Roy, there you go again - confusing the issue by re-stating the
bleeding obvious.

What happens to the ground wave AFTER it has been radiated is not
relevant to the efficiency problem. ( Which has now been sorted out
anyway.)

The losses we are concerned with all occur in the near field. They
are -

(A) Loss in the radials and loss in the soil in the vicinity of the
radials, which is represented by Rradials. It is the input resistance
of the radials. It can be determined by measurements. Rradials is the
value used in the usual formula -

Efficiency = Rr / ( Rr + Radials ), which, in the present context,
is incorrect.

(B) Loss in the soil surface and soil NOT in the vicinity of radials,
but still in the near field, represented by Rsoil.

Frank, using NEC4, has managed to seperate losses A and B although not
the resistance of Rsoil.

So, after finding a value for Rsoil, a more accurate formula is -

Efficiency = Rr / ( Rr + Radials + Rsoil )

Where Rr is the radiation resistance referred to the base of the
antenna.

Note that Rsoil cannot be measured but can be deduced from the actual
efficiency. Both Rradials and Rsoil are functions of the same soil
characteristics.
----
Reg,