[TowerTalk] EZNEC polar plot normalization

[jimlux]

Ken Brown wrote:
> Hi all,
> 
> I am trying to illustrate a comparison of low angle radiation from 
> horizontal antennas at low elevations versus vertical ground plane 
> antennas. The only antenna modeling program I have is EZNEC 3.0. I can 
> generate nice plots with it, but EZNEC automatically scales the plot so 
> that the outer circle is equal to the strongest part of the pattern. I 
> would like the two antennas I am comparing to have the same scale, so 
> that when the two plots are overlaid the gain can be compared 
> graphically, directly, without having to look at the "Outer Ring x.xx 
> dBi" Is there a way to do this with EZNEC.
> 
> 

Someone else will no doubt leap in with the info for EZNEC, but...

Are you just looking for generic plots (on the same scale), or do you 
have specific antennas in mind?  There are nice analytical equations for 
the pattern of a dipole/monopole over ground with specified dielectric 
properties, and maybe what you want is a good polar plot, more than an 
actual model.

If the latter, there are also a fair number of those plots out there 
already.. ARRL Antenna Book (and maybe the handbook) probably has them. 
Most text books probably have one too.

4nec2 will read EZNEC files, and it has pretty good plotting. I've 
stacked multiple plots on one set of axes, but I confess I haven't tried 
to get the "outer ring" to be a constant value, although I would imagine 
it's possible.

There are some matlab/octave codes out there to do decent polar plots 
for antennas as well. That lets you adjust the formatting of the plot 
nicely (font size, legends, colors, etc.)