On my web site is a little project about home brewing your own mobile antenna. It was meant for someone with very little money. It will work, and surprisingly well, in most cases. However...
Trying to duplicate say a GLA Systems TBC, that's a whole new ball game. I've seen some HB stuff, which looked and operated, top drawer. I'm sure the project was done as a labor of love, as it certainly wasn't meant to save money.
The point here is, you have to decide which end of the stick you're on (excuse the pun). This said, I suspect in most cases you're better off cost-wise buying ready-made parts and constructing your own. If you're into designing one from scratch, you'll need more than the aforementioned books.