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WORKING PAPER SUMMARY For decades governments have made rapidly increasing use of the high frequency (HF) portion of the electromagnetic spectrum and the Earth's ionosphere and surface to conduct public diplomacy by broadcasting speech and music throughout the world. These shortwave broadcasts are made directly to an enormous number of fixed and portable radio receivers used individuals in nearly every country in the world.40 This increasing use in the context of the limited number of frequencies available, and the limitations inherent in using the ionosphere and the Earth's surface for long-distance radiowave transmission of real-time audio programs, has resulted in broadcasters employing such practices as great transmitter power, simultaneous use of several frequencies for broadcasting the same program, and broadcasting on nonallocated, out-of-band frequencies. This has led to considerable overuse, congestion of the spectrum, and serious interference among signals. This situation has deprived many countries of the opportunity to meet their broadcasting needs at an acceptable financial cost and often results in a seriously reduced quality of reception over large areas. These trends will likely continue indefinitely as countries compete with each other for audience attention. Unfortunately, shortwave transmitters, the Earth's surface, and the ionosphere are dull and fuzzy tools for focusing broadcasting signals to specific distant listening audiences. by Important technological advance has taken place in the civilian space area, however, and further specific advances are reasonably, confidently expected. Therefore, attention now can be given to the use of orbiting satellites to supplement, and eventually to supplant, today's surface-based HE shortwave broadcasting plants and operations. The use of orbiting satellites could begin well within a decade. Technological, operational, cost, and financing considerations suggest that well before the end of this century space-based audio broadcasting transmitters could replace surface-based audio broadcasting transmitters, just as they have replaced surface-based, HE, long-hau] trunk communications plant and operations. Regional system-services, utilizing interconnected, in-space direct broadcast transmitters, could essentially replicate this Jong-hau] trunk communications experience and provide all of the governments of the world with the opportunity to continue their audio broadcasting, directly and easily, to individual spacewave receivers located essentially 40. The Voice of America (VOA) of the United States Information Agency and the Board for International Broadcasting (BIB), Radio Free Europe/Radio Liberty (RFE/RL), are now engaged in a multibillion-dollar modernization and expansion of their shortwave broadcasting plants and operati ons. - 68 - WORK] NG P AP ER
WORKING PAPER anywhere in the world. They could do this with enlarged and more focused coverage, with unexceptionable reliability, quality, and clarity, with little if any operating concern, and at a much lower cost than is the case today. This report has discussed the service requirements for broadcasting audio programs from space directly to surface receivers (DBS-A), and two conceptual space-related systems and the means of providing them. The two conceptual systems could operate in either of two quite different portions of the electromagnetic spectrum: the upper ends of both the ultra-high frequency (UHF) (0.3-3.0 GHz) and the high frequency (HF) (3.0-30.0 MHz) bands. The more important design and operating features of both surface segments (the individual receivers) and the space segments (the satellites, including their surface feeders) and their expected performance have been presented, along with their estimated costs for global, high-capacity, small individual surface coverage area operations. Such a space-redated system-service would provide a received signal reliability and quality easily the equal of today's popular, local, over-the-air AM and FM audio surface broadcasting stations. The surface segment "spacewave" receivers would be small, employ precise and repeatable electronic (not mechanical) tuning, have quite modest antenna directivity, and be easily transportable and used both outdoors and indoors. In mass production they should cost little if any more than today's local AM (MF) (300 kHz-3 MHz) and FM (VHF) (30 MHz-300 MHz) broadcasting receivers, i.e., a few lOs of dollars at most.4] Beyond the basic housekeeping in-orbit space-craft services (power, telemetry, orbit adjustment, etc.) each space segment would consist of an array of subtransmitters, each coupled to one or more large antennats) capable of radiating a large number of shaped, earthward-pointing beams. The selection of beams, the allocation of program channels to individual and/or groups of beams, and the setting of radio frequency (RF) power output levels for each beam would be accomplished by means of sophisticated and dynamic electronic switching in the satellite. This switching would be under the control of the space segment's surface feeder station. The switching would respond both to the broadcasters' changing needs for serving individual service areas, the quantity and quality of service for each, and the vagaries of both radiowave propagation and/or natural and commercial-industrial electrical noise in the regions being served by each beam. Each space segment would be designed to operate as part of a regional system and each segment could be interconnected with the others via optical or millimeter space links. They would be designed so that, in total, they could provide a fine level of service throughout the populated areas of the 41. All dollars in this paper are U.S. 1985. - 69 - WORKING PAPER
WORKING PAPER world. They would have sufficient capacity so that they could be operated in a common user42 manner, as are, for instance, long lines system-services operated by AT&T, GTE, MCI, SBS, etc., and the space communications system-services operated by Inte~sat and Inmarsat. This new space-related, common user, direct audio broadcasting service would be made available to every country of the world in an equitable fashion. In each case the space segment design, the character of the technology used, the method of operation, and the large capacity and large presumed use of the service, could see such a service provided at an acceptable, indeed a relatively quite low, cost per channel/surface square mile/year. Full advantage of Space Station infrastructure (physical assets and technicians) to assemble the space segments in orbit and, later, to service them there, thereby containing their acquisition and ongoing costs. The UHF conceptual system would provide approximately 1,OOO full-time audio channels on a global basis, and serve 99.9 percent + of the world's population residing throughout 30 million square miles (8O million square kilometers). The HE conceptual system would have a much lower capacity unless quite advanced technological steps were taken to provide extremely large space segment power. A government might not wish to make use of such a common user service to broadcast its programs and might not wish to have its population receive the other programs that such a service could provide. If this is the case, it need not send its programs to the system-service for broadcast and its population need not be supplied with the new kind of receiver requested for listening. Other governments that wish to broadcast directly to the people of such countries could do so by employing surface-based HE plants, as they do today by international agreement. A decade from now, the space segments of one or more regional DBS-A system-services of satisfactory reliability, quality, coverage, and great operating flexibility could be in operation. By the end of this century, a high-capacity, worldwide space segment coverage could be acquired at UHF for a cost of roughly i500 million and a total ongoing cost of roughly $100 million per year. Interconnected regional systems could be designed to operate in either a high HE band or, by inference, a very high frequency (VHF) band or, preferably, a UHF band. Significant advantages in cost and service area would lie with a UHF design, and perhaps some advantage in service quality as well, particularly if a truly superior service were desired. It would be more difficult and costly to obtain a large system capacity at HF. There are no flux density limitations at HE; this might be somewhat of a problem at UHF. Reception 42. In the United States, called common carrier. - 70 - WORKING PAPER
WORKING PAPER - could be more easily provided at HF in difficult terrain. A case could be made for concluding that the most efficient spectrum use for a DBS-A system-service would be obtained if a frequency band intermediate to the 26 MHz and 2.5 GHz bands (taken as illustrative examples here) were employed. It is not clear at this time which frequency region would be more acceptable, but particular attention should be given to the regions used for VHF FM audio and UHF television broadcasting. Over time the surface segment of an overall DBS-A system could be installed at a cost of $10 billion for the hundreds of millions of spacewave receivers that would be involved. The world's radio-listening general public (and not just those who now make up the worldwide shortwave broadcasting listening audience) would be prompted to make the relatively modest investment on an individual basis because, relative to today's shortwave broadcasting circumstances, DBS-A signals could then be received in areas not now reached by shortwave signals, and could be received easily (i.e., without periodic and vexing mechanical retuning of receivers) and with unparalleled reliability, clarity, and quality. In addition, expanded and more diverse programming could be offered. Perhaps the same entity that provides the space segment also could see to the provision of some or all of the surface segments. In this fashion a continuing balance of the cost allocation between them could be effected, much as it is in the long-hau] trunk satellite communications and telephone plant areas today, and the availability (and perhaps indigenous manufacturing) of truly low cost receiver models thereby assured, particularly in lesser developed countries. If the cost of acquiring, maintaining, and operating the space segments were to be borne by the broadcasting governments alone, the cost could be apportioned to each to reflect that fraction of the service's capability (i.e., the product of its capacity, quality, coverage area, and time) that the government would use. For instance, some countries (i.e., the United States, the Soviet Union, the United Kingdom, the Federal Republic of Gennany, the Netherlands) might wish to avail themselves of up to lO percent of the total available (at a cost to each of approximately $10 million per year); others might wish to purchase as little as a few tenths of a percent (at a cost to each of a few tens of thousands of dollars per year). The governments using the service should be able to do so for a fraction of the financial cost they now incur on an individual nation basis, and they would have access to a service of much greater and selective coverage and much higher quality and reliability. (If it becomes available within a decade, the VOA alone could expect to save $100 million per year.) Essentially all present frequency allocation and operating problems would be solved, and almost all governments could avoid most of the electromagnetic and political fallout associated with the conduct of electronic warfare, i.e., jamming, by a few countries. - 71 WORKING PAPER
WORKING PAPER As an alternative, the space segments' cost could be shared with or borne by the surface segment. Given the large potential market, the addition of only $l to 2 to the retail price of each receiver (i.e., a few percent of the expected average price) that would be used to pay for the acquisition of the space segments, would meet or nearly meet its cost. The clear and important advantages of having such a worldwide common-user audio broadcasting service available should appeal to almost al] countries of the world, developed and lesser developed alike. Such DBS-A services also could be used to meet national, i.e., domestic, broadcasting needs in many peaces throughout the world with cost and operating advantages over not only surface-based HE, but surface-based VHF as well. The availability of such services could be particularly important to many of the lesser developed countries and in low population density areas generally. With the cost of the basic worldwide system-service met by payments from governments for its use in nondomestic broadcasting, the marginal cost of providing domestic services as well, especially during the "working" hours of the day, should be quite low. And any net revenues generated by use of the system for domestic broadcasting could be used to lower the cost of the worldwide broadcasting service even further. Finally, the availability of a new DBS-A service such as that outlined here, one that provides the same service characteristics as today's local AM and FM audio broadcasting but on a wide-area, low-cost basis, could prompt private interests to reach listening audiences in this new way, thereby providing additional private revenues to the system-service. Listening to local AM and FM is extremely popular; there are now l.4 billion radios throughout the world. It remains very popular in the United States in spite of the great number and diversity of other media and activities that compete for listener's attention. Over 99 percent of the U.S. population has at least one radio; the average is 5.5 per household. A billion radios were sold in the U.S. over the last 37 years (over 50 million in 1983 alone), and the country supports 9,000 audio broadcasting stations. There is reason to expect that this medium would be further vitalized, both nationally and globally, and in both the public and private sectors, by the availability of a high-quality, high-capacity, space-related audio broadcasting system-service. The imaginative and sensible use of space technology should brook large in the future of worldwide audio broadcasting direct to the world's general public. The outlines of solutions to technological, operational, political, and financial problems that have long precluded its use are now clearly in sight. This is one societal area in which there are important needs clearly seeking, and now amenable to, space-related technological solutions. These solutions are in sharp contrast to some others where, unfortunately, space engineers have tended to evolve "solutions" that failed when tested in the real world. WORKING PAPER
