satellite radio report

7/30/2019 satellite radio report

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CHAPTER 1

INTRODUCTION

1.1 SATELLITE

A satellite is an object that goes around, or orbits, a larger object, such as a planet.

While there are natural satellites, like the Moon, hundreds of man-made satellites also

orbit the Earth.

Communications antenna, radio receivers and transmitters enable the satellite to

communicate with one or more ground stations, called command centers. Messages

sent to the satellite from a ground station are "uplinked"; messages transmitted from

the satellite to Earth are "downlinked."

1.2 RADIO

Radio is the transmission of signals by modulation of electromagnetic waves with

frequencies below those of visible light. Electromagnetic radiation travels by means

of oscillating electromagnetic fields that pass through the air and the vacuum of space.

Information is carried by systematically changing (modulating) some property of the

radiated waves, such as amplitude, frequency, phase, or pulse width. When radio

waves pass an electrical conductor, the oscillating fields induce an alternating current

in the conductor. This can be detected and transformed into sound or other signals that

carry information.

1.3 ORBITS

GEO

GEO stands for Geostationary Earth Orbit. This refers to satellites that are placed in

orbit such that they remain stationary relative to a fixed spot on earth. If a satellite is

placed at 35,900 km above the earth, its angular velocity is equal to that of the earth,

thereby causing it to appear to be over the same point on earth. This allows for them

to provide constant coverage of the area and eliminate blackout periods of ordinary

orbiting satellites, which is good for providing television broadcasting. However their

high altitude causes a long delay, so two way communications, which would need to


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be uploaded and then downloaded over a distance of 72,000 km, are not often used

with this type of orbit.

LEO

LEO stands for Low Earth Orbit, and it refers to satellites in orbit at less than 22300

miles above the earth. This type of an orbit reduces transmission times as compared to

GEO. A LEO orbit can also be used to cover a polar region, which the GEO cannot

accomplish. Since it does not appear stationary to earth stations, however, earth

stations need an antenna assembly that will track the motion of the satellite.

1.4 SATELLITE RADIO

We all have our favorite radio stations that we preset into our car radios, flipping

between them as we drive to and from work, on errands and around town. But when

travel too far away from the source station, the signal breaks up and fades into static.

Most radio signals can only travel about 30 or 40 miles from their source. On long

trips that find you passing through different cities, you might have to change radio

stations every hour or so as the signals fade in and out.

Now, imagine a radio station that can broadcast its signal from more than 22,000

miles (35,000 kill) away and then come through on your car radio with complete

clarity without ever having to change the radio station.

Satellite Radio or Digital Audio Radio Service (DARS) is a subscriber based radio

service that is broadcast directly from satellites. Subscribers will be able to receive up

to100 radio channels featuring Compact Disk digital quality music, news, weather,

sports. talk radio and other entertainment channels.

Satellite radio is an idea nearly 10 years in the making. In 1992, the U.S. Federal

Communications Commission (FCC) allocated a spectrum in the "S" band (2.3 GHz)

for nationwide broadcasting of satellite-based Digital Audio Radio Service (DARS).

In 1997 the FCC awarded 8-year radio broadcast licenses to two companies, Sirius

Satellite Radio former (CD Radio) and XM Satellite Radio (former American Mobile

Radio). Both companies have been working aggressively to be prepared to offer their

radio services to the public by the end of 2000. It is expected that automotive radios

would be the largest application of Satellite Radio.


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The satellite era began in September 2001 when XM launched in selected markets

followed by full nationwide service in November. Sirius lagged slightly, with a

gradual rollout beginning February, including a quiet launch in the Bay Area on June

15. The nationwide launch comes July 1.

To the average user, these systems will look very similar to conventional AM/FM

.radio systems, whether they are used in the home, office, or on the road. However the

real difference is in what the listener won't see. Rather than receiving a signal from a

tower antenna of a local radio station, these new radios will receive signals from a set

of satellites in geosynchronous orbit. Programming will be up linked from ground

stations to the satellites and then broadcast back to large geographic areas.

The programming will be up linked to the three geostationary orbit satellites and then

rebroadcast directly to radios in the vehicles of CD Radio subscribers. Ground based

repeaters will be used in urban areas to provide a clear and uninterrupted radio signal.

Figure.1.1: Basic Architecture


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CHAPTER 2

BASIC COMPONENTS OF SATELLITE RADIO

Each company has a different plan for its broadcasting system, but the systems doshare similarities. Here are the key components of the three satellite radio systems.

SATELLITES GROUND REPEATERS RADIO RECEIVERS

At this time, there are three space-based radio broadcasters in various stages of

development

XM Satellite Radio launched commercial service in limited areas of the United

States on September 25, 2001. (They were originally going to launch service

September 12. but postponed the event because of the terrorist attacks on the United

States.)

Sirius Satellite Radio is now operational in the United States, with its official launch

on July I, 2002.

WorldSpace is already broadcasting in Africa and Asia, and will begin broadcasting

in South America sometime soon.

XM Satellite radio and Sirius Satellite Radio have both launched such a service.

Satellite radio, also called digital radio, offers' uninterrupted, near CD-quality music

beamed to the radio from space.

2.1 SATELLITES

2.1.1 XM SATELLITE RADIO

While XM Radio and Sirius have merged into a single company, the two services

aren't fully integrated yet. Part of the reason for this is due to differences in hardware

and software.

XM Radio uses two Boeing HS 702 satellites, appropriately nicknamed "Rock" and

"Roll," and two BSS 702 satellites it calls "Rhythm" and "Blues," placed in parallel

geostationary orbit, two at 85 degrees west longitude and the other two at 115 degree


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west longitude. Geostationary Earth orbit (GEO) is about 22,223 miles (35,764 km)

above Earth, and is the type of orbit most commonly used for communications

satellites. The first XM satellite, "Rock," was launched on March 18, 2001, with

"Roll" following on May 8 of the same year. A design flaw in the HS 702 satellitecaused its solar panels to function inefficiently. XM launched "Rhythm" on February

28, 2005, and "Blues" on October 30, 2006, to replace the older satellites. Then XM

Radio powered down "Rock" and "Roll." The older satellites remain in orbit and can

serve as backups, if necessary.

XM Radio's ground station transmits a signal to its two active GEO satellites, which

bounce the signals back down to radio receivers on the ground. The radio receivers

are programmed to receive and unscramble the digital data signal, which containsmore than 170 channels of digital audio. In addition to the encoded sound, the signal

contains information about the broadcast. The song title, artist and genre of music are

all displayed on the radio. In urban areas, where buildings can block out the satellite

signal, XM's broadcasting system is supplemented by ground transmitters.

Each receiver contains a proprietary chipset. XM began delivering chipsets to its XM

radio manufacturing partners in October 2000. The chipset consists of two custom

integrated circuits designed by STMicroelectronics.

XM has partnered with Pioneer, Alpine, Clarion, Delphi Delco, Sony and Motorola

to manufacture XM car radios. Each satellite radio receiver uses a small, car-phone-

sized antenna to receive the XM signal. General Motors has invested about $100

million in XM, and Honda has also signed an agreement to use XM radios in its

vehicles. GM began installing XM satellite radio receivers in selected models in early

2001.

Currently, subscribers can receive the regular XM channel lineup for $12.95 per

month. For that price, listeners get more than 170 channels of music, talk and news.

They also get access to XM Radio online, a streaming audio service with more than

80 channels. Many of the channels have no commercials, and none of the channels

have more than seven minutes of ads per hour. XM's content providers include USA

Today, BBC, CNN, Sports Illustrated and The Weather Channel. The service bolsters

that lineup with its own music channels.


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Figure 2.1: XM Satellite Radio

2.1.2 SIRIUS SATELLITE RADIO

Unlike XM, Sirius does not use OED satellites. Instead, its three SS/L-1300 satellites

form an inclined elliptical satellite constellation. Sirius says the elliptical path of its

satellite constellation ensures that each satellite spends about 16 hours a day over the

continental United States , with at least one satellite over the country at all times.

Sirius completed its three-satellite constellation on November 30, 2000. A fourth

satellite will remain on the ground, ready to be launched if any of the three active

satellites encounter transmission problems.

The Sirius system is similar to that of XM. Programs are beamed to one of the three

Sirius satellites, which then transmit the signal to the ground where the radio

receiver picks up one of the channels within the signal. Signals are also be beamed to

ground repeaters for listeners in urban areas where the satellite signal-can be

interrupted.

While XM offers both car and portable radios, Sirius is concentrating on the car radio

market. The Sirius receiver includes two parts -- the antenna module and the receiver

module. The antenna module picks up signals from the ground repeaters or the


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satellite. Amplifies the signal and filters out any interference. The signal is then

passed on to the receiver module. Inside the receiver module is a chipset consisting of

eight chips. The chip set converts the signals from 2.3 gigahertz (GHz) to a lower

intermediate frequency. Sirius also offers an adapter that allows conventional carradios to receive satellite signals.

Figure 2.2: Sirius Satellite Radio

2.1.3 WORLDSPACE

So far, WorldSpace has been the leader in the satellite radio industry. It put two or its

three satellites, AfriStar and AsiaStar, in geostationary orbit before either of the other

two companies launched one. AfriStar and AsiaStar were launched in October 1998

and March 2000, respectively. AmeriStar, which will offer service to South America

and parts of Mexico, is not yet scheduled for launch. Each satellite transmits three

signal beams carrying more than 40 channels of programming, to three overlapping

coverage areas or about 5.4 million square miles (14 million square km) each. Each ofWorldSpace satellites' three beams can deliver over 50 channels of crystal clear audio

and multimedia programming via the 1,467- to 1,492- megahertz (MHz) segment of

the L-band spectrum which is allocated for digital audio broadcasting.

AfriStar is positioned in a 210 East geosynchronous orbit and is controlled by the

WorldSpace Operations Center located in Washington, DC. The prime contractor for

the satellite is Alcatel Space Industries, and Matra Marconi Space built the EuroStar

2000+ satellite bus. The uplink frequencies are 7.025-7.075 GHz, and the downlink


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frequencies are 1.452-1.492 GHz. Each AfriStar downlink spot beam has capacity for

ninety-six 16 kbit/s mono-AM-quality signals that can be combined for fewer

channels of higher audio quality. The downlink signals in each spot beam are

combined into two Time Division Multiple Access (TDMA) carriers. Uplink signalscan be. accepted as TDMA signals from control stations or, individually, as

Frequency Division Multiple Access (FDMA) signals from originating program

locations.

WorldSpace also launched AsiaStar in March 2000, a DBS radio satellite that

currently covers Asia(1050 East orbit). In late 2000, WorldSpace plans to launch

AmeriStar (950 West orbit) to cover Latin America.The United States is not currently

part of WorldSpace's coverage area. The company has invested in XM Radio and hasan agreement with XM to share any technological developments. WorldSpace is

going beyond one nation and eyeing world domination of the radio market. That

might be overstating the company's intent a bit. But WorldSpace does plan to reach

the corners of our world that most radio stations cannot. There are millions of

people living in WorldSpace's projected listening area who cannot conventional

radio station. WorldSpace says it has a potential audience of about 4.6 billion listeners

spanning five continents.

Figure 2.3: Worldspace


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WorIdSpace broadcasters uplink their signal to one of the three satellites through a

centralized hub site or an individual feeder link station located within the global

uplink beam. The satellite then transmits the signal in one, two or all three beams on

each satellite. Receivers on the ground then pick up the signal and provide CD-qualitysound through a detachable antenna.

Figure 2.4: World Space Integrated Solution

2.2 GROUND REPEATERS

Satellite radio reception, poses threats from weather, tall building and mountains that

can potentially interfere with broadcasts. To avoid the interference caused by tall

structures, both Sirius and XM Radio are supplementing their satellite coverage withterrestrial transmitters, called ground repeaters. If the satellite radio antenna is

blocked by a skyscraper, it should pick up signals from one of the ground repeaters.

Getting signals from a satellite to receivers in cars or in the home is a tall order.

Although the microwaves the satellites rely on are able to penetrate the atmosphere

from space, they need a "direct line of sight" and can only reach their target if

unimpeded by obstacles such as trees, houses, or thunderstorms. Therefore, ground-

based repeaters are needed to prevent service interruption in cities where tall buildings


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otherwise would block the line of sight between radio receivers and the satellites. XM

has employed more than 1,000 of these terrestrial repeaters, which have been

strategically placed throughout the continental United States to receive the XM signal

directly from the satellites, and then retransmit it to XM radios in cars and homes.These repeaters have been installed in densely populated cities, on the roofs of

buildings, and in mountainous areas where line of sight can be difficult to maintain.

Figure 2.5: Ground Repeater

2.3 SATELLITE RADIO RECEIVER

Existing AM/FM car radio will not be able to receive satellite radio broadcasts. Two

options are available. Replacement of the radio with a 3-band capable receiver (AM,

FM, Sirius or XM Satellite). Radios can be purchased as a dealer option or can be

directly purchased at consumer retail stores, mail order and Internet stores. All major

manufactures are prepared to provide radios capable of satellite radio reception.

A second option is the purchase an adaptor for existing AM/FM radios. The adaptor

will contain the satellite receiver, along with display and control functions. Sirius and

XM have developed slightly different technologies which mean that you can purchase

a radio capable of receiving satellite broadcasts from one company or the other. but

not both.. You need a receiver, about the size of squashed shoe box, which goes under

a car in the trunk, along with a fist-sized antenna that sits on the roof or trunk lid.

The receiving end is virtually the same for both companies, but the satellite

configurations are different: XM Radio will use two satellites, and Sirius will use a

combination three. These receivers, somewhat akin to AM/FM tuners, are made up of

two parts: an "active" antenna and a receiving module.

XM and Sirius Radio will work similarly. Each will beam a combination of original


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and syndicated programming to orbiting communications and terrestrial satellites

which will send out signals to the satellite radio receivers. These receivers, somewhat

akin to AM/FM tuners, are made up of two parts: an "active" antenna and a receiving

module.

The antenna is active because it basically looks for available signals to pick up from.

Satellites it recognizes. When it finds them, it amplifies them, filters out any

accompanying noise and interference, and then sends them to the receiver, where

most of the real work is done. En route to the receiver, the signals are converted from

analog to digital. Once in the digital realm, they are analyzed for quality, and then

processed and combined to produce the best digital "image" of the sound. The

receiver also decrypts the signals and finally converts them back to analog audio,which can be sent to the radio' s speakers so one can hear it.

The receiver connects to your existing car radio through a device called an FM

modulator that puts the signal on an unused portion of the FM band. On the open

road, the receivers pick up a signal from orbiting satellites. Sirius and XM have also

built repeater stations on the ground in major metropolitan areas to maintain reception

when the satellites are blocked by buildings or other large structures.

One receiver utilizes a vehicles existing FM radio. A small flat 2" disk antenna is

attached to the outside of the vehicle, a processing unit is placed in the trunk or

dashboard and a display and control screen mounted next to the vehicle's FM radio.

The display screen indicates the selected channel number, channel name, song title

and artist.

Each receiver contains a proprietary chipset. XM began delivering chipsets to its XM

radio-manufacturing partners in October 2000. The chipset consists of two custom

integrated circuits designed by ST Microelectronics. XM has partnered with Pioneer.

Alpine, Clarion, Delphi Deleo, Sony and Motorola to manufacture XM car radios.

Each satellite radio receiver uses a small, car-phone-sized antenna to receive the XM

signal. General Motors has invested about $100 million in XM, and Honda has also

signed an agreement to use XM radios in its cars. OM began installing XM satellite

radio receivers in selected models in early 2001.

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CHAPTER 3

TECHNOLOGY BEHIND SATELLITE RADIO

3.1 INTRODICTIONAny song you hear on satellite radio stars as a recording in a specific format on

different recording mediums. IN most cases, the recording quality has to be

maintained fairly high, usually around 384kb/s, while also being reasonably small

enough to be transported on CDs and DVDs. The music tracks used in satellite radio

are cataloged using a similar system to the MP3 cataloging criteria, the ID3 tags. The

choice for the music tracks that will be played is made by each channel individually.

The DJ selecting the tracks usually chooses about 20-30 minutes worth of music. TheDJ has to listen to the tracks to make sure they are in proper condition and then

simply lets the computer decode the original file. The same thing is repeated once the

initial 20-30 minutes are exhausted and the music playing cycle repeats itself.

3.2 SOUND ENCODING

Encoding is one of the key elements of digital radio. Each channel is handled by a

different encoder. The encoder basically takes the analog file and turns it into a digitalone. The digitalization process is made in real time and the music files are

transformed into 1's and 0's. This process is carried out by powerful computers that

analyze sound waves and frequency and break them into binary code. The encoding

process is carried out at 128kb/s, 44.1Kh which is actually CD quality. After the song

is encoded, it is transmitted to a multiplexer where other channels are also present

the multiplexer basically takes all the channels of the satellite radio provider and

combines them into a single broadcast transmission. The data is then sent to a satellite

modem device which modulates the data and sends it to the broadcasters satellites,

using unique transmission frequencies.

What happens above the Earth

Here is where the satellites are located. They receive the transmission and transmit it

to the receivers we have in our homes and cars. The satellites are located at 23,000

miles above usboth Sirius and XM Radio use satellites located at this distance from

the Earth. The satellites are located in geo-sync, which means that hey orbit above the


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location they are designated to service at all times. When the satellite receives the

transmission encoded at 128kb/s, 44.1 khz it rebroadcasts it to the geographical area it

covers. Both Sirius and XM Radio use satellites that cover certain areas of the United

states mostly the East and West coasts. For example, one of XM Radios satellitescovers the western part of USA, probably an area located roughly from Seattle to San

Diego on the West and Minneapolis to Houston on the east. The increased sound

quality is possible because the broadcasted data (music tracks, news, sports

transmission) dont get sliced up too many times in the decoding process. The

antenna connected to your satellite radio receiver picks up the transmission on L-

Band. The recent technological advances have allowed digital radio broadcasters to

create receivers small enough to fit mobile locations. In the early days of satellite

radio, a large parabolic dish would have to be mounted on the car in order to receive

signal. Also, before the more compact receivers were created, the early satellite radio

receivers needed electronic movements that directed the dish towards the satellite line

of sight. Modern flat panel receivers have eliminated all the problems of their

predecessors and can be fitted almost anywhere without taking up too much space.

The receiver is the device that decodes the data, basically doing the exact opposite of

what the encoding process was like. After receiving the signal from the antenna it

amplifies it and converts it to usable sound. The car or home audio system is then able

to play the selected satellite radio channel. The rest of the process is exactly like

analog broadcasts would work, with an amplifier and speakers outputting the sound.


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CHAPTER 4

TRANSMISSION AND RECEPTION

4.1 INTRODUCTIONDigital radio works by combining two digital technologies to produce an efficient and

reliable radio broadcast system.

Firstly, an audio compression system, called MPEG, reduces the vast amount of

digital information required to be broadcast. It does this by discarding sounds that will

not be perceived by the listener - for example, very quiet sounds that are masked by

other louder sounds - and hence not required to be broadcast, and efficiently packages

together the remaining information.

The second technology, COFDM (Coded Orthogonal Frequency Division Multiplex)

ensures that signals are received reliably and robustly, even in environments normally

prone to interference. Using a precise mathematical relationship, the digital data

signal is split across 1,536 different carrier frequencies, and also across time. This

process ensures that even if some of the carrier frequencies are affected by

interference. or the signal disturbed for a short period of time, the receiver is still able

to recover the original sound.

The interference which disturbs FM reception, caused by radio signals "bouncing" off

buildings and hills (multipath) is eliminated by COFDM technology. It also means

that the same frequency can be used across the entire country, so no re-tuning of sets

is necessary when traveling, or taking a portable receiver to a different area. Instead of

having a different frequency for each radio station, digital radio combines several

services together in what is called a multiplex.

The multiplex has a gross capacity of 2,300,000 bits. which are used for carrying

audio, data and an in-built protection system against transmission errors. Of these

about half the bits are used for the audio and data services. Throughout the day, the

data capacity allocated to each service can be varied by the broadcaster. The UK

Government has allocated seven multiplexes on the radio spectrum 217.5 230.0 MHz,

which will be used for BBC and Commercial Radio for national. regional and local

services..


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4.2 GENERATION OF THE DAB SIGNAL

How each service signal is coded individually at source level, error protected and

time interleaved in the channel coder is shown in Figure 3.1. Then the services

are multiplexed in the Main Service Channel (MSC), according to a pre-determined,but adjustable, multiplex configuration. The multiplexer output is combined with

Multiplex Control and Service information, which travel in the fast Information

Channel (FIC), to form the transmission frames in the Transmission Multiplexer. Fig

4.1 Finally, Orthogonal Frequency Division Multiplexing (OFDM) is applied to shape

the DAB signal, which consists of a large number of carriers. The signal is then

transposed to the appropriate radio frequency band, amplified and transmitted.

Figure 4.1: Generation of DAB Signal


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4.3 RECEPTION OF THE DAB SIGNAL

Figure 4.2 demonstrates a DAB receiver. The DAB ensemble is selected in the

analogue tuner, the digitized output of which is fed to the OFDM demodulator and

channel decoder to eliminate transmission errors. The information contained in theFIC is passed to the user interface for service selection and is used to setup the

receiver appropriately. The MSC data is further processed in an audio decoder to

produce the left and right audio signals or in a data decoder (packet Demux) as

appropriate.

Figure 4.2: Reception of DAB Signal

4.4 FREQUENCY OF OPERATION

Digital radio is operated in a frequency range of between 215 - 230 MHz (Mega

Hertz). This part of the radio spectrum is sometimes called Band III, or VHF, and was

previously used for some television transmissions and by the military. The central

frequency for the BBC National Multiplex is 225.648MHz.


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CHAPTER 5

SATELLITE RADIO COSTS

Satellite radio is a subscription radio service. Its somehow identical to cabletelevision, with the difference that it provides a wider range of stations not available

on a standard AM / FM radio.

Cost of a satellite radio is divided in two: installation (or activation) costs and the

monthly subscription fee.

Activation cost refers to the amount of money that are to be spent on a XM or Sirius

Satellite Radio to start the service. Although you can find many promotions that allow

you to save up money, the activation costs vary, being able to make the activation by

phone or by World Wide Web. To be more precise, if you activate your satellite by

phone, you will pay $15.00 if you choose Sirius Satellite or $14.99 by choosing XM

and, as for WWW activation, the cost of goods is somehow lower: $5 with Sirius or

$9.99 with XM. As for the monthly subscription costs we will discuss this below, but,

before that, I must say that recent media campaigns are dramatically dropping the

prices for installation and activation, both on Sirius or XM, in some cases even

offering free activation.

Typical costs for a car dedicated installation

If you want to install a satellite radio into your car you are to consider buying a new

satellite-ready car stereo if you dont have one. Although many local dealers offer

built-in car satellite radio, there is still the problem of having a satellite radio receiver.

And these, as you may notice, cost money. It is possible though to use the existing car

stereo that does not support satellite radio. How? There are two known ways of

connecting the receiver to the available non-satellite radio car stereo. First, by using

the radio inputs (usually the CD) and installing a control unit for tuning up the

satellite radio streams. The second method consists in installing a satellite radio

receiver, which broadcasts the satellite radio signal on a FM frequency. The place

where you can install the receiver depends: under the seat, in your trunk, etc. taking

care of connecting the receiver to the satellite radio antenna mounted on the cars

exterior.


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So, there will be a minimum cost of $350.00 and a maximum of $600, like below:

Receiver $75 - $125

Radio $125 - $250

Antenna $60.00Labor $80.00

Activation $10

Costs for a dedicated home installation

If you choose this option, that means you will have to install a dedicated stereo

receiver unit, which in some cases is similar to regular AM / FM receivers. As an

additional cost, you will have to buy an antenna, which can be found at a price of $60.

Receiver $150 - $300Antenna $60

Activation $10

Costs for a Portable Unit

Portable units gives you the ease of using you brand new satellite radio wherever you

want, but, in every room you will have to own a home kit (antennas, output cables and

power supplies). The price for this option is around $400.

Receiver $120

Home kit $140

Boomboxx2 $100

Activation $10

Subscription costs

As for the subscription costs, it depends if you own a Sirius or XM Satellite Radio.

Subscription costs for a Sirius Satellite Radio are paid monthly where the charge is

$12.95, with a low adjustment is you subscribe to a year or two. The highest number

of Sirius radios that can be activated are three for $6.99 each per month. Business

subscriptions are $24.99 per month. Another interesting thing is that for $499.99,

Sirius is offering a life time subscription. On the other hand, if you have a XM

Satellite Radio, you will have to pay a monthly charge of $9.99. Still, some channels

are to be paid separately, like Playboy Radio, which costs an additional $2.99 per

month. Commercial and Business Subscriptions cost $24.99 per month.


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CHAPTER 6

ADVANTAGES AND APPLICATION

6.1 ADVANTAGES

1. Over Analog Radio

Conventional analog radio cannot meet this standard, simply because of the

technology used and the transmission environment in which it is broadcast. In

contrast, an un-intelligent analog receiver cannot differentiate the useful information

from the useless noise. It reproduces the entirety of whatever signal it is tuned to

static, 'multipath' echoes, and all.

2. Multipath Interference

Multipath interference occurs when radio waves bounce off buildings, hills, or other

obstacles. This means the waves reach the set at different times, causing interference.

This is a particular problem in the car. Digital radio sets have processors which filter

out interference and correct errors, such as those caused by multipath, so no

interference. In fact, digital radio is designed to use multipath to its advantage.

3. Commercial Free

One of the biggest advantages of pay radio is that since it's a subscription-based

service that is supported by listeners rather than advertisers, its commercial free.

4. Lots of Programs To Choose From Uncensored

Pay radio services offer hundreds of programs in every genre, including music, talk,

sports, news, regional and comedy. And because they're subscription-based services

rather than licensed services, programming is not subject to the same regulatory

scrutiny as regular radio.

5. Outstanding Sound Quality

Crystal clear sound quality is one of the hallmarks of satellite radio. And since the

radio signal is digital, static is a thing of the past and signal strength isn't

geographically limited. You can enjoy your favorite programs no matter where you

are, with no degradation of sound quality.


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6. Programming Info Available

Ever hear a great song on the radio, but can't find out who the artist is? Satellite radio

tuners eliminate those annoyances by displaying comprehensive information about

whatever is playing.

7. Local Traffic and Weather Wherever You Are

Satellite radio programs also offer round-the-clock information about local traffic and

weather conditions. This can be a major timesaver for travellers, commuters, or

anyone who spends a lot of time of the road. An addition, if for any reason terrestrial

radio stations are off the air, you can always count on getting accurate information

from digital radio.

Radio format Satellite radio AM FM

8. Wide Range of Affordable Subscription Options

Digital radio is very affordable, with a wide range of programming packages that let

you pay for exactly the services you want and need. At the low end, "pick your

programs" packages are available for less than $7 a month, and comprehensive

packages that offer more than 160 programs come in at well under $20 per month.

6.2 APPLICATIONS

1. Virtual classrooms

2. Best teacher to reach all


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3. Professional needs ex. Health workers

4. Radio for information

Figure 6.1: Audio Broadcasting


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CHAPTER 7

CONCLUSION

Thus, taking into account all above mentioned, it is possible to conclude that the radioindustry, initially created by amateurs attempting to find the ways to increase the

ways of communication, gradually became a great business which potential was

revealed at early stages of the industries development. Nowadays, the radio industry

achieved really great results and the contemporary world is practically unimaginable

without radio which entered every household and at the present moment it is in a hand

reach of any individual.

It is obvious that radio became a powerful means of communication and one of the

major mass media This is why it is necessary to pay a particular attention to the

development of the radio industry. At the time of downfall, after the TV and II

revolution, the entry of satellite radio really helped the broadcasting industry to keep

it alive.

For many listeners who have experienced satellite radio, the enhanced features make

the small monthly fee for the service well worth it. Certainly it offers a broader and

potentially higher quality entertainment experience than its predecessor which makes

it worthy of a look by those who haven't yet experienced this newer version of radio.

Documents

satellite radio report