moxoncalc
As a little learning exercise, I’ve written a calculator for Moxon antennas in Java as a command-line utility called moxoncalc. Given a frequency in megahertz and a wire size, moxoncalc will spit back to you the dimensions of a Moxon antenna designed to work at that frequency. By default it includes a diagram of what a Moxon looks like, but there are also optional formats with a short display that merely lists the dimensions of the sides and elements and a JSON rendering of the short display.