Preface

My paternal grandfather was born and raised in Newfoundland, on the outskirts of St. John’s, its capital city. As a young man, he came to the United States in 1903 to find work. To his dying day he understood very little about radio or television beyond the simple mechanics of adjusting the volume control or changing the station. Yet he became directly responsible for my nearly lifelong love affair with “wireless” communications when he gave me an AM broadcast band clock radio for my thirteenth birthday. It was my very first radio receiver, and, although my grandfather thought I would prize the alarm on it, the “magical” feature I came to love instead was the Sleep knob. Now I could climb into bed and fall asleep to the sounds of faraway stations, my parents and I secure in the knowledge that the radio would turn itself off.

As I gained familiarity with my newfound window on the world, I marveled at the distant stations I could hear on certain nights, and soon I was keeping a paper diary, or log, of broadcast station call letters I was able to pluck from the cacophony of late-night radio waves. Without knowing the name of my obsession, I had become a broadcast band DXer! (“DX” is radio shorthand for “long distance”.)

At about the same time, my next-door neighbor obtained his amateur radio license, and soon I was spending occasional evenings in his basement, sitting silently by his side while he made two-way contacts with like-minded hobbyists around the world. The seed was sown, and with the help of the local radio club I obtained my own “ham radio” license before I turned 14. I had plunged headlong into a passionate love affair with a technology that has shaped my life ever since, from my choice of college major to my choice of career and even my choice of where to live on this planet.

But it wasn’t until I was in the midst of preparing new material for this fifth edition of the Practical Antenna Handbook that I realized my grandfather had another, albeit indirect, connection with the world of radio I had so quickly taken to.

Picture the world in the fall of 1901: The only way to travel between North America and Europe is by giant steamship; the Wright brothers haven’t yet made their first flight on the sands of the North Carolina Outer Banks; there is no such thing as radio or TV broadcasting; it will be more than a half century before the first artificial satellite beams its telemetry data down to Earth; and it will take three-quarters of a century for the Internet to be born. In 1901 the only way to communicate across the sea is by sending mail on the oceangoing steamships or by wire-line telegraphy, using the relatively new undersea cables that had been laid in the late 1800s.

In Europe, meanwhile, young inventor Guglielmo Marconi is having scant success convincing governments and corporations of the value of his recently discovered ability to signal across towns and villages without wires. Discouraged with his native Italy’s lackluster response to his experiments, he has come to England, where he has received encouragement from that government—especially after his success in communicating across the English Channel.

But something more is needed to capture the public’s attention. So Marconi boards a ship and, with some of his assistants, heads to Newfoundland after setting up a transmitting station overlooking the Atlantic near the westernmost point of England, at Poldhu, Cornwall. On December 11, 1901, Marconi and his North American team hoist a wire with a large kite launched from Signal Hill at the entrance to the bay at St. John’s, and on the following day Marconi reports hearing the letter “S”—the prearranged code letter being sent by other assistants back at Poldhu—in the headphones of his receiving apparatus! As they say, the rest is history.

Did my grandfather ever meet Marconi? Was he aware of the transatlantic experiments being conducted within a few miles of his home? Did he visit Signal Hill to see what all the fuss was about? I’ll probably never know. But it’s fun to speculate.

In distinct contrast to water waves and sound waves, or to the Internet, which moves information from place to place largely via optical fibers and other physical media, radio communication takes place with no supporting medium at all! Electromagnetic waves launched at the transmitting site travel essentially forever, until intercepted at a receiving site. The task of efficiently converting transmitter output power into radio waves capable of traveling into the infinite reaches of space or of picking up those waves for amplification and conversion to audible sound waves by my clock radio falls to a class of devices known as antennas.

It is no exaggeration to say that without antennas, there would be no radio. Thus, to design radio or television equipment, to be an amateur radio operator or shortwave listener, or to successfully install a wireless Internet service for a group of users, a practical understanding of antenna basics and basic antennas is a necessity—hence the title of this book.

In the decade since the fourth edition of the Practical Antenna Handbook first appeared, entirely new classes of specialized antennas—including medium-frequency (MF) directional receiving antennas for limited spaces and budgets—have come into existence and are in daily use by thousands of radio amateurs and shortwave listeners around the world. For many older antenna designs, theories of antenna operation originating in crude experiments from as long as a century ago have been either confirmed or supplanted by new theories and practices based on modern analytic techniques, coupled with tests conducted with new generations of test equipment, and backed up by extensive computer modeling using inexpensive and readily available software that until just a few years ago was found only in the laboratories of universities and large corporations.

Scientific and technical information transfer has also been upended by the Internet. Today, numerous online discussion groups (variously known as reflectors and listservs) allow experts to report and critique recent antenna findings in near real time while hundreds or thousands of other professionals and rapt hobbyists “listen in”.

In putting together the fifth edition, every chapter of the Practical Antenna Handbook has been reviewed and revisions made wherever appropriate. Occasionally, antenna designs or topics that are too esoteric or arcane for the overview of basic antenna types this book represents have been winnowed out to make room for new material of broader or more topical interest. In many chapters, new explanations of fundamental concepts are the result of developing and refining effective (i.e., “lightbulb”) answers to the most-asked questions during antenna talks I have long given at radio club meetings and conventions. Similarly, the use of the half-wave dipole as a conceptual building block for “quick and dirty” analysis of many other antenna types found throughout this book has been well-received over the years.

With few exceptions, the use of math in this book is kept at or below high school level. Appendix A has been added to give readers a foundation for understanding the decibel, since it is essential to the discussion of antenna performance, and to provide a summary of a few specific trigonometric right triangle and sine-wave relationships necessary for some of the explanations at various places in the text. Perhaps the only “advanced” math concept in the book is the use of the imaginary number operator j to simplify and clarify the manipulation and display of complex numbers.

Two structural changes have been made to the Practical Antenna Handbook:

• The order of presentation of the material has been revised to collect related topics in groups of chapters and to help the book as a whole flow logically from the most basic concepts and antennas to more complicated configurations and techniques.

• The fourth edition of the Practical Antenna Handbook included a CD with supplemental information and spreadsheets on it. Today it is far more practical to commit this material—and more—to a Web site, where it can be updated and augmented, as appropriate, over the lifetime of the book. Go to www.mhprofessional.com/carr5 for:

Tables of worldwide geographic coordinates and antenna dimensions vs. frequency

Supplier updates

Author’s blog

Additional photographs and schematics

Links to tutorials and specialized calculators

Before I became captivated by radio, my goal had been to be a journalist. Throughout my adult life I have never lost that love of writing, and during my career I have occasionally had the good fortune to be able to marry the two interests in a few brief work assignments. Ordinarily, writing a book about antennas would represent nirvana for me, except that I cannot lose sight of the fact that I have this opportunity only because Joe Carr passed away shortly after completing the fourth edition. So I hope you will find this fifth edition a worthy expansion and updating of Joe’s fine work over the years, and I ask your indulgence as I dedicate it to my grandfather, Archie Munn Hippisley, who started me on this path many years ago.

GEORGE W. (BUD) HIPPISLEY, W2RU
Old Forge, New York