Lawrence Livermore National Laboratory, which administers licensing for the copyrighted software NEC-4.2 and NEC-5.
The following links are valid as of Jan. 1, 2022 but might change in the future.
To obtain an NEC-5 license, go to https://ipo.llnl.gov/technologies/software/nec-v50-numerical-electromagnetic-code.
For instructions on updating an originally issued (unmodified) NEC-5 program to a modified (debugged) one, go to https://ipo.llnl.gov/technologies/software/nec-v50-numerical-electromagnetic-code. See NEC-5 for more information.
To obtain an NEC-4.2 license or upgrade NEC-4.1 to NEC-4.2 , email softwarelicensing@lists.llnl.gov