Walter Maxwell wrote:

On 15 Apr 2007 15:10:11 -0700, "Jim Kelley" wrote:


On Apr 15, 12:50 pm, Walter Maxwell wrote:


Seems to me that the only disagreement with my original posting is whether the condition at the stub point can
be called a 'virtual' short circuit.

Hi Walt,

Most everyone has directly expressed complete agreement with that
idea.


Here's the recurring theme:


*******Virtual impedance discontinuities do not cause
reflections.********


73, Jim AC6XG


OK Jim, if that's so, then I've got to figure out a new way to explain how antenna radiation patterns are
modified by changing the relative phase of the signals fed to multiple radiators, and by changing the spacing
between the radiators. Looks like I've had it all wrong for lo these many years. I thought I've been reading
the same references as all the other posters.

Walt

Hi Walt,

Your entire treatise is brilliant and useful with the one exception
noted clearly above. Perhaps you could cite a single one of those
references (other than Reflections of course) which directly
contradicts my simple observation of an extremely well understood
fundamental of nature.

Obviously a revision of that one circumstantial claim would have
absolutely no impact on element spacing or how waves interfere, and it
would in my view perfect the book. Once you have the currents and
fields worked out properly, they look after themselves. You don't
need to help them by inventing another mechanism for them to do their
job. Faraday, JC Maxwell and others have already worked that out to
most everyone else's satisfaction.

I think the discussion of virtual impedances and reflection
coefficients is useful as an analytical tool. But it should also
follow that the behavior being attributed to virtual entities is
likewise, virtual i.e. it behaves as though....; that the actual cause
of reflections is the real physical boundaries. That is the more
reasonable approach, Walt. IMO.

73, Jim AC6XG