Lambda Calculator is suitable for those using pre Windows 10 software such as Windows XP, Vista, Win7 or Win8. It is free to use and can be installed from here: Lambda_Calc.zip
Lambda Calc screenshot
Quad design Screenshot.
Quad Design v.2.4 is an easy to use app that can be used to help in the design of a quad beam antenna.
It is available Here for free download.
QUADDesign_readme.txt - the readme file (instructions)
However, if you find this software useful please consider making a donation Here.