From Dave G3YMC

The mails from Laurie and Rik on this subject are interesting. They show a 
reflection layer for sky wave at some 60-80km, with a first hop skip distance a 
little under 2000km.  Perahps that explains why the current distance record is 
not very much more than that.  It also explains why the better equipped G 
stations can relatively easily work Reino, whereas those of us with more modest 
set-ups with relatively low antennas (and high angle radiation) have difficulty 
even hearing him.  Presumably 2 hops are required to work the USA.

Cheers Dave G3YMC
[email protected]
http://ourworld.compuserve.com/homepages/sergeantd