Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America

A Report Prepared by the

Committee on Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America

Board on Telecommunications and Computer Applications

Commission on Engineering and Technical Systems

National Research Council

NATIONAL ACADEMY PRESS
Washington, D.C.
1988



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Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of AmericaA Report Prepared by the Committee on Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America Board on Telecommunications and Computer Applications Commission on Engineering and Technical Systems National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1988

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Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M.White is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Samuel O. Thier is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M.White are chairman and vice chairman, respectively, of the National Research Council. The project is supported by Contract No. IA-21130-23 between the United States Information Agency and the National Academy of Sciences. Copies available from: Board on Telecommunications and Computer Applications Commission on Engineering and Technical Systems National Research Council 2101 Constitution Avenue, N.W. Washington, D.C. 20418 Printed in the United States of America

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Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America COMMITTEE ON ANTENNAS, SATELLITE BROADCASTING, AND EMERGENCY PREPAREDNESS FOR THE VOICE OF AMERICA ROBERT P.RAFUSE (Chairman) Senior Staff Lincoln Laboratory Massachusetts Institute of Technology LEWIS S.BILLIG Director for Communications and Theater Systems MITRE Corporation (Retired) BERT COWLAN Telecommunications Consultant DOUGLASS D.CROMBIE Senior Engineering Specialist Aerospace Corporation J.KEITH EDWARDS Assistant Chief Engineer, External Broadcasting British Broadcasting Corporation (Retired) ROBERT S.FORTNER Associate Professor and Director of Radio and Television The George Washington University RAYMOND A.GREENWALD Section Supervisor, Ionospheric Physics Applied Physics Laboratory The Johns Hopkins University ROBERT C.HANSEN Consulting Engineer R.C.Hansen, Inc. OTTO W.HOERNIG, JR. Vice President, Business Development Contel ASC JOHN E.KEIGLER Chief Scientist GE Astro-Space Division WILBUR L.PRITCHARD President and Chief Executive Officer SSE Telecom, Inc. THOMAS F.ROGERS President The Sophron Foundation WILLIAM F.UTLAUT Associate Administrator for Telecommunications and Director, Institute for Telecommunication Sciences National Telecommunications and Information Administration ERIC K.WALTON Research Scientist The Ohio State University DANIEL J.FINK (Ex-Officio)* President D.J.Fink Associates, Inc. STAFF Richard B.Marsten, Study Director** John M.Richardson, Study Director*** Lois A.Leak, Administrative Assistant *   Until June 1987, as Chairman, Board on Telecommunications and Computer Applications **   Until January 1988 ***   From January 1988

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Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America BOARD ON TELECOMMUNICATIONS AND COMPUTER APPLICATIONS CHARLES W.STEPHENS (Chairman) President and Deputy General Manager TRW Electronics & Defense Sector (Retired) DANIEL BELL Henry Ford II Professor of Social Sciences Harvard University HERBERT D.BENINGTON Director of Planning UNISYS Defense Systems CARL J.CONTI Vice President and Group Executive Information Systems and Storage Group IBM Corporation ANTHONY J.DeMARIA Assistant Director of Research for Electronics and Electro-Optics Technology United Technologies Research Center DAVID J.FARBER Professor of Computer and Information Science and Electrical Engineering University of Pennsylvania DONALD M.KUYPER Group Vice President, Business Services GTE Telephone Operating Group JOHN C.McDONALD Vice President and Chief Scientist CONTEL, Inc. ALAN J.PERLIS Eugene Higgins Professor of Computer Science Yale University HENRY M.RIVERA Partner Dow, Lohnes and Albertson IVAN SELIN Chairman of the Board American Management Systems, Inc. ERIC E.SUMNER Vice President, Operations Systems and Network Planning AT&T Bell Laboratories GEORGE L.TURIN Professor of Electrical Engineering University of California, Berkeley KEITH W.UNCAPHER Executive Director, USC Information Sciences Institute and Associate Dean, School of Engineering University of Southern California STAFF John M.Richardson, Director* Richard B.Marsten, Executive Director** Anthony M.Forte, Senior Staff Officer Karen Laughlin, Administrative Coordinator Lois A.Leak, Administrative Assistant *   From January 1988 **   Until January 1988

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Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America PREFACE This is the interim report of the National Research Council’s (NRC’s) two-year study on antennas, satellite broadcasting, and emergency preparedness for the Voice of America (VOA). The committee conducting this study was established in September 1986 at the request of the Director, Engineering and Technical Operations, VOA, during the preparation of the final report of its predecessor, the Technical Operations Study Committee for the VOA, early in 1986. The objective of the current Committee on Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America (the Committee) is to provide advice, guidance, and recommendations on the VOA’s technical planning and management of its program to modernize, renovate, and expand its broadcast transmission and networking capabilities to support its overseas broadcasting requirements. To achieve this objective the Committee set out to review (1) technical aspects of distributed, electronically controlled antenna arrays and power amplifiers for their application to VOA transmission requirements; (2) backscatter monitoring techniques for assessment of the technical quality of high-frequency (HF) broadcast signals at foreign receiving sites; (3) satellite audio broadcasting as a supplement to, or possible eventual replacement for, high-power HF terrestrial broadcasting over the horizon; and (4) emergency preparedness telecommunications support for studio-to-transmitter links to broadcasting station sites. The Committee was also to review the VOA’s activities in advanced, experimental antenna techniques; planning for satellite broadcasting initiatives; and emergency preparedness telecommunications. The Committee was concerned with affordable, timely applications of advanced techniques appropriate to the VOA’s operating requirements and schedule and budgetary constraints. It was to suggest applications and initiatives consistent with forward planning to ensure continuing technical refreshment of the VOA’s broadcasting system to keep it current with evolving technology. The Committee’s inaugural meeting was held November 6 and 7, 1986. At that meeting the chairman reviewed the 11 principal points of the predecessor committee’s final report (National Research Council, 1986, referenced fully in Chapter 1), and the VOA’s Chief of Planning and Systems Analysis presented a summary of actions under way to respond.

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Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America Detailed presentations were given by VOA officials on their emergency preparedness program, current engineering activities in the modernization program, broadcast systems network analysis, and procurements for experimental antennas, radio-frequency subsystems, speech processing, and a satellite interconnect system. The Director, VOA Engineering and Technical Operations, addressed the Committee at length on VOA objectives for its engineering and technical operations programs and for the Committee’s work (see Statement of Task, below). A detailed presentation on VOA satellite broadcasting activities in 1986 concluded the presentations. The Committee formed three subcommittees—HF antennas and backscatter monitoring, satellite voice broadcasting, and emergency preparedness—to address the three major thrusts of its work. Five additional meetings of the full Committee were convened prior to preparation of this interim report. Numerous meetings on specific issues were also held by individual subcommittee members and the Director of the NRC’s Board on Telecommunications and Computer Applications (BOTCAP) with officials and members of the technical staffs of the VOA, the Institute for Telecommunication Sciences, the National Aeronautics and Space Administration, the National Communications System, and officials in the United Kingdom, the Federal Republic of Germany, and Finland. In addition to many continuing, detailed, technical presentations by VOA officials and technical staff, the Committee received briefings from MITRE Corporation; the National Communications System; the Federal Emergency Management Agency; Worth Research Associates; the Naval Research Laboratory; and Technology for Communications, International. We also wish to acknowledge the briefings on the new transmitters and the tour and explanation of the broadcasting site facilities and operations provided by the staff of the VOA’s Greenville, N.C. station. The committee concept of the NRC operates successfully and effectively in large part because of committee and staff members’ rapport with, and cooperation and support from, the agency the NRC is advising. From the VOA we appreciate sincerely the contributions and support of Dr. Robert Frese, Director, Engineering and Technical Operations, and Dr. Donald Messer, our VOA program manager, and we are particularly pleased to have had the sustained interest and attention of the Hon. Richard Carlson, Director, VOA, and Mr. Morton Smith, Deputy Director for Modernization. The Committee is particularly grateful to Dr. Richard B.Marsten, Director of BOTCAP, for his counsel, guidance, and contributions throughout this project, and for his continued support as Study Director. Dr. Marsten’s successor, Dr. John M.Richardson, completed the remaining work associated with publication of the report. A committee effort of this scope also imposes extraordinary requirements on the administrative staff. With pleasure, the Committee acknowledges Lois A.Leak for her expert administrative and secretarial support. Finally, as Committee chairman, I express my personal thanks to my colleagues, the Committee members, for their dedicated efforts. Robert P.Rafuse, Chairman Committee on Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America

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Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America CONTENTS     STATEMENT OF TASK   viii 1   EXECUTIVE SUMMARY   1     Some Background   1     Research and Development at the Voice of America   2     High-Frequency Antennas and Propagation   3     Direct Broadcasting by Satellite   5     Emergency Preparedness Telecommunications   6     References   7 2   ANTENNA, PROPAGATION, AND MONITORING CONSIDERATIONS FOR HIGH-FREQUENCY BROADCASTING SYSTEMS   8     Systems Modernization   8     Antenna Array System   9     Propagation and Data Sources   16     Monitoring   18     Recommendations   21     References   23 3   SATELLITE DIRECT AUDIO BROADCASTING AND RECEPTION   24     The Context for Development   24     Receiver Availability   26     Effectiveness of High Frequency vs Direct Broadcast Satellite   27     Forecasting Cost-Effectiveness of Services   30     Impact of Large Space Platform Technology   32     Worldwide Use   33     Augmentation of Terrestrial High Frequency   33     Conclusions   34     Recommendations   35     References   36 4   EMERGENCY PREPAREDNESS TELECOMMUNICATIONS   38     Missions   38     Roles, Responsibilities, and Requirements   40     Disasters and Priorities   41     The Voice of America’s Emergency Preparedness Requirements   43     The Voice of America’s Current Emergency Preparedness Plans   48     Systems Approach to Emergency Planning   49     Awareness of National Security Emergency Preparedness Planning   52     Recommendations   53     References   55     GLOSSARY   56

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Antennas, Satellite Broadcasting, and Emergency Preparedness for the Voice of America STATEMENT OF TASK This study has three principal concerns: incorporating phased-array antennas into the Voice of America’s (VOA’s) transmitter sites; the future installation of direct-broadcast satellite (DBS) systems worldwide in the VOA’s broadcasting complex; and emergency preparedness of VOA communications. There are five tasks: Technology and systems review of phased-array antennas at high frequency (HF). Review modern phased-array antenna techniques and identify those most likely to be applicable in the HF (3 to 26 MHz) band. Consider techniques that can be coordinated among different transmitter site locations for each frequency, and for numbers of frequencies transmitted to audience areas simultaneously from different sites. Consider requirements for overcoming jamming and the possibility of using superpower arrays to counter jamming at particular audience locations. Review techniques for monitoring phased-array and system performance. This review will include ground- and space-based techniques, including backscatter monitoring performance of phased arrays, transmitter-antenna combinations, and the ability of the VOA broadcast system to provide satisfactory-quality signals to listeners. It will identify effects of the parameters monitored on system performance, and possible reductions in numbers of frequencies and sites. Review the developing situation in DBS systems. This review will include developments in satellite broadcasting, and in low-cost earth receivers for use in VOA audience countries. Advances in space techniques will be compared with those in terrestrial systems using phased arrays. The committee will attempt to forecast when performance and cost-effectiveness of satellite broadcasting are likely to overtake those of terrestrial HF and will comment on the likely effectiveness of operating the two types of systems in parallel. Review emergency preparedness activities in the VOA. This review will cover the VOA’s activities in response to the President’s directives on emergency mobilization preparedness and national security telecommunications policies, National Security Decision Directives (NSDDs) 47 and 97. The committee will advise what technical operating capabilities the VOA could and could not rely on and how to use that information to meet the requirements of NSDDs 47 and 97. Review applicability of satellite facilities in emergencies. The committee will review the applicability of satellite communications and domestic DBS facilities to provide alternate information sources in emergencies and will advise the VOA on emergency planning and exercising actions that could avoid service outages. Date: October 9, 1986