"Cecil Moore" :
An antenna's abilty to "load"
is proportional to its electrical length. An antenna's
ability to radiate seems to be proportional to the
physical length of the antenna that is carrying the
highest current.
__________

Perhaps unexpectedly, the intrinsic pattern and directivity of a
physically/electrically short, unloaded monopole radiator are not greatly
different than those of a self-resonant 1/4-wave monopole. The big problem
with an unloaded, short radiator is the reactance at its feedpoint, which
means that very little current will flow into the short radiator from any
practical r-f source. But for the current that DOES flow in it, its
radiation performance will not be much different than that of a
self-resonant 1/4-wave monopole, at that same current flow (as NEC will
show).

Using a "loading" reactance to resonate the radiator allows maximum power
transfer from the r-f source into the feedpoint. But the remaining issue is
the low radiation resistance of the short radiator even when it is resonant,
which is a small fraction of the other series resistances in the antenna
system (ground and coil loss, mostly). As a result, much of the available
transmitter power produces heat rather than EM radiation.

RF