Cecil Moore wrote:
wrote:
Forget that forward and reverse stuff. That's not what is radiated.
Uh Keith, power delivered to the antenna equals forward power minus
reflected power. I notice you have not provided a way for standing
waves to develop without the existence of reflected waves. Do you
also believe that standing waves don't exist?
I think you have the tail wagging the dog a bit here.
It is the real voltages and currents on the line which deliver the
power to the antenna. These real voltages and currents sometimes
are in a standing wave pattern on the line. This standing wave
pattern can be described by postulating and using forward and
reflected voltage and current waves. Superposition lets you
compute the real voltages and currents but this does not make
the postulated forward and reflected voltages and currents
real.
And this model works so well (unfortunately) that, even though
in general you can not use superposition with power, in the
special case of lines with non-complex Z0, it even works for
power. This fluke, of course, serves to reinforce in the minds
of many the 'reality' of these forward and reflected powers.
When 'the many' encounter the general case, they are quite
perturbed that superposition no longer works for power and
strive mightily to modify the flawed model to account for
the discrepancies rather than just letting go of the model.
The reality is that forward and reflected voltage and current
waves are a convenience that assist in solving problems but
only real voltages and currents move energy.
....Keith