Direct Broadcast Satellite Research Articles

Govt. Seeks Ways to Reduce Kids' Exposure to TV Violence

Govt. Seeks Ways to Reduce Kids' Exposure to TV Violence

The development of radial line slot array antenna for direct broadcast satellite reception

Microwave antennas are extensively used in communications systems such as satellite, television and high-speed data transmission due to their wide and absolute bandwidth. Among the variety of microwave antennas, satellite communication commonly adopts an antenna of parabolic dish type, despite some drawbacks. In a primary fed design, there is considerable aperture blockage. An offset parabolic antenna design, which then eliminates the blockage, is susceptible to physical damage as its feed is significantly exposed from the body of reflector. The radial line slot array (RLSA) type antenna is thus designed to cope with the problems encountered in parabolic antennas. RLSA is a planar antenna suitable for direct broadcast satellite (DBS) reception, with advantages including high radiation efficiency (high gain), low profile, low cost and feed rear-mounted. The prototype development started with the selection of the cavity's dielectric material and construction of the feeding structure of coaxial-to-waveguide transition. Within the frequency band of interest, between 10.95 and 11.7 GHz, results, is showed a lower than −10 dB of return loss. A DBS receiver test-bed had been developed to test the constructed antenna prototypes and it revealed that the prototype has the capability of receiving TV programs from DBS.

Hybrid Ku-band low-noise amplifier for mobile DBS active phased-array antennas

In this article we present a two-stage Ku-band low-noise amplifier (LNA) using discrete pHEMT transistors on non-PTFE substrates for low-cost direct broadcast satellite (DBS) phased-array systems (...

Hybrid Ku-band low-noise amplifier for mobile DBS active phased-array antennas

In this article we present a two-stage Ku-band low-noise amplifier (LNA) using discrete pHEMT transistors on non-PTFE substrates for low-cost direct broadcast satellite (DBS) phased-array systems (patent pending). The vertical input configuration of the LNA lends itself to direct integration with input port of antenna modules of the phased array, which minimizes preamplification losses. DC decoupling between LNA stages is realized using interdigital microstrip capacitors such that the implementation reduces the number of discrete microwave components and thereby not only reduces the component and assembly costs but also decreases the standard deviation of such crucial parameters of phased-array systems as the end-to-end phase shift of the amplifier and the amplifier gain. Using the proposed printed decoupling capacitors, a cost reduction better than 30% of the original costs has been achieved. Additionally, we present a hybrid design procedure for the complete LNA, including its input and output connectors as well as packaging effects. This method is not based on parameter extraction, but encompasses electromagnetic (EM) field simulator results which are further combined using a high-level circuit simulator. According to the presented measurement results, the implemented Ku-band LNA has a noise figure better than 0.9 dB and a gain higher than 20 dB with a gain flatness of 0.3 dB over a 5% bandwidth. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.

The Market for Subscription Television Service in the United States

This study develops a simultaneous equations model of the market for subscription television service consisting of analog and digital cable service. Beyond modeling the market for subscription television service and identifying the factors that impact the demand and supply of analog and digital cable service, an effort is made to determine the extent to which direct broadcast satellite service competes with cable television for subscribers in this market. The model consists of four equations: demand equations for analog cable service and digital cable service and supply equations for analog cable service and digital cable service. The model is estimated using the full information maximum likelihood technique. A number of factors clearly impact the demand and supply of analog and digital cable service, and this impact is quantifiable. The size of the market measured as the number of households passed is, not surprisingly, a dominant factor in explaining analog and digital cable service demand and supply. Probably the most significant result is that the estimates indicate that while changes in the relative price of analog or digital cable service have no quantifiable impact on the demand for analog cable service, they do have a statistically significant effect on the demand for digital cable service. Finally, as the penetration of DBS service increases, the number of analog cable service subscribers is reduced.

Broadband Technologies in Australia 1993–98: Developing the Social Shaping of Technology Approach 1

Abstract The development and deployment of technologies for delivering broadband services to homes in Australia are investigated using the ‘social shaping of technology’ (SST) approach. The focus is on the period from 1993 to 1998 when there were five main technological options for delivering residential broadband services: ‘hybrid’ fibre coaxial (HFC) cable; direct broadcast satellite (DBS); multipoint microwave distribution systems (MDS); ‘Integrated Services Digital Network’ (ISDN); and ‘Asymmetric Digital Subscriber Line’ (ADSL). The main broadband services planned for delivery to homes over this period were pay television and fast Internet access. A sequence of snapshots of sociotechnical relationships at critical times during the study period, termed ‘sociotechnological configurations’, is used to track the evolutionary pathway of the broadband technologies. The mapping technique assists in identifying key features and explaining the driving factors of the pathway, including why HFC cable emerged as the predominant technology, and two competing HFC cable networks were rolled out in capital cities at an additional cost of over $2 billion when a single network would have had ample capacity.

Shaped‐reflector antenna designs using particle swarm optimization: An example of a direct‐broadcast satellite antenna

AbstractA novel shaped‐reflector antenna synthesis technique based on the particle swarm optimization (PSO) algorithm is presented. The reflector surface is expanded using the modified Jacobi polynomials, and the expansion coefficients and other antenna parameters compose a solution space to be explored by PSO in a global stochastic evolutionary manner. The conventional weighted aggregation (CWA) method is utilized when multiple objectives are considered. The validity of this technique is verified by an example application, a shaped‐reflector antenna for simultaneous reception from multiple satellites for direct‐broadcast satellite (DBS) services. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1341–1347, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21618

The satellite home viewer improvement act: Price and quality impact of direct broadcast satellite companies’ provision of local broadcast stations

Prior to 1999, direct broadcast satellite (DBS) companies were generally not permitted to deliver local broadcast stations to their subscribers while cable companies did not face this constraint. With the passage of the Satellite Home Viewer Improvement Act, the Congress removed this asymmetry and created a more level competitive environment. In this paper, reduced-form equations are employed to test the impact of DBS companies’ provision of local broadcast stations. When both DBS companies provide local broadcast stations, cable companies improve the quality of service they provide to their subscribers, although no impact on the price of cable service is found.

A Vertical Sundial as a DBS Antenna

In recent years, the Direct Broadcasting Satellite (DBS) system has induced the widespread use of dish installations in Italy, even in ancient cities and in areas of particular value. In many cases, they have compromised the beauty of the buildings and in some cities the uncontrolled installation of such antennas has been forbidden. This letter suggests an answer to this problem, as it proposes a low-cost solution which makes the antenna integration with the existing environment easier. An example is presented, where the proposed configuration, consisting of a tailor-made offset reflector, has been used to realize a vertical sundial. The antenna radiation patterns and the electrical characteristics are also reported

Broadcasting Satellite Services for Mobile Reception

This paper intends to introduce widely the broadcasting satellite services using Digital System E of Recommendation ITU-R BO.1130. The system is designed to provide high-quality audio and multimedia and data broadcasting services to mobile receivers, handheld and vehicular. The geostationary satellite specially designed for this system was launched successfully in March 2004, followed by the inauguration of regular broadcasting services on 20 October 2004. Due to the nature of satellite broadcasting, it covers the Japanese area widely. The system also adopts complementary terrestrial on-channel repeaters for shadowed areas from the direct satellite broadcasting signal. It should be noted that the system is the world first broadcasting satellite services for handheld and vehicular receivers with high-quality audio and multimedia and data receiving capability.

COMPETITION BETWEEN CABLE TELEVISION AND DIRECT BROADCAST SATELLITE: THE IMPORTANCE OF SWITCHING COSTS AND REGIONAL SPORTS NETWORKS

We use aggregate firm-level price data and other related demographic variables to examine the cost of switching between cable television and direct broadcast satellite (DBS). We find that switching costs appear to affect consumers' desire to switch from one service to another. We then use observation-specific dummy variables that stratify cable price to examine whether consumer behavior varies depending on the size of price change. We find that, when quality-adjusted prices for basic cable services increase substantially, subscribers will switch from cable to DBS, presumably at the point at which the price change is larger than the cost of switching. However, we find some evidence that DBS penetration is suppressed in areas where cable operators offer regional sports channels.

Effect of inset feeding on antenna properties in a superconducting microstripantenna

Effects of ‘inset feeding’ on microstrip antenna properties have been investigated byanalysing the designed and experimental results. Dimensions of a single-patch antennawith this feed architecture have been optimized with an operating frequency of11.74 GHz with the aim of using it to fabricate a superconducting microstrip arrayantenna for a direct broadcast satellite (DBS) communication system. In ourobservation, the antenna gain, resonant frequency and input impedance of theantenna are found to change with change of the feed architecture. A single-patchYBa2Cu3O7−δ (YBCO) superconducting antenna and a gold antenna with this optimized structure havebeen fabricated for the comparison of properties between these two types of antennas. Thecomparison of the gain between the YBCO superconducting and gold antennas measuredat 77 K shows that the YBCO antenna has 1.8 dB higher gain than the gold antenna withan identical configuration.

MBSAT A direct broadcast satellite for mobile users in Japan and Korea

The MBSAT spacecraft was launched on 13 March 2004 from Cape Canaveral Air Force Station on an Atlas III-A launch vehicle. The satellite is now in service at its orbital location of 144 ∘ E longitude. The satellite is designed to provide high-quality audio, video and data services to mobile users in Japan and Korea. Broadcast transmissions use 25 MHz of bandwidth at the S-band frequency of 2.6 GHz, while uplinks and feeder links to terrestrial repeaters use the Ku-band. The MBSAT satellite design incorporates a large, unfurlable, mesh reflector for S-band broadcast. This 12 m (effective aperture) reflector coupled with phase-combined arrays of Traveling Wave Tube Amplifiers result in Effective Isotropic Radiated Power levels of 67–69 dBW over Japan and Korea coverage areas. The use of Stationary Plasma Thrusters for North–South stationkeeping significantly enhances the mission lifetime as well as minimizes potential disturbances to the 12 m reflector.

Analog and Digital Must-Carry Obligations of Cable and Satellite Television Operators in the United States

This paper provides a concise summary of mandatory signal carriage obligations of cable television and direct broadcast satellite operators. The paper provides a timely update of recent changes in must carry responsibilities resulting from the onset of digital broadcast television and enactment of the Satellite Home Viewer Extension and Reauthorization Act of 2004.

The Seven Dirty Words YouCan Say on Cable and DBS: Extending BroadcastIndecency Regulation and the First Amendment

Congress has recently considered legislation that would increase the penalties for the broadcast of indecent content and extend broadcast indecency regulation to cable and direct broadcast satellite. Under existing case law this extension of indecency regulation likely would be unconstitutional for two primary reasons. First, many of the factors that justify broadcast indecency regulation are not present in cable or DBS. Second, both cable and DBS can provide subscribers with the ability to block unwanted programming, which would likely be found by courts to be a less restrictive way for the government to achieve its interest in protecting children from exposure to indecent cable or DBS programming.

Direct Broadcast Satellites and the Social Shaping of Technology: Comparing South Korea and Canada

Questions about the social shaping of technology are explored by comparing direct broadcasting satellite policy in two very different countries. Canada has a vast geography, low population density, extreme ethnic and linguistic diversity, and close proximity and long-time cooperation with its neighbour, the United States. South Korea is centralized around Seoul, has a high population density, is relatively homogenous culturally and ethnically, and has a history of conflict with the country sharing a common border. The specific goals set for satellite broadcasting arising from these differing national contexts are explored. The paper also compares services and audiences in South Korea and Canada, and it asks what these cases can illustrate about the relationship between industry, policy, audiences, and the shaping of a new media technology.

Compact antenna test range without reflector edge treatment and RF anechoic chamber

There are several types of CATRs (compact antenna test ranges) used in antenna-pattern measurements. An offset reflector is generally used to generate the quiet zone of a CATR. Serrated edges, rolled edges, or R-cards are generally chosen along the reflector's edge to reduce the edge-diffraction field inside the quiet zone of the CATR. In order to reduce stray signals from the environment, a high-quality RF anechoic chamber is required for a CATR. In this paper, a new type of CATR, without either a reflector edge treatment or an RF anechoic chamber, is developed. A commercially available DBS (direct-broadcast satellite) reflector antenna, without edge treatment, is used as the reflector antenna of the CATR to generate the quiet zone of the antenna test range. In order to improve the quiet zone's performance, the fields due to feed spillover, edge diffractions, and other stray signals are gated out by the ITDAMS (impulse time-domain antenna measurement system). The RF interference in the environment can also be reduced by time synchronization and pulse integration of the impulse time-domain antenna measurement system. In order to verify the capabilities of the proposed CATR, three kinds of antennas (a low-directivity horn antenna, a high-directivity 60 cm direct-broadcast satellite reflector antenna, and a 25 cm Ka-band Cassegrain LMDS - local microwave distribution system - antenna) were measured by the proposed CATR. The antenna-pattern results agreed quite well with those of a near-field range and a far-field range.

직접 위성방송 수신용 원편파 HTS 배열 안테나 관한 연구

We report the performance of a four-element, 11.67 GHz, <TEX>$high-{T}_c$</TEX> superconducting (HTS) microstrip antenna array with corporate feed network. The HTS antenna array used in this work had a circular polarization for direct broadcasting satellite (DBS) system. Our array antennas were designed and built on a 0.5 mm thick MgO substrate. To compare the superconducting antennas with normal conducting counterpart, One antenna pattern was fabricated from gold thin film, and a second pattern was fabricated from <TEX>${YBa}_2{Cu}_3{O}_7-x(YBCO)$</TEX> superconducting thin film. To improve the axial ratio of circularly polarized arrays, sequential rotation technique were used. Efficiency, radiation pattern, return loss and bandwidth were measured for both antennas at cryogenic temperature and room temperature. The array produced good circular polarization, and the gain of the array at 77 K, relative to a copper array at room temperature was approximately 1.54 dB. The measured return loss of our HTS antenna array was 35.79 dB at the resonant frequency of 11.67 GHz and The total effective bandwidth was about 3.4 %. The results showed that high-temperature superconductors, when used in microstrip arrays, improved the efficiency of the HTS antenna array for circularly polarization.

Modeling Polarization Mode Coupling in Frequency-Selective Surfaces

An analysis of scattering from frequency-selective surfaces (FSS) is developed that correctly accounts for coupling between scattered polarization modes. This is useful for the design of FSS structures with obliquely incident radiation, such as polarization converters (polarizers) for direct broadcast satellite reception by linearly polarized ground terminal antennas. In the past, the neglect of polarization mode coupling limited the performance range of various FSS structures, such as meander-line polarizers, to near normal incidence where mode coupling is weak. The following analysis shows how a suitable pair of polarization modes can be selected to maintain modal independence. The result is a pair of independent equivalent circuits representing scattering of the two modes, together with mode transformation networks. To illustrate the theory, a four-layer meander-line polarizer is designed for an incident angle of 45/spl deg/ off normal. The resulting axial ratio is measured to be 0.3 dB at 12.45 GHz.

Estimating the demand for cable service in the U.S. in the presence of measurement error in the data

This paper looks at the effect of direct broadcast satellite service on the demand for cable service in the United States. To measure the competitive influence of the noncable providers, the Direct Broadcast Satellite (DBS) share of video subscribers in each franchise area is used in modeling the demand for multichannel video programming subscription service. After examining some important econometric issues including the appropriate functional specification, whether the error terms are homoscedastic, and the presence of outliers in the data, data from the 2002 FCC Annual Cable Price Survey are used to estimate the demand for analog and digital cable service. One anomaly arises in the measurement error associated with the DBS penetration variable.