Japan's Signals Intelligence
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Antenna Theory and Design SECOND EDITION
Antenna Theory and Design SECOND EDITION Warren L. Stutzman Gary A. Thiele WILEY Contents Chapter 1 • Antenna Fundamentals and Definitions 1 1.1 Introduction 1 1.2 How Antennas Radiate 4 1.3 Overview of Antennas 8 1.4 Electromagnetic Fundamentals 12 1.5 Solution of Maxwell's Equations for Radiation Problems 16 1.6 The Ideal Dipole 20 1.7 Radiation Patterns 24 1.7.1 Radiation Pattern Basics 24 1.7.2 Radiation from Line Currents 25 1.7.3 Far-Field Conditions and Field Regions 28 1.7.4 Steps in the Evaluation of Radiation Fields 31 1.7.5 Radiation Pattern Definitions 33 1.7.6 Radiation Pattern Parameters 35 1.8 Directivity and Gain 37 1.9 Antenna Impedance, Radiation Efficiency, and the Short Dipole 43 1.10 Antenna Polarization 48 References 52 Problems 52 Chapter 2 • Some Simple Radiating Systems and Antenna Practice 56 2.1 Electrically Small Dipoles 56 2.2 Dipoles 59 2.3 Antennas Above a Perfect Ground Plane 63 2.3.1 Image Theory 63 2.3.2 Monopoles 66 2.4 Small Loop Antennas 68 2.4.1 Duality 68 2.4.2 The Small Loop Antenna 71 2.5 Antennas in Communication Systems 76 2.6 Practical Considerations for Electrically Small Antennas 82 References 83 Problems 84 Chapter 3 • Arrays 87 3.1 The Array Factor for Linear Arrays 88 3.2 Uniformly Excited, Equally Spaced Linear Arrays 99 3.2.1 The Array Factor Expression 99 3.2.2 Main Beam Scanning and Beamwidth 102 3.2.3 The Ordinary Endfire Array 103 3.2.4 The Hansen-Woodyard Endfire Array 105 3.3 Pattern Multiplication 107 3.4 Directivity of Uniformly Excited, Equally Spaced Linear Arrays 112 3.5 Nonuniformly -
Agricultural Environment of the Back Land of Nagura Bay, Okinawa Prefecture"
"Agricultural Environment of the Back Land of Nagura Bay, Okinawa Prefecture" 著者 "KATAYAMA Tadao C., SHINAGAWA Akio, HIGASHI Teruo" journal or 南海研紀要 publication title volume 6 number 1 page range 37-55 URL http://hdl.handle.net/10232/15660 Mem. Kagoshima Univ. Res. Center S. Pac. Vol.6, No. 1, 1985 37 Agricultural Environment of the Back Land of Nagura Bay, Okinawa Prefecture* Tadao C. Katayama**, Akio Shinagawa*** and Teruo Higashi*** Abstract The agricultural environment of the back land of Nagura Bay, Ishigaki Island, Okinawa Prefecture, /'. e., upland factors and cropping systems were discussed on the basis of references and observation in the area. There is a rapid consumption and a high turnover rate for organic matter, nutrients, minerals. To improve soil preserva tion, it is recommended utilization of natural topographical features and plants is more suitable than building artificial structures. Plants with a tap root and deep-rooted trees are good examples of natural stabilization structures. In comparison to the agricultural practices dominated by hand labor and small machines, procedures utilizing large machines are disadvantageous, because they increase the amount of times the land remains bare and they reduce the necessary elasticity in farm practices. It is recom mended to increase the agricultural development cautiously to preserve the environ ment and to keep the local population consensus. Introduction Ishigaki Island lies between 124°04'E and 124°20'E longitude and 24°19'N and 24° 36'N latitude (Fig. 1). In general, Ishigaki Island is said to be characteristic of a sub-tropical region. Because of its sub-tropical nature, it has higher temperatures and more abundant solar energy in comparison with Japan proper. -
Effects of Constructing a New Airport on Ishigaki Island
Island Sustainability II 181 Effects of constructing a new airport on Ishigaki Island Y. Maeno1, H. Gotoh1, M. Takezawa1 & T. Satoh2 1Nihon University, Japan 2Nihon Harbor Consultants Ltd., Japan Abstract Okinawa Prefecture marked the 40th anniversary of its reversion to Japanese sovereignty from US control in 2012. Such isolated islands are almost under the environment separated by the mainland and the sea, so that they have the economic differences from the mainland and some policies for being active isolated islands are taken. It is necessary to promote economical measures in order to increase the prosperity of isolated islands through initiatives involving tourism, fisheries, manufacturing, etc. In this study, Ishigaki Island was considered as an example of such an isolated island. Ishigaki Island is located to the west of the main islands of Okinawa and the second-largest island of the Yaeyama Island group. Ishigaki Island falls under the jurisdiction of Okinawa Prefecture, Japan’s southernmost prefecture, which is situated approximately half-way between Kyushu and Taiwan. Both islands belong to the Ryukyu Archipelago, which consists of more than 100 islands extending over an area of 1,000 km from Kyushu (the southwesternmost of Japan’s four main islands) to Taiwan in the south. Located between China and mainland Japan, Ishigaki Island has been culturally influenced by both countries. Much of the island and the surrounding ocean are protected as part of Iriomote-Ishigaki National Park. Ishigaki Airport, built in 1943, is the largest airport in the Yaeyama Island group. The runway and air security facilities were improved in accordance with passenger demand for larger aircraft, and the airport became a tentative jet airport in May 1979. -
Genetic Lineage of the Amami Islanders Inferred from Classical Genetic Markers
bioRxiv preprint doi: https://doi.org/10.1101/2021.04.18.440379; this version posted April 19, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Genetic lineage of the Amami islanders inferred from classical genetic markers Yuri Nishikawa and Takafumi Ishida Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan Correspondence: Yuri Nishikawa, Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan. E-mail address: [email protected] 1 bioRxiv preprint doi: https://doi.org/10.1101/2021.04.18.440379; this version posted April 19, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Abstract The peopling of mainland Japan and Okinawa has been gradually unveiled in the recent years, but previous anthropological studies dealing people in the Amami islands, located between mainland Japan and Okinawa, were less informative because of the lack of genetic data. In this study, we collected DNAs from 104 subjects in two of the Amami islands, Amami-Oshima island and Kikai island, and analyzed the D-loop region of mtDNA, four Y-STRs and four autosomal nonsynonymous SNPs to clarify the genetic structure of the Amami islanders comparing with peoples in Okinawa, mainland Japan and other regions in East Asia. -
Nansei Islands Biological Diversity Evaluation Project Report 1 Chapter 1
Introduction WWF Japan’s involvement with the Nansei Islands can be traced back to a request in 1982 by Prince Phillip, Duke of Edinburgh. The “World Conservation Strategy”, which was drafted at the time through a collaborative effort by the WWF’s network, the International Union for Conservation of Nature (IUCN), and the United Nations Environment Programme (UNEP), posed the notion that the problems affecting environments were problems that had global implications. Furthermore, the findings presented offered information on precious environments extant throughout the globe and where they were distributed, thereby providing an impetus for people to think about issues relevant to humankind’s harmonious existence with the rest of nature. One of the precious natural environments for Japan given in the “World Conservation Strategy” was the Nansei Islands. The Duke of Edinburgh, who was the President of the WWF at the time (now President Emeritus), naturally sought to promote acts of conservation by those who could see them through most effectively, i.e. pertinent conservation parties in the area, a mandate which naturally fell on the shoulders of WWF Japan with regard to nature conservation activities concerning the Nansei Islands. This marked the beginning of the Nansei Islands initiative of WWF Japan, and ever since, WWF Japan has not only consistently performed globally-relevant environmental studies of particular areas within the Nansei Islands during the 1980’s and 1990’s, but has put pressure on the national and local governments to use the findings of those studies in public policy. Unfortunately, like many other places throughout the world, the deterioration of the natural environments in the Nansei Islands has yet to stop. -
Mapping Small Islands Communicative Ecologies: a Case Study from the Amami Islands
South Pacific Studies Vol.39, No.1, 2018 Mapping Small Islands Communicative Ecologies: a Case Study from the Amami Islands Papoutsaki Evangelia 1* and Kuwahara Sueo2 1: School of Arts and Science, University of Central Asia, Naryn Campus, 310 Lenin St. Naryn, 722918, Kyrgyz Republic 2: Center for General Education, Kagoshima University *Corresponding author E-mail: [email protected] Abstract This paper provides a conceptual framework for an islands’ communication ecology (CE) approach and an overview of the key findings of exploratory ethnographic research that aimed at mapping the CE of the Amami islands. The communicative ecology approach refers to the various forms, resources, activities, channels and flows of communication and information unique to an island or group of islands, to the island context and identity and a milieu of island agents. This research contributes towards an in-depth understanding of these Islands’ communicative environment; identifies key island mediated communicative networks and practices; explores the role of media in localized information flows unique to the islands; and attempts to explore how small island experiences can help contextualize the theoretical approach of communicative ecology. Key words: Amami Island, Island Media, Island Radio, Islands Communicative Ecology, Mapping Islands Information Ecosystems ―――――――――――――――――――――――――――――――――――――――――――――― Received: 01 September, 2018 Accepted: 30 November, 2018 26 South Pacific Studies Vol.39, No.1, 2018 Introduction This article draws upon a research project aimed at exploring the Amami Islands’ communicative environment by identifying key communicative networks and practices that contribute to sustaining the Amami Islands’ sociocultural cohesion and investigating the role that key mediated forms of communication, particularly community based, play in localized information flows unique to these islands. -
Notes on HF Discone Antennas
Notes on HF Discone Antennas L. B. Cebik, W4RNL The discone antenna is a broadband basic antenna originally designed for VHF-UHF service. Indeed, it is a staple for upper-range scanning receivers. Developed during WWII by A. G. Kandoian, and brought to the attention of radio amateurs in the later 1940s, the following years saw conversions of the design to HF use. Amateurs have used it from 160 meters up through 10 meters, although the operating passband for any single implementation is limited to about a 2.5:1 frequency range. Even though the antenna is quite basic in concept, its shape seems to elicit strange reactions from newer amateurs. The reactions run from simple quizzical looks to occasional bizarre explanations of its operation. In these notes we shall look at the antenna with a series of inquiries. We shall start by putting the antenna into its proper class. Then we shall turn to questions of modeling the antenna, sorting out what we can glean from models and what we cannot. Since operating bandwidth is the most pressing question in many minds, we shall next look at that matter, followed by questions of performance. The performance facets of HF versions of the antenna over ground are perhaps the most important, since that is the environment in which we must use the antenna, if we choose to build one. To set a proper framework for judgment by the prospective builder, we shall look at a few other antenna designs that may be relevant. In order to focus our attention on the properties of the HF discone, we shall confine our attention to creating one to cover the upper HF set of amateur allocations from 14 to 30 MHz. -
High Frequency (HF)
Calhoun: The NPS Institutional Archive Theses and Dissertations Thesis Collection 1990-06 High Frequency (HF) radio signal amplitude characteristics, HF receiver site performance criteria, and expanding the dynamic range of HF digital new energy receivers by strong signal elimination Lott, Gus K., Jr. Monterey, California: Naval Postgraduate School http://hdl.handle.net/10945/34806 NPS62-90-006 NAVAL POSTGRADUATE SCHOOL Monterey, ,California DISSERTATION HIGH FREQUENCY (HF) RADIO SIGNAL AMPLITUDE CHARACTERISTICS, HF RECEIVER SITE PERFORMANCE CRITERIA, and EXPANDING THE DYNAMIC RANGE OF HF DIGITAL NEW ENERGY RECEIVERS BY STRONG SIGNAL ELIMINATION by Gus K. lott, Jr. June 1990 Dissertation Supervisor: Stephen Jauregui !)1!tmlmtmOlt tlMm!rJ to tJ.s. eave"ilIE'il Jlcg6iielw olil, 10 piolecl ailicallecl",olog't dU'ie 18S8. Btl,s, refttteste fer litis dOCdiii6i,1 i'lust be ,ele"ed to Sapeihil6iiddiil, 80de «Me, "aial Postg;aduulG Sclleel, MOli'CIG" S,e, 98918 &988 SF 8o'iUiid'ids" PM::; 'zt6lI44,Spawd"d t4aoal \\'&u 'al a a,Sloi,1S eai"i,al'~. 'Nsslal.;gtePl. Be 29S&B &198 .isthe 9aleMBe leclu,sicaf ,.,FO'iciaKe" 6alite., ea,.idiO'. Statio", AlexB •• d.is, VA. !!!eN 8'4!. ,;M.41148 'fl'is dUcO,.Mill W'ilai.,s aliilical data wlrose expo,l is idst,icted by tli6 Arlil! Eurse" SSPItial "at FRIis ee, 1:I.9.e. gec. ii'S1 sl. seq.) 01 tlls Exr;01l ftle!lIi"isllatioli Act 0' 19i'9, as 1tI'I'I0"e!ee!, "Filill ell, W.S.€'I ,0,,,,, 1i!4Q1, III: IIlIiI. 'o'iolatioils of ltrese expo,lla;;s ale subject to 960616 an.iudl pSiiaities. -
LUGGAGE-FREE TRAVEL Same-Day Delivery
LUGGAGE-FREE TRAVEL Same-day Delivery ◆Airport ✈ → Hotel Delivery Delivery City Drop-off Earliest delivery From To Narita Airport 6:30ー10:00 Tokyo(Chiba) Ibaraki、Tochigi、Gunma、Saitama、Chiba、Tokyo、Kanagawa、Yamanashi Haneda airport 00:00ー10:30 Osaka Kansai International Airport 6:30ー9:30 Osaka、Kyoto、Hyogo、Nara、Shiga Chubu International Airport Terminal 1 7:00ー11:00 Aichi、Mie、Gifu Nagoya 18:00ー21:00 Chubu International Airport Terminal 2 10:00ー11:00 Aichi、Mie、Gifu Sendai Station Sendai International Airport 8:00ー9:30 Within Miyagi Sapporo New Chitose Airport 7:30ー10:00 Within Sapporo Cuty Fukuoka Fukuoka Airport 7:30ー11:30 Within Chuo Area, Fukuoka Area *Luggage that is dropped-off after the above mentioned time, but before 18:00 will be delivered by the next day. ◆Station → Hotel Delivery Delivery City・Station Drop-off Earliest delivery From To Yamato Transport Asahikawa Station Kitasaito Center (JR Within Asahikawa Area・Furano City・Within Sounkyo-Onsen Kamikawagun Asahikawa Station 8:00ー16:30 Asahikawa Station) Kamikawa Town Yamato Transport Sendai Station 2F Baggage Service Sendai Station 9:00ー10:30 Within Miyagi Counter (JR Sendai Station) Ginza Yamato Transport Ginza Konyabashi Center (Tokyo Metro 8:00ー11:00 Ibaraki、Tochigi、Gunma、Saitama、Chiba、Tokyo、Kanagawa、Yamanashi Yurakucho Staion Ginza Station, JR Yurakucho Station) Yokohama Yamato Transport Sakuragicho Station Tourist Information Sakuragcho 9:00ー10:00 Ibaraki、Tochigi、Gunma、Saitama、Chiba、Tokyo、Kanagawa、Yamanashi Center (JR Sakuragicho Station) Station Nagano Yamato Transport MIDORI -
2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI National Radio Science Meeting
2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI National Radio Science Meeting Final Program 7–12 July 2019 Hilton Atlanta Atlanta, Georgia, U.S.A. Conference at a Glance Saturday, July 6 14:00-16:00 Strategic Planning Committee 16:15-17:15 AP-S Meetings Committee 17:15-18:15 JMC Meeting (Closed Session) 18:15-21:30 JMC Meeting, Dinner and Presentations 19:15-21:15 IEEE AP-S Constitution and Bylaws Committee Meeting & Dinner Sunday, July 7 08:00-10:00 Past Presidents’ Breakfast 10:00-18:00 AdCom Meeting 19:30-22:00 Welcome Dessert Reception at the Georgia Aquarium Monday, July 8 07:00-08:00 Amateur Radio Operators Breakfast 08:00-11:40 Technical Sessions 09:00-18:00 Technical Tour - “An Engineer’s Eye View” of the Mercedes Benz Stadium 12:00-13:20 Transactions on Antennas and Propagation Editorial Board Lunch Meeting 13:20-17:00 Technical Sessions 17:00-18:00 URSI Commission A Business Meeting 17:00-18:00 URSI Commission B Business Meeting 17:00-18:00 URSI Commissions C/E (combined) Business Meeting Tuesday, July 9 07:00-08:00 AP Magazine Staff Meeting 07:00-08:00 APS 2020 Committee Meeting 07:00-08:00 Industrial Initiatives 07:00-08:00 Membership Committee Meeting 07:00-08:00 Student Design Contest (Set-Up - Closed to Others) 07:00-08:00 Technical Committee on Antenna Measurement 08:00-11:40 Student Paper Competition 08:00-11:40 Technical Sessions 08:00-09:30 Student Design Contest (Demo for Judges - Closed to Others) 08:30-14:00 Standards Committee Meeting 09:30-12:00 Student Design Contest (Demo for Public) -
LISTENING STATION Music for Abandoned Structures and Shakuhachi
PRESS RELEASE CD RELEASE LISTENING STATION music for abandoned structures and shakuhachi For his first excursion into the world of the audio CD format, artist Thorsten Knaub climbed up a hill and into the main dome of the former US listening station at Teufelsberg at the outskirts of Berlin, Germany. His mission, to explore the particular reverb present in the dome through site-specific improvisation with the shakuhachi, a vertical, end-blown Japanese bamboo flute. The shakuhachi with its sonic potential and long history, including an era it was used by a wandering sect of spying ex-samurai, seemed an appropriate choice to engage with the space. The patterns and phrases of the played music developed through an ad hoc and in situ performance. In this way the recording documents as much the searching for the next note as the result of this process, often literally, as due the long decay times inherent in the space, the sounds start to overlap and layer into more complex textures. Long notes, abrasive sonic gestures, incidental sounds of other people present in the building and the occasional rumble of a plane flying overhead, intertwine to sculpt a multi-threaded narrative between the shakuhachi, the space and its location. Abandoned structures, buildings and defunct spaces, their architecture, a sense of location and a lot of other things were going through Knaub’s mind while breathing into the flute and listening to the dome throwing back its response. Listening Station – music for abandoned structures and shakuhachi caught and preserved these utterances, before all that was said faded away and dispersed into the realm of memory. -
The Development of HF Broadcast Antennas
Development of HF Broadcast Antennas FEATURES FEATURES Development of HF Broadcast Antennas the 50% power loss, but made the Rhombic fre - Free Europe and Radio Liberty sites. quency-sensitive, consequently losing the wide- Rhombic antennas are no longer recommend - The Development of HF bandwidth feature. The available bandwidth ed for HF broadcasting as the main lobe is nar - depends on the length of the wire and, using dif - row in both horizontal and vertical planes which ferent lengths of transmission line, it is possible to can result in the required service area not being Broadcast Antennas access two or three different broadcast bands. reliably covered because of the variations in the A typical rhombic antenna design uses side ionosphere. There are also a large number of lengths of several wavelengths and is at a height side lobes of a size sufficient to cause interfer - Former BBC Senior Transmitter Engineer Dave Porter G4OYX continues the story of the of between 0.5-1.0 λ at the middle of the operat - ence to other broadcasters, and a significant pro - development of HF broadcast antennas from curtain arrays to Allis antennas ing frequency range. portion of the transmitter power is dissipated in the terminating resistance. THE CORNER QUADRANT ANTENNA Post War it was found that if the Rhombic Antenna was stripped down and, instead of the four elements, had just two end-fed half-wave dipoles placed at a right angle to each other (as shown in Fig. 1) the result was a simple cost- effective antenna which had properties similar to the re-entrant Rhombic but with a much smaller footprint.