I think you can get some of the earlier versions on the official AppCAD download website.http://www.hp.woodshot.com/
Form thier site:
The AppCAD Story
The Application Engineering staff of the Microwave Semiconductor Division of Hewlett-Packard Co. created AppCAD as a design help for RF & Microwave ("wireless") designers. AppCAD was then, and still is, distributed free of charge as a service to the wireless engineering community. (The Microwave Semiconductor Division later merged with a different division of HP, all of which has since become part of Agilent Technologies.)
AppCAD was originally released in 1990 as version 1.02 (the "Classic" version). Version 1.02 was a DOS program that was compatible with Windows 3.x.
Although based on the original MS-DOS® version of RF and Microwave AppCAD "Classic," the current version of Agilent Technologies' AppCAD runs on 32-bit Windows® operating systems and contains many new and innovative design programs.
Click on the AppCAD Classic link.http://www.hp.woodshot.com/appcad/appcadcl.exe