One thing you can build by yourself is a wire-antenna. There are so much types
The one I build first was a G5RV-junior. You also can buy one but building it by yourself
will give you more satisfying I think. The G5RV antennas does have more versions.
Click on the picture for more sites and info about this great antenna.
Last year(2009) I decided to look for an antenna-analyzer. On the internet I did find
an Australian site with a Analyzer kit. After reading more articles about this kit I
decided to order this kit. Within less as one week after ordering and payment the package
was delivered allready by mail. Great job. The Analyzer I'm talking about is the VK5JST-analyzer.
You can build this kit within a couple of hours, but take your time for it.