Topband: Antenna patterns (in close)

[Tom W8JI]

Is there a cheap program that calculates and *displays* antenna patterns in 
close to the antenna?

I'm working on a better way to explain the limits of using receiving 
directivity, and explain why what might be phenomenal "this is the best 
thing ever" to one person might be "don't work for crap" to someone else.

I can do it in an excel sheet, but that it tedious and it doesn't paint a 
good visual picture.

I'm looking for a way to visually show why sometimes a certain thing works 
great, and other times the very same thing just stinks in very similar 
situations, and why things like noise cancellers might or might not work 
with multiple sources when the cases on the surface appear similar or to be 
easy solutions.

Thanks,
Tom