by L. B. Cebik, W4RNL (SK)
(A posthumous publication release)
Plus 182 Example Working Antenna Modeling Files
WHAT IS THE SCV? (In the words of LB Cebik)
he letters SCV are an abbreviation for Self-Contained Vertical. Although I generally do not favor adding terms to the lexicon of antennas, circumstances in the late 1990s led me to introduce the term. First, a debate was going on within amateur circles about whether all vertical antennas, especially those near to the ground, required a ground radial system in order to perform correctly. That discussion has largely ended, as folks began to understand some of the distinctions that mark talk about the ground relative to various parts of an antenna system.
Second, many amateurs seemed not to realize the close inter-relationship among members of the SCV family, let alone the fundamentals of their operation. Even the highly regarded compendium called Low-Band Dxing by ON4UN (John Devoldere) scattered members of the family in separate chapters (10 and 12) of his book (2nd Edition). Thus, in order to create a family union, I coined the term SCV.
An SCV is a self-contained vertically polarized antenna, usually constructed from copper wire for upper MF and lower HF use. Most basic family members use 1 wavelength of wire for the antenna structure, although there are also doubles and even larger members of the family. Among the basic SCV shapes are deltas (triangles), diamonds, rectangles, and open-ended versions (the half-square). The Fig. 0-1 shows some (but not all) of the basic family members.
Why Use an SCV?
The primary realm for the SCV is the upper MF region (160 meters) and the lower HF region (80 through 30 meters). Although we shall examine some special VHF and UHF applications for SCVs, the primary motivation for turning to the SCV designs was to improve performance of vertically polarized antennas without requiring a complex and often uncertain phasing system to interconnect vertical elements. In addition, all of the SCV designs require only inexpensive copper wire.
We Study the SCV?
A wide-ranging survey of antenna types calls for a systematic means of study. Antenna modeling software is the obvious tool for the investigation for two reasons. First it permits a rapid survey of antenna performance potential in a variety of situations in which we may vary the soil quality, the antenna size and height above ground, and the wire size. Second, modeling software is completely reliable with respect to these antennas because the antenna construction does not press any of the limits of most modeling software. The software of choice for these notes is NEC-4. For most models, NEC-2 would do very well. However, a few models used in the study will involve buried radial systems, which only NEC-4 can handle. Most of the models used in this study will employ EZNEC Pro/4. —LB Cebik
Like many of his other books and as explained above, The SCV Notes include a collection of 182 antenna models, most in EZNEC format, that track the antennas discussed in each chapter. The volume has 293 pages, with hundreds of illustrations and tables.
For much more information about the contents of this book, the SCV family of antennas and why use them, the following link will display a PDF of the book's preface: Click for the Preface
Considered an expert on antennas, LB has published 30+ books with works on antennas for both the beginner and the advanced student. Among his books are two tutorials in the use of NEC antenna modeling software and compilations of his many shorter pieces and some 800 modeling files, all of which are available here in the Shopping Shack. His articles have appeared in virtually every amateur radio publication, with translations of some into several languages. He is a retired Professor from the University of Tennessee, Knoxville and holds a PhD in Philosophy. Until his death in April 2008, LB was Technical & Educational Advisor to the ARRL and for 10 years was Technical Editor for antenneX. His contribution of articles to antenneX first appeared in early 1997 and a new monthly column, Antenna Modeling, appeared starting in 1999. He is greatly missed, but antenneX is pleased to be able to bring more of LB's contributions to those who seek to learn about the field of antennas.
Here is an index of the contents found in this book
|•||Preface to SCVs||5|
|||Part I: Basics|
|1||The Vertical Dipole||19|
|2||Multiple Vertical Dipoles||47|
|||Part II: SCVs|
|4||Deltas (Triangular SCVs)||103|
|5||Diamond (Quad) SCVs||141|
|8||The Bruce Array||255|
|||Appendix: Dimensions, Performance, and Models||285|
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