Hi Gary, seems like your the only one that is interesred in antennas on this
Jerry Springer group, so an answer there is.
Piddle means to mess around with things, since I am from
East London it could well be Olde English
With regard to efficiency per unit length. It is well known that the ends of
a 1/2 wave dipole can be lopped off without any noticable difference which
can be seen by the area lost under the normal current flow diagrams, so
efficiency can immediatly improved. When shortening the dipole even more we
get a transition to a straight line current flowline inplace of the sino
soidal curve which again shows a further inefficient portion at the ends
that can be lopped of. What this then shows that we can have a higher
current distribution per unit length with the mainly efficient portion in
the center of the dipole. Now one is in position to introduce a phase change
where one can have two dipoles in the same space taken up in the beginning,
collinier in form and containing only the mainly high efficient portions of
the center of a normal dipole. I see no reason why this transition can be
followed over and over again until the radiator contains an area under the
current curve that is uniform. Transformation to spot radiation
is totaly another matter which I believe should be left to our descendents.
Since you are an experimentor I would be happy to discuss my thoughts
privately rather than take up valuable space that is required for auguments
and pea shooters
Best regards
Art Unwin


"JGBOYLES" wrote in message
...
He may well be correct if we are all lemmings.

Are they the rats that jump off the cliff into the sea? If they are, I am
not
one of them.

people who piddle with antennas are a different breed.

I experiment with antennas, but piddle? I thought in Olde English that
meant
something else.

The rest of you post was interesting, could you provide more detail?
What is
"Yagi syndrome" and lossless coupling to the transmitter?


73 Gary N4AST

Art Unwin KB9MZ wrote:
Piddle means to mess around with things, ...

My unabridged dictionary says it has a second meaning.
There are many piddling contests on r.r.a.a :-)
--
73, Cecil, W5DXP

Cecil, are you discussing 'pea soup'?

Cecil Moore wrote:

Art Unwin KB9MZ wrote:

Piddle means to mess around with things, ...


My unabridged dictionary says it has a second meaning.
There are many piddling contests on r.r.a.a :-)
--
73, Cecil, W5DXP

Art wrote,
With regard to efficiency per unit length. It is well known that the ends of
a 1/2 wave dipole can be lopped off without any noticable difference which
can be seen by the area lost under the normal current flow diagrams, so
efficiency can immediatly improved. When shortening the dipole even more we
get a transition to a straight line current flowline inplace of the sino
soidal curve which again shows a further inefficient portion at the ends
that can be lopped of.


Hi, Art,
The above is untrue. Efficiency only has to do with the ratio of radiation
resistance
to total resistance. Also, the idea that the only part of an antenna that
contributes
to radiation is the center part because it carries most of the current is also
untrue.
The claim probably originates from the fact that most antenna parameters can be

calculated given a knowledge of current distribution. It's a false leap of
logic
to conclude that there are portions of a half wave dipole that don't radiate,
though. Since
those areas have high changing charge densities which are associated with
changing electrical fields which..., and so on, they radiate quite well.
I don't think most amateurs want to diddle around with infinitesimal
dipoles, anyway,
Art, which is what they'd end up with if they implemented your ideas. An array
of
infinitesimal dipoles such as you're suggesting would be fun to make, but I
doubt
the wisdom of expecting increased efficiency from it.
73,
Tom Donaly, KA6RUH

(P.S. Art, I hope you don't equate disagreement with ridicule. I reserve all my

ridicule for Cecil since he can take it.)

Tdonaly wrote:
(P.S. Art, I hope you don't equate disagreement with ridicule. I reserve all my
ridicule for Cecil since he can take it.)

.... .. .... ..

Tom, I notice you have not posted your calculations for
the phase angles of those superposed phasors I presented
yesterday. Did you come up with any phase angle other
than zero and 180 degrees? Do you understand why Kraus'
phase graph for standing wave current contains only two
possible values of phase?
--
73, Cecil, W5DXP

Cecil,

I am not Tom, but I will respond anyhow.

It is so hard to keep up with you. This entire thread started a few days ago
with a debate between you and Roy. You chastised Roy for considering the net
current instead of the individual components. Now you have switched back to
talking about net currents resulting from the addition of individual phasor
currents.

Which one do you want to talk about?

It is unlikely that anyone reading this newsgroup is confused regarding the back
and forth nature of the current on a thin wire. To insinuate such is merely a
cheap shot that appears intended to intimidate. (Go ahead, take your best shot.)
8-)

The concept of phasors is a common and useful tool for visualization and some
elementary numerical solutions. The simple standing wave analysis currently
under discussion and debate is certainly an appropriate subject for phasor
treatment. However, once outside of the realm of ideal one-dimensional systems
the use of phasors gets much more complicated. The use of conventional
mathematics for such problems is pretty standard.

The typical equation describing a standing wave is:

I = A * sin (kx) sin (wt)

The spatial phase of this equation is "kx", while the temporal phase is "wt". At
no time do these phases suddenly reverse direction. The resulting value for I
ranges through positive and negative values, and again it is unlikely that
anyone is confused.

If you choose to call the switch from current flow in the positive direction to
the negative direction a 180 degree phase shift, so be it. I prefer to keep the
phase in its place and let the sine function do its thing to reverse the value
of the equation.

73,
Gene
W4SZ


Cecil Moore wrote:

Tdonaly wrote:

(P.S. Art, I hope you don't equate disagreement with ridicule. I
reserve all my
ridicule for Cecil since he can take it.)


.... .. .... ..

Tom, I notice you have not posted your calculations for
the phase angles of those superposed phasors I presented
yesterday. Did you come up with any phase angle other
than zero and 180 degrees? Do you understand why Kraus'
phase graph for standing wave current contains only two
possible values of phase?
--
73, Cecil, W5DXP

Gene Fuller wrote:
It is so hard to keep up with you. This entire thread started a few days
ago with a debate between you and Roy. You chastised Roy for considering
the net current instead of the individual components. Now you have
switched back to talking about net currents resulting from the addition
of individual phasor currents.

Which one do you want to talk about?

Nice try, Gene. What got Roy into trouble is forgetting that the net
current consists of two components. One can choose to talk about either
the components or the net as long as one realizes that the net is the
sum of the components. Roy has said, in so many words, that I am stupid
to worry about the components when all I need to worry about is the net.
It's obvious that Kraus worries about the components and, therefore, I
have good reason for such. Great insight is afforded to he who considers
the primary components of the sum instead of ignoring them.

At no time do these phases suddenly reverse direction.

Aha, so you disagree with Kraus and apparently don't understand the
thin wire analysis of standing waves in his book.

If you choose to call the switch from current flow in the positive
direction to the negative direction a 180 degree phase shift, so be it.

A DDS chip can generate a sine wave. Are you telling me that +0.001 volts
out of a DDS chip is not 180 degrees different from a -0.001 volts out of
a DDS chip? At exactly what voltage level does it have to get to to call
it a 180 degree phase shift? If all you see is a step from +0.001 volts
to -0.001 volts, does the information that you don't know dictate whether
is is a 180 degree phase shift or some other phase shift? If so, you are
in deep doo-doo, my friend, and you cannot trust any measurements because
there are always unknowns.

This situation of math models dictating reality (instead of vice-versa) is
worse than I thought. In reality, there is no imaginary current when the
real current is zero. All current in the real-world is real. I suppose that
all current in the imaginary world is imaginary but that's not the world I
live in. If the real current is zero then, for people living in the real world,
the current is zero - there ain't no more. In reality, God doesn't control
everything about the universe according to his whim. HE allows HIS physical
laws to run the universe. If a 180 degree reversal in the direction of flow
of current is not a 180 degree reverse in reality, exactly what is it? If you
have a square wave with one amp as the maximum, and -0.1 amp as the minimum,
is that not a 180 degree phase shift? If you have a square wave with 0.00001
amp as the maximum and 0.00001 amp as the minimum is that not a 180 degree
phase shift? Is the quantum shift from +0.0000...01 volts to -0.0000...01
volts not a shift of 180 degrees?

Gene, I hate to burst your (sacred cow) bubble, but the imaginary part of
the current doesn't actually exist in my universe. If it exists in yours,
I suggest you subscribe to r.r.a.a in that universe, wherever it might be.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil,

What in the world are you blathering on about?

(That's a rhetorical question. No answer needed.)

I stated my position, and I have nothing more to add. Feel free to continue to
amuse yourself.

73,
Gene
W4SZ

Cecil Moore wrote:
Gene Fuller wrote:

It is so hard to keep up with you. This entire thread started a few
days ago with a debate between you and Roy. You chastised Roy for
considering the net current instead of the individual components. Now
you have switched back to talking about net currents resulting from
the addition of individual phasor currents.

Which one do you want to talk about?


Nice try, Gene. What got Roy into trouble is forgetting that the net
current consists of two components. One can choose to talk about either
the components or the net as long as one realizes that the net is the
sum of the components. Roy has said, in so many words, that I am stupid
to worry about the components when all I need to worry about is the net.
It's obvious that Kraus worries about the components and, therefore, I
have good reason for such. Great insight is afforded to he who considers
the primary components of the sum instead of ignoring them.

At no time do these phases suddenly reverse direction.


Aha, so you disagree with Kraus and apparently don't understand the
thin wire analysis of standing waves in his book.

If you choose to call the switch from current flow in the positive
direction to the negative direction a 180 degree phase shift, so be it.


A DDS chip can generate a sine wave. Are you telling me that +0.001 volts
out of a DDS chip is not 180 degrees different from a -0.001 volts out of
a DDS chip? At exactly what voltage level does it have to get to to call
it a 180 degree phase shift? If all you see is a step from +0.001 volts
to -0.001 volts, does the information that you don't know dictate whether
is is a 180 degree phase shift or some other phase shift? If so, you are
in deep doo-doo, my friend, and you cannot trust any measurements because
there are always unknowns.

This situation of math models dictating reality (instead of vice-versa) is
worse than I thought. In reality, there is no imaginary current when the
real current is zero. All current in the real-world is real. I suppose that
all current in the imaginary world is imaginary but that's not the world I
live in. If the real current is zero then, for people living in the real
world,
the current is zero - there ain't no more. In reality, God doesn't control
everything about the universe according to his whim. HE allows HIS physical
laws to run the universe. If a 180 degree reversal in the direction of flow
of current is not a 180 degree reverse in reality, exactly what is it?
If you
have a square wave with one amp as the maximum, and -0.1 amp as the
minimum,
is that not a 180 degree phase shift? If you have a square wave with
0.00001
amp as the maximum and 0.00001 amp as the minimum is that not a 180 degree
phase shift? Is the quantum shift from +0.0000...01 volts to -0.0000...01
volts not a shift of 180 degrees?

Gene, I hate to burst your (sacred cow) bubble, but the imaginary part of
the current doesn't actually exist in my universe. If it exists in yours,
I suggest you subscribe to r.r.a.a in that universe, wherever it might be.

Cecil, W5DXP wrote:
"If a 180 degree reversal in the direction of flow of current ia not a
180 degree reversal in reality, exactly what is it?"

From the 1937 second edition of Terman`s "Radio Engineering" page 70:

"In the case of both open- and short-circuited receivers (transmission
line loads) the voltage and current are substantially 90-degrees out of
phase at all places along the line except in the vicinity of the
quarter-wave-length points where the phase angle rapidly shifts from
nearly 90-degrees on one side of unity power factor to nearly 90-degrees
on the other side of unity power factor. The voltages on opposite sides
of a voltage minimum are therefore substantially 180-degrees out of
phase, as are also the currents on opposite sides of a current minimum.
In order to show this change of phase, the voltage and current
distributions in circuits with distributed constants are frequently
drawn as shown in Fig. 34---."

It helps to have Terman`s Figs. 33 and 34 in front of you to be
persuaded of the abrupt phase transistions. Terman can be accepted on
faith and his truth eventually sinks in.

Best regards, Richard Harrison, KB5WZI

My understanding is that the phase of the forward and reflected waves
varies along the transmission line. One 'rotates clockwise' the other
'rotates counterclockwise'. In the case of 'perfect reflection', a
mathematical study condition, the sum of these two waves varies along
the transmission line. The resultant sum produces the minimum and
maximum voltage we observe in a slotted line. It is to be noted that the
phase shifts at the all half wave points from the load, by convention,
rotate from the 'positive' two quadrants to the negative two quadrants.
Therefore, a polarity change exists.

Is this the 180 degree phase shift being discussed?

Deacon Dave, W1MCE
+ + +

SNIP

At no time do these phases suddenly reverse direction.


Aha, so you disagree with Kraus and apparently don't understand the
thin wire analysis of standing waves in his book.

If you choose to call the switch from current flow in the positive
direction to the negative direction a 180 degree phase shift, so be it.


SNIP