These codes are suited for complex environments that are large in terms of a wavelength. ESP is a moment method code primarily used for defining antenna parameters and scattering from small objects. This code is most useful for analysis of antennas and scatterers no bigger than a few wavelengths. The distribution of some of these codes, and their documentation, is limited to U. S. government agencies and their contractors. In particular, the computer codes and their documentation are subject to export controls.
Foreign disclosure is limited.
Foreign requests must be handled on a government to government basis through the appropriate embassy in Washington, D. C. See Non-U.S. Ordering Instructions for further information. Some of the codes no long have export control, however, higher order versions still do. The NEC-REF V3 code no longer has export control. The NEC-BSC Workbench also does not have export control. All the other codes listed presently still are export controlled.