When maritime tropo conditions are good QSO over 1000 Km in the VHF and UHF bands are not uncommon, and even stations with a modest equipment (even handhelds) can succeed in making such QSO.
The only requirements for working by this type of propagation are that both stations are close the coast, have a good take off to the sea and that the path goes over the sea all the time (no land in the middle). Inland QSO can be also achieved but then a combination of maritime and terrestrial tropo is necessary (and often don't happen at the same time), and also the losses of the path are much greater thus requiring a much better station.
The maritime tropo takes place more often in the summer (June to September), but occasionally also in winter. Signals are often quite strong and stable (little QSB) and openings use to last for many hours and even days. An interesting prediction of tropospheric conditions is made available by William Hepburn, but bear in mind that it is just an estimation and it is not confirmed to be 100% accurate !
When tropospheric conditions are excellent it's also possible to make QSO by reflection on the coast, when there is no direct path over the sea between the two stations involved.
A quite common and often used path from my QTH in Mallorca goes toward 9H (Malta Is), nearly 1100 km. away, but there are some other much longer paths that could be usable....here you have the maps of just a few of them.
Possible long paths from Ceuta (EA9) to
This path was used by I0SNY/EA9 in 1983 to make the QSO with I0YLI/IE9 (JM68NR) on 10 GHz
that was for many years the IARU reg.1 record distance on that band (1660 Km)
Possible long paths from Melilla (EA9)
to southern France and Italy
Notice that although from Melilla the angle is quite wide, the presence of Balearic Islands, Corsica and
Sardinia in the middle of the path limits very much the QSO that can be made at longer distances.
Possible long paths from Malta (9H) to
Spain and eastern Mediterranean
Malta Is. is located in a privileged location in the middle of the Mediterranean, and QSO can be
made either with Spain and Middle East countries.
Possible long paths from Mallorca Is.
As said before QSO with IT9 and 9H are relatively common from here, but in this map you can see
that contacts with the northern coast of Libya and Egypt could be possible if
there were any activity from there (unfortunately there isn't...)
Longest possible path by maritime tropo
over the Mediterranean
So...if you wonder what's the max. distance that could be worked by this type of propagation
the answer is that it's only limited by the presence of obstacles (land) in the middle of the path...
The longest distance that could be theoretically achieved in the Mediterranean is nearly 2900 km.
in an incredible path between IM99 (EA5) and KM51 (SU).....Who will be the first to be active from
the north-werstern coast of Egypt and make the QSO.... ?
If you have any comments to this information or know of other tropospheric paths over the Mediterranean you can often use, please let me know so that I can complete this page.
Look for long distance tropo QSO Watch real-time QSO maps