Sand is the least lossy ground beneath your feet, but how well does it
contribute to DX? Add some water and the loss skyrockets - and this
is called the boon of conductivity!

No, it is called the boon of reflectivity. The Z changed and power
CANNOT penetrate the interface. If you cannot get power into it,
there is nothing to conduct (and it is the molecular polarization and
relaxation moment that causes this, not conductivity).


It's been many years since my EM theory days in school, but I seem to
remember being taught that the way surfaces reflect EM waves is by being
excited by the impinging wave and then re-radiating due to the current flow
caused by the arriving wave. This would require the surface to be a good
conductor to be a good reflector.