This is a 3 rd party book and is not connected to Arie in any way. If you find mistakes in this book, they are all mine. The sample version of the book is complete but the full version is in progress. As chapters or appendices are completed, they will be released as updates. The full version of the book starts with chapter 4 that covers the different 4NEC2 editors.
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This is a 3 rd party book and is not connected to Arie in any way. If you find mistakes in this book, they are all mine. The sample version of the book is complete but the full version is in progress. As chapters or appendices are completed, they will be released as updates.
The full version of the book starts with chapter 4 that covers the different 4NEC2 editors. Other chapters will include using the optimizer and matching tools, using gnuplot for high resolution graphs, using ItsHF and VOACAP with the remaining chapters on design and analysis of various kinds of antennas such as verticals, multi-element, loops, satellite, and a grab bag of antennas the author finds interesting.
There is a Groups. IO mailing list dedicated to this book. Both menus and their options matches what is shown in the program. Program specific text IE: menu text and screen output, etc will look like this Program Specific Text a fixed monospaced font. Just about all computers of recent vintage can run 4NEC2 without issues. Obviously the more memory and CPU speed you have the faster the analysis will go and the more complex of an antenna that can be analyzed.
Mark Schoonover has been licensed since when he got his Novice license on a wager with his dad. Upon his return from Navy active duty in he got his Advanced license. Around he got his Extra. He enjoys homebrewing and contesting from his pip-squeak station in southern California. Professionally, he has a degree in Computer Science and Software Engineering. He switched from Electrical Engineering when the internet became publicly available.
Downloading and installing 4NEC2 will be covered in this chapter. Installation is straight forward and the default settings will be used throughout this book for all screen captures. The author is using Windows 8 64bit for this book. Screens in other operating systems may look slightly different but otherwise 4NEC2 will function identically. This book will cover version 5.
There are several different files available to download. Simply right-click on 4nec2 setup. Extract 4NEC2 by right-clicking on the 4nec2. Double-click on the 4nec2 folder that was created, then double-click again on the Setup4nec2. The following window will appear:. Click Next to continue and Next again to accept the default installation directory. Click Finish to continue. This completes the default 4NEC2 installation. Keep the Help File in mind as well. To access Help , at the point you want additional information, press the key.
General antenna discussions can be found on the eHAM. There is a Yahoo Group dedicated to this book. To subscribe send an email to:. The main source of announcements for this book are from Leanpub and will follow with the Yahoo Group then Facebook. The next group of settings should rarely be used and will be left at their defaults for this book.
Displays the Near field antenna pattern. This is covered in the Pattern Window section. Displays the vertical El and horizontal Az calculated patterns of the antenna under analysis. This is the field responsible for long distance communications and of primary concern to radio amateurs. This area is critical to antenna performance and matching because if other metallic objects are within this area, they could act like unintentional antennas, causing a change in the magnetic field about the antenna.
This change in magnetic field alters the overall impedance of the antenna impacting the match to the transmitter. The near field calculations are vastly different than far field calculations.
In order to calculate the near field, choose the Near Field radio button in the Generate window. Both the voltage field E field and magnetic field H field can be calculated.
Displays the pattern in three dimensions. The Geometry Builder is used to design complex antenna systems for analysis. See the Geometry Builder chapter in the full version of this book. An isotropic antenna is a theoretical antenna that is located out in free space. Free space is away from earth and far away from any other physical body. The sun would be a good analogy of an isotropic antenna. An isotropic antenna is used as a reference only antenna and has zero gain 0 dBi.
This gain is measured perpendicular to the antenna around the azimuth only. Real antennas are what we work with here on earth.
They are made from physical materials that impact radiation patterns, they interact with the ground beneath them and for several wavelengths away from the antenna. When we analyze antennas using 4NEC2, the measurements are compared to an isotropic antenna.
By subtracting 2. From an engineering stand-point, theoretical antennas are the standard by which real antennas are compared to. When discussing antennas with fellow hams, gain measurements will be assumed to be either isotropic or dipole in free space.
What about the measurement at your location? Would comparing your real antenna to theoretical antennas be beneficial? I would say yes and no. Analyze your new antenna design then compare the two. Antenna gain is always compared to another antenna, be it isotropic or a dipole in free space. On the Main Window, click on the toolbar button to display the Geometry Editor window. Name the file 20MDipole. Antennas exist in three dimensions in the real world which are easy enough to see.
The last three planes help us design an antenna two dimensions at a time. In the three dimension view, the X,Y, and Z axis all meet at the origin coordinates 0,0,0. Click on the button to display the X and Y axis.
For example, a three element beam looks like this:. Right now this antenna is laying on the ground! The Z-axis is the height of the antenna above ground. Working this way allows you to concentrate on drawing the antenna in two dimensions, then by adding in the antenna height in the Z-axis, the antenna will move up in height.
To raise the height of the antenna, click on a wire, then in the Wire data section, add the height to the Z-axis; the Z-axis is the highlighted text boxes. Remember you have to add height to the Z-axis for both ends of the antenna and the values are always positive. Putting a negative value for the Z-axis will place the antenna underground! Click on the button, the antenna will no longer be on the ground.
We can call that 33 feet for this demonstration. Plus, the ground underneath the antenna will also come into play so the length derived from the equation could be slightly shorter or longer. When the dipole is installed at the length of the standard equation determine the SWR at resonance. For example, resonance happens to be Slightly higher than calculated.
Do the calculation one more time using the new constant to determine the new length and the new dipole will be resonant at the design frequency. Anyway, back to using 4NEC2! To draw the antenna in the Geometry Editor, click on the toolbar button, on the right, use the Zoom slider to make each grid square 1 foot long, then enter the design frequency in the Frequency textbox.
Now that the Geometry Editor is configured, click on the button then draw a line as evenly as possible along the Y-axis with half the wire on the negative Y-axis, and the other half on the positive Y-axis. Click OK on the Wire Radius dialog box. We need 33 feet so enter. The dipole is one long segment, that needs to be changed as well. Enter the following into their respective textboxes:. Remember the Z-axis is for height above ground so enter 33 into both End-1 and End-2 text boxes.
Take a look around your location to see what the ground looks like. To choose which ground to use, click on the on the toolbar and the Ground Parameters pane will appear. Select Real Ground from the drop-down, then from the lower drop-down, select Dry, Sandy, Coastal or your own ground type if you prefer.
The settings look like this:. The source will be placed right in the center of the antenna, which would be segment 6.
Simulation of Wire Antennas using. A Tutorial for Beginners. Version 1. Gunthard Kraus , Oberstudienrat Email: mail gunthard-kraus. Hardy Lau , Dipl. August 12th,