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.

Art said, in part;

"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."

You are right, you didn't say that the ends of a dipole do
not
radiate. But, by the above quote, you have implied just the
opposite.
'Doc

PS - Peashooter is back on the rack again.

"Gene Fuller" wrote in message
...
Art,

OK, here is my contribution.

Short antennas are quite thoroughly understood.
Yes but all knoweledge obtained has not been utilised
or consideredin this area even tho the use of this knoweledge is considered
beforehand as useless.


Most of the analytical
treatments of antenna theory I have seen start with short dipoles and then
expand to longer dipoles and other types of antennas.

There have been any number of segmented antennas proposed and built,
including
multiple trap antennas, multiple capacitor antennas, curtain antennas,
fractal
antennas, and so on. Do you have some new idea that has not already been
tried?
Yes, you may well want to look at some old antenna patents of mine, I wrote
them up myself in a way I thought the patent office wanted it and then they
changed the hell out of it but I think the drawings I made should be enough
for anybody to follow. Some locals built them from the same drawings.
They are not considered valid by the gurus associated with this group.



Short antennas radiate just fine, IF one can feed the power into the
antenna and
avoid losing too much to non-radiative losses.
Exactly, a receiving antenna that many use can not be transmitted on where
as mine is a perfect match that are as good as say a beverage in terms of
gain yet are only a smidgeon of it's length.

It has already been pointed out that all parts of a dipole antenna
contribute to
the radiation. Sure, it is possible to shorten the antenna and even
maintain the
same total radiated power.
Good thinking
However, the pattern will change and the antenna may
become more difficult to feed. But what if the match is a perfect one?

It is not clear what issue you find with Yagi antennas. Keep in mind that
it is
unlikely that one can achieve high directionality and gain from an antenna
with
a size that is a tiny fraction of the wavelength.

Unlikely but I have done it!

This is the case for radio
waves, optics, or any other wave phenomena. The reason people choose to
use
large Yagi antennas is gain, not efficiency or cost.

Well my last yagi ( 20 metres )I built had a boom length of 80 feet if I
remember wrightly with 13 elements two of which were reflectors. After that
antenna I decided to devote time to small antennas of a type that has not
been written up before that are mathematically proven, duplicated by a pro
computor program and of course used by me on various frequencies albiet not
very often..
Some of the antennas broke over the years but were easily duplicated.

Soooo, the bottom line is that there are large antennas, and there are
small
antennas. Different applications favor one type over others.

Do you expect to develop some new antenna design concepts or even some new
science? If the former, then the field is well-plowed, even if it is
theoretically still infinite. If the latter, well, good luck.

Thank you but one never gets to the end..It is also hard to believe the new
when over the years so many people have made false claims which makes it
relatively safe to call all new claims as bogus and the claiment is a lier.
When I had to fill out papers to come to this country I was asked what my
rank was in the boy scouts,had I eve
committed adultery and several other penetrating questions. I would suggest
it would be rather odd if a lying pattern started only after I arrived in
this country and after I retired from G.E. but I suppose it could happen.
Art

73,
Gene
W4SZ


Art Unwin KB9MZ wrote:

Gene,
Brian is a fellow Brit why would I trash a fellow 'G'
Come to think of it why are you trashing me when you contributed nothing
?
Just try to get along and you are home free
Art

"I would suggest
it would be rather odd if a lying pattern started only after I
arrived in
this country and after I retired from G.E. but I suppose it
could happen."

.... No, I won't do it. It would be just too easy...
'Doc

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

Dave Shrader wrote:
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.

If a current is 0 + j1.0 amps, exactly where is that one amp of current
located? The real component of phasor current always lies along the 'x'
real axis. A change from +0.001 amp at zero degrees through a zero magnitude
to -0.001 amp at 180 degrees is a 180 degree phase shift in *real* current
that exists in the real world. Imaginary current is, well, imaginary, and
is an artifact of the phasor math model. Has anyone ever measured j1.0 amps
of current at a point where the real current is zero?

Is this the 180 degree phase shift being discussed?

Originally, the 180 degrees phase shift being discussed was concerning
a current standing wave in a thin wire where the forward current and
reflected current are equal in magnitude. The phase of the net current
is 0 degrees for awhile and then shifts abruptly to 180 degrees according
to Kraus.

There are only two directions in a wire. For an AC signal, the current
is flowing one direction for 1/2 cycle and the other direction for the
other 1/2 cycle. The *real* magnitude of the current varies with physical
length (sin kL) and can be analyzed without any reference to phase.
--
73, Cecil http://www.qsl.net/w5dxp



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Piddle means to mess around with things

So does that mean an experimenter attaching an antenna to his chimney is
a piddler on the roof?

Duane, N6JPO

(Art Unwin KB9MZ) wrote in message om...
I found it interesting to read on a particular
antenna page that the antenna future will revolve
around what the person was presenting.

This does not compute to me...
He may well be correct if we are all lemmings but
people who piddle with antennas are a different breed.
Personaly I see antennas gyrating towards smaller
antennas where radiation per unit length will finish
at the top of the heap

Belly dancing antennas? I've never actually seen an antenna gyrate,
but it sounds interesting...

Antenna engineers have become so focussed on the half
wave patterns that they have completely ignored the
low efficiency portions at the ends of a half wave
antenna.

Says who? BTW, there are no low efficiency portions of a dipole.

Future antennas most surely will remove these
low efficient radiator parts

Why remove something that doesn't exist?

together with the addition
of coupling techniques that will help to move away
from the Yagi syndrome,

What is the "Yagi syndrome"? A disdain for antennas that fail to
compete with yagi's?
together with resolving the
of a "lossless" coupling direct to the transmitter

Of all your wishes, to me, this is the most foolish . I think you
should erase this "lossless coupling" from your mind, when it applies
to very small antennas. It doesn't exist, and never will. I don't know
if superconductivity could change this or not....I don't have the
superconductive materials needed for such a test..

that will obsolete the need of matching interface.

You wish...

Ofcourse this is where my intersts lie, but does this
vision of the future match yours or am I thinking
of the impossible?

Well, let me give you a hint....I prefer the largest antennas I can
get away with...I doubt anything will be changing that anytime soon.

One noted Russion scientist stated
that theoretically radiation can come from a single point,
is this part of our future or just an impossible dream ?

How does this relate to small antenna's? I don't get your point
here...

Best regards, and please put your pea shooters aside
and try to get along rather than looking for
ten seconds of cheap glory.

I don't have a pea shooter. I can pee a long ways though, if I go into
a holding pattern for about 5 hours after drinking about 14 cups of
coffee...Maybe we should have a rraa peeing contest....I don't want
any glory, if it's cheap. :/ MK

Art, KB9MZ wrote:
"Personally, I see antennas gyrating towards smaller antennas where
radiation per unit length will finish at the top of the heap."

Kraus, W8JK is somewhat famous among many reasons for his experience
with close-spaced antenna elements.

On page 184 of the 3rd edition of Kraus` "Antennas for All
Applications", is Figure 6-12 containing an ordinarily-spaced broadside
driven-array of two dipoles and a driven array radiating in the plane of
the two dipoles (an end-fire array), the W8JK array.

A feature of the W8JK array is close-spacing (1/8-wavelength). Gain of
the W8JK array is a tiny bit more than that of the 4X wider-spaced
broadside array. It`s a pity if you don`t have a copy of Kraus
available.

Kraus says in his earl;ier 1950 edition of "Antennas" on page 295:
"The end-fire array of two side-by-side out-of-phase 1/2-wavelength
elements discussed in Sec. 11-3 produces substantial gains even when the
spacing is decreased to small values."

To my eye, the W8JK array resembles the Adcock antenna if so spaced and
polarized. The 1955 edition of Terman has the Adcock on page 1050.

Terman has a comment on page 906 of his 1955 edition regarding
"Close-spaced Arrays-Super-gain Antennas. A review of the behavior of
broadside and end-fire arrays make it appear that in order to achieve
high gain it is necessary that the antenna system be distributed over a
considerable space. However, the antennas of Figs. 23-35 and 23-39
obtain enhanced directivity by employing antennas that are closely
spaced. Moreover, it can be shown that an end-fire (like a Yagi) type of
array that is short compared with a wavelength can theoretically achieve
any desired directive gain provided enough radiators are employed and
they are suitably phased. Such antennas which give great gain using
small over-all dimensions are referred to as super-gain antennas."

Read on. There is a fly in the ointment. Terman says:

" A characteristic of all close-spaced arrays is that as the ratio of
size to antenna gain is reduced, the radiation resistance also goes
down; this is illustrated by Fig. 23-36. The result is a practical limit
to the amount of gain that can be achieved in compact antenna systems,
since as the radiation resistance goes down the fraction of the total
power dissipated in the antenna loss resistance goes up. The Yagi
antenna of Fig.23-39 andf the corner reflector represent about the best
that can be achieved----."

So, Art may be on to something to some extent.

Best regards, Richard Harrison, KB5WZI