UPS). As the name
suggests, a UPS provides uninterrupted power to the station even when the
mains supply is disturbed.
There are many different UPS systems that supply varying degrees of backup protection. The choice of system for your station should be made after
considering the quality of the power supply in your area. For example,
stations located in areas that suffer from constant power disturbances will
need a more complete power back-up system than stations located in areas
where the power supply is more stable.
What can disturb the mains electrical supply?
The mains supply is meant to be a stable AC voltage of 220 volts at
50 Hz, but there are several kinds of power line disturbances that affect
the mains supply:
Lightning, power network switching and the operation of other high
power equipment in your building, such as elevators, spot welders and
so on will cause spikes in the mains voltage. A power spike or a power
surge is when the mains voltage jumps to well over 220 volts for a short
time. The mains voltage can also can dip below 220V, providing an
undervoltage supply. This can be caused by faults in the power network
and sharp load changes. This kind of condition is often seen in light
bulbs that dim in intensity, a condition known as brownout.
The mains supply can also be noisy when signals at frequencies other
than 50 Hz find their way onto the power lines.
Lastly, the supply can black out. In this case there is a total voltage loss
and all electrical equipment is left without power. Blackouts can last for
a few moments, or sometimes they can last for a number of days - a
common condition especially in the remote parts of the country.
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A UPS counters power disturbances in two ways:
By acting as a buffer between the sensitive studio equipment and the
fluctuating mains power supply, providing protection from power surges,
dips and line noise.
By providing back-up power in the event of a complete power failure.
The duration of the availability of back-up power is dependent on the
batteries used as part of the UPS.
Types of UPS
There are three main types of UPS: off-line, line interactive and online UPS.
Each one has different features:
1. Offline UPS
Off-line UPSs only supply equipment with back up power when the
mains supply is not available; and are generally used on equipment
which can accept a momentary loss of power.
Offline UPSs be used in conjunction with surge protection devices often known as spikeguards, which may be built into the power supply
points themselves. Offline UPSs provide no inherent protection from
spikes and brownouts, both of which can be dangerous for electronic
equipment. In this sense, they are most appropriate for areas with minimal
power problems, though they are the cheapest of the three types in
terms of cost.
Fig 34: Offline UPS system
2. Line interactive UPS
Line-interactive UPSs are used when mains voltage fluctuations (dips and
spikes) are a problem. Like the offline UPS, in the line-interactive system,
battery power is only utilized when the mains supply is not available. But in
addition, the mains power itself is fed to the equipment through a transformer;
and a monitoring circuit watches the main supply for dips and spikes.
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Thus, it is line interactive because it corrects the voltage, or switches to
backup power, based on a constant assessment of the mains supply.
Though line interactive UPSs respond to spikes and drops in voltage,
there is still a distinct response time within which the change in
voltage could affect your electronic devices.
Fig 35: Line interactive UPS
3. Online UPS
The on-line UPS provides the greatest safety and the highest equipment
In the on-line UPS, mains power is converted to DC through a rectifier,
removing any chance of surges and dips. This is then converted through
an inverter to a completely back-up based AC supply. When mains
power fails completely, the system runs off the backup batteries.
Strictly speaking, these are the best UPSs for sensitive electronic
equipment - but they are the most expenive kind as well, often being
more than twice the cost of an offline UPS of similar rating.
Fig 36: Online UPS
UPS systems are only back up power supplies! Having a UPS system
is pointless if you have frequent interruptions of your mains power
supply, as the UPS batteries will only charge as long as it is plugged
into the mains supply
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Power rating and back up duration
There are two specifications for UPSs that you have to keep in mind beyond
the types specified above.
The first consideration is its power rating - that is, the maximum power
consumption that it can support. Each piece of equipment that you run off
any power supply will consume some power. The UPS you acquire must be
able to comfortably support all the equipment that you wish to connect to it.
UPS power ratings are usually given in Volt Amperes (VA) or Kilo-Volt
Amperes (KVA). Standard ratings include:
650 VA (about enough to support one computer with a 15" monitor)
1 KVA (enough for one computer with 15" monitors, along with a CD
player, 6 channel mixer, a cassette deck, studio audio monitors)
1.5 KVA (enough for two computers with 15" monitors, along with two CD
players, mixer, a cassette deck, powered studio monitors, amplifiers )
2 KVA (enough for all of the above, plus MD or flash based recorder units,
studio lights)
Large 5 KVA units and higher are used to back up entire offices.
A good rule of thumb is to get a UPS that can support about 30% more
than the maximum load that you will place on it. Another rule of
thumb for small and medium CR stations is to assume a minimum of
1.5 KVA per studio, not including transmission equipment and lights.
The second consideration is the amount of back up time that the UPS will
give you at the power rating it can support: This is dependent on the quality
and storage capacity of the batteries that the UPS system utilizes. In the
examples given above, the 650 VA UPS with a single battery can give about
15 minutes backup for the single computer it supports, with a simple two
wheeler automotive battery. But the 1.5 KVA UPS may be attached to two 25
plate truck batteries, and may give 3 - 4 hours backup for the entire load it
handles. UPSs can often be matched to a larger battery setup in order to
prolong the backup time.
Inverter batteries are a consumable: Whether you use it or not, batteries
have a limited life based on the number of charge-discharge cycles
they can handle. You must therefore count on changing the UPS
batteries every two years or thereabouts.
Remember that old batteries can be returned to dealers in exchange
for a discount on the price of a fresh battery!
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What kind of batteries?
Older battery technology involved the use of lead-acid batteries, which
remain the most easily available type of large rechargeable battery
anywhere in the country.
In lead acid batteries, the lead plates which form the cells of the battery
are bathed in sulphuric acid, which acts as the electrolyte, the charge
transporting chemical. In such batteries, it is important to maintain the
dilution of the acid at a specific level, which involves the topping up of
the liquid inside the battery with distilled water at regular intervals. The
distilled water is poured in through several rubber or plastic caps on the
top of the battery: Unscrewing the caps lets you access the insides of the
Though standard lead acid batteries are cheaper, and easy to obtain.,
an additional concern is that they should not be placed indoors or in
enclosed spaces, because the acid tends to give out fumes which are
harmful when breathed and corrosive to electronic equipment.
Modern rechargeable automotive and inverter batteries, however, are
maintenance free and need no topping up. They use a different
combination of chemicals to retain the charge; can be placed indoors;
and often last longer in regular use than the lead acid type (not least
because we often forget to top up the lead acid ones at the correct point
in time!). However, maintenance free batteries are much more expensive.
Nearly all major battery manufacturers provide both kinds of
batteries. Ask the UPS supplier which ones he recommends - in
most cases, he will be able to get you a good deal as a mass supply
agent. But remember to check the market price of the batteries he
suggests anyway!
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In essence, a generator is the reverse of an electric motor: Where the motor
consumes electricity in order to move, the generator uses a fuel source in
order to move a magnet and generate electricity. Thus where a UPS simply
stores existing power, the generator manufactures power. This means
generators can be used in places where electricity supply is erratic - as long
as fuel is available.
Generators also work on the principle of electric induction: A motor running
on kerosene, diesel, petrol or LPG (Liquefied Petroleum Gas) is used to spin
a powerful magnet within a coil of conducting wire. The movement of the
magnetic field around the coil generates an electric current in the coil that
can then be drawn off, corrected ('rectified') and supplied to devices.
Portable generators nowadays come in a range of capacities. Like UPSs,
they are usually rated in VA or KVA (Volt Amperes or Kilo Volt Amperes).
650 VA, 1250 VA, 1600 VA and 2400 VA generally fall into the portable
category. These usually run off petrol, kerosene or LPG. Larger generators
(5 KVA, 10 KVA and so on) are usually run off diesel.
Like any other fuel driven motor - a car engine, say, or a grain thresher generator engines need regular maintenance. Their engine oil (which
lubricates the moving parts of the motor) needs to be replaced, the sparkplugs
(which ignite the fuel mixture in petrol, kerosene or LPG units) cleaned - and
the fuel filters and tanks serviced. The additional maintenance can be a
hassle for a small CR station; but weigh this against the potential need for
continuous electricity supplies.
Generators are most often used in situations where power cuts are a norm,
or where power supply can be seriously interrupted for a long period of
time. A CR station cannot broadcast only when the power permits! So though
a good generator from a reputed company may cost a lot initially to install,
it should be factored in during the planning process itself if power is a
potential logistical problem.
Generators generate high voltages and need cabling to be connected to the
power supply of the station. They also give out exhaust fumes from the
internal combustion process they use. This can represent a potential hazard
to the people who work there if the cables are poorly managed or the
generator is installed in a place where the fumes cannot be vented properly.
Follow a safety code when using generators, and ensure that everyone
knows and follows this code when starting or operating the generator.
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Many generators are also attached to changeover circuits which let you
connect the generator to the power supply in parallel to your existing mains
supply. These changeover circuits often come in the form of a box, and are
often built to automatically cut off the generator when the power comes
back, so that both supplies do not add up and fry your electronics.
The installation of the generator and the disconnect and transfer
switches MUST be performed by a qualified electrical contractor.
This is not a job for the station's technical department. Do not attempt
to install these devices yourself or make repairs without adequate
knowledge of the devices and eletricals!
Safety code for generator operation
1. NEVER run an electric generator inside a building.
2. ALWAYS store the generator fuel (petrol, kerosene or diesel) in
proper containers, in a safe and secure place.
3. NEVER fuel an electric generator while the generator is running!
4. DO NOT smoke or bring naked flames near the generator, or when
handling fuel.
5. ENSURE proper ventilation around the generator.
6. ALWAYS have a fully charged, approved fire extinguisher located
near the generator.
7. ALWAYS disconnect from the mains supply BEFORE starting your
backup generator. The generator should normally be installed so
that this happens automatically: That is, you should have a
changeover switch so the generator cuts off automatically when the
mains power comes back. (Otherwise the circuits will suddenly be
charged with 220 + 220 = 440 Volts of electricity, and everything
in your studio will be destroyed! Automatic changeovers are the
best choice, failing which one can manually switch the mains isolator
off. Manual switching requires discipline and a systematic approach
- we may sometimes not know when the power comes back and
use the generator unnecessarily. Besides, forgetfulness can be
8. NEVER remove or tamper with safety devices - they are there to
protect you.
9. NEVER attempt to repair an electric generator yourself. ALWAYS
refer repairs to your supplier or other qualified serviceman.
10. Many engine parts are very HOT during operation. Don't touch
them as you could get severely burnt.
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Section C
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On the next few pages, you will see some suggested combinations of
equipment for CR stations of varying scales and scope. The tables present
an outline ready-reckoner that you can use to work out a list that will suit
your purposes and your CR station. There are three different suggestions
designed by three professionals working in the field of community radio in
India, and each is based on their individual experience and understanding
of the needs and imperatives of CR technology.
Remember that equipment models and technology change all the time: This
means the suggested models and prices indicated are subject to regular
revision. To get an up to date version of this table, you may have to spend
some time researching new models and prices.
Additionally, these are only suggested combinations of equipment. Ask
friends, professional acquaintances and colleagues from other CR stations
about their experiences with equipment – and for their recommendations
on what might work for your setup. Once you have a basic list of equipment,
get comparative estimates from a number of suppliers. Select the supplier
with the best reputation and the one who offers you a maintenance related
All prices and estimates included here are estimated street prices in India.
There may be huge variations between official billed prices from importers
and retail agents and the ‘grey’ (unofficial) market. Please treat these costs as
indicative only.
Suggested Setup 1A (Courtesy: N. Ramakrishnan, Ideosync Media Combine)
S.No. Equipment Description
Studio Equipment
Internet resource
Mixing Console, 1 mono mic 4/3 stereo line
Microphone (dynamic)
SM 58
Professional headphones
HPM 1000
PC Computer as DAW - Intel Core 2 Duo 2.16/
512 MB RAM/160 GB HDD/Combo drive/
17" CRT monitor/Creative Audigy 256 Sound
card/Intel motherboard/ATX cabinet/Creative
speakers/Windows XP SP2
Field recording Equipment
Microphone (condensor)
ECM MS 907
Compact Digital field recorder
Memory (SD cards: 2 GB)
Transcend SD
Transmission equipment
50W VHF FM transmitter
Dummy Load
5/8 Vertical omni directional antenna
LVB 206
5/8S Vertical
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Setup IA: Basic Community Radio Station (digital)
S.No. Equipment Description
RF Cable (RG 213)
Compressor limiter
Quantity Approx.
50 m
Internet resource
Local manufacturers
UPS system with maintenance free batteries
1250 VA
Guyed mast system/antenna tower
15 m – 30m
Local fabrication
Miscellaneous connectors/cables+low cost
acoustic treatment
As reqd
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Suggested Setup 1B (Courtesy: N.Ramakrishnan, Ideosync Media Combine)
S.No. Equipment Description
Quantity Approx.
Studio Equipment
Internet resource
Mixing console 4/5 Mono 4/3 stereo line
MG 12/4
Microphone, condensor 1" capsule
TSM 87
Microphone (dynamic)
SM 58
Professional headphones
HPM 1000
Studio Monitors
Truth B 2031
4-way headphone amplifier
Alto Pro
Telephone hybrid
TH 1
Sound card
Revolution 7.1
4 way line box
Ultra Di-pro
Mic stands
100 m Shielded audio cable with 30 pieces
each of XLR female & male, and 30 pieces RCA
Studio Compressor Limiter
Alto Pro
2 channel
PC Computer as DAW - Intel Core 2 Duo 2.16/
1 GB RAM/160 GB HDD/Combo drive/
17" CRT monitor/M-audio Sound card/Intel
motherboard/ATX cabinet/ /Windows XP SP2
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Setup IB: Middle level Community Radio Station (digital)
S.No. Equipment Description
Field Recording Equipment
Microphone (condensor)
ECM MS 907
Compact Digital field recorder
Memory (SD cards: 2 GB)
Transcend SD
Transmission Equipment
50W VHF FM transmitter
LVB 206
Dummy Load
Stacked dipole antenna
RF Cable (RG 213)
Compressor limiter
UPS system with maintenance free batt
Guyed mast system/antenna tower
Honda Siel
Carpentry + office furniture + racks
Office computer system Intel Core 2 Duo
2.16/256 MB RAM/120 GB HDD/Combo
drive/15" CRT monitor/ Intel motherboard/
ATX cabinet/Windows XP SP2
Internet resource
Stacked dipole
Nexus/Microtek 1250 VA
15 m – 30m
EXK 2000 S
50 m
Local manufacturers
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Quantity Approx.
~ 950000
Suggested Setup 1C (Courtesy N.Ramakrishnan, Ideosync Media Combine)
S.No. Equipment Description
On air studio Equipment
On AIR mixer/4-2-6 control room/studio
Internet resource
Rode Condensor Studio Microphone
CD player
DNC 630F
Double tape deck
Telephone Hybrid
Telos 1
Mic stands
ST232, 23850
Professional headphones
HPM 1000
Headphones Amplifier
HA 8000
Studio & Control Room Monitors (Pair)
Truth B2031
1 (pair)
Patch Bay
Patch Cords
19" rack
Assorted studio cables/Multi cable/Plugs
UPS 1250 VA double battery
El Nova
Studio Compressor Limiter
Alto Pro
2 channel
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Setup III: Large Community Radio Station (digital)
Production studio Equipment
Production Digital Mixer
Internet resource
Rode Condensor Studio Microphone
CD player
DNC 630F
Double tape deck
Telephone Hybrid
Telos 1
Mic stands
ST232, 23850
Professional headphones
HPM 1000
Studio & Control Room Monitors (Pair)
Truth B2031
Patch Bay
Patch Cords
1 (pair)
19" rack
Assorted studio cables/Multi cable/Plugs
UPS 1250 VA double battery
El Nova
PC Computer as DAW - Intel Core 2 Duo 2.16/
1 GB RAM/160 GB HDD/Combo drive/17"
CRT monitor/M-audio Sound card/Intel
motherboard/ATX cabinet/ /Windows XP SP2
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S.No. Equipment Description
Internet resource
Field Recording Equipment
Microphone (condensor)
ECM MS 907
Compact Digital field recorder
Memory (SD cards: 2 GB)
Transcend SD
Audio Editing Setup ( 3 editing systems)
PC Computer - Intel Core 2 Duo 2.16/1 GB
RAM/160 GB HDD/Combo drive/17" CRT
monitor/Creative Audigy 256 sound card/Intel
motherboard/ATX cabinet/ /Windows XP SP2
UPS 650 VA double battery
El Nova
Speaker units for editing units
SBS 380
Headphones for editing units
HPM 1000
Transmission equipment
50W VHF FM transmitter
LVB 206
Dummy Load
Stacked dipole antenna
RF Cable (RG 213)
Transmission Compressor limiter
Stacked dipole
50 m
Local manufacturers
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S.No. Equipment Description
Office Equipment
Office computer systems Intel Core 2 Duo 1.83/ Assembled
256 MB RAM/120 GB HDD/Combo drive/15"
CRT monitor/ Intel motherboard/ATX cabinet/
Windows XP SP2
Quantity Approx.
Internet resource
Carpentry + office furniture + racks
UPS 650 VA double battery
El Nova
Fax machine
Flatbed Scanner
Telephone connection + Internet
Network hub + cabling
Generator 5 KVA soundproof
Guyed mast system/antenna tower
15 m – 30m
Local manufacturers
~ 2066000
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S.No. Equipment Description
Suggested Setup 2 (Courtesy Ramnath Bhatt, VOICES - with additional inputs from Abhijit Shylanath, consultant)
Setup II: Basic Community Radio Station (digital)
Internet resource
Quantity Approx.
S.No. Equipment Description
HPM 1000
Studio Equipment
Mixing Console, 1 mono mic 4/3 stereo line
Microphone (Condensor)
Professional headphones
PC Computer as DAW - Intel Core 2 Duo 2.16/
512 MB RAM/160 GB HDD/Combo drive/17"
CRT monitor/Creative Audigy 256 Sound card/
Intel motherboard/ATX cabinet/Creative
speakers/Windows XP SP2
External Hard Drive (500 GB)
Toshiba, any
Using foam,
and heavy
curtains (for
roughly a
10x10 room)
Sound proofing basic
Studio amp and monitoring speakers
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S.No. Equipment Description
Internet resource
ECM MS 907
IC Recorder
Microphone (condensor)
Field recording Equipment
Compact Digital field recorder
Transmission equipment
1250 VA
15 m – 30m
As reqd
100/200 watt VHF antenna
50 m
50W VHF FM transmitter
RF Cable (RG 213 or 7/8)
Guyed mast system/antenna tower
(If this can be obtained through private telecom
UPS system with maintenance free batteries
Miscellaneous connectors/cables
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Suggested Setup 3 (Courtesy: Ashish Bhatnagar, Prasar Bharti)
S.No. Equipment Description
Quantity Approx.
Studio Equipment
Mixing Console, 1 mono mic 4/3 stereo line
Microphone (dynamic)
SM 58
HPM 1000
MDR- V150
Professional headphones
C Computer as DAW - Intel Core 2 Duo 2.16/
512 MB RAM/160 GB HDD/Combo drive/
17" CRT monitor/Creative Audigy 256 Sound
card/Intel motherboard/ATX cabinet/Creative
speakers/Windows XP SP2
DVD / CD player
Internet resource
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Very Basic Community Radio Station (digital)
Field recording Equipment
Compact Digital field recorder
Edirol R1
Zoom H1
Sony USB Rec
With external
Transmission equipment
Internet resource
50W VHF FM transmitter
100/200 watt VHF antenna
RF Cable (RG 213 or 7/8)
Inverter/ UPS with maintenance free batteries
(150 AH)
Guyed mast system/antenna tower
Miscellaneous connectors/cables
+ low cost acoustic treatment
Misc. (wiring /furniture/ earthing etc)
50 m
600 VA
15 m – 30m
As reqd
Local manufacturers
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S.No. Equipment Description
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The list below contains the details of the principal audio equipment
manufacturers globally, sorted by the type of equipment they specialize in.
Additional specifications and descriptions of the models of equipment they
manufacture are available at their respective websites.
1. Mixing consoles
AEQ Alice
Standard Allround
Standard Allround
Standard Allround
Standard Allround
Professional On Air and
Professional On Air and
Professional On Air and
Professional On Air and
PProfessional On Air and
Professional On Air and
Professional On Air and
Professional On Air and
Professional On Air and
Professional On Air and
Production with PC
Multitrack control 200
Production mixer and 4-8
Track digital recorder
Standard all round,
Production with PC
Multitrack control 200
Production mixer and 4-8
Track digital recorder
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Axel Tech
Mixer semi and Pro
Professional On Air and
Oxygen 4
Professional On Air and
Professional On Air - and
Studio, OB, PC
Studio, OB, PC
Studio, OB, PC
Studio, OB, PC
Studio, OB, PC
Studio, OB, PC
Studio, OB, PC
Studio, OB, PC
Studio, OB, PC
Studio,OB, PC
30 watt highly mobile
very small "one box"
Mixer, speakers, 1200
watts, 4 mic, stands,
Portable sound systems
12 volt
12 volt battery pack
PA Live
PA Live
JBL speakers, Soundcraft
mixer, AKG Mics
PA systems, mics,
amplifiers for PA
2. Monitor Loudspeakers
3. PA Systems
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4. Telephone Hybrids
Passive analogue and
Analogue and digital
Analogue and digital Comcon
JK Audio
All types
Dynamic, Electret
Condenser Large
Condenser, Dynamic
Audio Technica All types
All types
Dynamic, Electret
Dynamic, Electret
Dynamic, Condensor
5. Microphones Studio Projects
Condensor, Dynamic
Ribbon commentator
Electroacoustics mics
6. Headphones
Beyer Dynamics
Dynamic, Electret
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7. Processors, Compressors and Limiters
TC Electronics
Alto Pro Audio
8. Computers (Branded)
Macintosh OS based
Dell Corp.
Windows OS based
Hewlett Packard Windows OS based
systems / servers
Compaq Corp.
Windows OS
based systems
Windows OS based
Windows OS based
systems, servers
Asus Tech
Windows OS based
Windows OS based
Windows OS based
9. DVD,CD, MD, DAT, Cassette tape Player / Recorders
CD, Minidisc, DAT
CD, Minidisc, DAT,
CD, Minidisc, DAT,
CD, Minidisc, Dat,
CD, Casette
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10. Reel to reel 1/4" tape recorders
11. Turntables
Analogue with stylus
Analogue and Digital
output, with stylus
instant start
Analogue with stylus,
12. Digital Portable & Studio Recorders
Flash recorders
flash recorders
DAT, Minidisc. HDD and
Minidisc, flash recorders
Flash recorders
Mark of the
HDD recorders
and processing
Hi-quality pro recorders
Professional flash field
recorder units
Portable flash field
Microphone with
integrated flash recorder
13. Operating systems and basic PC
Windows OS (XP, Vista)
Apple OS
Apple OS 10.5
Links to Linux based OS
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14. Broadcast Software
Electronics Arrakis
Sound playback,
conversion, Play list (free)
On Air playout
On Air playout
On Air playout
commercial special price)
On Air playout
On air playout
automation (Some down
loads are free)
On air playout
On air playout
On air playout
On air playout automation
linked to Studer hardware
On air playout automation
On air playout automation
On air playout automation
Professional automation
15. Sound edit and processing software
Cubase, Nuendo software
Digi Design
Sony Creative
Pro Tools
Audition software
Cakewalk software
Audacity (Free)
Wavosaur (Free)
Soliton 2 (Free)
Nero Wave Editor
(Bundled with CD
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16. Soundcards
Turtle Beach
Mark of the Unicorn
17. XLR Plugs, cables and patch bays
18. Microphone stands
Konig Meyer
19. FM Transmitters
Ramsey Kits
Low Power and building
kits, low cost.
All types, low to medium
cost transmitters
DB Elettronica
All types, low to medium
cost transmitters
All types, low to medium
cost transmitters
Low - medium
power. Plug and Play
All powers, Analogue
and Digital, Expensive
Plug and Play
STL Link systems
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Heavy duty medium and
High power Transmitters.
Bext Corp.
All types, low to medium
cost Transmitters
Rohde Schwartz All powers, Analogue
and Digital, Expensive
Veronica Co.
PCS Electronics FM PCI card
Medium cost transmitters
Low cost Indian
Low cost Indian
All types of transmitters,
including digital radio
Audemat-Aztec All types of transmitters,
including digital radio
Harris Corp.
Low power, Low cost.
High End transmitters
20. FM Transmitting Antennas
Ramsey Kits
Building instructions for
"do it yourself people"
Low to medium power,
medium cost
Low to medium power,
medium cost
Low to High Power
DB Elettronica
Low to medium power,
medium cost
VHF Teknik
Low to medium power,
medium cost
Low to High
Low to High Power
Low to High Power, all
Radio Structures Various low power
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21. Masts and towers
Clark Masts
Teksam Ltd.
Pump up masts for mobile
Racal Antennas Pump-up
Different wind- and pumpStructures Ltd. up masts
22. Satellite Receivers
Digital reception
equipment (needs
23. Cases and furniture
Carry cases, packs
Airtight, Waterproof: Foam/
ABS/stainless steel
World leading designer of
blue nylon cases
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Beyond the basic information contained within this manual, and the
information you may be able to research on your own, there are several
individuals and organizations that you can contact for additional information,
advice or assistance in setting up your own community radio station.
This list gives the names and contact details of several of these organizations
and individuals. Please note that though their primary office locations are in
specific cities, many of these agencies and advisers have experience working
across the entire country.
Note: This is not a list of funding organizations!
Community Radio setup, community mobilization, content
and technical training, setup
1. United Nations Educational Scientific & Cultural
Organization (UNESCO)
Address: UNESCO House, B-5/29, Safdarjung Enclave, New Delhi 110029
Telephone: +91-011-36713000
Telfax: +91-11-26713001/02
Email: [email protected]
2. United Nations Children’s Fund (UNICEF)
Address: India Country Office, UNICEF House, 73, Lodhi Estate,
New Delhi - 110003
Telephone: +91-011-24690401
Telfax: +91-11-24691410/24627521
Email: [email protected] (Supriya Mukherji, Programme
Communications Officer)
3. United Nations Development Fund (UNDP)
Address: India Country Office, 55, Lodhi Estate, New Delhi – 110 003
Telephone: +91-011-24628877
Telfax: +91-11-46532333, 24627612
Email: [email protected] (John Borgoyary, Programme Officer)
4. Community Radio Forum - India (CRF)
Address: C/o Drishti Media Collective, 103, Anand Hari Tower, New Sandesh
Press Road, Opp. Chanakya Tower, Bodakdev, Ahmedabad ,
Gujarat - 380 054
Telephone: +91-79-26851235, 66614235
Email: [email protected] (K.Stalin, Convenor)
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5. Ideosync Media Combine
Address: 177, Ashoka Enclave III, Sector 35, Faridabad – 121 003 – Haryana
Telephone: +91-0129-4131883, 6510156 (Prefix 95129-from Delhi)
Telfax: +91-0129-2254395 (Prefix 95129- from Delhi)
Email: [email protected]
6. Panos Institute South Asia (India Country Office)
Address: D-302, 2nd Floor, Defence Colony, New Delhi - 110024
Telephone: +91-011-24615217, 24615219
Fax: +91-011-24615218
Email: [email protected]
7. Mysore Resettlement and Development Agency (MYRADA)
Address: No.2, Service Road, Domlur Layout, Bangalore 560071, Karnataka
Telephone: +91-080-25352028/3166
Fax: +91- 080-25350982
Email: [email protected]
8. Alternative for India Development (AID India)
Address: Plot No.1 V.G.N. Nagar, Iyyapanthangal, Chennai - 600 056 Tamil Nadu
Telephone: +91-044-26272336, 26490014
Fax: +91-044-26272340
Email: [email protected]
9. Drishti Media Collective
Address: 103, Anand Hari Tower, New Sandesh Press Road,
Opp. Chanakya Tower, Bodakdev, Ahmedabad - 380 054 - Gujarat
Telephone: +91-79-26851235, 66614235
Email: [email protected]
10. Deccan Development Society (DDS)
Address: 101, Kishan Residency, 1-11-242/1, Street No. 5, Shyamlal Buildings
Area, Begumpet, Hyderabad - 500 016 – Andhra Pradesh
Telephone: +91-040-27764577, 27764744
Telfax: +91-040-27764722
Email: [email protected], [email protected],
[email protected]
United Nations Educational, Scientific and Cultural Organisation
Address: No. 165, First Floor, 9th Cross, Indiranagar Ist Stage, Bangalore560038 - Karnataka
Telephone: +91-080-25213902, 25213903
Fax: +91-080-25213901
Email: [email protected] (Ramnath Bhatt)
12. One World South Asia (OWSA)
Address: C-5 Qutab Institutional Area, New Delhi – 110016
Telephone: +91-011-41689000
Fax: +91-011-41689001
Email: [email protected]
13. Commonwealth Educational Media Center for Asia
Address: C-5/4, Safderjung Development Area, New Delhi – 110016
Telephone: +91-011-26537146
Fax: +91-011-26537147
Email: [email protected] (Dr.R.Sreedher, Director)
14. Mahila Samakhya, Karnataka (MSK)
Address: No 68, 1st Cross, 2nd Main, HAL 3rd Stage, Near New Thippasandra
Main Road, Bangalore 560 075, Karnataka, India
Telephone: +91-80-25727471, 25262988
Web: (under construction)
Email: [email protected]
15. Mandaakini Ki Awaaz Samudayik Radio
Address: Kendra Bhanaj, P.O. Machkandi via Chandrapuri, Tehsil Ukhimath,
Distt. Rudraprayag, Uttarakhand - 246 425
Telephone: +91-01364-213114, 9411389062
16. Hevalvaani Samudayik Radio
Address: Kendra Chamba, Mussoorie Road, Chamba, Distt. Tehri Garhwal,
Uttarakhand - 249145
Telephone: +91-01376-256159
17. DHAN Foundation
Address: 18, Pillaiyar Koil Street, S.S. Colony, Madurai - 625 016 - TamilNadu
Telephone: +91-0452-2610794, 2610805
Fax: +91-0452-2602247
Email: [email protected]
United Nations Educational, Scientific and Cultural Organisation
18. Digital Empowerment Foundation
Address: D-307, 1st Floor, Sarvodaya Enclave, New Delhi – 110 017
Telephone: +91-11-51829729
Email: [email protected] (Osama Manzar)
19. Knowledge Networking for Rural Development in Asia/
Pacific Region (ENRAP)
Address: IDRC Regional Office for South Asia, 208, Jor Bagh,
New Delhi 110003
Telephone: +91-11-24619411 (Ext. 102)
Fax: +91-11-24622707
Email: [email protected] (Michelle Chawla)
20. Nomad India
Address: 1, Sapote building, Irani Road, Dahanu – 401602 – Maharashtra
Telephone: +91-02528-222241, 9860030888/9890150999
Fax: None
Email: [email protected] (Michelle Chawla)
21. Kutch Mahila Vikas Sangathan (KMVS)
Address: Media Cell, C/o Kutch Mahila Vikas Sangathan, 15-A, “Midhara”,
Himmat Nagar, Revenue Colony, Bhuj - 370 001 - Kutch District,
Telephone: +91-02832-222124, 223311
Email: [email protected], [email protected]
22. Auroville Radio
Address: Auroville Radio – TV, Town Hall Complex, Auroville – 605101
- Tamil Nadu
Telephone: +91- 0413-2622250, 2622170
Fax: +91-0413-2622055
Email: [email protected] (Andrea Tazzarri)
23. Anna FM 90.4, Chennai
Address: C/o EMRC, Anna University, Guindy, Chennai - 600025
Telephone: +91-044-22300106
Telefax: +91-044-22300105
Email: [email protected] (Dr.P.Lakshmi, Director-in-charge, EMRC)
United Nations Educational, Scientific and Cultural Organisation
24. IT for Change
Address: No.393, 17th Main, Jayanagar 4th ‘T’ Block, Bangalore - 560041 Karnataka
Telephone: +91-080-26654134, 26536890
Fax: +91-080-41461055
Email: [email protected]
25. Charkha
Address: Ground Floor, G-15/11-12, G - Block, Malviya Nagar,
New Delhi – 110 017
Telephone: + 91-11-26680688, 26680816
telfax: +91-11-26680816
Email: [email protected]
26. Aga Khan Foundation
Address: Sarojini House II Floor, 6 Bhagwan Dass Road,
New Delhi -110001
Telephone: +91-011-23782173
Fax: +91-011-23782174
Email: [email protected]
27. World Development Foundation (WDF)
Address: Plot 5, Sector 3, Karuna Kunj, Dwarka (Behind DPS, in front of
BSES), New Delhi – 110 075
Telephone: +91-011-25082764
Telfax: +91-011-25082764
Email: [email protected]
Independent Consultants
1. Ashish Bhatnagar (Technical) (Honorary Advisor)
Address: 313, Asia House, Kasturba Gandhi Marg, New Delhi - 110001
Telephone: +91-011-23073881
Mobile: +91-9868183881
Email: [email protected]
2. Jean Parker (Content Creation & Recording)
Address: A703 Supreme Green Woods, NIBM Road., Kondhwa,
Pune - 411048 - Maharashtra
Telephone: +91-020-4005582
Mobile: +91-9890436033
Email: [email protected]
United Nations Educational, Scientific and Cultural Organisation
3. Mahesh Acharya (Technical)
Address: No.307. B Block, Manjunatha Residency,
Opp. SCT College, Vigyan Nagar, Bangalore - 560 075 Karnataka
Telephone: +91-80-41709551
Mobile: +91-9886303077
Email:[email protected] [email protected]
4. Dr. Arun Mehta (Technical)
Address: B-69, Lajpat Nagar - I, New Delhi-110024
Telephone: +91-011-29817007
Email: [email protected]
5. Vickram Crishna (Technical)
Address: A31/32 Queens Apts, Pali Hill, Bandra, Mumbai – 400050 Maharashtra
Telephone: (Available on request)
Email: [email protected]
United Nations Educational, Scientific and Cultural Organisation
The list below contains the details of the key suppliers and vendors of audio
and radio related equipment in India. This is by no means an exhaustive list,
and is based on the agencies and vendors that many people who have
participated in the development of this manual have recommended. This
should provide you a starting point for your enquiries when you begin the
process of acquiring equipment.
A. Acoustics & Studio setup consultants
Broadcast Engineering Consultants India Ltd. (BECIL)
14-B, Ring Road, I.P. Estate,
New Delhi 110002
Tel: +91-11-23378823
Fax: +91-11-23379885
E-Mail: [email protected]
Technomedia Solutions Pvt. Ltd.
1001, Kailash Building
26, Kasturba Gandhi Marg
New Delhi 110001, INDIA
Tel: +91-11-23765169/70/7
Fax: +91-11-23765152
E-Mail: [email protected], [email protected]
All India Radio (AIR) Resources Unit
DG, AIR, Akashwani Bhawan
Parliament Street, New Delhi - 110001
Tel: +91-11-23421187, 23421221
E-Mail: [email protected], [email protected]
Noori Broadcast Solutions Pvt. Ltd.
99-National Park,
Lajpat Nagar-IV,
New Delhi-110024 (India)
Tel: +91-11-65636876
Mob: +91-9811983404, 98891070243
Fax : +91-11-65636876
E-Mail: [email protected]
United Nations Educational, Scientific and Cultural Organisation
Electro Dynamics
58/46, Birhana Road
Kanpur 208 001.
Tel: +91-11-41622014
Fax: +91-11-26430947
E-Mail: [email protected]
Rivera International
397/A, Mangaldas House,
Naaz Cinema Compound Lamington Road, Mumbai 400 004
Tel: +91-22-2200555/777
Fax: : +91-22-23862342
E-Mail: [email protected]
B. Multi-equipment providers
Advanced Telemedia Pvt. Ltd.
12 A Kalkaji
New Delhi -110019
Tel: +91-11-41675452-4
Fax: +91-11-41675451
Email: [email protected]
Falcon Technologies
102 Empire Apartments
98 M. G. Road, Sultan Pur
New Delhi 110 030
Tel: +91-11-26804631, 32 / 26804640, 51
Fax: +91-11-26806966
E-Mail: [email protected]
Trimurti Instruments
13, Sopariwala house No. 5,
1st floor, Chunam lane,
Lamington Road,
Mumbai - 400007 - Maharashtra.
Tel: +91-22-23858704, 25379253
Mob: +91-9869164174
Email: [email protected], [email protected]
Shaf Broadcast Pvt. Ltd.
B-4/142, IInd Floor
Safdarjung Enclave
New Delhi - 110029
Tel : +91-11-26169902, 03
Fax : +91-11-26169904
Email : [email protected]
United Nations Educational, Scientific and Cultural Organisation
Asia Pacific Broadcasting Union
PO Box 1164,
59700 Kuala Lumpur,
E-mail: [email protected]
Tel: +60-3-22823592
Fax: +60-3-2282-5292
Sony India
A-31, Mohan Cooperative Estate,
Mathura Road,
New Delhi 110044
Tel: +91-11-66006600
Fax: +91-11-26959141
E-Mail: [email protected]
"NVL House", 198/2,
Garhi, East of Kailash,
Opp. Sapna Cinema,
New Delhi-110065
Tel. : +91-11-26218527
Fax : +91-11-26225955
E-mail : [email protected]
Ahuja Radios
215, Okhla Industrial Estate
New Delhi - 110 020 - INDIA
Tel.: +91-11-26831549, 41612475
Fax: +91-11-26847287, 41616563
Email: [email protected], [email protected]
Hytech India
18, Poorvi Marg, Vasant Vihar,
New Delhi-110 057.
Tel: +91-11-41661709, 26140652
Fax: +91-11-26142084
E-Mail: [email protected], [email protected]
Telerad (A Division of ASE Ltd)
Head Office: 89-92, G.I.D.C Naroda Industrial Area,
Ahmedabad - 382 330 - Gujarat
Delhi: 408-810,
Vishwa Sadan, District Center,
Janakpuri - New Delhi - 110 058
Tel: (Ahmedabad) +91-79-22813017/3117
(Delhi) +91-11-25541731/9330
Fax: (Ahmedabad) +91-79-22821592 (Delhi) +91-11- 2554 8507
Email : [email protected], [email protected]
United Nations Educational, Scientific and Cultural Organisation
R-31, Laxmi Industrial Estate
Link Road,
Andheri (W)
Mumbai - 400 053
Tel: +91-022-67021711, 26354891
Fax: +91-22-67021714, 26354819
Mob: +91-9820023077
E-Mail: [email protected], [email protected]
AGP Broadcast Infrastructure Pvt. Ltd.
226-A, Pocket B, Mayur Vihar Phase II
New Delhi
Tel: +91-11-22783543, 22785668
Telfax: +91-11-22783543
Mob: +91-9811143367
Email: [email protected]
98, NB Block E, New Alipore
Kolkata - 700 053
Tel: +91-33-24570418, 24583406
Fax: +91-33-24787243
Mob: +91-9811143367
Email: [email protected]
Visual Technologies India Pvt. Ltd.
370-371/2, First Floor,
Hospital Road,
Jangpura, New Delhi - 110 014.
Tel: +91-11-24379961-64, 24378592-94, 24373965
Fax: +91-11-24378591, 2437 5843
E-Mail: [email protected], [email protected]
Setron India Private Limited
E-2, Greater Kailash Enclave -1,
New Delhi - 110048.
Tel: +91-11-26242250, 26241150/601
Fax: +91-11-26242150
E-Mail: [email protected]
Deepjyot Electronics
B-4/228, Safdarjung Enclave
(Behind Safdarjung Club)
New Delhi - 110 029
Tel: +91-11-26187495, 2617 7791
Fax: +91-11-4135 4357
E-Mail: [email protected]
United Nations Educational, Scientific and Cultural Organisation
C. Radio Automation and IT
ENCO India
A-238, 2 Floor
Defence Colony
New Delhi-110023
Tel: +91-9871580444
E-Mail: [email protected]
Contact Person : Arjun Srivastav
HCL Infinet Ltd.
E-4, 5, 6 ; Sector 11,
Noida 201301
Tel: +91-120-2552973
Fax: +91-120-2552973
E-Mail: [email protected]
D. FM Transmitter equipment
Bharat Electronics Ltd. (BEL)
Outer Ring Road
Bangalore - 560045 - Karnataka
Tel: +91-080-28303280 (Broadcast systems Division)
Fax: +91-080-25039305
Email: [email protected] (D.A.Mohan, GM Broadcast & Telecom)
West Bengal Electronics Industry Development Corp. (WEBEL)
Webel Bhavan,
Block - EP & GP,
Sector - V, Salt Lake
Kolkata - 700 091 - West Bengal
Tel: +91-33-23578392
Fax: +91-33-23571708/23571739
Email: [email protected]
Rohde & Schwarz India Pvt. Ltd.
A-27 First Floor,
Mohan Co-operative Industrial Estate
Mathura Road, New Delhi 110 044
Tel: +91-11-42535400
Fax: +91-11-42535433
E-Mail: [email protected]
Broadcast Electronics
A-238, Defence Colony,
New Delhi-110024
Tel: +91-11-24333340
E-Mail: [email protected]
United Nations Educational, Scientific and Cultural Organisation
One of the most useful resources available to any CR station or CR practitioner
is the internet, that worldwide network of computers and databases that
offers us the largest collection of information ever created. The list below
highlights a few of the most useful websites that will add and expand on the
information contained in this manual.
A website for CR practitioners and information seekers, run by Radio Regen
(Wales), and supported by the UK Dept. for Culture, Media and Sport (DCMS).
The website is a mine of information on CR - including the CRT Handbook
- and offers access to several online discussion fora for registered users, to
discuss various aspects of their experiences with CR. It is also a source of
information and news on CR related events in Europe and the UK area.
2. CR India (
A mailing list/discussion forum on community radio in India, with a rapidly
growing membership. A very useful platform for the exchange of queries
and information on CR regulations, technology and setup, the list includes
most of the organizations and individuals active in the CR movement in
The website of the Govt. of India’s Ministry of Information and Broadcasting.
It carries all the background to the current CR (FM) policy, including the
application documents and guidelines described in Section A, as well as a
very detailed FAQ on the application and licensing process, and the technical
parameters that have to be followed (see
The site also gives details on the current commercial FM rollout.
4. +
The United Nations Educational, Scientific and Cultural Organization
(UNESCO) and the United Nations Development Programme (UNDP)
websites. Both organizations are involved with development of community
radio worldwide, and have supported the establishment of CRS across the
globe. Both have also worked on the extensive documentation of CR best
practices and experiences. The websites need to be explored a bit to find
information relevant to Indian practitioners of CR – it is wise to narrow the
search in both cases to the sub-sites for India and South Asia – but there are
a huge number of links to documents and information on CR around the
world in the main sites.
United Nations Educational, Scientific and Cultural Organisation
The website of the Free Radio Berkeley movement, dedicated to international
radio action training. The FRB movement works on the ‘airwaves are free’
principle, and encourages the sharing of DIY radio information that removes
restrictions on access to technology and broadcasting controls. Focused
primarily on democratizing radio access in the United States – and
consequently, opposition to FCC control – the website contains information
on training courses run by the organization, as well as resources like circuit
diagrams and online ordering processes for radio related circuitry and DIY
kits. Also contains a numbetr of useful ‘how to’ pages.
Radiphony is an Indian company dedicated to the free airwaves principle,
that works to provide easy to use audio and radio technology solutions for
Indian users. The site allows access to resources like the eLocutor, a software
that allows severely physically challenged individuals to work on a computer.
The site also contains detailed FAQs on low power radio and the CR process
and setup in India. Also includes – like Free Radio Berkeley – access to
information on a DIY simple radio transmitter circuit which can be
constructed by most amateur enthusiasts.
The Prometheus Radio Project is a US based initiative to democratise media
access by promoting low power FM. While its events calendar is primarily
US-centric, the tech resources are exhaustive, with a number of pages devoted
to concepts around low power broadcasting, and galleries of photos
illustrating simple solutions and field radio techniques. The International
section includes their experiences is supporting and developing low power
FM stations in Tanzania. The project can also be contacted for radio station
setup consultancies.
The website of the All India Radio Resources Unit, which offers technical
consultancies to set up CRS. The website details the consultancy work they
undertake, and is an especially useful reference to understand the steps
involved in designing, setting up and testing a new FM station.
The website of Developing Radio Partners, a US based not-for-profit that
works towards empowering communities worldwide with access to low
cost radio technology. While there are no tech resources on the site, their
detailed case studies based on their experiences in Sierra Leone, Mongolia
and Southern Africa are interesting for the perspective they offer new CR
United Nations Educational, Scientific and Cultural Organisation
The website of Broadcast Engineering Consultants India Ltd. (BECIL). BECIL
has been one of the primary consultant agencies for broadcast setups in
India, especially where commercial radio and television have been
concerned. A Govt. of India enterprise, the website is a source for all kinds
of technical and broadcast event related news and information, and contains
links to CR application, licensing and guideline related information. The CR
link on the site explains BECIL’s consultancy work and the services it provides.
A website developed by VOICES (Bangalore, India) with UNDP support as
part of the same project under which the Community Radio Step by Step
manual was developed (See Bibliography). The website offers members a
discussion forum on various aspects of CR in India, as well as information
regarding setup, sustainability, technical know-how and equipment setups.
The website of OneWorld South Asia (OWSA), the South Asian arm of the
international development organization OneWorld. The website offers
networking opportunities to grassroot agencies, and includes an extensive
events listing that covers grassroot communication initiatives like CR, one of
OWSA’s focus areas. OWSA produces and disseminates radio programming,
and conducts capacity building programmes on radio and readio technology
for field level organizations.
iTrainonline provides online training resources on a number of media related
subjects, ranging from audio and video to community radio. The community
radio page has links to an extensive list of documents and websites that give
information on CR, content development for CR, standard stylesheets from
professional media organizations, story ideas, and journalism tips. The
resources are catalogued under the heads Basics, General, Technical, and
Content Development.
14. is an online resource site developed by Atlantic Public Media
to allow sharing and discussion on public media access. The site includes
several informative articles on recording and editing, selecting equipment,
and setting up a studio; as well as useful links to a variety of resources.
United Nations Educational, Scientific and Cultural Organisation
Though not directly a CR resource, the BBC Online training website is an
enormous resource for learning the technology of radio per se, and the
content production techniques that have made the BBC one of the most well
known and respected broadcasting organizations in the world. The website
also includes online training courses on a variety of recording and production
techniques for radio.
The website for the Association for Progressive Communication, an
international association that works on internet and ICTs for social justice
and development. The website offers a number of resources – shared with
the iTrainonline website mentioned above – on community radio, as well as
resources on networking civil society organizations.
The Asia Pacific Network Information Center is a resource sharing online
organization that facilitates discussion on a variety of ICT and media related
subjects amng civil society organizations in the Asia-Pacific. It has a large
resources section that, while not directly referring to community radio
practitioners, has a lot of ICT related guidelines, resources and information.
The online contributory resource Wikipedia has a very interesting section
on radio terminology and history. This resource provides simple definitions
and a number of links to other resources, and changes very rapidly to reflect
new media inputs.
Website of Circuit Design, Inc., a manufacturer of low cost radio solutions.
Includes an RF design guide with a discussion of circuit diagrams, and an
online resource for calculations, and online articles on low power FM
Website of Radioactive, a UK based organization that works to help
communities set up low cost CRS. Radioactive’s website offers a number of
turnkey CRS packages and setup diagrams that offer CR practitioners and
NGOs a point of reference for deciding their equipment combinations and
setups. Many of the packages offered have attached costings that allow an
assessment of the overall costs involved.
United Nations Educational, Scientific and Cultural Organisation
Tabing, Louie
How to do Community Radio: A
Primer for Community Radio
Operators. UNESCO (2005)
Fraser, Colin & Estrada, Sonia
Community Radio Handbook
UNESCO (2005)
Bandana Mukhopadhyay
Community Radio In India Step
by Step.
MacDonald, Max
Community Radio: A Marketing
Manual. Community Broadcasting
Foundation, Australia (1995)
Worsoe, Neil & Oesterlund, Per
Configuration of Radio Stations &
Media Centers: A Practical Guide to
procurement of technical
equipment for community media
UNESCO with DaniCom & Niels
Worsoe (2004)
Free Radio Berkeley
Micropower Broadcasting A Technical Primer.
Free Radio Berkeley, 2004
Ten Steps for Establishing a
Sustainable Multipuprose
Community Telecenter.
UNESCO Regional Office, Bangkok
Smith, Eric T.
Acoustics 101: Practical guidelines
for constructing acoustically
accurate spaces
Auralex Acoustics (2003)
Adam Gordon & Harford, Nicola
Radio & HIV/AIDS: A guide for
radio practitioners, health workers
and donors.
UNAIDS/Media Action International
Girard, Bruce & Van Der Spek, Jo
The Potential for Community Radio
in Afghanistan
Comunica (2002)
Radio Regen
Community Radio Toolkit: CRT
Radio Regen (2006)
Sims, Martin
Community Radio Manual
Open Society Foundation for
Southern Africa/National
Community Radio Forum/CAF-SCO
Sims, Martin
Community Radio Technical
Open Society Foundation for
Southern Africa/National
Community Radio Forum/CAF-SCO
Govt. of India
Policy Guidelines for setting up
Community Radio Stations in India
Ministry of Information &
Broadcasting, Govt. of India
Govt. of India
Application Form for Grant of
Permission to set up CRS (FM)
Ministry of Information &
Broadcasting, Govt. of India
United Nations Educational, Scientific and Cultural Organisation
United Nations Educational, Scientific and Cultural Organisation
United Nations Educational, Scientific and Cultural Organisation
United Nations Educational, Scientific and Cultural Organisation
United Nations Educational, Scientific and Cultural Organisation
United Nations Educational, Scientific and Cultural Organisation
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