Art Unwin wrote:
Since the radiator is
a full WL that represents a period it is of closed circuit form.
My comments were about a one-wavelength straight
wire dipole in free space. The reflections from
the ends are what result in that large resonant
resistance at the center.
--Vf
Open --If
----------------------fp----------------------
Circuit Vr--
Ir--
Zfp - feedpoint impedance, Vf - forward voltage,
Vr - reflected voltage, If - forward current,
Ir - reflected current
Zfp = (Vf+Vr)/(If-Ir) = thousands of ohms
However, if we fold the 1WL dipole into a circular
1WL loop it is still a standing-wave antenna but
the phase of the reflections is reversed.
Zfp = (Vf-Vr)/(If+Ir) = ~100 ohms.
Where are those reflections coming from in a
circular 1 WL loop? Why is the phase of the
reflections reversed?
--
73, Cecil, IEEE, OOTC,
http://www.w5dxp.com