As more proof were needed...

This morning, between 08 and 09UT, I visited Red Wharf Bay, which has a wide, open sea horizon to the eastern hemisphere.  Last year, I had great DX results with low power from mobile whip and magnetic loop antennas.

Today, I decided just to listen from the car whilst the delta loop was also listening back home.

At Red Wharf Bay, September 2018, when the tide was at its highest.

Once again, the results are spectacular, and firmly highlight why, if you can, you should get a HF station down to your nearest beach.  The tide need not be in; it was about 2km away from me this morning, although the vast sandy bay was saturated with sea water.

In four out of seven cases, my simple mobile whip for 14MHz, coupled to a TS480SAT and Raspberry Pi 3B+ running WSJT-X, latest edition, could hear stations that my full wave delta, even though it is on elevated and highly mineralised ground and in an open environment, could not hear at all.

MW1CFN/M (beach), where the same stations were not heard at home:

JA9TTT, spots = 4, median S/N= -13dB.  
R2ARX, spots = 3, median S/N= -22dB
OH8GKP, spots = 5, median S/N = -04dB
UB1NDF, spots = 4, median S/N = -24.5dB


Here are the comparisons for those stations that were heard by both antennas, although the beach location produces more spots, and the difference in strengths is fairly small:

RA6AAW, beach spots = 5, median S/N = -2dB, home spots = 1, median S/N = -07dB
UR5KHL, beach spots = 9, median S/N = -20dB, home spots = 3, median S/N = -24dB

Proving that very low angle radiation is important in producing these differences, my delta was hearing the nearby PA1JT stronger than at the beach, although with the same number of spots:

PA1JT, beach spots = 4, median S/N = -3.5dB, home spots  = 4, median S/N = +07dB

It's very satisfying to obtain these results, especially when one recounts the words of the late Les Moxon, G6XN, when he thought (p. 168, HF Antennas for all Locations) about what the seaside could bring - without the benefit of WSPR and other digimodes that make his suggested experiments now, 26 years since his book's second edition, so easy and objective:

"At the Seaside.

...This is a complicated situation which is diffiult to analyse, though it can be assumed that, for some very low angle (possibly well under 1 degree) even the near edge of the [Fresnel] zone will be pushed out to sea.  This suggests dramatic possibilities but (from the lack of published information) either these have not yet been explored or there is a hidden catch somewhere.  It is hoped that readers in suitable locations will be encouraged to experiment on these lines." 

Well, Les, you were right. The effects are, indeed, dramatic!  A quick comparison with G0CCL, putting out 7dB more power than me, yet getting far weaker reports from VE6EGN, suggests a minimum 18dB advantage conferred by being near the sea. Wow!  Take a 10W QRP transceiver, and you could be putting out the equivalent of 640W!