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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An elevation of 90 degrees will correspond to the perpendicular to the ground plane. It is so good, it should be called 4NEC8! Coordinate system used in 4nrc2. One wire must have at least segments per each semi-wavelength [Ref. In summary, its free, its professional, works great and once you penetrate its outer crust of seeming complexity, its simple to operate. A spreadsheet also allows initial entry or adjustments after initial entry.
If a wire is a quarter-wavelength long, 5 segments will be a good minimum [Ref.
This problem can be minimized making the diameter of the wires to change in a series of steps through several additional intermediate wires [Ref. Contact the site with comments or questions. My problem was to get a reasonable, low-cost m attic antenna in a crowded urban setting with metal surfaces everywhere.
We will name Ns the 4nwc2 of segments making up a wire. In the simulations, the input impedance of manuual antenna would be erroneous, reaching too high values especially in the reactive part and a too low level current would be generated through the mutual coupling between the mwnual of the generator connected to the antenna and the piece of segment connected to the other pole of the generator, which remains in open circuit.
By proper definition of dimension variables, it is even possible to optimize while enforcing symmetry for example. Putzing with it has filled many binders and files. Then, if that variable length for example needs changing, it can be changed in one place in the model much like a software program. They must be placed at a height over the ground of at least one fifth of the working wavelength: Folded dipole with resistive load model. I got LB Cebik’s Antenna Modeling book and have begun to learn this software in an incredibly exciting voyage thru these dreary winter months!
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.
I used this view to understand my 80m OCF on 40m, 20m, 17m, 12m, and 10m. The method of the moments [Ref.
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Then start modeling your antenna ideas! In the simulations in free space, logically there is no ground. The distribution of currents may be asymmetric and the values of the input impedance of the antenna may be inaccurate. Expect a little learning curve; once you get the hang of it the interface is actually quite intuitive.
Today, I designed and optimized a 3-element Moxon-like wire beam to hang vertically from the trees. Saves me wasting time physically testing poor configurations.
If you want to edit the antenna, press the open book icon to get into the editor. 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 kanual described in the previous sections are observed.
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Program Description – Code”. In a model with several wires, it is advisable not to connect short segments with long segments [Ref. Having an optimizer makes it possible to design multiple element arrays that would be extremely time consuming or impossible otherwise.
In this manner I can tell if I need a 4: No need to manually change the variable multiple times due to “hardcoding”.
Take into account that mwnual is not allowed to use generators or loads in the ends of wires in open circuit [Ref.
The failure to comply with the rules of design inherent in the NEC-2 algorithm may have a great impact on the simulation results.