There seems to be mass confusion even among the gurus on
this newsgroup as to the difference between standing-wave
current, as exists on a 1/2WL dipole, vs traveling-wave
current, as exists on a terminated antenna like a rhombic.

I have prepared two EZNEC files that should run on the
free demo version of EZNEC as well as on the commercial
edition. These two files clearly show the difference in
the two types of currents.

The standing-wave example is designed to illustrate
standing-wave current. All of the forward energy is
reflected at the open end of the wire. The total
current displayed by EZNEC is the sum of the forward
and reflected currents which are close to equal.

The traveling-wave example is designed to illustrate
traveling-wave current. Most of the forward energy
is dissipated in the load resistor rather than being
reflected. The total current displayed by EZNEC is
the sum of the forward and reflected currents with
the reflected current minimized to a negligible value.

Each EZNEC file consists of a 1/4WL wire run horizontal
one foot above ground at 4 MHz. In the standing-wave file,
the wire is open and unterminated. In the traveling-wave
file, the wire is terminated to ground by its characteristic
impedance. To view EZNEC's tabulated current at each of the
18 segments along the 1/4WL, simply click on "Load Dat".

The standing-wave file is:

http://www.w5dxp.com/StndWave.EZ

The traveling-wave file is:

http://www.w5dxp.com/TravWave.EZ

In the following results (directly from EZNEC) please
note the almost constant phase reported for the
standing-wave current vs the continuously changing
phase reported for the traveling-wave current.

Here are the values of current at each segment for the
standing-wave example as reported by EZNEC:

EZNEC+ ver. 4.0

standing wave 12/18/2007 9:11:33 AM
--------------- LOAD DATA ---------------
Frequency = 4 MHz

Load 1 Current = 0.9974 A. at -0.01 deg.
Load 2 Current = 0.9874 A. at -0.02 deg.
Load 3 Current = 0.9703 A. at -0.03 deg.
Load 4 Current = 0.9461 A. at -0.04 deg.
Load 5 Current = 0.915 A. at -0.05 deg.
Load 6 Current = 0.8773 A. at -0.06 deg.
Load 7 Current = 0.8332 A. at -0.07 deg.
Load 8 Current = 0.783 A. at -0.08 deg.
Load 9 Current = 0.7271 A. at -0.08 deg.
Load 10 Current = 0.6659 A. at -0.09 deg.
Load 11 Current = 0.5999 A. at -0.09 deg.
Load 12 Current = 0.5295 A. at -0.10 deg.
Load 13 Current = 0.4553 A. at -0.10 deg.
Load 14 Current = 0.3777 A. at -0.10 deg.
Load 15 Current = 0.2974 A. at -0.10 deg.
Load 16 Current = 0.2148 A. at -0.11 deg.
Load 17 Current = 0.1307 A. at -0.11 deg.
Load 18 Current = 0.0447 A. at -0.11 deg.

Here are the values of current at each segment for the
traveling-wave example as reported by EZNEC:

EZNEC+ ver. 4.0

traveling wave 12/18/2007 9:18:19 AM
--------------- LOAD DATA ---------------
Frequency = 4 MHz

Load 1 Current = 0.9992 A. at -3.12 deg.
Load 2 Current = 0.9983 A. at -8.11 deg.
Load 3 Current = 0.9977 A. at -13.08 deg.
Load 4 Current = 0.9972 A. at -18.05 deg.
Load 5 Current = 0.9970 A. at -23.02 deg.
Load 6 Current = 0.9970 A. at -27.99 deg.
Load 7 Current = 0.9973 A. at -32.96 deg.
Load 8 Current = 0.9978 A. at -37.92 deg.
Load 9 Current = 0.9985 A. at -42.87 deg.
Load 10 Current = 0.9993 A. at -47.82 deg.
Load 11 Current = 1.0000 A. at -52.75 deg.
Load 12 Current = 1.0010 A. at -57.67 deg.
Load 13 Current = 1.0030 A. at -62.58 deg.
Load 14 Current = 1.0040 A. at -67.48 deg.
Load 15 Current = 1.0050 A. at -72.36 deg.
Load 16 Current = 1.0060 A. at -77.23 deg.
Load 17 Current = 1.0070 A. at -82.09 deg.
Load 18 Current = 1.0080 A. at -86.97 deg.
--
73, Cecil http://www.w5dxp.com