Topband: EZNEC and RDF

[Bill Tippett]

ZL3IX:

>Does anyone know a short way using EZNEC to show the RDF of a TB
antenna?

1.  In Main Screen select Plot Type Elevation (in desired Azimuth direction).
2.  Click FF Plot and note Slice Max Gain (e.g. 4.69 dBi) at bottom of
2D Plot screen.
3.  Select Plot Type 3D.
4.  Click FF Plot and note Average Gain (e.g. -0.53 dBi **at bottom of
Main Screen**).
5.  RDF = #2 - #4, (e.g. 4.69 - [-0.53] = 5.22 RDF)

Some use Gain at a common takeoff angle like 20 degrees in #2 above
but I use Max Gain.  My example is using Eznec 3.0 for a vertical.
Yes a vertical has an RDF because it rejects noise at high angles,
unlike a true isotropic radiator.

73,  Bill  W4ZV