Richard Fry wrote:

No matter how short a dipole antenna is in wavelengths, current is
always zero at the ends of each arm of that dipole.

The current distribution on a thin, wire dipole takes the form of a
sine wave. If the antenna is short, as in this case, then the only
part of the sine that can exist is nearly linear. Hence the
~triangular shape for the total current on the dipole.

Confirm this for yourself using Figure 2-2(b) on page 2-4 of the
following link.

http://books.google.com/books?id=xTS... tenna&f=false

RF

You can also do it in a few seconds using the free EZNEC demo program.
Open the Dipole1.ez example and the View Antenna display. Click the
Currents (or FF Plot) button and see the current distribution in the
View Antenna display. Then change the frequency to 3 MHz to make the
dipole 0.05 wavelength long and click Currents or FF Plot again and see
the altered current distribution. You can see the shape better by using
the Current zoom control at the left of the View Antenna display.

As an additional educational exercise, compare the gains and patterns of
the lossless 0.5 and 0.05 wavelength antennas.

Roy Lewallen, W7EL