DOCSLIB.ORG

Introduction to Rf Propagation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

INTRODUCTION TO RF PROPAGATION John S. Seybold, Ph.D. JOHN WILEY & SONS, INC. INTRODUCTION TO RF PROPAGATION INTRODUCTION TO RF PROPAGATION John S. Seybold, Ph.D. JOHN WILEY & SONS, INC. Copyright © 2005 by John Wiley & Sons, Inc. All rights reserved Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 750-4470, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at http://www.wiley.com/go/permission. Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at (800) 762-2974, outside the United States at (317) 572-3993 or fax (317) 572-4002. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic formats. For more information about Wiley products, visit our web site at www.wiley.com. Library of Congress Cataloging-in-Publication Data: Seybold, John S., 1958– Introduction to RF propagation / by John S. Seybold. p. cm. Includes bibliographical references and index. ISBN-13 978-0-471-65596-1 (cloth) ISBN-10 0-471-65596-1 (cloth) 1. Radio wave propagation—Textbooks. 2. Radio wave propagation—Mathematical models—Textbooks. 3. Antennas (Electronics)—Textbooks. I. Title. QC676.7.T7S49 2005 621.384¢11—dc22 2005041617 Printed in the United States of America 10987654321 To: My mother, Joan Philippe Molitor and my father, Lawrence Don Seybold CONTENTS Preface xiii 1. Introduction 1 1.1 Frequency Designations 1 1.2 Modes of Propagation 3 1.2.1 Line-of-Sight Propagation and the Radio Horizon 3 1.2.2 Non-LOS Propagation 5 1.2.2.1 Indirect or Obstructed Propagation 6 1.2.2.2 Tropospheric Propagation 6 1.2.2.3 Ionospheric Propagation 6 1.2.3 Propagation Effects as a Function of Frequency 9 1.3 Why Model Propagation? 10 1.4 Model Selection and Application 11 1.4.1 Model Sources 11 1.5 Summary 12 References 12 Exercises 13 2. Electromagnetics and RF Propagation 14 2.1 Introduction 14 2.2 The Electric Field 14 2.2.1 Permittivity 15 2.2.2 Conductivity 17 2.3 The Magnetic Field 18 2.4 Electromagnetic Waves 20 2.4.1 Electromagnetic Waves in a Perfect Dielectric 22 2.4.2 Electromagnetic Waves in a Lossy Dielectric or Conductor 22 2.4.3 Electromagnetic Waves in a Conductor 22 2.5 Wave Polarization 24 2.6 Propagation of Electromagnetic Waves at Material Boundaries 25 2.6.1 Dielectric to Dielectric Boundary 26 vii viii CONTENTS 2.6.2 Dielectric-to-Perfect Conductor Boundaries 31 2.6.3 Dielectric-to-Lossy Dielectric Boundary 31 2.7 Propagation Impairment 32 2.8 Ground Effects on Circular Polarization 33 2.9 Summary 35 References 36 Exercises 36 3. Antenna Fundamentals 38 3.1 Introduction 38 3.2 Antenna Parameters 38 3.2.1 Gain 39 3.2.2 Effective Area 39 3.2.3 Radiation Pattern 42 3.2.4 Polarization 44 3.2.5 Impedance and VSWR 44 3.3 Antenna Radiation Regions 45 3.4 Some Common Antennas 48 3.4.1 The Dipole 48 3.4.2 Beam Antennas 50 3.4.3 Horn Antennas 52 3.4.4 Reflector Antennas 52 3.4.5 Phased Arrays 54 3.4.6 Other Antennas 54 3.5 Antenna Polarization 55 3.5.1 Cross-Polarization Discrimination 57 3.5.2 Polarization Loss Factor 58 3.6 Antenna Pointing loss 62 3.7 Summary 63 References 64 Exercises 65 4. Communication Systems and the Link Budget 66 4.1 Introduction 66 4.2 Path Loss 67 4.3 Noise 69 4.4 Interference 76 4.5 Detailed Link Budget 79 4.5.1 EIRP 80 4.5.2 Path Loss 80 4.5.3 Receiver Gain 82 4.5.4 Link Margin 83 4.5.5 Signal-to-Noise Ratio 83 CONTENTS ix 4.6 Summary 84 References 85 Exercises 85 5. Radar Systems 87 5.1 Introduction 87 5.2 The Radar Range Equation 88 5.3 Radar Measurements 93 5.3.1 Range Measurement 93 5.3.2 Doppler Measurement 95 5.3.3 Angle Measurement 95 5.3.4 Signature Measurement 98 5.4 Clutter 99 5.4.1 Area Clutter 99 5.4.2 Volume Clutter 105 5.4.3 Clutter Statistics 106 5.5 Atmospheric Impairments 106 5.6 Summary 107 References 108 Exercises 109 6. Atmospheric Effects 111 6.1 Introduction 111 6.2 Atmospheric Refraction 112 6.2.1 The Radio Horizon 112 6.2.2 Equivalent Earth Radius 113 6.2.3 Ducting 116 6.2.4 Atmospheric Multipath 117 6.3 Atmospheric Attenuation 121 6.4 Loss From Moisture and Precipitation 125 6.4.1 Fog and Clouds 126 6.4.2 Snow and Dust 130 6.5 Summary 131 References 132 Exercises 132 7. Near-Earth Propagation Models 134 7.1 Introduction 134 7.2 Foliage Models 134 7.2.1 Weissberger’s Model 135 7.2.2 Early ITU Vegetation Model 135 7.2.3 Updated ITU Vegetation Model 137 x CONTENTS 7.2.3.1 Terrestrial Path with One Terminal in Woodland 138 7.2.3.2 Single Vegetative Obstruction 138 7.3 Terrain Modeling 141 7.3.1 Egli Model 141 7.3.2 Longley–Rice Model 143 7.3.3 ITU Model 144 7.4 Propagation in Built-Up Areas 146 7.4.1 Young Model 146 7.4.2 Okumura Model 146 7.4.3 Hata Model 151 7.4.4 COST 231 Model 152 7.4.5 Lee Model 153 7.4.6 Comparison of Propagation Models for Built-Up Areas 157 7.5 Summary 159 References 160 Exercises 161 8. Fading and Multipath Characterization 163 8.1 Introduction 163 8.2 Ground-Bounce Multipath 164 8.2.1 Surface Roughness 174 8.2.2 Fresnel Zones 175 8.2.3 Diffraction and Huygen’s Principle 179 8.2.4 Quantifying Diffraction Loss 179 8.3 Large-Scale or Log-Normal Fading 186 8.4 Small-Scale Fading 193 8.4.1 Delay Spread 194 8.4.2 Doppler Spread 198 8.4.3 Channel Modeling 199 8.4.4 The Probabilistic Nature of Small-Scale Fading 200 8.5 Summary 203 References 205 Exercises 206 9. Indoor Propagation Modeling 208 9.1 Introduction 208 9.2 Interference 208 9.3 The Indoor Environment 209 9.3.1 Indoor Propagation Effects 209 9.3.2 Indoor Propagation Modeling 210 CONTENTS xi 9.3.3 The ITU Indoor Path Loss Model 210 9.3.4 The Log-Distance Path Loss Model 214 9.4 Summary 216 References 216 Exercises 216 10. Rain Attenuation of Microwave and Millimeter Wave Signals 218 10.1 Introduction 218 10.2 Link Budget 219 10.3 Rain Fades 222 10.3.1 Specific Attenuation Due to Rainfall 222 10.3.2 The ITU Model 224 10.3.3 The Crane Global Model 229 10.3.4 Other Rain Models 234 10.3.5 Rain Attenuation Model Comparison 234 10.3.6 Slant Paths 234 10.4 The Link Distance Chart 234 10.5 Availability Curves 237 10.6 Other Precipitation 237 10.7 Cross-Polarization Effects 239 10.8 Summary 239 References 240 Exercises 241 Appendix 10A: Data for Rain Attenuation Models 242 11. Satellite Communications 246 11.1 Introduction 246 11.2 Satellite Orbits 247 11.3 Satellite Operating Frequency 249 11.4 Satellite Path Free-Space Loss 249 11.5 Atmospheric Attenuation 252 11.6 Ionospheric Effects 255 11.7 Rain Fades 255 11.7.1 ITU Rain Attenuation Model for Satellite Paths 257 11.7.2 Crane Rain Attenuation Model for Satellite Paths 264 11.7.3 The DAH Rain Attenuation Model 270 11.8 Antenna Considerations 273 11.9 Noise Temperature 274 11.9.1 The Hot-Pad Formula 276 11.9.2 Noise Due to Rain 278 11.9.3 Sun Outages 279 11.10 Summary 279 xii CONTENTS References 280 Exercises 281 12. RF Safety 283 12.1 Introduction 283 12.2 Biological Effects of RF Exposure 285 12.3 CC Guidelines 287 12.4 Antenna Considerations 290 12.5 FCC Computations 292 12.5.1 Main Beam and Omnidirectional Antenna Analysis 292 12.5.2 Antenna Directivity 293 12.6 Station Evaluations 297 12.7 Summary 298 References 298 Exercises 299 Appendix A: Review of Probability for Propagation Modeling 301 Index 317 PREFACE With the rapid expansion of wireless consumer products, there has been a con- siderable increase in the need for radio-frequency (RF) planning, link plan- ning, and propagation modeling.
Recommended publications
  • Radio Communications in the Digital Age

    Radio Communications in the Digital Age

    Radio Communications In the Digital Age Volume 1 HF TECHNOLOGY Edition 2 First Edition: September 1996 Second Edition: October 2005 © Harris Corporation 2005 All rights reserved Library of Congress Catalog Card Number: 96-94476 Harris Corporation, RF Communications Division Radio Communications in the Digital Age Volume One: HF Technology, Edition 2 Printed in USA © 10/05 R.O. 10K B1006A All Harris RF Communications products and systems included herein are registered trademarks of the Harris Corporation. TABLE OF CONTENTS INTRODUCTION...............................................................................1 CHAPTER 1 PRINCIPLES OF RADIO COMMUNICATIONS .....................................6 CHAPTER 2 THE IONOSPHERE AND HF RADIO PROPAGATION..........................16 CHAPTER 3 ELEMENTS IN AN HF RADIO ..........................................................24 CHAPTER 4 NOISE AND INTERFERENCE............................................................36 CHAPTER 5 HF MODEMS .................................................................................40 CHAPTER 6 AUTOMATIC LINK ESTABLISHMENT (ALE) TECHNOLOGY...............48 CHAPTER 7 DIGITAL VOICE ..............................................................................55 CHAPTER 8 DATA SYSTEMS .............................................................................59 CHAPTER 9 SECURING COMMUNICATIONS.....................................................71 CHAPTER 10 FUTURE DIRECTIONS .....................................................................77 APPENDIX A STANDARDS
  • Analysis of Outdoor and Indoor Propagation at 15 Ghz and Millimeter Wave Frequencies in Microcellular Environment

    Analysis of Outdoor and Indoor Propagation at 15 Ghz and Millimeter Wave Frequencies in Microcellular Environment

    Advances in Science, Technology and Engineering Systems Journal Vol. 3, No. 1, 160-167 (2018) ASTESJ www.astesj.com ISSN: 2415-6698 Special issue on Advancement in Engineering Technology Analysis of Outdoor and Indoor Propagation at 15 GHz and Millimeter Wave Frequencies in Microcellular Environment Muhammad Usman Sheikh*, Jukka Lempiainen Tampere University of Technology, Department of Electronics and Communications Engineering, Finland. A R T I C L E I N F O A B S T R A C T Article history: The main target of this article is to perform the multidimensional analysis of multipath Received: 26 November, 2017 propagation in an indoor and outdoor environment at higher frequencies i.e. 15 GHz, 28 Accepted: 07 January, 2018 GHz and 60 GHz, using “sAGA” a 3D ray tracing tool. A real world outdoor Line of Sight Online: 30 January, 2018 (LOS) microcellular environment from the Yokusuka city of Japan is considered for the analysis. The simulation data acquired from the 3D ray tracing tool includes the received Keywords: signal strength, power angular spectrum and the power delay profile. The different Multipath propagation propagation mechanisms were closely analyzed. The simulation results show the difference Microcellular of propagation in indoor and outdoor environment at higher frequencies and draw a special 3D ray tracing attention on the impact of diffuse scattering at 28 GHz and 60 GHz. In a simple outdoor System performance microcellular environment with a valid LOS link between the transmitter and a receiver, 5G the mean received signal at 28 GHz and 60 GHz was found around 5.7 dB and 13 dB Millimeter wave frequencies inferior in comparison with signal level at 15 GHz.
  • Comparative Analysis of Path Loss Prediction Models for Urban Macrocellular Environments

    Comparative Analysis of Path Loss Prediction Models for Urban Macrocellular Environments

    COMPARATIVE ANALYSIS OF PATH LOSS PREDICTION MODELS FOR URBAN MACROCELLULAR ENVIRONMENTS A. Obota, O. Simeonb, J. Afolayanc Department of Electrical/Electronics & Computer Engineering, University of Uyo, Akwa Ibom State, Nigeria. aEmail: [email protected] bEmail: [email protected] cEmail: [email protected] Abstract A comparative analysis of path loss prediction models for urban macrocellular environments is presented in this paper. Specifically, three path loss prediction models namely free space, Hata and Egli were used to predict path losses. The calculated path loss values were compared with practical measured data obtained from a Visafone base station located in Uyo, Nigeria. The comparative analysis reveals that the mean square error (MSE) for free space, Hata and Egli were 16.24dB, 2.37dB and 8.40dB respectively. The results showed that Hata's model is the most accurate and reliable path loss prediction model for macrocellular urban propagation environments, since its MSE value of 2.37dB is smaller than the acceptable minimum MSE value of 6dB for good signal propagation. Keywords: macrocellular areas, path loss prediction models, Hata model, mean square error 1. Introduction nals generally propagate by means of any or a combination of these three basic propaga- Nowadays, wireless communication technol- tion mechanisms; reflection, diffraction, and ogy is influencing every area of modern life, scattering [2, 3]. One of the most impor- and has encouraged useful researches in nearly tant features of the propagation environment all fields of human endeavour. Cellular ser- is path (propagation) loss. Path loss is de- vices are today being used by millions of peo- fined as the difference (in dB) between the ple worldwide.
  • On Adaptive Neuro-Fuzzy Model for Path Loss Prediction in the Vhf Band

    On Adaptive Neuro-Fuzzy Model for Path Loss Prediction in the Vhf Band

    ITU Journal: ICT Discoveries, Special Issue No. 1, 2 Feb. 2018 ON ADAPTIVE NEURO-FUZZY MODEL FOR PATH LOSS PREDICTION IN THE VHF BAND Nazmat T. Surajudeen-Bakinde1, Nasir Faruk2, Muhammed Salman1, Segun Popoola3, Abdulkarim Oloyede2, Lukman A. Olawoyin2 1Department of Electrical and Electronics Engineering, University of Ilorin, Nigeria 2Department of Telecommunication Science, University of Ilorin, Ilorin, Nigeria 3Department of Electrical and Information Engineering, Covenant University, Ota, Nigeria Email: [email protected]; [email protected]; faruk.n, deenmat, oloyede.aa, olawoyin.la{@unilorin.edu.ng} Abstract – Path loss prediction models are essential in the planning of wireless systems, particularly in built-up environments. However, the efficacies of the empirical models depend on the local ambient characteristics of the propagation environments. This paper introduces artificial intelligence in path loss prediction in the VHF band by proposing an adaptive neuro-fuzzy (NF) model. The model uses five-layer optimized NF network based on back propagation gradient descent algorithm and least square errors estimate. Electromagnetic field strengths from the transmitter of the NTA Ilorin, which operates at a frequency of 203.25 MHz, were measured along four routes. The prediction results of the proposed model were compared to those obtained via the widely used empirical models. The performances of the models were evaluated using the Root Mean Square Error (RMSE), Spread Corrected RMSE (SC-RMSE), Mean Error (ME), and Standard Deviation Error (SDE), relative to the measured data. Across all the routes covered in this study, the proposed NF model produced the lowest RMSE and ME, while the SDE and the SC-RMSE were dependent on the terrain and clutter covers of the routes.
  • Atmospheric Anisotrophy and Its Effect on the Delay Power Spectra of Tropospheric Scatter Radio Signals Hosny Mohammed Ibrahim Iowa State University

    Atmospheric Anisotrophy and Its Effect on the Delay Power Spectra of Tropospheric Scatter Radio Signals Hosny Mohammed Ibrahim Iowa State University

    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1982 Atmospheric anisotrophy and its effect on the delay power spectra of tropospheric scatter radio signals Hosny Mohammed Ibrahim Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Electrical and Electronics Commons Recommended Citation Ibrahim, Hosny Mohammed, "Atmospheric anisotrophy and its effect on the delay power spectra of tropospheric scatter radio signals " (1982). Retrospective Theses and Dissertations. 7507. https://lib.dr.iastate.edu/rtd/7507 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This reproduction was made from a copy of a document sent to us for microfilming. While the most advanced technology has been used to photograph and reproduce this document, the quality of the reproduction is heavily dependent upon the quality of the material submitted. The following explanation of techniques is provided to help clarify markings or notations which may appear on this reproduction. 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure complete continuity.
  • Development of a Radiowave Propagation Model for Hilly Areas

    Development of a Radiowave Propagation Model for Hilly Areas

    International Journal of Electronics Communication and Computer Engineering Volume 4, Issue 2, ISSN (Online): 2249–071X, ISSN (Print): 2278–4209 Development of a Radiowave Propagation Model for Hilly Areas Famoriji J. Oluwole, Olasoji Y. Olajide Abstract – Achieving optimal performance is a paramount III. THE COST-231 HATA MODEL FOR URBAN concern in wireless networks. One of the strategies is to use wireless empirical models to predict wireless link quality ENVIRONMENT factors such as path loss and the received power in any given transmission domain with irregular terrain. Measurement The COST-231 Hata wireless propagation model was results of signal strength in UHF band obtained in Idanre devised as an extension to the Hata-Okumura model and Town of Ondo State Nigeria were validated against the Hata model as reported by Abhayawardhana et al.,[3]. theoretical estimations. Okumura-Hata model, COST231- The COST-231Hata model is designed to be used in the Hata model and Egli model applicable for path loss frequency band from 500 MHz to 2000 MHz. It also prediction in area with high hill were examined. These models predictions were compared with predictions from contains corrections for urban, suburban and rural (flat) measurements taken in Idanre to determine the path loss environments. [3] also noted that ”although this models’ prediction error for each model. Consequently, modified frequency range is outside that of the measurements, its COST231-Hata model was developed for path loss prediction simplicity and the availability of correction factors has in the hilly areas. The model developed has 6.02% error seen it widely used for path loss prediction at this which made it applicable for hilly areas (Idanre).
  • Noise and Multipath Characteristics of Power Line Communication Channels

    Noise and Multipath Characteristics of Power Line Communication Channels

    University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 3-30-2010 Noise and Multipath Characteristics of Power Line Communication Channels Hasan Basri Çelebi University of South Florida Follow this and additional works at: https://scholarcommons.usf.edu/etd Part of the American Studies Commons Scholar Commons Citation Çelebi, Hasan Basri, "Noise and Multipath Characteristics of Power Line Communication Channels" (2010). Graduate Theses and Dissertations. https://scholarcommons.usf.edu/etd/1594 This Thesis is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Noise and Multipath Characteristics of Power Line Communication Channels by Hasan Basri C»elebi A thesis submitted in partial ful¯llment of the requirements for the degree of Master of Science in Electrical Engineering Department of Electrical Engineering College of Engineering University of South Florida Major Professor: HÄuseyinArslan, Ph.D. Chris Ferekides, Ph.D. Paris Wiley, Ph.D. Date of Approval: Mar 30, 2010 Keywords: Power line communication, noise, cyclostationarity, multipath, impedance, attenuation °c Copyright 2010, Hasan Basri C»elebi DEDICATION This thesis is dedicated to my fianc¶eeand my parents for their constant love and support. ACKNOWLEDGEMENTS First, I would like to thank my advisor Dr. HÄuseyinArslan for his guidance, encour- agement, and continuous support throughout my M.Sc. studies. It has been a privilege to have the opportunity to do research as a member of Dr. Arslan's research group.
  • Recommendation ITU-R V.573-4

    Recommendation ITU-R V.573-4

    Rec. ITU-R V.573-5 1 RECOMMENDATION ITU-R V.573-5* Radiocommunication vocabulary (1978-1982-1986-1990-2000-2007) Scope This Recommendation provides the main vocabulary reference, giving synonymous terms in three languages and the associated definitions. It includes terms given in Article 1 of the Radio Regulations (RR) and extends the list to technical terms defined in texts of the ITU-R. The ITU Radiocommunication Assembly, considering a) that Article 1 of the Radio Regulations (RR) contains the definitions of terms for regulatory purposes; b) that the Radiocommunication Study Groups have a need to establish new and amended definitions for technical terms that do not appear in RR Article 1 or that are so defined as to be unsuitable for Radiocommunication Study Group purposes; c) that it would be desirable for some of these terms and definitions established by the Radiocommunication Study Groups to be more widely used within the ITU-R, recommends that the terms listed in RR Article 1 and in Annex 1 below should be used as far as possible with the meaning ascribed to them in the corresponding definition. NOTE 1 – Study Groups are invited, where there is a difficulty in using any of the terms with the meaning given in the corresponding definition, to forward to the Coordination Committee for Vocabulary (CCV) a proposal for revision or alternative application, accompanied by substantiating argument. NOTE 2 – A number of terms in this Recommendation appear also in RR Article 1 with a different definition. These terms are identified by (RR . ., MOD) or (RR . .(MOD)) if the modifications consist only of editorial changes.
  • Radio Astronomy

    Radio Astronomy

    Edition of 2013 HANDBOOK ON RADIO ASTRONOMY International Telecommunication Union Sales and Marketing Division Place des Nations *38650* CH-1211 Geneva 20 Switzerland Fax: +41 22 730 5194 Printed in Switzerland Tel.: +41 22 730 6141 Geneva, 2013 E-mail: [email protected] ISBN: 978-92-61-14481-4 Edition of 2013 Web: www.itu.int/publications Photo credit: ATCA David Smyth HANDBOOK ON RADIO ASTRONOMY Radiocommunication Bureau Handbook on Radio Astronomy Third Edition EDITION OF 2013 RADIOCOMMUNICATION BUREAU Cover photo: Six identical 22-m antennas make up CSIRO's Australia Telescope Compact Array, an earth-rotation synthesis telescope located at the Paul Wild Observatory. Credit: David Smyth. ITU 2013 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. - iii - Introduction to the third edition by the Chairman of ITU-R Working Party 7D (Radio Astronomy) It is an honour and privilege to present the third edition of the Handbook – Radio Astronomy, and I do so with great pleasure. The Handbook is not intended as a source book on radio astronomy, but is concerned principally with those aspects of radio astronomy that are relevant to frequency coordination, that is, the management of radio spectrum usage in order to minimize interference between radiocommunication services. Radio astronomy does not involve the transmission of radiowaves in the frequency bands allocated for its operation, and cannot cause harmful interference to other services. On the other hand, the received cosmic signals are usually extremely weak, and transmissions of other services can interfere with such signals.
  • Influence of Terrain on Multipath Propagation of Fm Signal

    Influence of Terrain on Multipath Propagation of Fm Signal

    Journal of ELECTRICAL ENGINEERING, VOL. 56, NO. 5-6, 2005, 113–120 INFLUENCE OF TERRAIN ON MULTIPATH PROPAGATION OF FM SIGNAL J´an Klima ∗ — Mari´an Moˇzucha ∗∗ FM signal propagating through the troposphere interacts with the terrain as a reflecting plane. These reflected signals are not included into calculations and predictions of the field strength. The reason is simple — it is too difficult for processing, and demanding high quality data. For recent capabilities of computers and resolution level of digital terrain models this is not an irresolvable problem. In the report the authors show a practical demonstration how to include the reflected FM signals into the field strength calculations as well as the comparison with standard methods of field strength predictions. K e y w o r d s: digital terrain model (DTM), reflections, diffraction, multipath propagation 1 INTRODUCTION Here GRF represents a set of points of the terrain, z is the height in a point located in coordinates [x,y], A digital terrain model, as a discrete field of repre- KN F M is the curvature of the terrain as it is seen from sentative and positionally expressed points of the terrain the transmitter, FF M is the form, γF M is the slope, AF M and its approximation equations securing its continuity is the aspect, and δexp F M is irradiation — all from the [8] can serve, besides many other tasks, as a tool for lo- direction of the transmitter. cating, testing and calculating the reflecting planes for We will come from the known fact that the received propagating FM signals.
  • Modem Equipment for the New Generation Compact Troposcatter Stations

    Modem Equipment for the New Generation Compact Troposcatter Stations

    5 UDC 621.396 MODEM EQUIPMENT FOR THE NEW GENERATION COMPACT TROPOSCATTER STATIONS Serhii O. Kravchuk, Mikolay M. Kaydenko National Technical University of Ukraine “KPI”, Kyiv, Ukraine Background. Modem equipment of tropospheric communication lines is an important component of modern means of telecommunication. The theoretical and practical aspects of choosing a preferred embodiment of modem equipment, taking into account the aggregate indicators of quality. Objective. Presentation features the construction of modem equipment of the tropospheric stations of new generation that can provide high data transfer rates with guaranteed quality of service in complex stationary and non-stationary noise inherent in tropospheric channels. Methods. This goal is achieved by using new technical and architectural solutions to build a modem equipment, spectrally efficient modulation types and coding algorithms of effective adaptation to changing operating conditions. Feasibility of the proposed approaches to the construction of the modem hardware is fulfilled on a prototype of the equipment based on the HSMC ARRadio Daughter Card debugging modules. Results. The features of constructing of modem equipment of troposcatter stations with high data transfer rate are provided. To reach the limiting parameters of such stations proposed in the application of modem equipment of new technical and architectural solutions, spectrally efficient modulation types (OFDM plus linear modulation) and error-correcting coding, efficient algorithms of adaptation to changing conditions of work, the SDR technology, frame structures of physical layer. The variants of the configuration of modem equipment in relation to the modes of operation of compact troposcatter station. Conclusions. Ways of improving modem performance to improve the efficiency of modern compact troposcatter radiorelay stations.
  • Outdoor Propagation Models-Comparison Literature Review

    Outdoor Propagation Models-Comparison Literature Review

    International Journal of Electronics Communication and Computer Engineering a Volume 4, Issue 3, ISSN (Online): 2249–071X, ISSN (Print): 2278–4209 Outdoor Propagation Models-Comparison Literature Review Mr. Umesh Yadav Department of Wireless and Mobile Communication GRD-IMT, Rajpur Road Dehradun, India Email: [email protected] Abstract - The aim of comparing different outdoor like: adhoc wireless network, wireless sensor network, propagation models is to study the earlier introduced models mobile communications etc. Between the two extremes of in the present environment of RF technology and present & past times, the mid-time arena have seen requirement. In the present era of telecom services coverage development of various propagation models like: Line of is not enough but we need to introduce cellular network with sight, okumura-Hata, cost etc. In order to facilitate better high quality parameters. In this comparison review we will focus on the type of terrain/ environment which will best suit planned & resource specific developments for the bet the different outdoor propagations models. HHHterment of QOS. This period of time also noticed several developments in the field estimation path loss in Keywords - Pathloss, Attenuation, Optimization, Antenna different propagation scenario profiles deploying variable Gain, Interference. modelling strategies. I. INTRODUCTION II. RADIO PROPAGATION The ability to communicate with people on the move has A. Types of Radio wave propagation mechanisms evolved remarkably since Guglielmo Marconi first To study and understand the modelling of radio wave demonstrated radio‟s ability to provide continuous contact propagation, it is first required to know the basics of its with ships sailing the English Channel. That was in year propagation mechanism.