Controls menu

This menu simplifies the use of Control Cards with NEC. However, by no means does it replace the necessary knowledge of the NEC structure required by the user. The ``Command list'' shows the complete list as it will be passed to the NEC file. This enables the experienced user to see exactly what he is specifying. An example of this window is shown in Figure [*]. From this figure it is clear that the user can, for example, check the positions of frequency loops and radiation pattern cards and consequently determine which patterns will appear inside the frequency loop.

In order to simplify visualisation, the 10-digit spacing format used in NEC2 is preferred. The control cards are saved to a separate ASCII file with a *.wgb extension.

Figure: The Control Card Editor
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Cards specifying tag and segment numbers (such as voltage sources, transmission lines, two-port networks and coupling requests) can only be applied to straight wire (two node) elements. If a segment on a major element with more than 2-nodes needs to be used with these Control Cards, a two-node wire can be placed on the appropriate side of the major element. The Control Cards can then be applied to this two-node element. (In such a case the mesh generation procedure will ensure that no duplication of segments will occur. This is done by suppressing the segments on the related side of major element containing more than two-nodes.)

When a model is added to an existing one the Control Cards are appended.
Note, however, that when one model is added to an existing one, the major element numbers in the combined model will be different from those of the original model. The corresponding Control Cards are not modified, and Cards where tag and segment numbers are specified might therefore be wrong. This also applies to the segment number on a given wire if the maximum segment length is changed such that the wire is divided into a different number of segments. (This problem can be overcome by adding a very short wire element for the excitation. Provided the maximum segment length remains longer than this element, it will always contain only one segment. Be careful, however, not to violate the NEC criterium for the ratio of adjacent segment lengths — this can especially be critical near the feed of a structure.) It is recommended that all Control Cards be checked carefully, immediately before the NEC file is created.

Certain functions in the Control Card ``editor'' simplify the addition of certain cards, while others enable the user to manipulate the list or visualise what a certain card entitles. The different functions of the buttons in the Control Card editor will now be considered.


Subsections