Walt, W2DU wrote:
"Have you guys ever considered that since the infinitesimally short
dipole radiates only 4 percent less than a resonant dipole, the only
reason for having any longer length than the infinitesimally short is to
make it resonant."

I`ll assume Walt`s infinitesimally short dipole is the same as Terman`s
elemental dipole. If so, I`ll quibble over the 4% . Terman`s table 23-1
on page 871 of his 1955 edition gives the directive gain of the
elementary doublet as 1.5 over the isotropic. The resonant dipole has a
1.64 gain . The difference is 0.14 or about 10% more from the 1/2-wave
dipole. Still no big deal.

Current is in the same direction in both halves of the elementalary
dipole no matter how short it is. Opposite charge polarities occupy
both elements and their effects tend to cancel on charges equidistant
from the middle of the antenna.

The field radiated in any direction is the vector sum of fields radiated
from infinitesimal elements, and field strength is proportional to
current.

Directional gain ignores losses. That`s the rub with the tiny antenna of
high capacitive reactance (the capacitance is small) and low radiation
resistance. The gain ratios are only valid with equal powers in
comparison antenna and subject antenna. To get the large current
required in the infinitesimal antenna to radiate the same power as the
1/2-wave dipole would be extremely difficult without enormous loss in
the match and load circuits.

Best regards, Richard Harrison, KB5WZI