Practical_Antenna_Handbook_0071639586

C h a p t e r 2 5 : A n t e n n a M o d e l i n g S o f t w a r e 549
A Typical NEC-Â2 GUI
Roy Lewallen, W7EL, produces the EZNEC family of software for Windows PCs. The
software extends Roy’s earlier work on DOS versions of EZNEC but is still based on the
NEC-Â2 engine. (A professional version based on the NEC-Â4 engine is available for those
who obtain the required government license.)
Figure 25.3A shows the opening screen in EZNEC+ ver 5.0 for a typical antenna
project (in this case, an 80-Âm bent dipole). Visible in this window are file name, frequency,
free-Âspace wavelength (in meters), number of wires and segments, number of
sources, number of loads, transmission lines, ground type, wire loss, the units employed
(meters, feet, etc.), plot type (azimuth, elevation), elevation angle, step size, a
reference level, and an alternate Z 0 for the SWR plot (to conveniently handle both 50-Â
and 75-ÂΩ system impedances).
Command buttons to the left of the main window include Open, Save As, Ant[enna]
Notes, Currents, Src [Source] Dat[a], Load Dat[a], F[ar]Field] Tab[le], N[ear]F[ield]
Tab[le], SWR, View Ant[enna], and F[ar]F[ield] Plot. The “FF Plot” button graphs the far
Figure 25.3A EZNEC+ ver. 5 opening screen.