On Oct 4, 11:40*am, Art Unwin wrote
about "computer programs," e.g., NEC
So when these programs show that a radiator is tipped against the
ground to arrive at "100% efficiency"...

Your conclusion is faulty. See
http://groups.google.com/group/rec.r...19e5b91e29e0be

and...

A conductive radiator can be of any shape, size or elevation as
long as it is in equilibrium

Any conductor exposed to space will produce far-field EM radiation
from nearly 100% of the r-f current that can be made to flow along it,
in directions where fields from various parts of the conductor do not
cancel each other.

Those that will radiate most of the rated power of a transmitter will
have a high radiation resistance compared to the sum of the other
ohmic losses in the antenna system, whatever matching network is
required at the feedpoint to match the feedpoint Z to the transmission
line connected there, and a transmitter designed to supply its rated
power into that net load impedance.

Wire conductors and configurations that are small in terms of
wavelength necessarily have low radiation resistance. So systems
using them do not radiate a very high percentage of the available
power of the transmitter.

RF