"Jim Kelley" wrote in message
ps.com...
On May 9, 2:54 pm, Cecil Moore wrote:

I agree that there is a logical contradiction between standing
waves and electromagnetic waves.

If there is, then there must also be contradiction between traveling
waves and destructive interference, and between two dissonant notes
and the beat they create. They are all simply the result of
superposition. Two things happening at the same time in the same place
with one result. But nothing more.

Take two sound waves of identical frequency and superpose them. The
result is a single waveform. Now decrease the frequency of one just a
bit. They still superpose to create a single waveform but now the net
amplitude varies with time according to the difference in frequency.
Decrease the frequency even more. We still have a single waveform,
and the beat frequency may now be too rapid to easily discern, but now
we can begin to discern two distinct pitches. Look at it on a
spectrum analyzer and we can see each of the two frequencies
individually. Yet all we see on the oscilloscope is one waveform.

Is that the contradiction?

73, Jim AC6XG


No, Its an illusion. The same thing happens when you view an AM signal. On
an oscilloscope the pattern you see may give you the impression that the
carrier is changing in amplitude with the modulation. Perhaps standing waves
are this same type of illusion.

Jimmie