Re: Wire diameter vs Impedance

Roy Lewallen wrote:
Suppose you have a thin antenna of any length. Look at the current distribution on the last few degrees of the antenna. I believe you'll find that it's the same regardless of the antenna length.

For a 1/2WL dipole, it is also the same at the center of the
antenna and at all other points anywhere on the antenna. The
standing wave current phase cannot be used to measure phase
shift in a wire or a coil or a top hat or a stub. The phase
of standing wave current is meaningless.

If one makes the top hat large enough, one should see an
abrupt ~180 phase reversal in the standing wave current.
This happens on each side of a current minimum point.
--
73, Cecil http://www.qsl.net/w5dxp
.

Relevant Pages

  • Re: Current through coils
    ... I have done a number of "peer reviews" for IEEE and AIP publications ... The Tesla coil crowd seems to contain an unusually large fringe. ... merely discuss the actual current in the antenna. ... not a traveling wave or a standing wave. ...
    (rec.radio.amateur.antenna)
  • Re: colinear representation in NEC
    ... is the primary current that exists on standing wave ... antennas like the antenna Roy used to measure his currents. ... standing wave antenna to a traveling wave antenna ...
    (rec.radio.amateur.antenna)
  • Re: Standing morphing to travelling waves, and other stupid notions
    ... If so, then for a single element radiator, the field pattern would appear as though a standing wave on the antenna had created the field. ... Since the standing wave energy is being used to transform ...
    (rec.radio.amateur.antenna)
  • Re: Dish reflector
    ... phase measurements along a standing wave. ... wave antenna with a current standing wave in the shape of a ... peak amplitude at the same time, and cross zero at the same time. ...
    (rec.radio.amateur.antenna)
  • Re: Current through coils
    ... The mobile antenna is a standing wave antenna. ... The forward current flowing through the coil is close to the same ... phasor sum of the forward current phasor and the reflected current ...
    (rec.radio.amateur.antenna)