Yes, summertime temp inversions along coastal areas and over areas of open ocean between land masses, etc. can introduce significant tropo enhancement, and in this case here tropo ducting....
Originally Posted by monte
some pretty serious AIS
propagation going on in the South of Portugal
But FYI, the world record
(144mhz ham SSB/CW vs. 156mhz marine
FM) distance for two-way contacts is 6412km!! (via Trans-Equatorial / TE F-layer prop)....
And, the Atlantic VHF
My personal VHF tropo scatter record is ~ 820 miles (about 1250km).....and my personal terrestrial VHF record (Es) was 2075 miles (about 3350km)....
(now if you count non-terrestrial paths, bouncing my vhf signal off the moon, gives us about 480,000miles / 769,000km....but that's using the Moon, so doesn't count regarding "propagation"....)
s/v Annie Laurie