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Space industrial radio communication, broadcasting and television antennas

Space industrial radio communication, broadcasting and television antennas

This antenna is tunable from 25 to 30 MHz. The first category is an indoor antenna and the second one is the outdoor antenna. Antennas for TV white space applications. You can enjoy high definition television without spending on cable or satellite.

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Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. This chapter presents the Voice of America VOA with a roadmap for introducing satellite audio broadcasting technology, and the improved services which it allows, into its operations to compensate for many of the transmission and reception limitations of its terrestrial, high-frequency HF , relay network.

The related question of television broadcasting must receive only passing mention at this point, although that medium is an increasingly effective one. There might be merit in assessing the relative emphasis on the two media, but that assessment lies outside the scope of this report for the following reasons. First, the VOA has elected to pursue its informational programs through the audio medium and has not formulated a role for itself in television.

Therefore, analysis of the value of television broadcasting and the various technical opportunities for implementing it would be more properly addressed to units of USIA other than VOA. The topical sections that follow correspond closely to items described in the Statement of Task. A phased introduction of direct audio broadcasting by satellite DBS-A is shown to be technologically, economically, and politically feasible, within certain limits that the VOA should recognize in its planning for use of this transmission system.

Even though a new generation of receivers for satellite reception is required, they can be produced on a short lead time, and this new transmission system can eventually complement the ongoing modernization of the terrestrial HF facilities.

The long-term goal to be addressed is the provision of a global service that offers the promises of international political acceptability, lower cost per channel, excellent reliability and quality, and less vulnerability to interference. The development of DBS-A is not merely a question of exploiting technological possibility.

HF is currently an accepted form of international broadcasting, with a long history of development and use.

Introduction of a new satellite service by one or more major international broadcaster s will require not only that satellites be put into orbit and receivers designed, manufactured, and marketed, but also that parallel strategies be developed to overcome economic and political obstacles to effective deployment of the system.

On the economic side, the development of DBS-A must contend with problems of international debt, trade restrictions, and manufacturer attitudes, which could delay introduction of receivers or keep their prices artificially high for an extended length of time. Deployment of DBS-A as a system directed primarily at developing countries, for instance, must contend with the attitude among Asian manufacturers that their profitability is best assured by concentrating on markets with high income elasticity of demand, which is not the case outside a few countries of the industrial West, Japan, the Pacific rim, and Australia and New Zealand.

On the political front, achieving a dedicated DBS-A band allocation for regional and international broadcasting must be made a priority of U. This is essential to gain the cooperation of other countries to accept DBS-A signals into their territories, as they could broadcast their DBS-A programs in turn to yet other countries.

The attitude of the Soviet Union is perhaps most crucial, since the VOA has major audiences there and should continue to develop such audiences. But the opposition of the Soviet government to such a broadcasting system would slow the ability of its people significantly to acquire the necessary technology to receive such signals. Pursuing the opportunities provided by glasnost would seem to be in order.

In any event, the VOA could use a space-based broadcasting service to reach most of the audiences of the world while continuing to use HF, as it does today, to reach those remaining, non-cooperative ones. Finally, the VOA should recognize, and adopt policies to address, the fact that both economic and political difficulties for this new system could be ameliorated by its own programming changes.

People will seek ways to overcome obstacles to access to technology if they have an incentive to do so. But merely providing news programming already available through other channels may not provide the incentive required for people to invest in the necessary reception technology.

The programming must exploit the fidelity potential of the technology and compete well against the other options available. Otherwise, investment in such a system would be a waste of resources. This context requires that the VOA undertake planning not only on the technological questions of transmission but also on effective means to overcome economic and political obstacles and on programming developments that can create the demand necessary to spur production, purchase, and use of the required receivers.

In detailed and quantitative terms, the report showed that present receiver populations are very unevenly distributed around the globe because of different economic conditions and national, political regulation. Technically, the receiver characteristics in various regions depend directly on the types of signals locally available, medium wave MW and short wave SW being dominant, with a much lower quantity of VHF units.

With no microwave signals at the frequencies from 1 to 12 GHz that are efficient for DBS-A purposes currently available, there are, of course, no microwave receivers.

Such receivers are not currently produced because there is no consumer demand, and there is no demand because there are no satellite transmitters delivering quality programming. However, several manufacturers have observed that appropriate receivers could be delivered within only six months of a perceived demand. The history of frequency-modulation FM radio and color television outside the developing world has shown that, when new classes of signals with desired program content are made available, user demand and receiver production expand rapidly to exploit the additional benefits of the new medium.

These receivers could be used provided that some satellite audio broadcast services were made available in an introductory or auxiliary way, using existing satellites. It could well result in establishing a viable manufacturing business in the U. Rogers , noted that the limitations of surface-based, HF short-wave transmissions are generally well known throughout the community of international, long-distance, audio broadcasters.

The following is a partial list of these limitations:. Complexity in selecting useful operating frequencies and in reaching international agreements for their specific allocation and use. Fading, distortion, and loss of the received signal because of variations in the altitude and charge density of the ionosphere brought about by solar-diurnal, seasonal, storm, and sunspot-cycle effects.

Interference from commercial and industrial noise emanating from the machinery of expanding industrialization in the receiving areas. Intentional interference, i. Changes in the transmitter frequency and corresponding, required retuning of the receiver by the listening audience throughout the day, to offset the variations in ionospheric reflection or to counteract jamming.

Technical complexity and high costs, both for initial acquisition and installation and for continuing operation and maintenance, of the many high-power transmitting stations distributed around the world to achieve the desired audience coverage. The utility of overseas repeater sites dependent upon the stability of agreements between the United States and host countries. For the VOA in particular, these general limitations of long-distance, HF broadcasting have several impacts on its modernization program.

To increase audience coverage and improve probability of satisfactory reception, additional distant repeater sites located within foreign countries and operating with high-power transmitters are being constructed. The effectiveness of these stations depends upon the availability of many frequencies and upon audience willingness to retune to track VOA broadcasts. Even so, the VOA must accept significant degradations in service quality, reliability, and availability compared to commercial, over-the-air, AM and FM service in the United States.

In contrast, a DBS-A service promises widespread and predictable surface-area audience coverage and excellent reliability and quality of reception.

Offered as a large-capacity, common-carrier, common-user service it should find general acceptance among the countries of the world; also, it would confront any potential jammer with severe political repercussions.

However, the relevant physical laws for radio-wave propagation, transmitter power, antenna gain, receiver sensitivity, and signal quality are well known; furthermore, there is extensive satellite communications experience at many frequencies from both low- and high-altitude orbits to guide the choice of system parameters for DBS-A service.

This experience, together with the current state of space technology, provides a sound basis, both technically and economically, for the phased introduction of DBS-A, initially as a supplement and ultimately i. Numerous studies Bachtell et al. Similarly, at or near the FM band, 88 to MHz, where millions of receivers already exist, space-segment antennas of the directivity required for regional coverage need apertures beyond the state of the art for space structures.

In addition, the required power density incident on earth would create unacceptable interference with the reuse of certain terrestrial FM and television frequencies and therefore contravene the Radio Regulations of the International Telecommunication Union ITU. However, satellite system configurations become feasible for audio broadcasting channels at microwave frequencies above 1 GHz. Correspondingly, 2. This advantage stands in contrast to the fading and interference of terrestrial, HF signals caused by the vagaries of the ionosphere.

The only significant variable in the satellite-to-earth transmission path is a frequency-dependent attenuation through foliage, building walls, and heavy precipitation, varying from nearly negligible at the end of the ultra-high frequency band UHF to high 10 to 20 dB at 12 GHz. In general, a statistical base must be established to account for such excess attenuation values—values which can be expected to vary with receiver location e.

Therefore, a single, fixed frequency can provide continuous service to a given area, freeing the listener from retuning. The service area available for satellite broadcasting is a function of satellite altitude, orbit inclination, and antenna beamwidth.

Studies of low- vs. The Molniya orbit has been employed extensively by the Soviet Union because of its northern latitude coverage. The geostationary orbit has been found more advantageous in the Western world, including northern Canada and Alaska, because of its freedom from satellite tracking requirements by the earth stations. Lower orbits, such as the eight-hour, near-equatorial, and sun-synchronous orbits studied in these references, have the appeal of lower cost per pound of communications payload into orbit, but their short time in view and multiple frequency demands limit their utility for broadcast service.

The Committee understands that the VOA has further study of particular, eight-hour orbits under way but has not yet reviewed that work. Accepting the higher cost of launching hardware to geostationary orbit and the greater demand on satellite effective antenna gain, the primary limitation of such orbits is the geometrical constraint in northern- and southern-latitude coverage.

Use of microwave frequencies for satellite broadcasting offers a degree of immunity from intentional interference, i. Line-of-sight properties of microwave propagation restrict the influence of interfering transmitters with a 1,foot antenna height to a radius of 40 to 50 miles, so that prevention of broadcast reception over large areas involves great cost.

Antijam techniques already used on military satellites employ uplink receiving antennas of high directivity, spread-spectrum modulation, and multiple linear receivers. Furthermore, mutual self interest encourages international compliance with ITU conventions in the use of a large-capacity, common-carrier, common-user system. At this time, before any DBS-A system has been defined or procured, the accuracy of cost comparisons between terrestrial HF and satellite broadcasting operations is perforce limited.

However, the relative magnitudes can be estimated based on the known history and projections of the VOA and the histories of satellite communications systems already in use for domestic and international fixed service. Table 3—1 summarizes the capitalization and operating costs of one VOA relay site, one international satellite, and one domestic satellite over a ten-year period. Each site contains several transmitters and antennas.

Figures for the two satellite columns in the table are based on actual, commercial experiences of international and domestic owners and operators. This gross comparison illustrates that the annualized cost of one terrestrial, HF relay station is approximately equal to that of one satellite, taking into account their respective equipment lifetimes of 20 and 10 years. It is, of course, significant that a typical VOA relay site can transmit only on the order of five to eight signals simultaneously, all with the geographical and time-dependent coverage limitations discussed above.

Thus for total VOA coverage comparisons, there would be a large, per-channel cost difference in favor of four geostationary satellites over a total of 10 to 15 terrestrial HF sites. Also, the useful lifetimes of in-orbit satellites continue to grow. Studies over the past several years have addressed the future implications of large space platforms, both in geostationary orbit Edelson et al.

As emphasized by Rogers , and the National Research Council the time scale for developing and demonstrating the technology for very large geostationary satellites is greater than 10 years. Neither antennas in the range of m diameter nor power systems in the range of hundreds of kilowatts are likely to be available in space for the next several decades within the current and planned programs for large space station development and deployment.

The recent schedule stretchout for the Space Station deployment following the loss of the Challenger probably will delay their availability further. The above considerations argue strongly that large geostationary platform technology will not affect DBS-A in the near term.

Meanwhile, present communications satellites could be employed initially, with special earth receivers used to allow local rebroadcast of the received signals. Finally, a true, large-capacity, DBS-A system and service could be introduced. Before speculating on the future applications of DBS-A by third-world nations, it is well to note that two satellites owned and operated by two third-world countries for the purpose of direct satellite broadcasting, both television and audio, are already in geostationary orbit.

Two Arabsats, located at 19 and 26 degrees east longitude, serving the seven nations of the Arabian Satellite Organization, are also multimission satellites with twelve fixed-satellite channels at C-band 4 and 6 GHz and two DBS channels at 2. Those satellites are still young in their respective lifetimes, so the extent of DBS service and the number of receivers are constrained by their current experimental nature.

As the technology, service, quality, and receiver affordability are demonstrated over the next several years, DBS-A will become attractive to other third-world countries that can neither afford their own satellites nor have the abundance of terrestrial broadcasting services available in the West and in Japan.

Broadcast satellites are being vigorously developed by Japan, Europe and Australia, primarily for television. The feasibility and desirability of incorporating DBS-A into these television broadcast satellites are recognized, and plans are in place to utilize them accordingly Miller, ; Treytl, ; Johnson, By contrast, the United States has no current DBS program commitment to such an international activity in broadcasting satellite development, deployment, and use. While not strictly a satellite broadcasting service in the sense of direct user reception, radio programs are regularly distributed by satellite communications circuits in the United States, for example, by public radio, to affiliated amplitude modulation AM and FM stations.

Equatorial Communications employs spread-spectrum techniques to broadcast Muzak service directly to franchised users with small-antenna terminals 2 to 3 feet at C-band, 4 GHz. However, the state of the art of satellite technology does offer several options for introductory use of satellite transmitters by the VOA and others for limited broadcasting or auxiliary functions.

Does Tv Antenna Attract Lightning

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Today's cars have multiple antennas. The car's design does not usually allow these antennas to be positioned vertically in the center of the car roof, although this would provide optimal functionality.

TV White Space technology is revolutionizing traditional broadband. In the past, these buffers were placed between active TV channels to protect broadcasting interference. It has since been researched and proven that this unused spectrum can be used to provide broadband Internet access while operating harmoniously with surrounding TV channels. In , the FCC made this highly effective yet underutilized spectrum available for unlicensed public use.

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Antenna Sales. Welcome to Antennawarehouse. Today's HDTV antennas will get you loads of free over-the-air broadcast television, and in some cases even free 4K programming, but setting them up can be a challenge. Outdoor TV antennas hdtv antenna sales are an excellent solution for many people who want to cut the cord. Discounted Satellite Antennas Products on sale now for a limited time! If you have an older version of a Directive Systems antenna that needs repair, please see the following link in our Tech Notes section for Updating Older Antennas. Thousands of items in stock. He joins us from a large consulting firm where he helped clients with marketing data- and technology-driven solutions that enhance the customer experience. And that's why TV antenna sales and installation is growing years after people ditched cathode-ray-tube TVs. Use this TV Antenna help tool to determine which TV Antenna models have been recently installed in your zip code and surrounding areas.

We Create Connectivity

Antenna Farm Reviews. It may be the antenna, but I suspect the attic radiant barrier was to blame. Best on the market today. Our motorized antennas and stainless steel mounts are designed with the most avid HAM radio operator in mind, as well as commercial applications.

Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium , but typically one using the electromagnetic spectrum radio waves , in a one-to-many model.

Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. This chapter presents the Voice of America VOA with a roadmap for introducing satellite audio broadcasting technology, and the improved services which it allows, into its operations to compensate for many of the transmission and reception limitations of its terrestrial, high-frequency HF , relay network.

Antenna Farm Reviews

Radio is the technology of signaling and communicating using radio waves. They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by a radio receiver connected to another antenna. Radio is very widely used in modern technology, in radio communication, radar , radio navigation , remote control , remote sensing and other applications.

SEE VIDEO BY TOPIC: How does Satellite Television work? - ICT #11

Antennas shall each have an area no more than 8. We also offer signal boosters, cell phone boosters, cell signal boosters and cell phone antenna boosters from WeBoost, Laird, Digital Antenna, SureCall, and Panorama. We also feature popular products from our catalogue as well as products you might not have known we carry. Portable and mobile radios, both digital and analog, are available in all business band or consumer frequencies. The advantages of switching from analog to digital broadcasting include the.

Efficiently testing car TV antennas

Tv transmitter. Tv transmitter Purchasing an additional back up transmitter dongle serves as a simple solution for sepearate location usage. Questions, corrections or concerns? Contact Us Our full line of passive components include waveguides, filters, terminations, adapters, couplers, combiners, power dividers and many other necessary components for all your telecom and broadcasting needs The site carries the current and many back issues of the RF Technology column I write for TV Technology, news on TV transmission, production and distribution, a two year archive of Mario Orazio's relevant, if often irreverent, comments on TV technology, product reviews, classifieds and more. There is a transmitter map in which you can select the main transmitter for Here's a simple schematic of a TV transmitter circuit or video transmitter circuit which is able to broadcast on VHF between 60 to MHz. The transmitter is therefore compatible with TV systems B and G, but check transmitter frequencies used, as they are different for each country; see the links at the bottom of the page. Email: mightycelestin yahoo.

0 needs quickly emerging for broadcast TV owners — are all set to ship for to repack TV stations and free up spectrum for wireless communications 14 Oct in the limited space of the transmitter room, installing auxiliary or new antennas, and Industry watchers say once the auction is completed, the release of the FCC's.

This industry comprises establishments primarily engaged in manufacturing radio and television broadcast and wireless communications equipment. Examples of products made by these establishments are: transmitting and receiving antennas, cable television equipment, GPS equipment, pagers, cellular phones, mobile communications equipment, and radio and television studio and broadcasting equipment. Amplifiers, e.

NAICS 33422 - Radio and Television Broadcasting and Wireless Communications Equipment Manufacturing

The NIIR has considerably contributed into development of advanced info-communication technologies; the NIIR specialists perform up-to-date studies and develop advanced radio equipment and implement telecommunication projects. Design and implementation of federal-wide systems and regional networks of digital broadcasting;. Development of on-board repeaters and terrestrial stations for satellite communication and broadcasting systems;. Research and technical support of international activities of the Russian communications Administration.

Tv transmitter

Radiocommunication is made possible when a transmitter converts an intelligible message into radio frequency and radiates a signal through an antenna. Depending on the directivity of the antenna, the signal may radiate in all directions at once omnidirectional or it may, by design, cancel signal in some directions and intensify it in others. Footnote 4 The signal travels or propagates through space via radio waves and at the point of reception another antenna collects the signal as electrical current. The current passes to a receiver which converts the energy into the original message.

In radio transmission a radiating antenna is used to convert a time-varying electric current into an electromagnetic wave or field , which freely propagates through a nonconducting medium such as air or space.

Чатрукьян посмотрел на телефонный аппарат и подумал, не позвонить ли этому парню: в лаборатории действовало неписаное правило, по которому сотрудники должны прикрывать друг друга.

В шифровалке они считались людьми второго сорта и не очень-то ладили с местной элитой. Ни для кого не было секретом, что всем в этом многомиллиардном курятнике управляли шифровальщики. Сотрудников же лаборатории безопасности им приходилось терпеть, потому что те обеспечивали бесперебойную работу их игрушек.

Чатрукьян принял решение и поднял телефонную трубку, но поднести ее к уху не успел.

SIC Industry Description

Время от времени, когда надо было продлить членство в теннисном клубе или перетянуть старую фирменную ракетку, он подрабатывал переводами для правительственных учреждений в Вашингтоне и его окрестностях. В связи с одной из таких работ он и познакомился со Сьюзан. В то прохладное осеннее утро у него был перерыв в занятиях, и после ежедневной утренней пробежки он вернулся в свою трехкомнатную университетскую квартиру. Войдя, Дэвид увидел мигающую лампочку автоответчика. Слушая сообщение, он выпил почти целый пакет апельсинового сока.

Послание ничем не отличалось от многих других, которые он получал: правительственное учреждение просит его поработать переводчиком в течение нескольких часов сегодня утром. Странным показалось только одно: об этой организации Беккер никогда прежде не слышал.

【Massimo Dutti】幅広いシーンで活躍間違いなし☆おすすめです 46967353

Я понимаю, - сказал.  - Извините за беспокойство. Повернувшись, он направился через фойе к выходу, где находилось вишневое бюро, которое привлекло его внимание, когда он входил.

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    I here am casual, but was specially registered to participate in discussion.