John Plimmer wrote:
SEA GAIN is indeed a very interesting phenomena. A group of MW DXer's
throughout the world have been researching this and confirmed the very
beneficial results obtained when DXing by or near the sea. A couple of the
fella's unearthed research done by the BBC over forty years ago when they
were researching the best siting of MW transmitters. This was the definitive
paper that confirmed the existence of "sea gain" on the MW band.

I did a sea gain experiment with my Drake SW8 at Veldrif in 2005. Using a
reference station of France Info, Nice on 1557 I travelled inland from the
beach. By the time I got 10km's/6 miles inland the signal had dropped off
minus -23dB!

I can confirm after 40 years of DXing in various sites that DXing by the sea
is spectacularly better than the best inland location.
Most of your top American DXer's head for the coast during the DX season and
get amazing catches not possible inland.

--

John, may I ask a possibly stupid question? Does it make a difference
as to which direction the signals are coming from in relation to where
you are on the coast? For example, I live on the Gulf Coast side of
Florida, so European signals would have to come over the peninsula of
Florida to reach my antenna. Would being located on the other side of
Florida, say near Miami, be better for European signals, where there
would be nothing but ocean between my antenna and the radio station, or
is it an omnidirectional effect?