There are some good sites to read: "how to become an antenna guru" http://www.borg.com/~warrend/guru.html W4RNL with both practical info and background, excellent: http://www.cebik.com/ Lots of info can be found in the discussion archives on contesting.com: http://lists.contesting.com/_towertalk/ I am sure there are many more. 73, Chris DL4YAO