I am in kindergarten with 4NEC2 and trying to model a Gray-Hoverman TV antenna. I have someone else's model and understand most of the file parameters. I have added VHF elements that have S curves at each end but I can't find any info as to how to model the curves. I also want to model a folded dipole. Is there any hope for me? Thanks
Curves must be broken into a series of straight segments. The accuracy of your results will depend on the size of the segments relative to the wavelength of operation.
For the example below, I used the Create > Loop feature of EZNEC to produce numbered segments, each of which is further broken down (see the green dots), then reconfigured into an "S" shape:
There are many other means and tools for doing this. I have used spreadsheets to generate segment endpoints, a feature which is now powerfully amplified in AutoEZ by AC6LA (I take no credit for this, I just appreciate and routinely use the tool's many powerful features). The spreadsheet-like formula features of 4NEC2 could also be used in this application.
I have no affiliation with any of the products mentioned in this post.