There seems to be a dozen ways to get an individual amateur's zip code, but
finding all the amateurs in a particular zip code(s) doesn't seem to be so
easy.

I'd like to find half a dozen extras in about five zip codes around the
Rocklin or Roseville CA area that would be willing to sign up with Smitty's
VEC (GLAARG) to give exams with me at the local community college. Does
anybody have a good way of getting a listing either by zip code or (even
better) a defined radius from a given point?

(GLAARG does the exams for $4 and I am dealing with relatively low income
students, so ARRL is a bit pricey for them.)

Jim