---
name: "nec2"
section: "1"
platform: "linux"
package: "nec"
version: "2-16"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/nec2"
---

# nec2(1)

Numerical Electromagnetics Code (Antenna Modelling Program)

## NAME

nec2, nec2small - Numerical Electromagnetics Code (Antenna Modelling Program)

## SYNOPSIS

**nec2** \[*INPUT*\] \[*OUTPUT*\]\
 **nec2small** \[*INPUT*\] \[*OUTPUT*\]

## DESCRIPTION

**nec2,** is a versatile numerical Boundary Element Method (commonly called  Method of Moments) antenna modelling code for the analysis of antennas and other metal structures.  It solves the integral equations for the currents induced on the structure by sources or incident fields.  The structure may either be excited by voltage sources on the structure, or by an incident plane wave of either elliptic or linear polarisation. The structure and excitation are described in the *INPUT* file and the output is written to *OUTPUT*.

## OPTIONS

Due to the age of the program, it expects input in the form of punched cards fed into a hopper.  It currently does not accept any options.

If *OUTPUT* is  omitted, output is written to stdout and if *INPUT* and  *OUTPUT* are omitted then the input is taken from stdin and the output written to stdout.

The maximum size of problem which the code can handle must  be hard coded at compile time and no dynamic memory allocation is performed.  Two versions are therefore provided suitable for different sizes of problem, **nec2** is compiled for a maximum of 10000 wire segments and 5000 surface patches, while **nec2small** is compiled for a maximum of 600 wire segments and 200 surface patches.

## SEE ALSO

[somnec(1)](/somnec/1.md)

The NEC-2 code is fully documented in the report  *Numerical Electromagnetics Code (NEC)* -- Method of Moments" by Burke and Poggio, which is  available as a printed publication in three parts covering the theory of operation, the program code and the users' manual.  An updated form of the users' manual part of this report can be found in /usr/share/doc/nec/NECdoc

## BUGS

**nec2** has been superseded by  **nec4,** but this revised code has not been made available to the public, so it is possible that some bugs remain in this version.

Also note that many variant source codes exist based on the original FORTRAN-IV listing in the report.  This one is believed to be correctly working, but may still contain extra errors.

## AUTHOR

This manual page was written by  \<alanb@chiark.greenend.org.uk\>. The program was developed by G. J. Burke and A. J. Poggio of the Laurence Livermore Laboratory.