Broadcasting Day – 12 Nov 1947 Doordarshan Start in 1959 (B&W) Upgrah Doordarshan Kendra (UDK) – 1977 Transmitter Used 10 Kw, 100Kw, 500Kw. Transmitter used in Jaipur 5 Kw. Signal Coverage Area

1. 65 Km Primary (Approx)

2. 75 Km Secondary (Approx)

Omni Directional Pattern

An antenna (or aerial) is a transducer designed to transmit or receive electromagnetic waves. In other words, antennas convert electromagnetic waves into electrical currents and vice versa

Electromagnetic wave

Electrical signal

Transmitting Antenna

Receiving Antenna

1. Select audio out put of required equipment

2. Mix outputs before feeding to an amplifier

PadVCD/DVD Etc.

70 dB0 dBm

-70 dBm

MIXER

Loss12 dB

Fader

-82 dBm

O/P

-70 dBm connector -70 dBmMicrophone

PadVTR Room/Feeds

0 dBm 70 dB-70 dBm

Isotropic antenna (idealized)Radiates power equally in all directions

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

antenna) Parabolic Reflective Antenna

Ground-wave propagation Sky-wave propagation Line-of-sight propagation

SafetyStandard operating procedure

priority Grounding

Lightning strikesStatic charges

Surge protectionLightning searches for a second

path to ground

Components of Audio Chain

1. Microphones

2. VCD / DVD Audio

3. Live Feeds

4. Satellite Feeds

5. Studio Console

6. Switching Console / Master Switching Console

7. Microwave Link Etc

Earth station

Downlink

Uplink

Frequency band Up Link Down LinkC-band 6 GHz 4 GHzX-band 8 GHz 7 GHzKu-band 14 GHz 11 GHzKa-band 30 GHz 20 GHz

The most widely used narrow beam antennas are reflector antennas. The shape is generally a paraboloid of revolution.

For full earth coverage from a geostationary satellite, a horn antenna is used. Horns are also used as feeds for reflector antennas.

A small earth terminal, the feed horn is located at the focus or may be offset to one side of the focus.

Large earth station antennas have a sub reflector at the focus. In the Cassegrain design, the sub reflector is convex with an hyperboloid surface, while in the Gregorian design it is concave with an ellipsoidal surface.

A Typical Uplink PDA

The word DSNG means DIGITAL SATELLITE NEWS GATHERING. it is just like a Digital Earth Station. Programme may be up-linked through DSNG from any place. Its up-linking chain have a MPEG-2 Encoder, Modulator, Up-converter, wave guide mechanism and PDA.

Types of TV transmitters Based on POWER:-

VLPT/Transponser (10W)LPT (100W, 300W, 500W)HPT (1kW, 10kW, 20kW)

Based on FREQUENCY:-VHFUHF

About OB VAN1.This is mainly used for outside

Broadcasting for all live telecasting.2. In this VAN sound mixing and video

mixing facilities are available.3.Mainly used for Cricket, Hocky and

other games live coverages.

TYPES OF COVERAGES

• CEREMONIAL FUNCTIONS

• CULTURAL PROGRAMS

• ORGANISED EVENTS

• SPORTS EVENTS