“DEPARTMENT OF ELECTRONICS & COMMUNICATION”

SEMINAR REPORT

ON

“DIRET TO HOME (DTH)”

SUBMITTED TO :- SUBMITTED BY :-

Mr. Rohit Tripathi Vidhu Shekhar Singh

(Seminar Incharge) EC 4th year

(0616431117)

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ACKNOWLEDMENT

I would like to thank everyone who helped to see this seminar to completion. In particular, I
would like to thank my seminar incharge Mr. Rohit Tripathi for his moral support and
guidance to complete my seminar on time.

I express my gratitude to all my friends and classmates for their support and help in this seminar.

Last but not the least I wish to express my gratitude to God almighty for his abundant blessings
without which this seminar would not have been successful.

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 ABSTRACT

DTH is a new technology and it has matured to its full potential in other parts of the
world. There are many application has been found everyday for exploitation of benefits
of DTH?

The word ‘DTH’ is synonymous with transmission of digital video channel to home subscriber’s
using a small dish antenna. The DTH utilizes a technology which enables a home to receive high
speed internet broadband access data communication, voice over internet protocol (IP) telephony
and much more using an open standard Digital Video Broadcasting (DVB) technology. The
video channels are received with a suitable set top box. Capable of demodulating Motion Picture
Engineering Group (MPEG-2) standard videos. It is for the return channel required for other
services such as voice over internet protocol and broadband access data communications, that a
return channel is also required for the home terminal. The return channel via the satellite is called
RCS and is an open standard.

Hardware compatible with DVB-RCS technology are readily available in the market in both Ku-
band and C-band. DVB-RCS is an international open standard for multimedia satellite network
where the return data rates in access of 2 Mbps are possible using low cost user terminals. The
forward ink is usually at 40 Mbps.

Today, most satellite TV customers in developed television markets get their programming
through a direct broadcast satellite (DBS) provider, such as DISH TV or DTH platform. The
provider selects programs and broadcasts them to subscribers as a set package. Basically, the
provider’s goal is to bring dozens or even hundreds of channels to the customer’s television in a
form that approximates the competition from Cable TV. Unlike earlier programming, the
provider’s broadcast is completely digital, which means it has high picture and stereo sound
quality. Early satellite television was broadcast in C-band - radio in the 3.4-gigahertz (GHz) to 7-
GHz frequency range. Digital broadcast satellite transmits programming in the Ku frequency
range (10 GHz to 14 GHz). There are five major components involved in a direct to home (DTH)
satellite

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 CONTENTS

 A PATH TOWARDS DTH

 WORKING OF DTH

 HOW DOES DTH REALLY DIFFER FROM CABLE TV?

 DTH RATHER THAN CABLE TV

 WILL DTH BE CHEAPER THAN CABLE OR MORE EXPENSIVE?

 HISTORY OF DTH IN INDIA AND MARKETCOMPARISON OF DTH AND CABLE

TV

 OVERVIEW OF DTH SYSTEMS

 NSS 6

 The COMPONENTS

 THE SATELLITE

 THE PROGRAMMING

 ENCRYPTION AND TRANSMISSION

 DISH MATERIALS AND CONSTRUCTION

 DTH APPLICATIONS

 DTH BENEFITS

 CONCLUSION ANS FUTURE WORKS

 REFERENCES

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 A PATH TOWARDS DTH

On June 25, 1967, for two hours 26 nations of the world were joined together by an invisible
electromagnetic grid utilizing four satellites. The London-based production, in glorious black
and white, was the first-ever use of satellites to simultaneously interconnect remote corners of
the world to a single program event. The program, appropriately entitled "Our World," included
the Beatles debuting the song "All You Need Is Love" to an audience estimated at more than 600
million.

During the course of the telecast, live feeds were interconnected through a pair of early design
Intelsats, an American experimental satellite (ATS-1), and a Russian Molniya class bird. The
New York Times would write about the ground-breaking telecast, "Our World was a compelling
reaffirmation of the potential of the home screen to unify the peoples of the world."

Less than three decades later, or approximately the period of one generation of mankind, more
than 30 million homes in the world are equipped with their own satellite dishes. The early
Intelsat, ATS, and Molniya satellites were capable of relaying one (or at most, two) simultaneous
TV programs; each satellite of the current generation easily can deliver as many as 200 program
channels to dish antennas less than one-thirtieth of the size required for reception of the original
"Our World" telecast.

Well before the turn of the century, virtually any location in Asia or the Pacific will have direct
access to hundreds of channels of TV, high-speed Internet links, and thousands of radio program
channels. It is not an exaggeration to suggest that satellites are redesigning the very fabric of life
by creating full-time universal access to "our world."

All of this technology creates virtually unlimited opportunities for new business enterprise and
personal development. You are holding in your hand a key that will unlock for you, your family,
and your business the "secrets" of the 21st century "Information Revolution." There has never
been a point in the history of the world when so much opportunity has presented itself to
mankind. Use what you learn here wisely and your life will forever be changed.

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 The DTH

DTH stands for Direct-To-Home television. DTH is defined as the reception of satellite
programmes with a personal dish in an individual home.

DTH does away with the need for the local cable operator and puts the broadcaster directly in
touch with the consumer. Only cable operators can receive satellite programmes and they then
distribute them to individual homes.

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 Working of DTH

A DTH network consists of a broadcasting centre, satellites, encoders, multiplexers, modulators

and DTH receivers.

A DTH service provider has to lease Ku-band transponders from the satellite. The encoder
converts the audio, video and data signals into the digital format and the multiplexer mixes
these signals. At the user end, there will be a small dish antenna and set-top boxes to decode
and view numerous channels. On the user's end, receiving dishes can be as small as 45 cm in
diameter.

DTH is an encrypted transmission that travels to the consumer directly through a satellite.
DTH transmission is received directly by the consumer at his end through the small dish
antenna. A settop box, unlike the regular cable connection, decodes the encrypted
transmission.

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 HOW DOES DTH REALLY DIFFER FROM CABLE TV?

The way DTH reaches a consumer's home is different from the way cable TV does. In DTH, TV
channels would be transmitted from the satellite to a small dish antenna mounted on the window
or rooftop of the subscriber's home. So the broadcaster directly connects to the user. The
middlemen like local cable operators are not there in the picture.

DTH can also reach the remotest of areas since it does away with the intermediate step of a cable
operator and the wires (cables) that come from the cable operator to your house. As we explained
above, in DTH signals directly come from the satellite to your DTH dish.

Also, with DTH, a user can scan nearly 700 channels!

Does one need to put two dish antennae and pay double
Subscription per month if one has two TVs?

For multiple connections in the same premises, one can use the same connection. However,
every television set will need to have an individual STB.

Also, DTH is a national service and the STBs enable a viewer to change service providers
without changing the STB, even if one moves from one city to another.

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 DTH RATHER THAN CABLE TV

DTH offers better quality picture than cable TV. This is because cable TV in India is analog.
Despite digital transmission and reception, the cable transmission is still analog. DTH offers
stereophonic sound effects. It can also reach remote areas where terrestrial transmission and
cable TV have failed to penetrate.
Apart from enhanced picture quality, DTH has also allows for interactive TV services such as
movie-on-demand, Internet access, video conferencing and e-mail. But the thing that DTH has
going for it is that the powerful broadcasting companies like Star, Zee, etc are pushing for it.

In DTH, the payments will be made directly by the subscriber to the satellite company offering
the service.

A big problem that broadcasters face in India is the issue of underreporting of subscribers by
cable operators.

Consider the cable operators pyramid. Right at the top is the broadcaster. Next comes the Multi
Service Cable Operator (MSOs) like Siticable, InCable, etc. Below them are the Access Cable
Operators (ACOs) or your local cable guy who actually lays the wires to your house.

The local cable operators or the ACOs then allegedly under-report the number of subscribers
they have bagged because they have to pay the MSOs something like Rs 30-45 per household.
Showing a lesser number of households benefits ACOs.

With no way to actually cross check, the MSOs and the broadcasters lose a lot. Broadcasters do
not earn much in subscription fees and are mostly dependent on advertisement revenue to cover
their costs, which is not sustainable and does not
offer high growth in revenues for broadcasters.

The way out of this is to use a set-top box so that it will be clear how many households are
actually using cable or going for DTH where broadcasters directly connect to consumers and can
actually grow revenues with a growth in the subscriber base.

Today, broadcasters believe that the market is ripe for DTH. The prices of the dish and the set-
top box have come down significantly. Overall investments required in putting up a DTH
infrastructure has dropped and customers are also reaping the benefits of more attractive tariffs.

The major thing that DTH operators are betting on is that the service is coming at a time when
the government is pushing for CAS (conditional access system), which will make cable
television more expensive, narrowing the tariff gap between DTH and cable.

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 WILL DTH BE CHEAPER THAN CABLE OR MORE EXPENSIVE?

DTH will be definitely more expensive than cable as it exists today.

A set-top box is a must for DTH. Earlier, when CAS made set-top box mandatory for
households, the costs between DTH and cable would not have been too wide.
But CAS on the backburner now -- which means no set-top box (a must for DTH), the price gap
between DTH and cable, will be wide.
In Oct 2002, Siticable, which is owned by Zee, said that the cost of the installation equipment,
which includes the receiver dish and the set-top box, would be priced at around Rs 3,900.
Siticable is looking to rope in 1 million subscribers in 15 months.

Other estimates say that digital cable set-top box may cost Rs 4,000, a DTH decoder dish is
unlikely to cost less than Rs 7,000.

DTH's minimum subscription could be priced around Rs 500 per month.

Some reports say that an entry level DTH STB will cost about Rs 7,000 (including taxes and
installation cost at consumers end). A more advanced STB with value added features like PVR
(Personal Video Recorder), PSTN connectivity, Gamming console, channel management system,
etc. may cost as much as Rs 15,000.

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 HISTORY OF DTH IN INDIA

DTH services were first proposed in India in 1996. But they did not pass approval because there
were concerns over national security and a cultural invasion. In 1997, the government even
imposed a ban when the Rupert Murdoch-owned Indian Sky Broadcasting (ISkyB) was about to
launch its DTH services in
India.

Finally in 2000, DTH was allowed. The new policy requires all operators to set up earth stations
in India within 12 months of getting a license. DTH licenses in India will cost $2.14 million and
will be valid for 10 years. The companies offering DTH service will have to have an Indian chief
and foreign equity has been capped at 49 per cent. There is no limit on the number of companies
that can apply for the DTH license.

MARKET COMPARISON OF DTH AND CABLE TV

The cable system is well entrenched in India and is showing quite rapid growth. If DTH had
come to India in 1996-97 (like Star had originally attempted), then it could have made a
significant breakthrough.
Europe is an example of this. DTH developed there before cable and now controls nearly 80 per
cent of the total satellite television subscriber base. But in US, cable rules because it came before
DTH.

DTH will definitely cut into the existing cable user base. It will make the local cable operator
less important and take business away from him. It will give consumers greater choice.

But it is likely to be an up market premium product and most middle class households will stick
to cable.

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 OVERVIEW OF DTH SYSTEMS

Direct to Home are nothing but the Direct Broadcast Satellite Television and Radio Systems.
Geostationary satellites play an important role for DTH systems. In general, DTH service is the
one in which a large number of channels are digitally compressed, encrypted and beamed from
very high power Geostationary satellites. The programs can be directly received at homes. Also,
DTH transmission eliminates local cable operator completely, since an individual user is directly
connected to the service providers.

An individual user has a small dish usually 45 to 60cm in diameter and Low Noise Block
Converter (LNBC) pointed towards satellite. At home digital receiver i.e. Set top box is
connected to TV which receives digitally multiplexed channels from LNBC and gives RF output
for TV.

The satellite transmission is usually in Ku-Band. The digital channels are first multiplexed and
then QPSK modulated before transmission. The small dish along with LNBC receives the signals
and LNBC converts these Ku band signals to Intermediate Frequency based on the local IF
which is typically 10.7GHz. Now, the set top box receives the down-converted satellite signals
and performs the demodulation and de-multiplexing and finally D to A conversion before
making signal competent to TV.

The DTH receivers available in the Market are affordable and the use of such systems is
nowadays increasing dramatically in urban as well as ruler areas.

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 NSS 6

NSS 6, Ku-band satellite with Ka band uplink capabilities, will provide fully interactive access to
high speed internet and other multimedia communications. Additionally, it will provide direct to
home broadcasting services a well AS THE full compliment of traditional enterprise
telecommunications services across the large coverage area stretching from the eastern
Mediterranean and southern Africa to Australia, Japan and Korea.

Access Cable Operators (ACOs) or your local cable guy who actually lays the wires to your
house. The local cable operators or the ACOs then allegedly underreport the number of
subscribers they have bagged because they have to pay the MSOs something like Rs 30-45 per
household.

Showing a lesser number of households benefits ACOs. With no way to actually cross check, the
MSOs and the broadcasters lose a lot. Broadcasters do not earn much in subscription fees and are
mostly dependent on advertisement revenue to cover their costs, which is not sustainable and
does not offer high growth in revenues for broadcasters.

The way out of this is to use a set-top box so that it will be clear how many households are
actually using cable or going for DTH where broadcasters directly connect to consumers and can
actually grow revenues with a growth in the subscriber base.

Specifications of NSS-6 Satellite:

Location: 95 degree East

No. of Ku-Band Transponders (36MHz wide): 60
Saturated EIRP: 44-55 dBW.
Ku Band Uplink: 13.75 to 14.5 GHz
Ku Band Down links: 10.95 to 11.2 GHz
11.45 to 11.70 GHz
12.50 to 12.75 GHz
Modulation Type: QPSK

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 THE COMPONENTS

Programming sources are simply the channels that provide programming for broadcast. The
provider doesn't create original programming itself; it pays other companies (HBO, for example,
or ESPN) for the right to broadcast their content via satellite. In this way, the provider is kind of
like a broker between you and the actual programming sources. (Cable television companies
work on the same principle.)

The broadcast center is the central hub of the system. At the broadcast center, the television
provider receives signals from various programming sources and beams a broadcast signal to
satellites in geostationary orbit.

The satellites receive the signals from the broadcast station and rebroadcast them to the ground.

The viewer's dish picks up the signal from the satellite (or multiple satellites in the same part of
the sky) and passes it on to the receiver in the viewer's house.

The receiver processes the signal and passes it on to a standard television.

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 SATELLITE

Geostationary satellites play an important role for DTH systems.

WHAT IS GEO STATIONARY SATELLITE?

 Geostationary satellites are positioned at an exact height above the earth (about 36000
Km).

 At this height they rotate around the earth at the same speed as the earth
rotates around its axis, so in effect remaining stationary above a point on
the earth (normally directly overhead the equator).

 As they remain stationary they are ideal for use as communications satellites and also
for remote imaging as they can repeatedly scan the same points on the earth beneath
them.

 Polar Orbiting satellites by comparison have a much lower orbit, moving around the earth
fairly rapidly, and scanning different areas of the earth at relatively infrequent periods.

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 Motion of Geostationary Satellite around EARTH

 In above fig. , it is clear that geostationary satellite has circular orbit.

 In each orbit the time period remains same.

 Orbital plane is same as equator.

 Above 3 condition are necessary for a satellite to be a geostationary

satellite.

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 Otherwise it will become geo synchronous satellite, which appears oscillating to an
observer on the earth at fix location in sky.

Focusing of a particular position on earth

 Above fig. shows how geostationary satellite focuses a part of earth.

 We know that earth rotates on its axis.

 Each such rotation has time period 24 hours.

 Fig. explains how the same part of earth remains always in the focus of
geostationary satellite.

 Geostationary satellite and earth both rotate in same direction with same speed.

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A stationary satellite and orbit

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 THE PROGRAMMING

Satellite TV providers get programming from two major sources: national turnaround channels
(such as HBO, ESPN and CNN) and various local channels (the NBC, CBS, ABC, PBS and Fox
affiliates in a particular area). Most of the turnaround channels also provide programming for
cable television, and the local channels typically broadcast their programming over the airwaves.

Turnaround channels usually have a distribution center that beams their programming to a
geostationary satellite. The broadcast center uses large satellite dishes to pick up these analog
and digital signals from several sources.

Most local stations don't transmit their programming to satellites, so the provider has to get it
another way. If the provider includes local programming in a particular area, it will have a small
local facility consisting of a few racks of communications equipment. The equipment receives
local signals directly from the broadcaster through fiber-optic cable or an antenna and then
transmits them to the central broadcast center.

The broadcast center converts all of this programming into a high-quality, uncompressed digital
stream. At this point, the stream contains a vast quantity of data -- about 270 megabits per
second (Mbps) for each channel. In order to transmit the signal from there, the broadcast center
has to compress it. Otherwise, it would be too big for the satellite to handle. In the next section,
we'll find out how the signal is compressed.

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 ENCRYPTION AND TRANSMISSION

After the video is compressed, the provider needs to encrypt it in order to keep people from
accessing it for free. Encryption scrambles the digital data in such a way that it can only be
decrypted (converted back into usable data) if the receiver has the correct decryption algorithm
and security keys.

What is Encryption?

Encryption is an electronic method of securing the video and audio of any TV program so that
satellite, cable, and broadcast TV services can maintain control over the distribution of their
signals. To receive encrypted or "scrambled" TV services, cable and SMATV system operators,
hotel chains, private satellite networks, and home dish owners must possess a compatible
decoder that can sense the presence of the encrypted TV signal and then automatically decode
the pictures and sound Premium program services purchase the rights to movies from film
production companies with the understanding that every individual will pay for the right to view
them. Programmers also are very concerned about hotels, bars, and other commercial
establishments that derive monetary benefit from signal piracy.

Within a particular region, program producers may license more than one broadcast outlet for
use of their programs. The program producer may require that broadcasters encrypt their signals
whenever the broadcaster airs the producer's copyrighted material. This strictly limits reception
of the programming to the market for which each broadcaster is licensed. In some areas of the
world, satellite broadcasters periodically must switch from a free-to-air to an encrypted
transmission mode whenever required under their respective agreements with the program
copyright owners.

Each IRD contains a unique numerical address number that is installed at the factory. The
satellite TV programmer's authorization center sends a coded conditional access message over
the satellite that includes this unique address. This authorization message can turn on an
individual IRD so that it can receive a particular service or group of services, or turn off an IRD
in the event that the subscriber fails to pay the required monthly subscription fee.

Moreover, the authorization center can use this addressable feature to selectively turn off and on
large groups of decoders. Group IRD control is used to selectively "black out" TV events, such
as a live championship boxing match, in certain countries for which the programmer does not
own the distribution rights.
Once the signal is compressed and encrypted, the broadcast center beams it directly to one of its
satellites. The satellite picks up the signal with an onboard dish, amplifies the signal and uses
another dish to beam the signal back to Earth, where viewers can pick it up.

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 COMMUNICATION CHANNEL AND BAND-WIDTH

In a communications system, the part that connects a data source to a data sink is known as
channel.

Bandwidth refers to the data transmission capacity of a communications channel. The greater a
channel's bandwidth, the more information it can carry per unit of time.

The term technically refers to the range of frequencies that a channel can carry. The higher the
frequency, the higher the bandwidth and thus the greater the capacity of a channel. This capacity
might more appropriately be referred to as throughput.

For digital devices, the bandwidth is usually expressed in bits per second (bps), kilobits per
second (kbps) or megabits per second (mbps). For analog devices, the bandwidth is expressed in
cycles per second, or Hertz (Hz).

The required bandwidth can vary greatly according to the type of application. For example, the
transmission of simple ASCII text messages requires relatively little bandwidth, whereas the
transmission of high resolution video images requires a large amount of bandwidth.

A major trend in networks at all levels (i.e., from LANs to the Internet) has been increasing
bandwidth. For example, the development of optical fiber cable made possible a huge increase in
bandwidth as compared with copper wire cable, and the bandwidth of optical fiber cable
continued to increase both as a result of improvements to the optical fiber itself and to the
transmitters and other devices used with it.

Nevertheless, bandwidth is often insufficient. This is due to such factors as the continued
increase in the numbers of users (especially of the Internet), the growth in the demand for
applications which require more bandwidth and the high cost of upgrading some portions of
networks (particularly replacing copper wire connections to individual homes and offices with
optical fiber). Thus, an important principle in the design of network protocols continues to be the
conservation of bandwidth.

For DTH system communication channel is air and Band-Width is :

Ku Band Uplink : 13.75 to 14.5 GHz

Ku Band Down links : 10.95 to 11.2 GHz

11.45 to 11.70 GHz
12.50 to 12.75 GHz

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 DISH MATERIALS AND CONSTRUCTION

The reflector's surface material must be constructed out of metal in order to reflect the incoming
microwave signals. Some antenna reflectors appear to be manufactured out of plastic or
fiberglass; however, these dishes actually have an embedded metal mesh material that reflects
the incoming satellite signals to the front and center of the dish.

The solid one-piece metal antenna is most always the dish with the best performance
characteristics because there can be no assembly errors and the reflector normally will maintain
its precise shape over the lifetime of the system. Solid petal antennas constructed out of four or
more metal panels are generally the next best performance value, as potential assembly errors are
limited to variations along the seams between panels. The installer can visually inspect these
seams during assembly to ensure that there are no variations in the surface curve from one petal
to the next. Installation errors almost never occur when this type of antenna is assembled face-
down on a flat, level surface.

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 DTH APPLICATIONS

a) To view pay & free-to-air TV channels of various DTH platform on your home TV.

b) Doordarshan free-to-air services providing 40 TV channels with no subscription fees is an

attractive preposition to people in urban and rural areas. These
channels comprises of DD channels and popular channels of news , sports , information ,
entertainment etc.

c) One can scan the entire globe with a motorized dish using a CI set top box with CAM modules
and watch TV channels of several DTH platforms visible to the
dish terminals.

d) A number has started IP broadcast with return channel on PSTN line and this would be for
education and other application.

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 DTH-BENEFITS

Benefits of DTH extends to all sections of the society since DTH has a reach in all areas whether
it is remote or urban , it provides equal benefits to everyone. Benefits of DTH are listed below:

• Cost effective communication, information and entertainment to all .

• Small size terminals can provide up to 4000 TV channels and 2000 radio channels through a
click of a button and thus brings world’s at least information, news, entertainment to your home .

• DTH services bypasses mediators and thus content provider comes with customer directly.

• DTH services are transparent providing digital quality video, audio, radio, and IP to all at equal
prices and other benefits with reliability.

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 CONCLUSION

DTH projects in India are just a beginning and we are taking the advantage of DTH revolution.
Direct to home connects urban, rural and remote areas of the country and provides desire
information communication, education and entertainment at the click of a button.

1. Broadband noise will have negligible effect on GMRT Observations, as the minimum
separation distance is 90 meters with the assumption that there is no DTH system in 100
meter circle from any of the GMRT antennas. Care must be taken for arm antennas.

2. Narrow band noise can cause RFI, in spectral line observations below 400MHz, if located at
about 2 km from a GMRT antenna.

Further Work
1. It is useful to be able to control LNB without set top box so as to understand the exact
spectrum at LNB o/p. Effort is to be put to make the circuit on page 18 (or some other
approach) work.

2. Effect of Narrow band noise on GMRT must be studied in detail. Towards this, a DTH
Receiver needs to be installed on an evaluation basis at the GMRT Guest Housel Recreation
Room and test observations in spectral line mode perfonned with different "poorly made"
coaxial cables to link the LNB and STB. Careful check for lines seen in nearby antennas like
C3, C4, and C9 etc in 235 and 325 MHz bands would help in getting a clearer picture
regarding the severity of the problem/s in a controlled manner.

3. Finally, to restrict possible RFI, one can design a Hair Pin Filter with provision of passing
DC and 22 KHz tone which can be added between the LNB and set top box. This will only
allow the required satellite signals and attenuate noise in the GMRT band. Depending on the
result of (2) above, we may have to plan a strategy of adding such units BEFORE THE STB
at installations in nearby villages.

4. We may find that a simpler solution might be to buy a good quality double shielded cable,
assemble connectors professionally and supply to the nearby villages, if the tests as in (2)
above does show interference to operation of GMRT.

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 REFERENCES

1. THE DIGITAL SATELLITE TV HANDBOOK

MARK E. LONG

2. www.mindstien.net

3. www.scribd.com

4. www.wikipedia.com

5 . www.howstuffwork.com

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