4nec2\exe” folder, in your Word or Wordpad text editor. Other recommended sources for NEC related informations are the Nec-2 and Nec-4 user-manuals and . 4NEC2 is a freeware antenna simulation software program. The program can be used to model an antenna, and then determine through. Antenna Modeling With 4NEC2. Presented to HOTARC. By Craig Weixelbaum. May 22, Basic Modeling Approach using 4Nec2. The goals of this

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It took 24 iterations mqnual about 4 seconds. It shows you 3 dimensional views if you want and gives great graphs. This view enables detailed 3D analysis of antenna pattern, in the context of the antenna placement, for understanding peaks, nulls, and all aspects of complex far field propagation.

In order to determine the optimum segment densityit is interesting to perform a convergency test see section 7. Saves me wasting time physically testing poor configurations. Now that would be an antenna! For each case, specifications are provided regarding whether the wires may touch ground 4nwc2 not and in the negative case at which height over ground must be placed.

V The data information returns, after running the model, on the main page, antenna efficiency and radiated power relative to fed power. Mmanual the optimization functions I could find the best SWR and launch angles for the geometries.

Note that some of the rules are not applicable to later versions of the algorithm NEC3 and NEC-4which are more advanced and whose code is not available to the public.

I built it, installed it and manuual the AIM C analyzer was able to verify the design. The Other Edge of the Sword”. Coordinate system used in 4Nec2.

W8IO Antenna Site – TANT and 4NEC2

Study and Experiences ESP. This enables rotating through user specified slices around degrees and manuxl detailed gain data as a function of angle and azimuth angle.

This article summarizes some useful advices for efficient antenna simulation with programs based on the NEC-2 algorithm, developed by the Lawrence Livermore Laboratory.


Once the model has been defined, some programs implementing the NEC-2 algorithm provide options for geometric validation in order to look for non-connected wires or incorrect crossings, as well as segment validation options to verify whether the rules described in the previous sections are observed.

Press the space bar to toggle between side and top view. I was able to just fit a beam into a 32’x 33′ attic with a pyramidal roof and truss members everywhere. The AGT consists in placing the model, without loads and transmission lines, in the free space horizontal antennas or over perfect ground vertical antennas and then to simulate the 3D radiation pattern. Any modelling software has some learning curve.

I finally discovered 4NEC2, thanks to the eHam reviews. Once you have ascended the learning curve, this piece of software can be fully appreciated for how amazing it is. In the case of wideband or multiband antennasrepeat the convergency test in a representative set of frequencies within all the working band of the antenna. It has tools to auto generate grids, radials, and some quite complex geometries, provides scaling, translation, and rotation of antennas and subsets, replications of antenna subsets, and many other aids far too numerous to list.

In the case of wideband or multiband antennas operating between a minimum frequency Fmin and a maximum frequency Fmax, I suggest the following strategy of design, for example with the help of a spreadsheet Once the geometry of the antenna is defined, number the wires, identifying also their diameter Dh i and their length Lh i. In complex antenna models, the variable name can be re-used in multiple locations. One wire must have at least segments per each semi-wavelength [Ref.

American Radio Relay League. Placing the generator in the apex of two wires.

At first, antenna modeling software is difficult to understand, primarily because of the Cartesian coordinate method used. If this rule is not observed, the model probably has defects in the specifications of the generator or maybe the generator is located in the wrong place.

If this rule is not observed, the simulations with NEC-2 will provide as a result erroneus impedances and anomalous high gains, especially for horizontal polarization.


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By proper definition of dimension variables, it is even possible to optimize while enforcing symmetry for example. It provides graphical display of antenna currents and phase, and allows selecting segments for numerical current display in complex format. And, once they are translated, you can modify the card format, and, turn them into variable based models for optimization. In the simulations in mamual space, logically there is no ground.

The azimuth angles are measured clockwise from the Y axis towards the X axis. I find it far faster for initial entry than X-Y-Z entry of coordinates. If the wire is not paralell to the ground, the height manhal the end nearest to the ground will be considered. Average gain test AGT. I spent a couple of days installing the software and reading the tutorials. Two wires may majual meet in the intermediate points of any of their segments [Ref.

Therefore, the number of segments employed must be 4bec2 with the frequency, or must be calculated in order to be above the recommended minimum corresponding to the highest working frequency lower wavelength [Ref.

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Once you start with just a basic dipole, moving on to base-fed verticals, Yagis, quads and other geometrically complex antennas becomes much easier to model. They must be placed at a height over the ground of at least one fifth of the working wavelength:.

Using mnaual S-N ground it is important to take into account that both the vertical and the horizontal wires cannot touch ground.

Let Zs be the height of the wire over the ground. In order to check the validity of a model, it is recommended to perform both the convergency test and the average gain test.

I normally always just run the 4nec2X 3d version. So, if you define a LC network in the model, the code will compute loss.

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