Much more detailed info than the keynote is Trevor Marshall‘s talk on security and antenna design and how not to leak signals in directions you don’t want. Or, alternately, given that Marshall designed a parabolic feed that secured a 125Km WiFi link using standard Cisco cards, how to leak in exactly the directions you do want.) I suspect the talk is similiar to the one he gave to the SoCal Wireless Users group, which is streamed on the Linux Public Broadcasting Network if you want to learn more.
He also has some ugly-ass plots of PCMCIA antenna signal strengths (below – the two colours are different polarisations). WiFi card signals are all over the place, which I found out to my cost when I was trying to write a triangulating utility a while back.
