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Richard Clark wrote:

wrote:
Cecil's antennas may be lossless,

Even more amazing is that they are linear transmission lines.

In spite of W7EL's assertions that antennas generate
nonsinusoidal waveforms, they indeed are linear and bear a
striking resemblence to a lossy transmission line. Why do
you think they are called standing wave antennas?

Take a look at page 18 of Balanis' "Antenna Theory", 2nd
edition, Figure 1.15. He shows how to turn a transmission
line into an dipole with exactly the same standing wave
current distribution before and after.
--
73, Cecil http://www.qsl.net/w5dxp

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On Wed, 17 May 2006 17:45:08 GMT, Cecil Moore
wrote:

Even more amazing is that they are linear transmission lines.
they indeed are linear

What is distinctly NOT amazing, is to see foolishness repeated.

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Richard Clark, KB7QHC wrote:
"Even morte amazing is that they (antennas) are linear transmission
lines."

Antennas and transmission lines are linear, passive, and carry incident
and reflected waves in much the same manner.

Look at "Current Distribution in Wire Antennas" on page 866 of Terman`s
1955 edition of "Electronic and Radio Engineering":
"A wire antenna is a circuit with distributed constants; hence the
current distribution in a wire antenna that results from the application
of a localized voltage follows the principles discussed in Chapt. 4---."
Chapt.4 is entitled "Transmission Lines".

Best regards, Richard Harrison, KB5WZI

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On Wed, 17 May 2006 13:04:51 -0500, (Richard
Harrison) wrote:

Richard Clark, KB7QHC wrote:
"Even morte amazing is that they (antennas) are linear transmission
lines."

morte indeed.

Antennas and transmission lines are linear, passive, and carry incident
and reflected waves in much the same manner.

Hi Richard,

I note you do NOT say "in exactly the same manner," which is
unsupportable in the literature. So, when you abstract from antennas
to
Chapt.4 is entitled "Transmission Lines".
it is apparent that to a first approximation, and for the purposes of
illustration (not engineering, except for amateur purposes) that it
may seem to be so.

Of course, all things are possible when the limits of Cecil's error
band encompass ±59%. Even White can be darn dark.

73's
Richard Clark, KB7QHC

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Cecil Moore wrote:
Tom Donaly wrote:

Cecil Moore wrote:

Assuming the source signal is sinusoidal, your above assertion
would require non-linearity in the antenna. Since antennas are
generally considered to be linear systems, would you please
explain where the nonlinearity is coming from?


No it wouldn't, Cecil. Even you know better than that. For those who
believe Cecil, consider a lossy transmission line terminated in a
short, or open. The signal is attenuated as it goes down the line, and
also
attenuated as it comes back up the line, in an exponential fashion.
The envelope is thus not sinusoidal.


An attenuated (damped) sinusoidal signal is still sinusoidal, Tom.
The fact that such a signal doesn't generate harmonics proves
that it is sinusoidal. If it were not sinusoidal, it would
by definition, be generating harmonics. Are you really asserting
that a damped sinusoidal signal generates harmonics? That's the
only way to prove it has gone nonsinusoidal.

All non-sinusoidal waveforms contain harmonics of the fundamental
frequency. Every competent engineer in the world is aware of that
technical fact. If the source signal to an antenna is a pure single-
frequency sine wave, and if the standing wave current is non-
sinusoidal, then the antenna has necessarily introduced harmonics,
i.e. the antenna is non-linear.

W7EL is simply mistaken when he says the standing wave current
waveform is not sinusoidal. If the standing wave current waveform
ever was nonsinusoidal, the antenna would, by definition, be
non-linear and be generating harmonics not present in the source
waveform.

Seems you guys need to review your Math 202 course covering Fourier
transforms.

We're talking about the envelope, Cecil, what are you talking about?
Since you've become so enamored of math all of a sudden, go ahead and
plot the current envelope on a length of very lossy transmission line
and tell me, with a straight face, that it follows a sine
function. On the other hand, don't bother. I know it's too hard
on your head, but it's an interesting exercise for everyone else.
73,
Tom Donaly, KA6RUH

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Richard Clark wrote:
Cecil Moore wrote:
Even more amazing is that they are linear transmission lines.

they indeed are linear

What is distinctly NOT amazing, is to see foolishness repeated.

Either transmission lines are linear or they are not linear.
The only way for them to generate nonsinusoidal signals is
for them to be nonlinear. The same goes for antennas.
--
73, Cecil http://www.qsl.net/w5dxp

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On Wed, 17 May 2006 20:11:55 GMT, Cecil Moore
wrote:

Richard Clark wrote:
Cecil Moore wrote:
Even more amazing is that they are linear transmission lines.

they indeed are linear

What is distinctly NOT amazing, is to see foolishness repeated.

Either transmission lines are linear or they are not linear.

Now there's a motto to live by.

The only way for them to generate nonsinusoidal signals is

Oh this is going to be good...

for them to be nonlinear.

Transmission lines generate signals? What a guffaw!

The same goes for antennas.

Double chuckle.

Talk about linear thinking
woops
Binary thinking, nothing linear from you this round.

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Richard Clark wrote:
I note you do NOT say "in exactly the same manner," which is
unsupportable in the literature.

"Exactly" is one of the buzz words like "perfect", "always",
"never", "infinite", "lossless", etc. that invariably make
any statement using them false. Nobody, except some "experts"
on this newsgroup, is ignorant enough to use those words in
a supposedly technical valid sentence.
--
73, Cecil http://www.qsl.net/w5dxp

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Tom Donaly wrote:
We're talking about the envelope, Cecil, what are you talking about?
Since you've become so enamored of math all of a sudden, go ahead and
plot the current envelope on a length of very lossy transmission line
and tell me, with a straight face, that it follows a sine
function. On the other hand, don't bother. I know it's too hard
on your head, but it's an interesting exercise for everyone else.

The envelope of an unattenuated sine wave is a straight line, Tom.
Is a straight line sinusoidal? Give us an everloving break! You
can fool half the people half the time but please stop trying to
fool all the people all the time.

Here is an example that should put an end to your foolishness.

100W-----50 ohm coax------50 ohm load dissipating 50 watts

Please explain how the 3dB attenuation in the coax causes
nonsinusoidal signals in the system. Proof of nonsinusoidal
signals would be the generation of harmonics. We are all
awaiting your reinvention of the laws of physics.
--
73, Cecil http://www.qsl.net/w5dxp

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Richard Clark wrote:
Transmission lines generate signals? What a guffaw!

Put a diode in a transmission line and it will definitely
generate a signal on a frequency that didn't exist before.
I'm really surprised that you don't know that fact of physics.
--
73, Cecil http://www.qsl.net/w5dxp