Although
this program by K4VX is simpler than Yagi Optimizer, yet I find myself
using it more often to get a design start because of that simplicity.
Also, once I have working model on the screen I often use it to quickly
test for optimum spacing etc.
Yagi Optimizer and the rest of the NEC programs are superb software, but often much too complex or lengthy in use for the basic amateur needs. I use them! At the same time, for those basic amateur needs I suggest EZNEC. You will find a logo for that on my home page.
Once I have a working model, I move the data into EZNEC or Yagi Optimizer (as fits my needs) and do the fine work there.
In short I use the two in conjunction, for the sake of efficiency.
Yagimax is a DOS program, but this fact is what permits it to do speedy, repetitive calculations - exactly what occurs when you have iteration after iteration for a slight change in element length and spacing. All in all it has served me very well.
Clicking on the Yagimax button above will take you to the QRZ Antennas section of their download files. Scroll down the list until you find 'Yagimax', and commence the download. The software is free for Amateur Radio operators.