On 6M K9ppy and W4IMD using HB portable rig at 820mW. into the
4 element beam at 33ft.
For 5W using my Argonaut 505 on 40m the best was SV54rwu from W1 country.
For the Slopbucket 20, DL5ARH
These two using LNR EF-quad at 30ft.
For the KNQ7A (40M) VK3 foundation station while mobile (8ft centerloaded whip).
That radio does about 7-8W at 13.8V.
For 10m during the last solar minimum all of South America, the carib islands,
Falklands and Antartica all using 4W SSB HB into one of two antennas the
PAR EF40/20/10 and the K6STI 10M loop with the top 20ft up. That was
over a 5 month period. I credit the K6STI 10M loop a 73" wide by 146" high
rectangle for the better part of all that as it was aimed to favor South America.
The par EF40/20/10 as set up then favored east west paths.
Antennas that are oriented in the desired direction and high enough to
be effective seem to make a difference.