VPlot shows the different take off angels and db gain of different yagi and dipole antennas at different heights and terrain. You can compare different configurations to determine the best for you QTH.
My good friend Adam, N6QR wrote that program back in 1991. I have uploaded the zip file with all original files included. The program is shareware so please read the instruction for use.
http://groups.yahoo.com/group/DeltaKilo/files/