Hi Richard,
my feeling is that in the past some studies have tried to find out the
structure and relative strenght of the ground/space wave fields.
Experience has then given rules to evaluate the losses due to the high
reactive fields near the antenna with the lossy ground (i have seen a
paper using a 6 dB factor to take into account antenna mismatch and
such nearby losses).
It maybe that this is almost all that has been done.
Do you agree?


Maurizio