Revised 14 June 2003
B-1
Appendix B
PATTERNS AND GRAPHS
The following patterns are based on NEC-2 modeling. They do not represent measured
patterns. However, both forward gain and relative response Front to Rear (F/R ratio)
have been verified (for relatively clean sites) by antenna range field strength
measurements. Patterns actually achieved in practice will be affected by many aspects
of the actual site where the antenna is installed.
All patterns modeled over ground use 5 milliSiemens for earth conductivity and 13 for
earth dielectric constant. We believe that this represents “average” ground conditions.
The modeling program used for the electrical modeling is EZNEC V2.0 by Roy Lewellen,
W7EL. Very accurate EZNEC models for the 2D-40A are available for download from
the Cal-Av Labs, Inc. website <www.cal-av.com>.
Figure 1-B
2D-40A Azimuth Plot
(antenna in free space)
