Richard:

[snip]
"Richard Clark" wrote in message
...
On Sat, 06 Dec 2008 18:46:16 GMT, "Dave" wrote the
lamentations of a weak mind struggling with the high concepts of an
infinitely Byzantine theory from the laboratories of Ærthur:

on the contrary, i believe antenna programs and understand how they work,
at
one time i wrote one of my own that did well on designing phased vertical
arrays... and not a single reference to the weak force in it at all!
..
..
..
73's
Richard Clark, KB7QHC
[snip]

Hmmmm you guys are just to sceptical of poor Art's "different" biases.

The one eyed man in the land of the blind, indeed.

Have ya'll considered that Art may not be fully occupying our own four-space
and may in fact be operating in several of modern string theory's higher
dimensions.

After all, modern we now know as explained by John Moffat [1], that from the
view of modern Physicists unfettered by actual observation and experiment
that there may be at least 11 of those dimensions available to someone of
Art's calibre and that perhaps... just perhaps, we "flatladers" may not even
be able to comprehend Art's machinations from our own puny four space
viewpoint.

All that said... we've got to get around to viewing emag fields from the
viewpoint of circular components. The universe may well be better
understood when viewed by circular polarization rather than by rectilinear
polarization. No?

[1] John W. Moffat, "Reinventing Gravity", HarperCollins Publishers, New
York, 2008. ISBN: 978-0-06-117088-1. May be found at LC under LCC
QC178.M64 2008.

Cheers!

-- Pete K1PO
-- Indialantic By-the-Sea, FL

On Sat, 6 Dec 2008 17:10:39 -0500, "Peter O. Brackett"
wrote:

"Reinventing Gravity",

I prefer the original over ersatz.

73's
Richard Clark, KB7QHC

Peter O. Brackett wrote:
. . .
By "mixed" polarization, I assume you mean a single polarization which
is neither horizontal nor vertical and can be described as a "mixture"
of a purely horizontal and a purely vertical wave.
[snip]

No. What I meant by "mixed" was that, just as with daylight for example,
the field contains many polarization orientations. In fact usually outside
in daylight most of the light we see with our eyes contains very nearly
an equal distribution of all polariztions. An exception in the sky's light
is perpedicular to the suns rays where because of upper atmospheric
conditions light becomes slightly polarized. It is claimed that some
people
can actually "see" this polarized light differently than normal light.
(Haider's
Brush) Of course many people know that reflected light, for example
from the surface of a lake, becomes highly polarized. This is the
reason that "Polaroid" sunglasses are used by sportsmen and others
to reduce perceived glare from reflective surfaces.

That said, mixed polarization, is also largely the case of HF waves
received over ionospheric paths. In other words HF waves received
over long distances will contain a wide distribution of linear
and perhaps circular polarizations. Thus rendering the use of single
polarized antennas relatively useless at HF by amateurs. Unless of
course one is prepared to pay the significant price in space and
equipment to implement a polarization diversity receiving system.

There is only one E field associated with a wave and, if linearly
polarized, it has only one orientation or polarization. It's not like
incoherent light, but akin to a laser. There is no "mixture" of
polarizations in an EM wave.

. . .

True for a single antenna and receiver, which is the usual case for a ham,
see my remarks above.

However if one is willing to pay the price for several antennas and
synchronous
receiving systems then receiving gains can often be obtained by the
exploitation
of polarization diversity.

Actually, you don't want synchronous receivers, or else you get a single
effective polarization just as though the antennas were combined into a
phased array. For spacial or polarization diversity, you need
intentionally non-coherent receivers.

[snip]
Interesting. Can you work an example for us? I'm curious as to what
you use for theta in the "law's" equation.
[snip]

Theta is just the relative orientation of the polarization of the
transmitting
and receiving antennas, or in the case of an optical polarimeter, the
relative orientations of the polarizing and analyzing polarizer.

Theta is commonly illustrated in undergraduate optical laboratories and
science
experiment kits, using a couple of pieces of "Polaroid" film with the
polarization
angle marked on the film by a notch or other marking. When the
two films are aligned with their polariztion direction perpendicular
there is no
light propagation, i.e. theta is 90 degrees, and when they are aligned
with theta
equal to zero then light is propagated.

In the case of dipole antennas, theta is zero when two antennas are
co-linear and theta is 90 degrees when the antennas are perpendicular.

So in your equation, what are theta for RHP and LHP, since you've said
that the equation applies to circular polarization?

. . .

[snip]
angular velocity of rotation is one revolution per cycle of the RF
carrier, or in other words one radian of circular rotation for each
radian of frequency transmitted. In other words most well known CP
antennas produce ONLY synchronous CP, where the angular velocity of
rotation of the E vector is synchronized exactly with the frequency
of the wave being transmitted.

That is, in fact, the definition of circular or elliptical polarization.
[snip]

Agreed, both you and I and thousands of others know that. [smile]


Then why are you calling your non-synchronous system "circular
polarization"?


Definition! Gosh where is Cecil when you need him? The only
problem with definitions is that there are so many of them!

---------------------------------------------------------------------------------------------


"When I use a word, Humpty Dumpty said in a rather scornful tone,

"It means just what I chose it to mean - neither more nor less."

"The question is," said Alice, "whether you can make words mean so many
different things."

"The question is," said Humpty Dumpty, "which is to be Master - that's
all."

-- Lewis Caroll, from Through the Looking Glass

--------------------------------------------------------------------------------------------


[grin]


That's a great attitude for a politician, philosopher, or biblical
scholar. But engineers and scientists depend on universally understood
technical terms in order to communicate. I'm free to say that my car
gets a gas mileage of 30 miles/hour and weighs 420 miles. But it
wouldn't be a smart thing to do if I intend to convey information.

[snip]
Sorry, it doesn't. An unavoidable side effect of the synchronicity
change is that the amplitude of the E field still changes at a 1 GHz
rate, going through a complete cycle from max to zero to max to zero
to max each nanosecond. A circularly polarized wave doesn't change
amplitude with time. A non-circular elliptical wave changes amplitude
but not fully to zero each cycle.
[snip]

Here there is a bit of fuzziness...

I agree that the E field of a wave is always changing at the RF carrier
frequency
since it is an AC waveform. Alternating current is always changing!
And so a
1 GHz carrier will always have an E field that oscillates back and forth
at the
carrier (center?) frequency when analyzed by a (linear) polarimeter.

I disagree with you that a circular polarized wave has a constant E field.

Even in the case of a purely circularly polarized the E field still
oscillates
at the carrier (center?) frequency when analyzed by a linear polarizer.

i.e. if a purely CP wave is received on a linear polarized antenna the
detected E field (Volts per meter) will be observed to be oscillating
at the carrier frequency. However if received on a purely CP responding
antenna this oscillating E fileld will appear to be constant.

The E field vector can be considered to be similar to the image of a
spoke on a rolling wheel. The radius of the spoke is constant, but
it's projection on the ground over which the wheel is rolling will
always be oscillating in length.

When you receive a circularly polarized wave on a linearly polarized
antenna, you're seeing only the component of the wave that's linearly
polarized in the orientation of the antenna. This is exactly the same
process as filtering a complex waveform. You've removed part of the
field and are observing what's left after the filtering process, then
drawing conclusions about the original waveform based on those
observations, much like listening to a concert orchestra through a long
pipe and deciding that orchestral sound is very ringy and limited in
tonal range. It would benefit you to gain a bit of education about
circularly polarized waves. You'll find that a circularly polarized wave
can be created from (or broken into) two linearly polarized waves
oriented at right angles and in phase quadrature. So each of the
components has a time-varying amplitude, but the sum, which is the
circularly polarized wave, has a constant amplitude but time-varying
orientation. Your linear antenna filters out one of the components,
leaving you to observe only the other.

[snip]
Circularly polarized waves have many characteristics and particular
relationships to linearly polarized waves. The waves you're producing
don't have some of these characteristics, like the constant amplitude.
Your method doesn't produce circularly polarized waves even though the
polarization does indeed change with time.
[snip]

I beg to disagree. The waves that I am describing are exactly the same.

Consider if the mechanical motor that spins my linear antenna spins at
exactly the carrier frequency. There would be then no way to tell the
difference between the two.

That's right, in that case you would be producing circularly polarized
waves. But only with a synchronous spin speed. As soon as you separate
the rotational speed from the wave's oscillation, you have something
else with different characteristics, e.g., a time varying amplitude.

[snip]
Because a circularly polarized antenna responds equally well to all
orientations of linear polarization, the normal helix wouldn't be
aware of the polarization rotation -- unless the polarization rotation
was fast enough to be nearly synchronous.
[snip]

Heh, heh... what would you consider to be "fast enough"?

Would the rate of spin have to be 99-44/100 percent of the synchronous
frequency? Or would it have to be closer than that?

At what magic spin frequency would the two be indistinguisable.

FWIW... I can propose a scheme that will electronically rotate the
linear antenna
at any desired frequency, at least up to the accuracy of modern atomic
clock standards.

What you'll end up with is amplitude modulation with the modulating
frequency being the beat note between your spinning speed and the wave
frequency. This creates sidebands. You'll see this when the sidebands
are within the bandwidth of the helix. Outside that, the helix will
filter off the sidebands and you'll just see the "carrier" -- the
original wave with no modulation.


[snip]
Sorry, I didn't find it "mind-blowing".
[snip]

Roy, I don't belive you have thought about it hard enough yet, for
clearly this idea
has already "blown" your mind!

If you say so.

For did you not state above that a circular carrier wave has a constant
amplitude?

Yes, I did. Circularly polarized, that is.

A radio wave with constant aplitude, indeed! Something must be blown!

At zero frequency, how would a constant wave propagate?

Here's a really neat little trick you might want to add to your bag --
superposition. As I mentioned, you can create a circularly polarized
wave from two linearly polarized waves. The linearly polarized waves are
of course normally time-varying. As long as the propagation medium is
linear (such as air), superposition says you can split the circularly
polarized wave apart into two linearly polarized waves, study and
analyze how they propagate, then add the two components back together
again after the propagation. This is, incidentally, a very simple way to
see what happens when a circularly polarized wave reflects from a
surface -- analyze the linear components separately and add the results.

This assumption/view that zero frequency wave can propagate is akin to
Cecil's
view that there are no reflections at DC.

No, it isn't.

I don't mean to be facitious and I am quite serious about all of this.

Just because no one has ever considered non-synchronous circular
polariztion before
does not mean that it doesn't exist, or that it may not be useful.

Me? I have already thought of several potential uses for
non-synchronous circular
polarization. How about polariztion frequency modulation? Or... how about
polariztion phase modulation? Or...

Got you thinking yet?

Sorry, I don't recall having stopped thinking. If I have, this isn't the
way to get me started.

Thanks again for your clearly interesting comments and feedback.

More thoughts, comments?

-- Pete K1PO
-- Indialantic By-the-Sea, FL

That's about all I can do at this end. I can't make you actually pick up
a text and learn about circularly polarized waves, and until you do,
you'll have some fundamental misconceptions about them.

Guess I'm one of those folks who someone described recently as "having
the common sense educated out of me". It's served me well, since it's
enabled me able to spend a career designing a wide variety of state of
the art electronic circuits and antennas, successfully mass produced,
which work as designed. But I know it's not for everyone.

Roy Lewallen, W7EL

On Dec 6, 12:46*pm, "Dave" wrote:
"Art Unwin" wrote in message

...

You can have diversity with respect to all polarizations except
circular where you only have the choice of one.

why can't you do lhcp and rhcp diversity?

If you believe that antenna programs
are utter idiocy then that will be inline with your general attitude.
I am sure that some have taken up my suggestion to check for
themselves instead of resorting to knee jerk reactions with out foundation.

on the contrary, i believe antenna programs and understand how they work, at
one time i wrote one of my own that did well on designing phased vertical
arrays... and not a single reference to the weak force in it at all! *nor
will you find any of the existing antenna modeling programs that use the
weak force. *which kind of contradicts your whole rant, you say you believe
in the modeling programs and that they give results that agree with your
corrupted weak force model, and yet they don't use the weak force at all....
never have, and never will. *nor can you state where the weak force is
included in Maxwell's equations, which of course all the modeling programs
are based on. *so that just leaves you hanging by your magical equilibrium
levitating diamagnetic neutrinos... which you still haven't explained how
they work with my ferromagnetic radiators.

I explained ferro magnetism and antennas a long time ago where the
weak force becomes swamped
You should be able to come to your own conclusions when evatuating
the effect on the Tank Circuit
With respect to the weak force action it was that addition to Maxwells
laws that provided equilibrium.
Kraus gave an example of it when he empirically created pitch angle
with respect to other parameters
without a full understanding of what created it. In this Universe
there is no such thing as a straight line tho a helicoptor can
simulate it with two rotors at right angles to create equilibrium the
same as a gyroscope or a Sedgeman.
The Universe is contained within an arbitrary border in equilibrium,
you can't get away from that.
The pitch angle that Kraus uses is a creation of the weak force which
thus forbids parallelism
in antenna arrays. If your antenna that you are bragging about
contains parallelism between elements and or the ground surface
then you are NOT obtaining maximum radiation but in fact you are
increasing your losses. You really have a long way to go with respect
to antennas
and the answers you search for are not to be found in Snakesphere that
is muddied to prevent understanding.
As far as antenna programs not using the weak force, that is stupid as
it is what is termed as the "displacement" current a guess arrived at
based on the units required
But rarely do hams use computer programs as initially designed around
Maxwell but instead use a modification of such in following Yagi and
Uda
planar design which is an aproximation. All you have to do is to
provide a one liner to a optimiser to realise you are stating a load
of crap and have reached a point where you cannot handle the truth as
it reveals exactly who and what you are. Some day a knoweledgable
person will arrive on this group and ram a computer sample down your
throat and expose you and the others as just talking heads. Most of
you are like a high school student who wondered into a post graduate
lecture room where all appeared as a torrent of babble until the time
you grew up, if you ever did.
Have a great week end
Art

Roy:

[snip]
That's a great attitude for a politician, philosopher, or biblical
scholar. But engineers and scientists depend on universally understood
technical terms in order to communicate. I'm free to say that my car gets
a gas mileage of 30 miles/hour and weighs 420 miles. But it wouldn't be a
smart thing to do if I intend to convey information.

[snip]
Sorry, it doesn't. An unavoidable side effect of the synchronicity
change is that the amplitude of the E field still changes at a 1 GHz
rate, going through a complete cycle from max to zero to max to zero to
max each nanosecond. A circularly polarized wave doesn't change
amplitude with time. A non-circular elliptical wave changes amplitude
but not fully to zero each cycle.
[snip]

Here there is a bit of fuzziness...

I agree that the E field of a wave is always changing at the RF carrier
frequency
since it is an AC waveform. Alternating current is always changing! And
so a
1 GHz carrier will always have an E field that oscillates back and forth
at the
carrier (center?) frequency when analyzed by a (linear) polarimeter.

I disagree with you that a circular polarized wave has a constant E
field.

Even in the case of a purely circularly polarized the E field still
oscillates
at the carrier (center?) frequency when analyzed by a linear polarizer.

i.e. if a purely CP wave is received on a linear polarized antenna the
detected E field (Volts per meter) will be observed to be oscillating
at the carrier frequency. However if received on a purely CP responding
antenna this oscillating E fileld will appear to be constant.

The E field vector can be considered to be similar to the image of a
spoke on a rolling wheel. The radius of the spoke is constant, but
it's projection on the ground over which the wheel is rolling will
always be oscillating in length.

When you receive a circularly polarized wave on a linearly polarized
antenna, you're seeing only the component of the wave that's linearly
polarized in the orientation of the antenna. This is exactly the same
process as filtering a complex waveform. You've removed part of the field
and are observing what's left after the filtering process, then drawing
conclusions about the original waveform based on those observations, much
like listening to a concert orchestra through a long pipe and deciding
that orchestral sound is very ringy and limited in tonal range. It would
benefit you to gain a bit of education about circularly polarized waves.
You'll find that a circularly polarized wave can be created from (or
broken into) two linearly polarized waves oriented at right angles and in
phase quadrature. So each of the components has a time-varying amplitude,
but the sum, which is the circularly polarized wave, has a constant
amplitude but time-varying orientation. Your linear antenna filters out
one of the components, leaving you to observe only the other.
[snip]

Yes indeed, we must be talking at cross purposes, since we seem to
have no disagreement on any of the above. I don't see where we differ at
all!

[snip]
Would the rate of spin have to be 99-44/100 percent of the synchronous
frequency? Or would it have to be closer than that?

At what magic spin frequency would the two be indistinguisable.
[snip]

I would repeat the above question in a slightly different way...

How much frequency, or for that matter phase, difference must there
be between the mechanical spin frequency and the carrier frequency
before you could tell the difference between your "conventionally defined"
circular polarization and my definition?

If my antenna was spining with an angular velocity within say,
0.000000000005% of the carrier frequency, would that do it?

Or perhaps my spin rate would have to be closer to the carrier
frequency than that?

If so, then how close does it have to be to qualify to be called
circular polarization under (your) traditional/conventional
definition?

[snip]
What you'll end up with is amplitude modulation with the modulating
frequency being the beat note between your spinning speed and the wave
frequency. This creates sidebands. You'll see this when the sidebands are
within the bandwidth of the helix. Outside that, the helix will filter off
the sidebands and you'll just see the "carrier" -- the original wave with
no modulation.
[snip]

Hmmm... Yes, I agree and that's partially correct, but some of the above
paragraph is
somewhat "fuzzy" to say the least.

That helix must be a very sharp [brick wall???] filter, no?

Let's get real here, no practical implementation of any kind of physical
filtering
mechanism can filter with infinitely sharp transition bands. It just
doesn't happen
in nature.

[snip]
Here's a really neat little trick you might want to add to your bag --
superposition. As I mentioned, you can create a circularly polarized wave
from two linearly polarized waves. The linearly polarized waves are of
course normally time-varying. As long as the propagation medium is linear
(such as air), superposition says you can split the circularly polarized
wave apart into two linearly polarized waves, study and analyze how they
propagate, then add the two components back together again after the
propagation. This is, incidentally, a very simple way to see what happens
when a circularly polarized wave reflects from a surface -- analyze the
linear components separately and add the results.
[snip]

Heh, heh... Superposition is not a 'trick' it is a well known principle and
Roy, I agree with all of the above!

What's your point?

Bringing up superposition is fine, but you seem to raise the concept of
superposition simply as a digression here, not as a means of disproving my
assertion that mechanically spinning a linear antenna is tantamount to
conventional circular polarization.

[snip]
That's about all I can do at this end. I can't make you actually pick up a
text and learn about circularly polarized waves, and until you do, you'll
have some fundamental misconceptions about them.
[snip]

Hmmm... that was a cheap shot! Unfortunately I agree, YOU cannot
make me pick up a text.

However, I can make myself do so myself, and... it may (or may not)
interest you to know that I have done so on many occasions.

In fact I have picked up several such texts, addressing such subject matter
authored by Physicists and Engineers ranging over subjects
as diverse as radio frequency antennas and optics.

Would it impress you if I sent you a picture of my personal library
of several hundred volumes, which contains perhaps a dozen or more
textbooks on electromagnetics. Since I have been examined on these
subjects at graduate degree levels by the faculty at several duly accredited
Universities it seems that there is some evidence that I may have read and
understood at least a few paragraphs from those texts that I "picked up"!
[smile]

[snip]
Guess I'm one of those folks who someone described recently as "having the
common sense educated out of me". It's served me well, since it's enabled
me able to spend a career designing a wide variety of state of the art
electronic circuits and antennas, successfully mass produced, which work
as designed. But I know it's not for everyone.
[snip]

Hmmm... I too have spent (wasted?) most of several decades designing
electronic products and equipment for international markets sold in more
than 40 countries with at total sales volume exceeding $5BB dollars.

And it seems in today's world that if you combine that Engineering
experience with $2.50 you can buy a cup of coffee at Starbucks!

Now that we have suitably set the stage, lets get back to the common
sense Engineering question at hand!

All I need is a number!

Perhaps I should regurgitate the statement of Lord Kelvin about knowledge
that dear departed Reg used to quote. You know... the one about quantifying
things, the one that says you know nothing unless you can put a number to
it!

Do I really need to do that here? Reggie dear friend, are you watching from
above?

Roy, please answer the following common sense Engineering questions, just
how close must the angular velocity of my spinning antenna be to the carrier
frequency before YOU will allow it to be called circular polarization?

A simple numerical value in percentage form would do fine!

[smile]

-- Pete K1PO
-- Indialantic By-the-Sea, FL

On Sun, 7 Dec 2008 00:22:05 -0500, "Peter O. Brackett"
wrote:
On Sat, 06 Dec 2008 15:49:26 -0800, Roy Lewallen wrote:
Guess I'm one of those folks who someone described recently as "having the
common sense educated out of me".

Roy, please answer the following common sense Engineering questions,

And I thought Abbott and Costello were dead - but evidently not their
"Who's on First?" routine. :-/

73's
Richard Clark, KB7QHC

Peter O. Brackett wrote:
. . .
Yes indeed, we must be talking at cross purposes, since we seem to
have no disagreement on any of the above. I don't see where we differ
at all!

For starters, a circularly polarized wave, as universally understood,
has an E field which is constant in amplitude, rotates in synchronism
with the rotational frequency of the field, and has a particular
relationship to constituent linearly polarized components. The field
you're generating doesn't, yet you're calling it "circularly polarized".

[snip]
Would the rate of spin have to be 99-44/100 percent of the synchronous
frequency? Or would it have to be closer than that?

At what magic spin frequency would the two be indistinguisable.
[snip]

I would repeat the above question in a slightly different way...

How much frequency, or for that matter phase, difference must there
be between the mechanical spin frequency and the carrier frequency
before you could tell the difference between your "conventionally defined"
circular polarization and my definition?

Any difference at all. If there's even a tiny difference, the E field
will change in amplitude with time. If it's perfectly synchronous it
won't. The rate at which it changes with time is the difference between
the field rotation frequency and the frequency of the generated signal.
If they're synchronous, the difference is zero, and no change in
amplitude with time.

If my antenna was spining with an angular velocity within say,
0.000000000005% of the carrier frequency, would that do it?

If by "it" you mean make the difference non-discernible, the answer is
no. See above.

Or perhaps my spin rate would have to be closer to the carrier
frequency than that?

See above.

If so, then how close does it have to be to qualify to be called
circular polarization under (your) traditional/conventional
definition?

They have to be identical. See above.

The question you posed earlier was different, involving detection of the
difference with a particular kind of antenna. Like the linear antenna
you used in another example, it filters the signal which alters its
properties. So my answer to this new question is different.

[snip]
What you'll end up with is amplitude modulation with the modulating
frequency being the beat note between your spinning speed and the wave
frequency. This creates sidebands. You'll see this when the sidebands
are within the bandwidth of the helix. Outside that, the helix will
filter off the sidebands and you'll just see the "carrier" -- the
original wave with no modulation.
[snip]

Hmmm... Yes, I agree and that's partially correct, but some of the above
paragraph is
somewhat "fuzzy" to say the least.

That helix must be a very sharp [brick wall???] filter, no?

No.

Let's get real here, no practical implementation of any kind of physical
filtering
mechanism can filter with infinitely sharp transition bands. It just
doesn't happen
in nature.

That's not required, although I see it's how you've interpreted my use
of "bandwidth". There is no such brick wall rejection region.

[snip]
Here's a really neat little trick you might want to add to your bag --
superposition. As I mentioned, you can create a circularly polarized
wave from two linearly polarized waves. The linearly polarized waves
are of course normally time-varying. As long as the propagation medium
is linear (such as air), superposition says you can split the
circularly polarized wave apart into two linearly polarized waves,
study and analyze how they propagate, then add the two components back
together again after the propagation. This is, incidentally, a very
simple way to see what happens when a circularly polarized wave
reflects from a surface -- analyze the linear components separately
and add the results.
[snip]

Heh, heh... Superposition is not a 'trick' it is a well known principle and
Roy, I agree with all of the above!

What's your point?

You don't believe that a wave with constant amplitude E field can
propagate. My point is that the constant E field amplitude circularly
polarized wave can be made of the sum of two time-varying waves. Each of
these waves can propagate. If you're familiar with superposition it
should be obvious that the original wave can be split into those
components, each component and its propagation can be analyzed
separately, and the results summed at the far end of the path. That's
how a CP wave having a constant amplitude can propagate.

Bringing up superposition is fine, but you seem to raise the concept of
superposition simply as a digression here, not as a means of disproving my
assertion that mechanically spinning a linear antenna is tantamount to
conventional circular polarization.

No, it was brought up to demonstrate how a wave having a constant
amplitude E field can propagate. You had used the argument that a
circularly polarized wave can't propagate because its E field has a
constant amplitude, as support for your incorrect assertion that the
amplitude of the E field of a circularly polarized varies with time. A
circularly polarized wave has a constant amplitude E field, which can be
easily demonstrated from the equations describing it. It propagates.
Your pseudo-circularly polarized wave doesn't have a constant amplitude
E field, which is only one way it differs from a circularly polarized wave.

[snip]
That's about all I can do at this end. I can't make you actually pick
up a text and learn about circularly polarized waves, and until you
do, you'll have some fundamental misconceptions about them.
[snip]

Hmmm... that was a cheap shot! Unfortunately I agree, YOU cannot
make me pick up a text.

However, I can make myself do so myself, and... it may (or may not)
interest you to know that I have done so on many occasions.

In fact I have picked up several such texts, addressing such subject matter
authored by Physicists and Engineers ranging over subjects
as diverse as radio frequency antennas and optics.

Would it impress you if I sent you a picture of my personal library
of several hundred volumes, which contains perhaps a dozen or more
textbooks on electromagnetics. Since I have been examined on these
subjects at graduate degree levels by the faculty at several duly
accredited
Universities it seems that there is some evidence that I may have read and
understood at least a few paragraphs from those texts that I "picked
up"! [smile]

I'm impressed, but it's not apparent to me why, with those resources
available, you're having trouble finding how the amplitude of the
circularly polarized wave E field varies with time, or applying
superposition to discover how it propagates. Choose one or two of your
texts which has the equations for circularly polarized waves. Chances
are good that I have the same text, and if you'd like I can show you how
to derive the instantaneous E field amplitude from the equations. But
I'm afraid you would have to pick it up to find the equations.

But if you can do that, you might be able to write the equations
describing your signal, and then the differences between it and the CP
equations should become obvious.


[snip]
Guess I'm one of those folks who someone described recently as "having
the common sense educated out of me". It's served me well, since it's
enabled me able to spend a career designing a wide variety of state of
the art electronic circuits and antennas, successfully mass produced,
which work as designed. But I know it's not for everyone.
[snip]

Hmmm... I too have spent (wasted?) most of several decades designing
electronic products and equipment for international markets sold in more
than 40 countries with at total sales volume exceeding $5BB dollars.

And it seems in today's world that if you combine that Engineering
experience with $2.50 you can buy a cup of coffee at Starbucks!

Now that we have suitably set the stage, lets get back to the common
sense Engineering question at hand!

All I need is a number!

Oh, if that's all you need, 42 is always a good choice.

Perhaps I should regurgitate the statement of Lord Kelvin about knowledge
that dear departed Reg used to quote. You know... the one about
quantifying
things, the one that says you know nothing unless you can put a number
to it!

Do I really need to do that here? Reggie dear friend, are you watching
from above?

Roy, please answer the following common sense Engineering questions, just
how close must the angular velocity of my spinning antenna be to the
carrier
frequency before YOU will allow it to be called circular polarization?

It must be exactly the same.

A simple numerical value in percentage form would do fine!

0.

Peter O. Brackett wrote:

Now transmit on that dipole antenna whilst mechanically spinning it
clockwise [RHCP?] (with a mechanical motor of some kind).

The dipole antenna is linear and thuse emits linear polariztion, except it
is mechanically spinning, and so the E vector emanating from the antenna
will be rotating with respect to its direction of travel.

In this case the angular velocity of the motor that spins the linear antenna
need not be synchronous with the frequency being radiated.

For example we could mechanically spin the antenna at 330 rpm while
transmitting a carrier of 1 GHz.

This would most certainly produce circular polarization. For is not the E
vector spinning at 330 revs!


Andy writes:

It sounds to me like you are describing the technique for generating
an aircraft VOR signal, which has been in use for well over 50 years.

The VOR band is 108 - 117 Mhz, and the antenna is a cardoid
pattern
that is rotated mechanically at a 30 hz rate. At a distant point
this
results in a 30 hz amplitude modulation of the received signal, which
is one of the components used in the signal processing for the
receiver to determine the direction to or from the ground VOR station.

Simply rotating the antenna does not result in circular
polarization, but
rather it changes the field strength of the radiated signal at a point
in
space.... The received signal is therefore modulated in amplitude as
the pattern passes a singular distant point in space.....

I just wanted to throw this in the mix, since rotating the antenna
has
been around for a long time.

Of course it can be done electronically now, but the initial
systems
were simply turned by a motor.

Andy W4OAH , ex- aircraft nav system
designer....long retired.

Andy:

Hey, thanks for your input.

I know about VOR systems and other similar systems such as TACAN. Indeed
they do use rotating antennas.

However VOR and TACAN use rotating antennas in the same way as rotating PPI
radar antennas, that is they emit linearly polarized
waves whilst rotating the direction of highest directivity/gain.

They do not emit circular polariztion as such.

Rather they emit linear polarization whilst aiming or directing the 'beam'
of linear polarized waves as they rotate.

Sort of like rotating a flashlight, or the beam of a searchlight or coastal
lighthouse.

I'm not sure that anyone yet (that includes Roy Lewalen) has fully
understood exactly what I was trying to convey.

I'm afraid that the true nature of circular polarization is not well
understood by many.

Perhaps opitical scientists understand circular polarization best, if only
because most of the important 'applications' of circular polarization are in
the field of optics rather than radio.

-- Pete K1PO
-- Indialantic, By-the-Sea, FL


"AndyS" wrote in message
...


Peter O. Brackett wrote:

Now transmit on that dipole antenna whilst mechanically spinning it
clockwise [RHCP?] (with a mechanical motor of some kind).

The dipole antenna is linear and thuse emits linear polariztion, except
it
is mechanically spinning, and so the E vector emanating from the antenna
will be rotating with respect to its direction of travel.

In this case the angular velocity of the motor that spins the linear
antenna
need not be synchronous with the frequency being radiated.

For example we could mechanically spin the antenna at 330 rpm while
transmitting a carrier of 1 GHz.

This would most certainly produce circular polarization. For is not the
E
vector spinning at 330 revs!


Andy writes:

It sounds to me like you are describing the technique for generating
an aircraft VOR signal, which has been in use for well over 50 years.

The VOR band is 108 - 117 Mhz, and the antenna is a cardoid
pattern
that is rotated mechanically at a 30 hz rate. At a distant point
this
results in a 30 hz amplitude modulation of the received signal, which
is one of the components used in the signal processing for the
receiver to determine the direction to or from the ground VOR station.

Simply rotating the antenna does not result in circular
polarization, but
rather it changes the field strength of the radiated signal at a point
in
space.... The received signal is therefore modulated in amplitude as
the pattern passes a singular distant point in space.....

I just wanted to throw this in the mix, since rotating the antenna
has
been around for a long time.

Of course it can be done electronically now, but the initial
systems
were simply turned by a motor.

Andy W4OAH , ex- aircraft nav system
designer....long retired.

Peter O. Brackett wrote:

Sort of like rotating a flashlight, or the beam of a searchlight or
coastal
lighthouse.



Andy comments:

Exactly right !!! And a good analogy....

Consider this then:

A patch antenna, circularly polarized, mounted at the end of a
motor shaft, rotating in the opposite direction of the polarization...
..... at a speed equal to the frequency...

Does the polarization "unravel" and emit a linear, non-rotating
polarization ?

Is this the sort of principle that you were trying to convey ??

If this is the case, any discrepancy in the motor, say 1 hz out of
10 Mhz , would result in an Efield rotating at a 1 hz rate.... and
the
receiving antenna would have to be very very very long in order
to fully receive the polarized wave....... I think....

And if the motor shaft and the frequency were identical, the Efield
would be linear, stable, and non-rotating.....


This is getting beyond my personal antenna expertise, but I still find
it
interesting....... Please pardon my lack of understanding, .... if I
still
don't "get" it....

Andy W4OAH