Alex Wulff

Beginning Radio Communications

Radio Projects and Theory

Alex Wulff
Cambridge, MA, USA
ISBN 978-1-4842-5301-4e-ISBN 978-1-4842-5302-1
https://doi.org/10.1007/978-1-4842-5302-1
Standard Apress
© Alex Wulff 2019
This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed.
Trademarked names, logos, and images may appear in this book. Rather than use a trademark symbol with every occurrence of a trademarked name, logo, or image we use the names, logos, and images only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights.
While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.
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I dedicate this book to my family—their unwavering support in all my endeavors means the world to me.

Table of Contents

Chapter 1:​ Introduction and Materials 1
Materials 2
Chapter 4:​ Project:​ Satellite Imagery 3
Chapter 6:​ Exploring Radio 4
Chapter 8:​ Handheld Transceivers and Repeaters 7
Chapter 9:​ Amateur Radio Satellites 8
Uses of Radio Communications Systems Today 11
Wireless Device Connectivity 11
Long-Distance Communications 16
Space-Based Communications 19
Broadcasting 20
Summary 22
Chapter 2:​ Basic Radio Theory 23
The Electromagnetic Spectrum 23
Wavelength and Frequency 25
Radio Bands and Their Uses 26
ELF, SLF, ULF, and VLF 26
LF, MF, and HF 28
VHF, UHF, and SHF 29
EHF 31
THF 33
Propagation 33
Diffraction 34
Reflection 35
Absorption 36
Noise 37
The Doppler Effect 38
An Aside on “Radiation” 40
General Trends 41
Summary 42
Chapter 3:​ Antennas 45
Electromagnetism​ 46
Current and Voltage 47
Power 48
Resonance 50
Antenna Properties 51
Gain 51
Beam/​Radiation Patterns 53
Dipole 54
Monopole/​Whip 56
Yagi 59
Log-Periodic 62
Parabolic 62
Bandwidth 66
Polarization 66
Summary 67
Chapter 4:​ Project:​ Satellite Imagery 69
Software-Defined Radio 70
The Satellites 71
Initial Antenna Setup 73
Necessary Software 73
SDR Software:​ CubicSDR 74
Decoding Software:​ WXtoImg 79
Piping Program 81
First Test 81
Antenna Setup 83
First Flyover 86
Summary 90
Chapter 5:​ Communications and Modulation 91
“Figure 1” 91
Analog vs.​ Digital Information 95
Continuous Analog Signals 96
Discrete Analog Signals 97
Continuous Digital Signals 99
Discrete Digital Signals 100
Modulation 101
Amplitude Modulation (AM) 102
Frequency Modulation (FM) 103
Phase Modulation 104
Frequency Division 105
Quadrature Encoding 107
Summary 111
Chapter 6:​ Exploring Radio 113
Microcontrollers​ 114
The Arduino IDE 116
The Code 118
The Radio Module 122
The Circuit 123
Experimentation 131
Software Modifications 133
Summary 133
Chapter 7:​ Amateur Radio 135
What Is It?​ 135
Frequency Allocations 138
Uses of Amateur Radio 139
“Rag Chewing” 140
Contests 140
Emergency Communications 141
Event Coordination 142
Education 143
Remote Communications 144
Licensing 145
Technician 146
General 147
Amateur Extra 147
The Technician Test 147
Sample Questions 148
Answers 151
Finding a Test 154
Summary 154
Chapter 8:​ Handheld Transceivers and Repeaters 155
Your Handheld Transceiver 155
Using Your Handheld Transceiver 159
Repeaters 162
Repeater Frequency 164
Repeater Offset 165
PL Tone 166
Finding a Repeater 168
Making a Repeater Contact 168
Summary 171
Chapter 9:​ Amateur Radio Satellites 173
Ham Satellite Overview 174
CHIRP 177
Acquiring Satellite Frequencies 178
Programming via CHIRP 180
Programming Satellite Frequencies 182
Hardware Preparations 186
Satellite Tracking 189
Working a Satellite 190
What You’ll Hear 192
Summary 193
Chapter 10:​ Ham Nets, Volunteering, and More 195
Making Contacts 196
Amateur Radio Nets 196
Volunteering 197
Interesting VHF and UHF Signals 200
NOAA Weather Radio 200
Police/​Fire/​EMS Radio 202
Scan Mode 203
Miscellaneous Radio Topics 204
Radar 204
5G 207
LoRa 208
Satellite Internet and TV 210
Radio Astronomy 213
Moving Forward and Closing 215
Index 219

About the Author

Alex Wulff

is a maker and student of electrical engineering at Harvard. Alex has always had a passion for sharing his love of technology with the world and has given numerous talks encouraging youth and adults alike to get involved with the maker movement. He has a special interest in radio technologies and their increasingly important role in today’s connected society.

Alex is very active in the maker community and posts a variety of projects online. To see his work, visit www.AlexWulff.com/go

 
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