hasan schiers wrote:

Are you saying (for example), that the feedpoint R of a 1/4 w vertical
against perfect ground cannot be reliably estimated at 37 ohms?

No. I'm not saying that.

If it can,
then isn't 37/R a measure of efficiency?

No. A ground can have transmission line effects. As such, it can modify
impedances.

Is it really possible to reduce ground losses to the absolute minimum and
not have a corresponding increase in field strength?

You are assuming a reduction of ground loss or an increase of ground
loss always indicates a certain resistance change at the feedpoint.
That assumption is not correct Hans.

For example, I can measure feed resistance of a mobile antenna on my
truck. By moving the antenna around I can vary the "apparent" ground
resistance from a few ohms to perhaps 30 ohms with very little change
in ground loss.

All I'm saying is the feedpoint reistance change when using a 1/4 wl
series fed radiator does not correspond to change in field strength. I
know that to be absolutely true, because I and others have seen that
happen.

73 Tom