SHRI GURU GOBIND SINGHJI INSTITUTE OF ENGINEERING AND TECHNOLOGY, NANDED.

An

INPLANT TRAINING

REPORT

On

PRASAR BHARATI

BROADCASTING CORPORATION OF INDIA

ALL INDIA RADIO, NANDED.

Guided By :

Mr. S. M. Choudhary,

Station Engineer,

A.I.R. Nanded.

1 | P a g e

By :

Shirule Raviraj P.

Reg No. 2004BIT045

Choudhary Ashish U.

Reg No. 2005BIT221

Deshmukh Varun V.

REg No.2006BIT201

CONTENTS

1. Salient Features of LRS Nanded…………………… 3

2. Power Supply…………………………………………… 4

3. A.C. Plant……………………………………………….. 4

4. Multipurpose Studio………………………………….. 5

5. Control Room…………………………………………... 8

1. Switching Console……………………………. 8

2. Transmitter……………………………………. 10

3. Radio Networking Terminal………………... 11

6. FM Antenna…………………………………………….. 12

2 | P a g e

Salient Features of LRS Nanded

Power of T/R : 6 kW

Type of modulation : Frequency modulation

Operating Frequency : 101.1 MHz

Height of Tower : 100 m

Coverage Area : 60 km radius

Places under coverage : Parabhani, Vasmat, Kandhar,

Degloor, Ahemadpur, Mukhed,

Hingoli.

Overall Radio Station can be studied by dividing the whole arrangement into following different categories :

1. Power Supply2. A.C. Plant3. Multipurpose Studio4. Control Room5. FM Antenna.

3 | P a g e

POWER SUPPLY

A] From MSEB

1. 11kV Feeders : 2 nos.

2. Transformer capacity : 160 KVA

3. H.T. voltage : 11 kV

4. H.T. current : 8.39 A

5. L.T. voltage : 415 V

6. L.T. current : 213.34 mA

B] Own Generator

Diesel generator – two sets

Capacity : 40 KVA & 10 KVA

A.C. PLANT

1. Capacity : 3 tons (9000cal/h)

2. Total plants : 6 nos.

3. Serial Nos. : 23573, 23552, 23553,

23568, 23578, 23577.

4 | P a g e

MULTIPURPOSE STUDIO

Multifunction Stereo Audio Console

Introduction:

The audio console in broadcast studios is utilized for mixing of various audio sources and also to facilitate the operator to control some of these audio sources remotely from the console.

Special Features:

1. Modular Construction.2. Easy Access to wiring and component in module &

motherboard.3. Frame Size to accept 12 input modules with user indicated

configuration.4. Remote mute facility for microphone channel.5. Stereo Pre Fade Listen (PFL) facility.6. Talkback send and receive facility to/from 8 locations.7. Balanced Inputs & Outputs.

Technical Specifications:

Input channels : 12 (max)

Output channels : 2

Input Impedance

Microphone : 2 kohm

Line : 10 kohm

Input Level

Microphone : -70 dB

Line : 0 dB

5 | P a g e

Output Impedance : < 50 ohm

Frequency Response : 40 Hz – 50 Hz.

The multifunction stereo audio console consists of 12 input modules, 2 output modules, one monitor module, one talkback module and a power module.

A] Input Module :

a) mono mic/line :

Line level signals from mono sources and mic level signals from announcer/studio mics are fed to the mono mic/line modules. The mic level signal is amplified with a 5 step gain control amplifier and after optionally switchable low frequency roll off and phase reversal, fed to the program selector. The gain is variable from -30 dB to -70 dB in the five steps.

b) stereo high level :

Stereo high level modules are of two types, one with remote sources selection and other without remote source selection.

The two channels, L & R are separately amplified by a variable gain of -10dB to +10dB & fed to a line/oscillator selector.

B] Output Module :

Signals on the master 1 & master 2 buses routed from the input modules as left and right channels are mixed separately in the output modules. This signal is then fed to an oscillator/signal selector along with the signal from test oscillator. The selector circuit (depending on OSC ON) selects mixed or oscillator signal.

C] Monitor Module :

The monitor module of the console contains the hardware for selection and monitoring of different signals on the console. Provision is made for monitoring the signal in mono mode in the console PFL speaker and in stereo mode at CR and studio on external amp/speaker.

6 | P a g e

D] Talkback Module :

The talkback module of the console houses the hardware for an 8 stations two-way communications facility, auxiliary mixers, circuits for signaling and relay operators and the test oscillator are also housed in his module.

The talkback mic signal after amplification & level control is routed as TB SEND signal through an eight by one selector.

The return signal from eight stations mixed & level controlled before sending to the monitor module for listening. The presence of these signals are indicated on the panel by lightening of LED’s corresponding to each station.

E] Power Module :

The power supply has outputs of +48 V, +18 V, -18 V, +5 V. These DC voltages are routed through the motherboard to power the various module of the console.

CONTROL ROOM

7 | P a g e

1)Switching Console (X062A)2)FM Transmitter (2x3 kW type HVB 164/A)3)Radio Networking Terminal (RNT)

SWITCHING CONSOLE

Introduction :

These consoles have been specifically designed for broadcast application keeping in mind the stress for high reliability and continuous operation. Special design with digital control minimizing the signal path gives a superior performance with low distortion and noise. Because of exceptionally clean path the console provides high dynamic range & headroom at any stage.

Specifications :

Program Inputs –

No. of channels : 6 (expandable to 8)

Level : 0 dB (nominal)

20 dB (maximum)

Impedance : 600 ohm

Program Outputs –

No. of channels : 2 (expandable to 4)

Level : +4 dB (nominal)

+20 dB (maximum)

Impedance : <= 50 ohm/ 600 ohm (balanced)

8 | P a g e

Description :

This console consists of six(expandable to 8) input modules, two(expandable to 4) output modules, one monitor module and one talkback module. Power supply model PS80C supplied along with the console provide DC power for all the modules.

Line signals which are fed to the input modules reach the line amplifier through back panel (XLR) connector and comes to the audio distribution amplifier (ADA) after proper amplification. The oscillator test signal can be selected using the “OSC ON” switch provided on the input module.

Two of the input modules (input channels 1 & 8) receives signal from the remote selector modules kept adjacent to these modules. The remote selector selects one out of 8 programs connected to its input through the back panel terminals.

The output from the ADA is fed to the channel fader. The post fade signal is again amplified to the required level and forms the main output channel. The pre fade signal is fed to the monitor module for PFL monitoring using “PFL ON” switch.

This module also gives the DC control voltage for routing the signals to master 1, 2, 3, 4 output channels.

The input module also contains the hardware for the channel ON indicator LED which lights when the fader is faded IN from OFF position.

Other input channels have functions similar to input channel one. The main channel outputs from input channels 1 to 8 are connected to the corresponding signal inputs of master output channels.

FM TRANSMITTER

9 | P a g e

Introduction :

The new generation FM transmitters in the AIR network can be classified according to their output power as follows :-

1) 3 kW FM Transmitter2) 2x3 kW FM Transmitter3) 2x5 kW FM Transmitter.

Salient Features :

1. Completely solid state

2. Local/Remote operation capability

3. Forced air cooled

4. Digitally synthesized crystal oscillator which can be set in steps of 10 kHz in frequency band of 87.5 to 108 MHz.

5. Broadband VHF power amplifiers require no tuning.

6. Full power output just by pressing a single button.

7. Automatic output power reduction in following cases :

a. Mismatch

b. Expressive heat sink temp. of output RF transistors (>800 C)

8. The switching and operating status of the system is indicated by LED’s.

AIR Nanded uses 2x3 kW FM Transmitter.

10 | P a g e

RADIO NETWORKING TERMINAL

Introduction :

The INSAT-II series of satellites are designed to have more no.

of radio channels as compared to that of INSAT-I series.

Out of these channels AIR has been allotted 28 channels for

their broadcast purpose.

Therefore the RN terminal already supplied, capable of

receiving 5 channels (fixed only) is being modified to receive

any 6 channels out of 28 channels allotted.

11 | P a g e

FM ANTENNA

The antenna system of FM transmitter consists of three main sub system –

a. Supporting Tower.b. Main Antenna.c. Feeder Cable.

Tower :

Since coverage of FM transmitter also depends on the tower height therefore, a suitable height of tower is required. If the tower height is very large then it may not be economical. Moreover, it may also not get SACFA clearance.

Facilities on AIR Tower :

a. Provision of top mounting of additional antenna.b. Climbing ladder with cage up to 82 m height and free fall prevention

system above this height.

Antenna :

The main requirement of the antenna to be used for FM transmitter are –

a. Wide band usage from 87.5 to 108 MHz.b. Omni-directional horizontal radiation pattern.c. Circular polarization for reception even in mobile conditions.d. High gain for both vertical and horizontal signal.e. Two degree beam tilt below horizontal.f. Study design for maintenance free services.

THE END.

12 | P a g e