[Antennas] Radiation Efficiency?

[C Whitaker]

de WB2CPN
Since the radiating element is so short, the
losses are the heat dissipated by the L and C
circuitry that matches the short antenna to
a 50 Ohm source.  The "efficiency" of the
short antenna is low because there is very little
current flow in it, (zero at the end because
there's no place for it to go).  Now, if this little
antenna was made longer, there would be more
current flow because of the added section, and
the L and C components wouldn't have to eat
up so much power.  If you want to make the
antenna 1/4 or 1/2 wave length long you'll have
about as much current flowing it it as you're ever
going to get.   (You  can force more current into
the tiny antenna if you "top load" it.  Then the
efficiency becomes almost directly proportional
to the length.    Here's where a picture, even a
pencil scribble, equals 1000 words. 
73  Clete