In June I gave a four hour antenna workshop at the Seapac hamfest in Seaside, OR. There were 200 plus slides and the file was too large (21 MB) to post on this blog but I've gone through and pulled out those parts which apply to short antennas and ground systems. This may be of some help to those working with the 600 m experimental group and on 80/160 m also.
Download seaside_2007_antenna_workshop_mod_3.pdf . This is about a 1.4 MB file.