"frnec2X" is a no-cost Linux application which assists in making antenna modeling calculations by acting as an interface between a Linux X-Windowing system user and a modified version of the Lawrence Livermore National Laboratory's Numerical Electromagnetics Code, Version 2 (NEC-2). "frnec2X" uses a number of "dialogs" to assist in preparation of the kinds of data needed to specify an antenna model in the somewhat arcane formats expected by NEC-2. In addition to that, "frnec2X" has the ability to display simple graphs of radiation patterns, feed point impedance (or admittance) vs. frequency, and simple fixed-plane near electric fields.

The most tedious aspect of setting up NEC input data files is getting the data entered in the expected formats. "frnec2X" provides some help along those lines by displaying descriptions of relevant input data along with structured entry boxes in the data setup dialogs.

No attempt has been made to include dialogs for many of the more complicated NEC capabilities (surface patches, helical antennas, antenna models formed by reflection about various coordinate systems, etc.), "frnec2X" does handle the parameters most commonly used by this author. Those who wish to utilize the omitted NEC-2 features can do so by revision of the NEC-2 input data files.

Last, but far from least, no attempt is being made in "frnec2X" or its documentation to provide much in the way of tutorial assistance in how to model antenna systems using NEC-2. For such assistance users are referred to the extensive series of articles by L. B. Cebik which appeared in QST magazine in November and December 2000, and in subsequent issues in 2001. Anyone using NEC really ought to try to obtain a copy of the NEC manual. try clicking here as a start.

System Requirements:

Computer system requirements of "frnec2X" are fairly modest: At least an 80486 CPU running a recent version of Linux, 128 MB ram or more, at least 10 to 15 megabytes of hard disk space (mostly on a user's /home drive, and at least a VGA color monitor. Normal distribution is via internet download of an installation package in the form of a ".zip" file. The frnec2X.zip file size is approximately 3 MB and can be obtained by clicking here. Before you do that however, be sure that you have read the disclaimer file and the notes about linux file ownership settings that are found further down in this document. The ".zip" file also contains a complete copy of all the source code files needed to revise or recompile the program in a GTK-2, GLADE-2 development environment. Revision of the NEC2D based subroutine subnec.c probably should be done via the parental "subnec.f" fortran code and the fortran-to-c converter program named "f2c"(it is probably available at www.SourceForge.net). "frnec2X" is free and maybe used in any manner that is consistent with the rights and limitations set forth in the GNU General Public License. A copy of that document can be found here

Some documentation for "frnec2X", will be found in the file "mynecdoc.html" located in the "frnec2X/program/nechelp" created by unzipping the frnec2X-1.0.4.zip archive. That file was created by partial editing of the documentation written for NEC2D and found at www.nec2.org.

Ownership and group membership of all files in the frnec2X-1.0.4.zip are assigned to "root". To install them switch to a directory in which you are willing to create a subdirectory name "frnec2X" (but do not create the directory yourself; it will be created when you unzip the file). Then unzip frnec2X-1.0.4. Once the files have been extracted you may need to change the ownership to yourself using commands like "chown your_username -R *" and "chgrp your_username -R *". You will need root priviliges to do that or will need to get someone with root priviliges to do it. I do not know why it is so, but I have never been able to get the help file of "frnec2X" to function properly if I try to execute the program as "root".

frnec2X is still under development and revisions are being made as unexpected problems or needs arise. Consequently users may want to check occasionally for updates. Anyone who is trying out the program or using it is encouraged to send me any comments on bugs or suggestions for changes via the email address given below.

Users who find the program useful are encouraged to indicate that fact via a donation to support the Student Physics Society - Sigma Pi Sigma Chapter at the Physics Department, New Mexico State University, whose address is:

   SPS - Sigma Pi Sigma Chapter
   Physics Department (Mail Stop 3D)
   New Mexico State University
   PO Box 30001
   Las Cruces, NM 88003-8001 USA

For additional information (or to communicate bugs and/or gripes) send email to w5ygr@yahoo.com

It would be nice if anyone who uses the source code to improve the overall capabilities of (or fix bugs in) "frnec2X" please post their revised source codes on a publicly accessible web site and also make me aware of their existence via email to the address above.

The last revsion of the program archive was posted on 13 Mar 2009.