Satellite Television 2011
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2011 SATELLITE TELEVISION BS Electronics Engineering Page 1 SATELLITE TELEVISION 2011 I. OBJECTIVES To demonstrate the operation of satellite TV. To be able to use the Agila 2 and other satellite as the signal server. To determine parameters affecting its proper operation. II. MATERIALS Satellite receiver Low Noise Block Down Converter Receiver (set-up box) Television set Coaxial cable Magnetic compass III. PROCEDURE 1. Set up the satellite receiver. 2. Attach the LNB to the receiver properly and connect it at a distance to the set-up box or the receiver using the coaxial cable. 3. Connect the box to the TV and set the proper parameters. 4. Align the reflector to proper elevation and azimuth. IV. DISCUSSION Satellite television is television programming delivered by the means of communications satellite and received by an outdoor antenna, usually a parabolic mirror generally referred to as a satellite dish, and as far as household usage is concerned, a satellite receiver either in the form of an external set-top box or a satellite tuner module built into a TV set. Satellite TV tuners are also available as a card or a USB stick to be attached to a personal computer. In many areas of the world satellite television provides a wide range of channels and services, often to areas that are not serviced by terrestrial or cable providers. Direct-broadcast satellite television comes to the general public in two distinct flavors - analog and digital. This necessitates either having an analog satellite receiver or a digital satellite receiver. Analog satellite television is being replaced by digital satellite television and the latter is becoming available in a better quality known as high-definition television. BS Electronics Engineering Page 2 2011 SATELLITE TELEVISION Fig. 1 Simple Satellite Television The Figure 1 shows a simple system of a satellite television. The satellite that receives signals from the broadcast station rebroadcasts the signals down to Earth. The satellite dish or antenna picks up the signal from the satellite and passes it on to the receiver through the coaxial cable. Then the receiver processes the signal and passes it on to a standard TV to display the signal. THREE PRIMARY TYPES OF SATELLITE TELEVISION USAGE 1. reception direct by the viewer 2. reception by local television affiliates 3. reception by head ends for distribution across terrestrial cable systems Direct to the viewer reception includes direct broadcast satellite or DBS and television receive-only or TVRO, both used for homes and businesses including hotels, etc. DIRECT BROADCAST VIA SATELLITE Direct broadcast satellite, (DBS) also known as "Direct-To-Home" can either refer to the communications satellites themselves that deliver DBS service or the actual television service. DBS systems are commonly referred to as "mini-dish" systems. DBS uses the upper portion of the Ku band, as well as portions of the Ka band. Modified DBS systems can also run on C-band satellites and have been used by some networks in the past to get around legislation by some countries against reception of Ku-band transmissions. Most of the DBS systems use the DVB-S standard for transmission. With Pay-TV services, the data stream is encrypted and requires proprietary reception equipment. While the underlying reception technology is similar, the Pay-TV technology is proprietary, often consisting of a Conditional Access Module and smart card. This measure assures satellite television providers that only authorized, paying subscribers have access to Pay TV content but at the same time can allow free-to-air (FTA) channels to be viewed even by the people with standard equipment (DBS receivers without the Conditional Access Modules) available in the market. BS Electronics Engineering Page 3 SATELLITE TELEVISION 2011 TELEVISION RECEIVE-ONLY The term Television receive-only, or TVRO, arose during the early days of satellite television reception to differentiate it from commercial satellite television uplink and downlink operations (transmit and receive). This was before there was a DTH satellite television broadcast industry. Satellite television channels at that time were intended to be used by cable television networks rather than received by home viewers. Satellite TV receiver systems were largely constructed by hobbyists and engineers. In 1978 Microcomm, a small company founded by radio amateur and microwave engineer H. Paul Shuch, introduced the first commercial home satellite TV receiver. These early TVRO systems operated mainly on the C band frequencies and the dishes required were large; typically over 3 meters (10 ft) in diameter. Consequently TVRO is often referred to as "big dish" or "Big Ugly Dish" (BUD) satellite television. TVRO systems are designed to receive analog and digital satellite feeds of both television and audio from both C-band and Ku-band transponders on FSS-type satellites. The higher frequency Ku-band systems tend to be Direct To Home systems and can use a smaller dish antenna because of the higher power transmissions and greater antenna gain. TVRO systems tend to use larger rather than smaller satellite dish antennas, since it is more likely that the owner of a TVRO system would have a C-band-only setup rather than a Ku band-only setup. Additional receiver boxes allow for different types of digital satellite signal reception, such as DVB/MPEG-2 and 4DTV. The narrow beam width of a normal parabolic satellite antenna means it can only receive signals from a single satellite at a time. Simulsat or the Vertex-RSI TORUS, is a quasi-parabolic satellite earth station antenna that is capable of receiving satellite transmissions from 35 or more C- and Ku-band satellites simultaneously. DIRECT TO HOME TELEVISION Many satellite TV customers in developed television markets get their programming through a direct broadcast satellite (DBS) provider. 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 customers 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 services broadcast in C-band - radio in the 3.7 GigaHertz (GHz) to 4.2 GHz frequency range. Digital broadcast satellite transmits programming in the Ku frequency range (10 GHz to 14 GHz ). Programming sources are simply the channels that provide television programming for broadcast. The provider (the DTH platform) doesn’t create original programming itself. The broadcast center is the central hub of the system. At the broadcast center, the television provider receives signals from various programming sources, compresses these signals using digital video compression, and sends a broadcast signal to the proper satellite. BS Electronics Engineering Page 4 SATELLITE TELEVISION 2011 The Satellite Antenna Reflection Principle in the Satellite Antenna The schematic above shows the reflection of the signal as it hits the reflector. The signal is focused at a specific point directly towards the front of the dish reflector. The satellite TV antenna comes with a collection device at the same exact point for catching the signal, commonly referred to as feedhorn. The feedhorn plays a viable role in sending the collected signal to a LNB or a low noise block. Low Noise Block down Converter Low noise block down converter (LNB) diagram The diagram shows the input waveguide on the left which is connected to the collecting feed or horn. The satellite signals first go through a band pass filter which only allows the intended band of microwave frequencies to pass through. The signals are then amplified by a Low Noise Amplifier and thence to the Mixer. At the Mixer all that has come through the band pass filter and amplifier stage is severely scrambled up by a powerful local oscillator signal to generate a wide range of distorted output signals. These include additions, subtractions and multiples of the wanted input signals and the local oscillator frequency. Amongst the mixer output products are the difference frequencies between the wanted input signal and the local oscillator frequencies. These are the ones of interest. The second band pass filter selects these and feeds them to the output L band amplifier and into the cable. Typically the output frequency = input frequency - local oscillator frequency. In some cases it is the other way round so that the output frequency = local oscillator frequency - input frequency. In this case the output spectrum is inverted. BS Electronics Engineering Page 5 SATELLITE TELEVISION 2011 Latest Equipments for Satellite Television HOT KU Band 45CM Satellite dish Antenna FOB Price: US $ 2.8 - 6.6 / Set Quick Details Place of Origin: China Brand Name: hengxin Model Number: KU band 45cm Type: Outdoor Frequency Range: ...... Color: customized color Specifications satellite dish steel Type: pole/ wall / ground mount Thickness: 0.4 /0.5 /0.6 F/D ratio: 0.6 High Quality KU-45CM Satellite Antenn 1.Pole mount / Wall mount 2.Thickness 0.4 /0.5/0.6mm 3. Steel 4. Customized color 5.Excellent quality with reasonable competitive price Model KU Band 45CM Panel 1 Short Axis 45cm Long Axis 49.5cm KU-Band Gain 12.5GHz 34.22dB F/D Ratio 0.6 Focus Length 270mm Material Steel Finish Polyseter Power Coating Mounting Type Much Use With Elivation Alignment 0°~90° Azimuth Alignment Fixed 0°~360° Operational Winds Able to receive 25m/sec Able to re-set 40m/sec Without Damange 60m/sec Ambient Temperature -40oC~+60oC BS Electronics Engineering Page 6 2011 SATELLITE TELEVISION Satellite dish (C Band 210CM) FOB Price: US $ 40 - 46 / Set Quick Details Place of Origin: Hebei China (Mainland) Brand Name: Hengxin Model Number: C band 210cm Type: Outdoor Frequency Range: y type: outdoor Specifications ku band satellite dish Six Panels.