So I'm really trying to get to grips with antenna radiation patterns, and more importantly things that are to close to the antenna that might interfere.

I've downloaded Qantenna and 4NEC2 to try and model my antenna and see what I can do, however neither of these programs allow you to 'make' an antenna (as far as I can tell) they require you to import an NEC file. Is there a free piece of software that will make a NEC file for a simple quarter wave whip antenna?