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Business Development (Service)

What is DTHWhat is DTH

How DTH worksHow DTH works

Type of DTH Connections Type of DTH Connections

Advantages of DTH Advantages of DTH

Components of DTH Components of DTH

Sun Direct ParametersSun Direct Parameters

Elevation & AzimuthElevation & Azimuth

SkewSkew

BER – Bit Error RateBER – Bit Error Rate

MER – Modulation Error RatioMER – Modulation Error Ratio

Rain FadeRain Fade

Solar FadeSolar Fade

Health & SafetyHealth & Safety

DTH stands for Direct To Home

DTH is the direct mode of transmission between ‘Broadcaster’ and ‘Subscriber’

through satellite.

Broadcaster

Subscriber

Satellite

Advantages of DTH

High quality Picture & SoundHigh quality Picture & Sound

Un-interrupted ViewingUn-interrupted Viewing

Reaches Remote AreasReaches Remote Areas

Pay only for your choice ChannelsPay only for your choice Channels

Interactive Features (like, Video on Interactive Features (like, Video on Demand)Demand)

Foot Prints

The Geographic area covered by

satellite is called as its Footprint

Contour of the footprint matches

that of the geographical boundaries

of the area intended to be covered.

How does DTH work ?

Type of DTH Connections Type of DTH Connections

Maximum 4 STBs can be connected from Single Dish

More than 4 STB can be connected from Single Dish Used to provide DTH Solution for High Rise / Multi Story Building.

0 Multi Switch0 Multi Switch

0 Multi Switch0 Multi Switch

0 Multi Switch

SDU – Single Dwelling Unit MDU – Multi Dwelling Unit

Components of DTH Components of DTH

Reflector

Function : -

Reflector receive the Signal & focus to the LNBF.

Installation Precautions : -

There should not be any scratch on the reflector surface Reflector / LNBF Arm should not deform or bend.

LNBF

Function : -

Down converts RF signals to IF signals ( From High Frequencyto Low Frequency ). Types : -

Universal / Single - Used for SDU Connection ( Single STB ) Dual - Used for SDU Connection ( Maximum Two STB ) Quad - Used for SDU Connection ( Maximum Four STB )Quattro - Used for MDU Connection ( More than Four STB )Installation Precautions : -

LNBF should be installed at Focal Point of Reflector Proper Skew Alignment should be done as per Look angle Chart.

Components of DTH Components of DTH

Connector

Function : -

Connector connects cable with Equipment.Type : -

RG - 6 (F type Compression)

RG - 11 (F type Compression)

Installation Precautions : - Take extreme care while Connectorisation to avoid repeated

complaints

Function : -

Carries Signals from one end to other end.Types : -

RG - 6 (Coaxial Cable- 3Ghz)RG – 11 (Coaxial Cable- 3Ghz)

Installation Precautions : -

Take extreme care during Cabling to avoid cable damage.

Take extreme care while taking out cable from cable drum

Components of DTH Components of DTH

Smart Card

Set Top Box

Function : - Function : -

STB decodes the signals

Provides supply to LNBF

Converts Digital signals into Analog signals

Installation Precautions : - TV & STB should be switched OFF while connecting cables

Function : - Function : -

Smartcard works as an access card for channel viewing .

Installation Precautions : -

Insert Smart card with care.

SUN DTH ParametersSUN DTH Parameters

Our Satellite : INSAT 4B (93.50 E)

Satellite Position : 93.50 East

S.No.Transponder Frequency Polarisation FEC Symbol Rate

( MHz )

1 11030 Vertical 3/4 27500

2 11110 Vertical 3/4 27500

3 11185 Vertical 3/4 20000

4 11530 Vertical 3/4 27500

5 11610 Vertical 3/4 27500

6 11645 Vertical 3/4 20000

Elevation & AzimuthElevation & Azimuth

The vertical movement of Reflector to track The vertical movement of Reflector to track

the satellite is called Elevation Adjustment.the satellite is called Elevation Adjustment.

Elevation Azimuth

The horizontal movement of Reflector to track The horizontal movement of Reflector to track

the satellite is called Azimuth Adjustment.the satellite is called Azimuth Adjustment.

SkewSkew

LNBF

Vertical Antenna

Horizontal Antenna

Horizontally Polarized Signal

Skew is the amount of rotation of LNBF to match

LNBF antenna with polarized signal direction.

LNBF contains two antenna (Vertical & Horizontal)

with 90 degree phase shift .

To get maximum signal we have to match

Antenna angle with received signal angle.

If SKEW is not done properly, few channels If SKEW is not done properly, few channels may not be seen.may not be seen.

SkewSkew

9 divisions

9 divisions

5 Degree

For example: - If Polarization is -23 degree for a city, so set at 4.6(approx) division of the LNBF (Left side division) with the centre point of the LNBF Clamp.

Look Angle Chart

Marking on LNBF & LNBF top clamp are for Skew adjustment .

BER – Bit Error BER – Bit Error RateRate

Customer House

INSAT 4B Satellite

3E-4 = 3x10-4 = 3/104 = 3/10000 = 3 bit error in 10,000 bit

2E-4 means 2/10000 = 2 bit error in 10,000 bit

6E-5 means 6/100000 = 6 bit error in 1,00,000 bit

A good quality of Signal has BER of 1E-4 or 1E-5.A good quality of Signal has BER of 1E-4 or 1E-5.

For Example

BER is the ratio between total bits transmitted and the number of bit not interpreted bythe de-modulator.

Total bits transmitted(e.g. 10000 bit )

No of Bit not interpreted by Demodulator(e.g. 3 bit error)

Rain FadeRain Fade

During Raining or snow fall, Rain, Snow or Rain filled clouds can reduce intensity of Ku

band signals coming from satellite to the subscriber.

For example MER = 13 dB

For example MER = 7 dBPicture freezing / No PicturePicture freezing / No Picture

Under Clear Sky condition During Rain fall

How to Counter-act

Tracking should be done up to peak level.

Exact time depends upon the position of the Satellite.

What happens

The sun passes through this plane. As seen from the ground, the sun seems to pass behind the satellites once a day. During the time when both the satellite and the sun are in the ground station's field of view, the energy from the sun can overpower the signal from the satellite, as shown in the below diagram

Solar Fade