If you look on the 'software' topic you should see a topic about free ware programs also I think, there have been a few other freeware programs mentioned and one was definitely for aerial design of Yagis etc...

John.

Look on the various Ham radio sites and newsgroups. You might start with www.arrl.org as well as the alt.rec.radio.amateur...... newsgroups, there is one for antennas. The ARRL also prints an antenna handbook which includes a CD with associated software.

Some of the programs may be DOS oriented but that should not be an automatic show stopper.

Here is a couple which may help;

http://www.netscum.com/~clapp/wireless.html

http://www.ifwtech.co.uk/g3sek/diy-yagi/index.htm

http://vk5dj.mountgambier.org/Yagi/Yagi.html