Quite correct Euro man - we know the sea carries LF frequencies very well, a very wet landscape can help too, though the lack of salt is a factor too, I suspect. A ship at sea, also has the perfect earth - Orford, by the sea is nearly as good 😡
In the 1960s, Radio 390 astonished the "experts" with her huge signal, with just a 10kw TX on Red sands fort. Radio Veronica also showed the way, when changing from the very high frequency on MW to one of the lowest 😡.
BTW it's raining again here in Suffolk - though we are still on a hosepipe ban 😐