

=head1 NAME

  necview - a program to view antennas

=head1 SYNOPSIS

  necview

=head1 DESCRIPTION

B<necview> is based on P.T. de Boer's
(pa3fwm@amsat.org/ptdeboer@cs.utwente.nl) xnecview program (which is written in C), and borrows
very heavily from that program.
This program is
written in Perl/Tk, and utilizes color and sliders to animate
visualization of antennas described by input files for NEC2, (or somnec).

The program is simple to use.  The geometry of an antenna is described
to NEC2 via a data file that contains, among other things, (usually many)
lines of the form

S<GW tag segments x0 y0 z0 x1 y1 z1 radius>

This line represents an antenna element whose endpoints have coordinates
(x0,y0,z0) and (x1, y1, z1).  

Some versions of NEC2 use an alternate data representation of the
form

S<GWtag,segments,x0,y0,z0,x1,y1,z1,radius>

B<necview> is able to read data lines of either form and provide
a graphic representation of the antenna.  Each element of the antenna
is colored differently, and the structure can be "rotated" in several
directions by the use of "sliders".  

B<necview> reads the same data files that NEC2 does, 
but the only data lines of interest to B<necview> are the
lines which begin with "GW" or "GR" (as of July 25, 1999).  B<necview> does not attempt to follow
any scaling in the data file, and instead provides its own scaling 
for the visual window.  

The NEC2 file which describes the antenna can be selected
by using the mouse.  After the file is selected, the antenna is
depicted in a window.  The user's view of the antenna can be varied
by using the sliders provided.  As a slider is moved with the mouse
the antenna will appear to "rotate" in the window, affording 
differing views of the same antenna.


A sample data file which describes a rhombic is included.  B<necview> has
successfully modeled antennas with more than 1500 elements.

B<necview> is part of the W5GFE Perl Antenna Toolkit.  It is released
under terms of the GNU Public License.



=head1 AUTHOR

Bill Walker, W5GFE, bw@cs.ecok.edu

=head1 SEE ALSO

perl(1), Wires.pl (W5GFE), Elevation.pl (W5GFE), Azimuth.pl (W5GFE)



=cut
  
