All India radio, CBS,Kanpur

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All India Radio (Akashvani) :At a glance Gandhi ji in his eloquent speech exclaimed AIR as a miraculous power. He called out AIR, 'A medium of unparalleled immediacy, intimacy and power!' Sound broadcasting started in India in 1927 with the proliferation of private radio clubs. All India Radio (abbreviated as AIR), officially known as Akashvani (Devanagari:vkdk”kok.kh ) is the radio broadcaster of India with clear objectives to inform, educate and entertain the masses keeping in view the motto, "Bahujan Hitaya; Bahujan Sukhaya" i.e. the benefit and happiness of large sections of the people. Now AIR is a division of Prasar Bharati (Broadcasting Corporation of India), an autonomous corporation of the Ministry of Information and Broadcasting, Government of India. Doordarshan is the sister service of Prasar Bharati, the national television broadcaster.The word Akashavani was coined by Professor Dr. M.V. Gopalaswamy for his radio station in Mysore during 1936. All India Radio is one of the largest radio networks in the world. The headquarters is at the Akashvani Bhavan, New Delhi. The Doordarshan Kendra (Delhi) was located on Mandi House Phase –II, Copernicus Marg, New Delhi. When India became independent, the AIR network had only six Stations located at Delhi, Mumbai, Kolkata, Chennai, Lucknow and Tiruchirapalli with a total complement of 18 transmitters - six on the medium wave and the remaining on short wave. The coverage was 2.5% of the area and just 11% of the population Radio listening on medium wave was confined to urban limits of these cities. As against a mere 2,75,000 receiving sets at the time of Independence, now there are about 132 million estimated radio sets in the country. Now the broadcast scenario has drastically changed AIR today has a network of 237 broadcasting centres with 149 medium frequency(MW), 54 high frequency (SW) and 177 FM transmitters. The coverage is 91.85% of the area , serving 99.18% of the people in the largest democracy of the world. AIR covers 24 Languages and 146 dialects in home services. The External Services Division of All India Radio ranks high amongst the External Radio networks of the world, both in reach and range, daily in 55 transmissions with almost 72 hours covering over 100 countries in 27 languages, out of which 16 are foreign and 11 are Indian. AIR has many different services each catering to different regions/languages across India. AIR has a three-tier system of broadcasting, namely, national,regional and local. Vividh Bharati Seva (roughly translating to "Multi-Indian service") of All India Radio was conceptualized to combat 'Radio Ceylon' in 1957. Vividh Bharati celebrated its Golden Jubilee on 3 October 2007. Vividh Bharati has the only comprehensive database of songs from the so termed "Golden Era" of Hindi film music (roughly from 1940s to 1980s). to presents a mix of film music, skits, short plays and interactive programmes, Some of the old popular programmes of Vividh Bharati are 'SANGEET SARITA', 'BHULE BISRE GEET', 'HAWA MAHAL', 'JAIMALA', 'INSE MILIYE', 'CHHAYA GEET' ETC., are still distinctly recongnised by the listeners. From time to time new programmes were introduced like 'BISCOPE KE BATEIN', 'SARGAM KE SITARE', 'CELLULOID KE SITARE', 'SEHATNAMA', &' HELLO FARMAISH',. All these programmes are produced centrally at Vividh Bharati Service,Borivili, Mumbai and up-linked to the satellite. 40 Vividh Bharati stations are known as Commercial Broadcasting Service Stations and are

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located at all major and commercially vibrant cities covering 97% of the Indian population. Commercials were introduced initially in the Vividh Bharati Service in the year 1967 & extended to Primary channels including FM & Local Radio Stations. Advertsing on Radio is not only cost effective but also has the potential to reach far flung areas where no other mass media has succeeded in making any tangible dent. AIR had been receiving advertisements through its registered agencies. With the changing demand of the environment, direct clients are also entertained by all AIR stations. Commercial Broadcasting Service, All India Radio, Kanpur is situated at Dr. Ambedkar Road, Benajhabar, Kanpur about 6 K.M. away from Kanpur Central Railway Station. The geographical coordinates of the Station are; Latitude - 26º28'42" N, Longitude - 80º19'25" E and height above mean sea level 120 meter. The Centre was commissioned on 15th September 1963 as an auxiliary Centre for Broadcasting 'Vividh Bharti' Programs. Commercial were introduced over this Vividh Bharti Centre on 27th December, 1970 and since then booking of advertisements are being accepted for the A.I.R. Stations of U.P. & Uttranchal too through various agencies and Government Departments. In the 10th plan the existing 1kW, MW BEL transmitter is being replaced with 10 kW FM transmitter & the existing studio set up has been replaced with stereo facilities. Gyanvani FM Service on 10kW FM Harris make transmitter has been started from 22-06-2006 on 106.4 MHz and FM Rainbow service of AIR on 1kW FM Ecresso make transmitter has been started from 11-07-2006 on 103.7MHz.AIR's DIRECT TO HOME(DTH)Service (24 hours free-to-air Radio Channels) Technical information :Satellite –INSAT-IV B (93.5°E), Symbol rate – 27.5 MSPS, polarization – VerticalD/L Frequency (MHz) AIR Channels 10990 Vividh Bharati Service, Telugu, Marathi, Tamil 11070 Gujarati, FM Rainbow (Delhi), Punjabi, FM Gold (Delhi) 11150 Kannada, Bengali, Hindi, NE Service 11490 Malayalam, Assamese, FM Rainbow (Chennai), FM Gold (Mumbai), Radio Kashmir 11570 Ragam, FM Rainbow (Bangalore), Urdu, Oriya Private operators under FM phase-II scheme have also started their FM services on 92.7 MHz, 93.5 MHz & 98.3 MHz respectively w.e.f. 19.06.2007 . Rabindranath Tagore awarded AIR a poem which is worth for its services: Hark to Akashvani up-surgingFrom here below....From earth to heaven, distanceconquered,In waves of LightFlows the music of man's divining,Fancy's flight..."

For more detail, visit: www.allindiaradio.org

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STUDIO CHAIN IN A TYPICAL AIR STATIONIntroductionThe broadcast of a programme from source to listener involves use of studios, microphones, announcer console, switching console, telephone lines / STL and Transmitter. Normally the programmes originate from a studio centre located inside the city/town for the convenience of artists. The programme could be either “live” or recorded”. In some cases, the programme can be from OB spot, such as commentary of cricket match etc. Programmes that are to be relayed from other Radio Stations are received in a receiving centre and then sent to the studio centre or directly received at the studio centre through RN terminal/telephone line. All these programmes are then selected and routed from studio to transmitting centre through broadcast quality telephone lines or studio transmitter microwave/VHF links. A simplified block schematic showing the different stages is given in Fig. 1.

Fig. 1 Simplified block schmatic of broadcasting chain

Studio Centre

The Studio Centre comprises of one or more studios, recording and dubbing room, a control room and other ancilliary rooms like battery room, a.c. rooms, switch gear room, DG room, R/C room, service room, waiting room, tape library, etc. The size of such a centre and the number of studios provided depend on the programme activities of the station. The studio centres in AIR are categorised as Type I, II, III and IV. The number of studios and facilities provided in each type are different. For example a type I studio has a transmission studio, music studio with announcer booth, a talks studio with announcer booth, one recording/dubbing room and a Read Over Room. Type II has one additional drama studio. The other types have more studios progressively.

Broadcast Studio

A broadcast studio is an acoustically treated room. It is necessary that the place where a programme for broadcast purposes is being produced should be free of extraneous noise. This is possible only if the area of

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room is insulated from outside sound. Further, the microphone which is the first equipment that picks up the sound, is not able to distinguish between wanted and unwanted signals and will pick up the sound not only from the artists and the instruments but also reflections from the walls marring the quality and clarity of the programme. So the studios are to be specially treated to give an optimum reverberation time and minimum noise level. The entry to the studios is generally through sound isolating lobby called sound lock. Outside of every studio entrance, there is a warning lamp, which glows ‘Red’ when the studio is ‘ON-AIR’. The studios have separate announcers booths attached to them where first level fading, mixing and cueing facilities are provided.Studio Operational RequirementsMany technical requirements of studios like minimum noise level, optimum reverberation time etc. are normally met at the time of installation of studio. However for operational purposes, certain basic minimum technical facilities are required for smooth transmission of programmes and for proper control. These are as follows:

Programme in a studio may originate from a microphone or a tape deck, or a turntable or a compact disc or a R-DAT. So a facility for selection of output of any of these equipments at any moment is necessary. Announcer console does this function.

Facility to fade in/fade out the programme smoothly and control the programme level within prescribed limits.

Facility for aural monitoring to check the quality of sound production and sound meters to indicate the intensity (VU meters).

For routing of programmes from various studios/OB spots to a central control room, we require a facility to further mix/select the programmes. The Control Console in the control room performs this function. It is also called switching console.

Before feeding the programmes to the transmitter, the response of the programme should be made flat by compensating HF and LF losses using equalised line amplifiers.(This is applicable in case of telephone lines only)

Visual signalling facility between studio announcer booth and control room should also be provided.

If the programmes from various studios are to be fed to more than one transmitter, a master switching facility is also required.

Announcer Console

Most of the studios have an attached booth, which is called transmission booth or Announcer booth or play back studio. This is also acoustically treated and contains a mixing console called Announcer Console. The Announcer Console is used for mixing and controlling the programmes that are being produced in the studio using artist microphones, tape playback decks and turn tables/CD players. This is also used for transmission of programmes either live or recorded.The technical facilities provided in a typical announcer booth, besides an Announcer Console are one or two microphones for making announcements, two turn tables for playing the gramophone records and two playback decks or tape recorders for recorded programmes on tapes. Recently CD and Rotary Head Digital Audio Tape Recorder (R-DAT) are also included in the Transmission Studio. Audio block schematic of transmission studio is shown in Fig. 4.

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Fig. 4 Announcer Console

Control Room

For two or more studios set up, there would be a provision for further mixing which is provided by a control console manned by engineers. Such control console is known as switching console. Broad functions of switching console in control room are as follows:

Switching of different sources for transmission like News, O.Bs. other satellite based relays, live broadcast from recording studio.

Level equalisation and level control.

Quality monitoring.

Signalling to the source location.

Communication link between control room and different studios.

Audio block schematic of control room is shown in Fig. 5.

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Fig. 5 Block Schematic of Control Room

Direct-to-Home Satellite Broadcasting (DTH)

IntroductionDirect-to-Home satellite broadcasting (DTH) or Direct Satellite Broadcasting (DBS) is the distribution of television signals from high powered geo-stationary satellites through a small dish antenna and satellite receivers in homes across the country. Since DTH services are fully digital, it can offer value added services, video-on-demand, Internet, e-mail and lot more in addition to entertainment. DTH reception requires a small dish antenna (60 cm), which can be easily mounted on the roof top, feed along with Low Noise Block Converter (LNBC) and Set-top Box (Integrated Receiver Decoder, IRD) with CAS (Conditional Access System). A bouquet of 40 to 50 video programs can simultaneously be received in DTH mode.

Uplink Chain

DTH broadcasting is basically satellite broadcasting in Ku-Band (14/12 GHz). The main advantage of Ku-Band satellite broadcasting is that it requires physically manageable smaller size of dish antenna compared to that of C-Band satellite broadcasting dishes. C-Band broadcasting requires about 3.6 m PDA (41dB gain at 4 GHz), while Ku-Band requires just 0.6 m PDA (35 dB gain at 12 GHz). The shortfall of this 6 dB is compensated by using Forward Error Correction (FEC), which can offer 8 to 9 dB coding gain in the digital broadcasting. Requirement of transmitter power (about 25 to 50 W) is less than that of analog C-band broadcasting. The major drawback of Ku-Band transmission is that the RF signals typically suffer 8 to 9 dB rain attenuation under heavy rainfall while rain attenuation is very low at C-Band. Fading due to rain can hamper the connectivity of satellite and therefore rain margin has to be kept for reliable connectivity. Rain margin is provided by operating the transmitter at higher powers and by using larger size of the dish antenna (6.2 m).

Fig.1 shows the schematic of uplink chain proposed to broadcast a bouquet of 30 video programs by Doordarshan. The video , programs in digital format, are fed to a Router whose outputs are divided into three groups A, B and C. Each group contains 10 video sources multiplexed in a multiplexer. These three multiplexed streams are digitally (QPSK) modulated individually at 70 MHz Intermediate Frequency (IF). Each group is further doubly up-converted, first conversion at L-Band (950-1450 MHz) and second conversion at

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Ku- Band (12-14 GHz). Groups A, B and C are up-converted to Ku-Band frequencies, (=13891 MHz),

(=13973 MHz) and (=13839 MHz) respectively and are individually amplified through Klystron High Power Amplifiers (KHPA). The three RF signals are combined in RF combiner and then finally fed to 6.2 m dish antenna for up-linking. Down-Link ChainDown-Link or receiving chain of DTH signal is depicted in Fig. 2. There are mainly three sizes of receiving antenna, 0.6 m, 0.9 m, and 1.2 m. Any of the sizes can be easily mounted on rooftop of a building or house. RF waves (12/14 GHz) from satellite are

Fig.1: DTH Up-linking Setup

picked up by a feed converting it into electrical signal. The electrical signal is amplified and down converted to L-Band (950-1450) MHz signal. Feed and LNBC are combined in single unit called LNBF. The L-Band signal goes to indoor unit, consisting of a set-top box and TV receiver through coaxial cable. The set-top box or Integrated Receiver Decoder (IRD) down converts the L-Band first IF signal to 70 MHz second IF signal, perform digital demodulation, de-multiplexing, decoding and finally gives audio/video output to TV for viewing.

AIR's DIRECT TO HOME(DTH)Service (24 hours free-to-air Radio Channels) Technical information :Satellite –INSAT-IV B (93.5°E), Symbol rate – 27.5 MSPS, polarization – VerticalD/L Frequency(MHz) AIR Channels 10990 Vividh Bharati Service, Telugu, Marathi, Tamil 11070 Gujarati, FM R'bow(Delhi),Punjabi,FM Gold (Delhi) 11150 Kannada, Bangali, Hindi, NE Service 11490 Malayalam, Assamese,FM Rainbow(Chennai),FM Gold(Mumbai), Radio Kashmir 11570 Ragam, FM Rainbow(Bangalore),Urdu, Oriya

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Fig.2: Receiving Chain of DTH signal

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