On 22 Dec 2007, 12:57, John Smith wrote:
Cecil Moore wrote:
...
Why is the ignorance level about traveling waves so high
on this newsgroup? It's the result of those inadequate
lumped circuit models.

In Einsteins' spirit, let's have a real look at waves (basically the
KISS rule):

http://www.colorado.edu/physics/2000...ing_wave1.html

you must go to the bottom of each page and click to view the next of the
series.

The standing wave is "driven" by the forward & reverse traveling waves,
yet best thought of as being "separate in existence" (there are a total
of 3 waves!) ... and can only/really exist within strict confines of
design--or, resonance ...

But then, this is nothing new, or, you already knew that ... I just like
the way this is all presented--on those pages, or, even newbies are
introduced to the depth of the argument ...

Regards,
JS

John, There is no way you have a standing wave. I know the books
suggest
that but the books are wrong. When current gets to the top of a
fractional
wave antenna it just does not turn back. It has to wait until half a
period time has
elapsed The turning around point is determined by frequency and
frequency alone regardles of the length of the radiator. I f the
forward time has not run out the current must continue going forward
and that means going down the center of the wire which is resistive
only and does not generate radiation. The current traverses the center
twice and it is when it starts to return on the outside is when
propagation comences. So at no time is the current changing direction
except at a time of half a period. It only has one pulse per period
and that pulse is dependent on the surface content that it traverses.
If it is a full wave where the length equates to half a period then
the capacitance and inductance is comensurate with length.
If it is a fractional wavelength it only radiates when returning on
the surface where the energy storage content is half that of a full
wave
This particular point has arrested the advances in antennas for 100
years just because man does not accept change.
Regards
Art