> David, I am also interested in the subject, and being new at this, I
> missed the 802.11b discussion on this (Is there an FAQ?).
Although it's a FAQ there isn't a FAQ!
In order to answer the question, you need to state very specifically
what you want to achieve. Saying that you want to increase the signal
isn't enough.
Think bare light bulb (=antenna 0dBi) compared with same bulb with a
reflector behind it (=antenna with parabolic reflector > 10dBi).
However, there's no light above or behind, that's what you have achieved
by increasing gain in one direction.
So the question is where do you need the signal, where is the antenna
and so on.
I'll point you to my web site as a starting point which has links to
plenty of other similar sites.
http://www.nodomainname.co.uk/cantenna/cantenna.htm
David.