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Old April 11th 07, 09:33 PM posted to rec.radio.amateur.antenna
Owen Duffy Owen Duffy is offline
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First recorded activity by RadioBanter: Dec 2006
Posts: 1,169
Default Constructive interference in radiowave propagation

Cecil Moore wrote in
t:

Owen Duffy wrote:
Roy, one of the questions I continue to ask myself is why certain
explanations of transmission line / load behaviour seem inconsistent
with basic AC circuit theory as it applies at 50Hz or 60Hz, ...


That's an easy one, Owen. The wavelength is so long at

....

Cecil, you have conveniently clipped the context (as you do), the
relevant context being the line-load interface and source-line interface.

Statements in some explanations (by others) like "This clearly proves
that reflected power and forward power in a transmission line are both
real power, and that no fictitious power, or reactive volt-amperes,
exists in either one." seem incompatible with the basic AC circuit theory
explanation of a reactive load which must exchange reactive energy with
the transmission line over a complete cycle (and the same effect at the
source end).

Perhaps it is explained by hopping in an out of the instantaneous and
average context, just like switching between lossless lines and lossy
lines context with declaration, while actually carrying the analytical
simplicity of lossless lines and selectively layering selected aspects of
the loss.

BTW, I am not surprised at your dissertation apparently dismissing the
distributed impedance model of a line, because after all it is the
solution of that model that gives us the classic transmission line
equations that you seem to not want to use.

If the distributed network model you favour is the S paramater model,
properly applied, it is in fact entirely consistent with the distributed
impedance line model because the parameters are derived from the solution
to the distributed impedance line model.

Owen