Models for Antenna Modelers: 2nd Edition

L. B. Cebik

There has been a need for exemplary models for newer antenna modelers to use to gain experience. As well, experienced modelers have no wish to reinvent models already in existence. To serve both groups, I have gleaned--from my accumulation of over 4000 models--sets of models that may serve as a foundation for modelers to build upon. The antenna designs consist of published or shared work or of original work by the collection compiler. To the best of my knowledge and by intention, the collections includes no commercially available antennas.

A few years back (1999), I made available over 400 models from my personal collection of non-commercial antennas. Both the response to those models and the elapsed time since their release has suggested that a new and expanded edition is in order. The new edition aims to be more useful to users in at least two major ways.

1. The number of categories has shrunk by one, since 10-meter antenna models are now distributed throughout the other categories. However, each of the 7 categories of antennas has doubled in size. There are from 100 to 140 models in each set. The total number of models in the complete collection is over 800, with no more than about 10% maximum overlap among sets. (For example, I could not have a Yagi set without a wire beam for 75 meters, which also must be in the wire-array collection.)

2. The first edition used a code for filenames to hold them within the old 8-character filename limit. The 2nd edition uses long filenames to more fully describe the antenna type, variation, frequency of use, and--if known--the designer. You will still have to work your way through some abbreviations in the compacted filenames, but these names will give you a better clue as to what you are likely to see.

As with the first edition, each collection comes in two forms: a set in EZNEC (.EZ) format and the same set in generic NEC (.NEC) format. Virtually all programs besides the entry-level EZNEC can read the generic NEC ASCII text format file. However, I have added to the collection a few files that are larger than the 500-segment entry-level EZNEC limit in order to provide a glimpse at some very large quads, adequately sized planar and corner reflectors, and very large radial systems.

Each set consists of over 100 models focused around a central antenna category. The available sets are these:

102 HF Yagis
130 HF and VHF Quads
111 HF-UHF LPDAs
103 Vertical and Horizontal Phased Arrays
103 HF Horizontal Wire Antennas/Arrays
108 HF and VHF Vertical Antennas/Arrays
144 VHF/UHF Antennas

Virtually every model can be effectively scaled from the frequency of design to a desired frequency, with care to adjusting the element diameter(s) as well as element lengths. These models are not finished products. While a few may translate directly into antennas that might be constructed at home, the primary intention is to provide models that allow you to study antenna types and their performance. As well, they may form the basis for design improvements that you may make as you perfect your modeling skills. In short, these models are not a substitute for a thorough knowledge of the modeling software or fundamental antenna principles. Additional information on each collection appears in the individual set descriptions.

HF Yagis: 102 Models

The collection includes both wire and tube models, with tubular elements including some stepped-diameter versions and some uniform-diameter versions. Models cover all of the HF bands: 80, 75, 60, 40, 30, 20, 17, 15, 12, and 10 meters. If you see a design for one band without a counterpart for another band, you may scale the element lengths, spacing, and diameters to create the desired beam. There are 85 true Yagis, although there are a few V-Yagi designs that combine parallel-element coupling and element-end coupling. As well, the collection includes 15 Moxon rectangles, which also use both parallel-element and element-end coupling. See the VHF-UHF antenna collection for Yagis covering these higher frequencies.

Quad Antennas: 130 Models

The models cover quad sizes from 1 element up to 6 elements for 3.6 MHz through 1296 MHz. The set of 10-meter models especially shows a wide variety of variations, especially for diamond-shaped and square models with loading at the high-voltage points. The models with "opt" included in the filename are the products of a set of equation-based models in .NWP-format that cannot be included here. However, the calculation instruments are available at numerous sources. AWG #12 copper wire sample optimized quads appear for all bands from 80 meters to 1296 MHz. Besides monoband quad beams, the collection also includes a good number of 2-, 3-, and 5-band models ranging in size-per-band from 2 elements to 6-elements.

LPDAs: 111 Models

The collection of LPDAs includes both log periodic dipole arrays and log-cell Yagis, which use LPDA structures for their drivers. The log-cell Yagi models (labeled LC) are mainly on the very wide 10-meter band. The LPDAs proper (labeled LP) cover a very wide frequency range beginning at 3.5 MHz and ending at about 2 GHz. There are 3+ octave models, but most examples cover a 1-octave (2:1-frequency) range. Models also vary widely in size, with a preference for relatively high-performance LPDAs. Many include performance-enhancing modifications. The collection also contains some special purpose or non-amateur range models, including 3 FM LPDAs, some single-band LPDAs, and some government and commercial communications band versions.

Verticals: 108 Models

The collection of verticals includes both vertical element antennas and antennas with predominantly vertically polarized radiation. The models tend to focus on the 160-meter through 30-meter bands. For those bands, there are simple monopoles over radial systems, shortened monopoles with a variety of hat structures, and numerous wire structures whose dominant radiation is vertically polarized. This group includes rectangles, hentennas, delta loops, quad loops, half-squares, bobtail curtains, Sterba curtains, and Bruce arrays. There are also a few parasitic and phased monopole structures. Besides these basic vertically polarized HF antennas, there are a number of others, including J-poles, the L-antenna, the collinear vertical, and a trio of dipole arrays.

Wire Arrays: 103 Models

The collection of wire arrays covers perhaps the widest territory of any of these collections, since there are collinear, end-fire, and broadside arrays. Hence, you will find extended double Zepps, 8JKs, and lazy-Hs among the offerings. The collection also includes some wire Yagis for the low HF range. As well, you will discover loops oriented both vertically and horizontally. Indeed, you will find rectangles, double rectangles, hentennas, half-squares, and bobtail curtains for the vertical radiation aficionado. Among the larger arrays are collinear extended double Zepps, Sterba curtains, and Bruce arrays. In addition, there are a number of wire loops potentially usable on several bands. The collection even includes a few long wires, Vee-beams, a rhombic, and some challenging NVIS arrays. Virtually all of the antennas use either AWG #12 or AWG #14 copper wire as the main ingredient.

Phased Arrays: 103 Models

The collection of phased-array models covers the HF spectrum from 80 through 10 meters, with a few models at VHF and UHF frequencies. Phased arrays (for the purposes of this collection) include any antenna that provides a feed to more than one element. Many are vertical arrays--especially in the MF and lower HF range, and some models are for the AM broadcast range. Upper HF designs are mostly horizontal, although some of these antennas may be used vertically to good effect. Among the antenna types included are collinear, broadside, and endfire wire arrays, 2-element horizontal phased arrays (ZL Specials, HB9CVs, and variations), stacked beams, dipole arrays, and turnstiles. Some models use the TL facility of NEC-2 to provide one or more phasing lines, while others use separate feedpoints.

VHF-UHF Antennas: 144 Models

The collection has samples of many kinds of antennas, including Yagis, quads, corner reflectors, planar reflectors, simple and collinear verticals, and dual rhombics. However, Yagis dominate the collection, since there are so many sizes, designs, and variations on them. The collection only touches on quads, since the separate collection of quad designs includes both HF and VHF/UHF quad beams. Some designs, like the DL6WU Yagi, may only have a small sample on a particular band, because you may create other lengths simply by removing directors one-at-a-time from the forward end. As well, many designs for 50 through 432 MHz scale readily to the upper UHF region. There are also a few FM band antennas, including a triplet of LPDAs. However, most VHF/UHF LPDAs appear in the separate LPDA collection.

The complete set of models can be downloaded here, 801 models in eznec and nec format (2 MB zip).

The files in these collections are copyright by L. B. Cebik. All original designs, that are not already the property of others, are also copyright by L. B. Cebik and may not be used for the production of any commercial or proprietary product without prior written agreement with the designer.

Updated 08-10-2003.

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