Szczepan Bialek wrote:
Somebody wrote here that the current radiate.

In all AC circuits the same current if flowing in the live conductor and in
the ground (return).

Can 0V radiate?

That is why it only radiates when the currents do not flow in the
opposite direction!

So, a balanced feeder line with two parallel wires carrying the HF current
(in opposite directions) does not radiate.

But in a dipole antenna, the currents in the two wires do flow in the
same direction. So a dipole radiates.

On Thursday, July 12, 2012 3:30:02 AM UTC-5, Rob wrote:
But in a dipole antenna, the currents in the two wires do flow in the
same direction. So a dipole radiates.

Sorry, there are two currents, forward and reflected, flowing in opposite directions on a standing wave antenna. A 1/2WL dipole is a standing wave antenna where the SWR at the ends is infinite and the SWR at the feedpoint is ~20:1. There is forward and reflected wave energy flow on each element of the dipole. At the ends of the 1/2WL dipole the forward and reflected currents are 180 degrees out of phase and equal in magnitude so they phasor add to zero, i.e. a standing wave current minimum (null). Since the forward and reflected current phasors rotate in opposite directions, they are in phase at the feedpoint and phasor add (constructively interfere) to a standing wave current maximum (loop) and most of the radiation is from the center of the antenna.

The feedpoint impedance of a dipole is Zfp = (Vfor+Vref)/(Ifor+Iref) phasor math.
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73, Cecil, w5dxp.com