4NEC2 is a freeware antenna simulation software program. We've recently been informed that Mark Schoonover KA6WKE, is writing an eBook guide on this topic. I would like to see an EPUB download for my tablet. . (1,), Satellite ( ), SDRplay (), Security (), Transceivers (4), Tutorial (71). 4NEC2 is a NEC based antenna modeler and optimizer developed by Arie Voors . This is and it's available in PDF, ePUB, and MOBI formats. Simulation of Wire Antennas using 4NEC A Tutorial for Beginners. Version Author: Gunthard Kraus., Oberstudienrat Email.
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Simulation of Wire Antennas using 4NEC2. A Tutorial for Beginners. Version Author: Gunthard Kraus, Oberstudienrat, Elektronikschule. [PDF] wire antenna modelling with nec 2 1 numerical pdf books epub. Read online wire wire antenna modelling with http://qsl/4nec2/incacimelmons.ml File title. A Tutorial for Beginners. net. It is very useful for those designing home made antennas for their RTL-SDR or other A Simple Pull-up Mono-Band Verticle Dipole .
The only difference to the last chapter is an increase of 1.
Second project: MHz Dipole using thick wires 7. The Thick Wire Problem In the last examples an ideal and infinite thin wire was used for the simulation.
But in practice the wire radius must be increased to get some mechanical stability. Choose 3 with a diameter of 5. Open the NEC file with the editor, enter this value and save all.
So the Geometry card must now look like in the new 4NEC2 editor: Caution: Now you must open Others to activate the extended kernel for the fat wire support!
Sweeping the SWR and the Input Reflection This is the influence of the thick wire: the frequency for minimum reflection has decreased to a value with is 10MHz lower. Sweeping the Antenna Gain At first repeat the simulation of the vertical radiation pattern see chapter 7. In the left lower corner of the diagram an azimuth angle of degrees is indicated this means that we see a cut through the 3D pattern at this angle.
Press F7 to enter the following options: a b c d e Frequency sweep Gain Angle resolution of 1 degree Sweep from to MHz with a step width of 0. A wonderful toy: the Smith Chart Machine When a simulation is successfully done a Smith chart symbol is highlighted in the menu bar. So we repeat the frequency sweep of the SWR and the Input reflection over a frequency range from to MHz with a step width of 0. This gives the following screen: The simulated S11 is shown as black coloured curve.
In the right lower corner of the screen you find the actual frequency here.
Use the right resp. Caution: The information Mouse in the next line shows always the impedance value at the actual mouse cursor position. This impedance is indicated in serial and in parallel form. Additionally we find a pink curve and a green vector running through the actual point of the S11 curve. The circle radius gives the S11 magnitude here: 0. The phase of S11 is indicated by the green vector..
In the lower half the relations between reflection loss, return loss in dB , power reflection coefficient and voltage reflection coefficient are indicated.
In the menu for this presentation you find Export and Import. Also Z parameter files can be produced and exported. Optimizing Key F12 What is an antenna design worth without optimizing? This can be done after pressing F12, but some preparation is always necessary: Every antenna data which shall be varied for optimizing must before in the NEC file be replaced by a variable with a definite default value.
Optimizing the Antenna Length thick wire dipole of chapter 7 Task: The resonant frequency of the thick dipole see chapter 7 should be MHz. Ground used, ends of wires not connected to ground. GN ground card necessary 0 0 1 0 0 0 5 0 13 0. Then select the variable by clicking in the list which shall be varied for optimization.
In this example we have only len as variable and this variable can be activated by a mouse click on its name. But check whether len now can be found under Selected. At last we set the goal of optimization. There select minimize as optimization goal.
At last press Start and wait. This is the result after 23 seconds and you can press OK 28 In the center of the screen changes something and you have now the choice between Resume and Update NEC-File. So start a new simulation F7 with the same frequency sweep as before.
Here is the result: A fine done job! Parameter Sweep Often it is of interest how some characteristic antenna data e. To get a good overview in this case you can use the parameter sweep for this purpose. Here comes an example. Replace the value of 1m in the GW card by the variable hght. Sweep the height over ground from 0. Step 3: Start the sweep and wait for the message End of Sweep.
Then click on OK. F5 opens the access to the impedance, the SWR ratio and the gain. Use the Show menu to get the simulation result for the impedance versus the antenna height over ground. But the reactance. First open the windows F3 and F4. F3 is a resume of all simulated patterns.
But in F4 only one pattern can be indicated for the choosen height over ground. Click on F4 to activate it and use the horizontal Cursor tabs to regard the pattern collection.
Caution: these are the tabs on the right hand side of your keyboard. The actual height is indicated in the left upper corner of F4, the actual pattern is up lighted in red colour in F3.
An excellent book which must be recommended A helix antenna consists of more but three turns of alumina or copper wire and constant pitch.
This gives a circular polarized radiation in direction of the antenna axis in the left illustration: upwards and an antenna gain of more but 8dBi. The radiation resistance has a value of approx. Increasing or decreasing the ratio of circumference and wavelength alters the radiation resistance in the same manner.
So the perfect matching of the antenna to 50 is sometimes heavy work. But one important advantage is the large usable frequency range with nearly constant gain and radiation resistance and the circular polarization.
This antenna shall work over perfect ground and so in practice you often find a metal plate or disc or sometimes a little alumina pot! In the Web lot of information and design software for a helix antenna can be found.
Especially the Online Calculator are a real help and easy to use. Design using the Geometry Builder Start main, then run. Select Geomtry Builder. Go to the Helix card for the necessary entries: Caution: Let us use 24 segments per turn. For a wire diameter of 2mm the radius is 1mm. Be aware that 3 different units Meters, Centimetres and Millimetres are used when entering data! Then press F6.
On the Geometry Card you find the entry for segments with the all the coordinates and the wire radius of 0. No sweep is used.
The last card of the menu is used for comments. Now it is time to save the finished NEC file. The result is a maximum gain of 9. The left end of the first segment is connected to ground and the voltage source is applied to the centre of this segment. Frequency Sweep of Gain and Impedance A sweep of the gain from to MHz shows very clear the promised wide band properties of a Helix antenna.
The gain starts at 9. But a video is worth a thousand pictures. In the video demo, I use the program to design a 20 meter dipole which is to be installed 30 feet above ground. The video will take you through the basic steps. Initial setup of antenna and environment parameters. Basic antenna design experimentation. The documentation is very complete and well written.
It is in the form of Windows help files. The contents are very well structured and easy to navigate. You can follow the help as if it were a tutorial in antenna design.
You can also skip and jump to specific sub-topics using the detailed table of contents. On with the show Please note that the video may take a some time to load if you do not have a broadband Internet access.
I have had to limit the resolution to limit the size of the file. On top of being educational, the software will enable you to analyze and design most of the common types of antennas that amateur radio operators use. When you feel comfortable with the program, and like what it can do for you, then you can go for the commercial version which will enable you to explore much more complex antenna systems.
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