Circular polarization... does it have to be synchronous??
Peter O. Brackett
Warning... this could be mind blowing!
Conventionally electromagnetic wave 'polarization' refers to the relative
physical spatial orientation of the electric field vector (E) of an
electromagnetic wave.
It is commonly understood that polarization of electromagnetic waves may be
either linear or circular.
Linear Polarization (LP):
Of course waves that are linearly polarized may have any arbitrary
orientation angle (theta) with respect to a reference frame such as the
earth's surface. For example most common linear amateur antennas produce
and/or respond to waves of linear polarization, and these antennas produce
either either horizonally or vertically polarized waves depending upon the
orientation of the (linear) antenna with respect to the earth's surface
(ground).
As examples; a 1/2 wave length dipole for 10 meters hung at 30 feet between
two trees of equal height produces a largely horizonally polarized wave and,
a 2 meter 1/4 wave dipole mounted in the center of the roof of an automobile
produces a largely vertically polarized wave.
Of course as electromagnetic waves are propagated throughout an environment
are never purely orientated and usually contain an ensemble of many
orientations, because the waves are reflected from the ground, trees,
buildings, mountains, bridges, moving vehicles, and sometimes propogated
through moving and anisotropic media such as the ionosphere, etc... and so
the multiple reflection surfaces at various angles to the earth's surface
and/or refractions and Faraday rotations will conspire to "mix up" the
original orientation of the E vector of a purely linear transmitted wave and
usually produces a quite mixed polarization at distance from an emitting
antenna.
Malus' Law {I = Io [cos(theta)]^^2} describes the response of a linearly
polarized receiving antenna to waves arriving at a polarization angle theta
relative to the receiving antenna's preferred orientation. i.e a
horizontally polarized antenna will produce maximum response to horizontally
polarized waves and a minimum response (zero) to a vertically polarized wave
and vice versa.
Of course in practice, because of the multipath reflections and refractions
the 'cross response' is never exactly zero or maximum as predicted by Malus
Law.
Just the same it is preferable to have the orientation of a receiving
antenna 'aligned' with that of a particular transmitting antenna. In the HF
region it is difficult for hams to "rotate" the orientation of their
receiving antennas to maximize signal pickup based upon polarization, and so
most hams are forced to take whatever response their relatively fixed
antennas produce to the relatively unknown orientation of received waves.
In military or commercial installations, where money and space may not be an
issue, either electronically or mechanically derived spatial antenna
polarization diversity can be utilized to maximize received signal strength
based upon arriving polarization. Polarization diversity receivers...
Circular Polarization (CP):
Circular polarization describes the condition when an electromagnetic wave
is spinning or rotating with around its direction of transmission. That is
the electric vector (E) of a circularly polarized electromagnetic wave is
rotating with an angular velocity as the wave travels through space. This
is in contrast to the E vector of a linearly polarized wave which merely
oscillates in one linear direction.
Just as with linear polarization (horizontal and vertical) there are two
different distinctly possible orientations for circularily polarized waves,
these are known as Right Hand Circular Polarization (RHCP) and Left Hand
Circular Polarization (LHCP). There are actually two well known
conventions used to label R and L CP depending upon the community of
interest, namely physics/optics and electrical/electronics. Usually
electronics folks refer the direction of rotation to the rotation of the E
vector around the direction of travel from a transmitting antenna, whilst
the optical physicists refer the rotation of E around the direction of
travel towards a receiving lens. It's the same as the definition of up and
down, it's all in the eye of the beholder. Regardless there are two
orientations for CP
Apparently circular polarization is less commonly known and understood than
linear (horizontal/vertical) polarization especially among hams.
There exist RHCP antennas and there are LHCP antennas. Perhaps one of the
easiest forms of CP antennas for hams to understand are the axial mode helix
antennas first discovered/studied by the great radio astronomer/ham John
Kraus W8JK. Axial mode helix antennas may be "wound" with either a right
hand thread or a left hand thread.
Again Malus Law applies, in an easily applied modified form and so... RHCP
receiving antennas respond to RHCP waves and LHCP receiving antennas
respond to LHCP waves. A purely RHCP antenna will produce zero response to
an LHCP wave, etc...
An interesting effect happens upon reflection of CP waves. An RHCP wave
reflected from a perfectly reflecting surface returns (is echoed) as a LHCP
wave!
CP propagation is often used in Satellite communications where a satellite
may use both RHCP and LHCP transmitting antennas on the same frequency for
communicating independently with two different ground stations using R and L
CP antennas on the same frequency. CP frequency diversity doubles channel
capacity!
Yet another common form of CP antenna uses crossed linear antennas fed with
a 90 degree (Pi/2) phase difference excitation.
As far as I know all currently known CP antennas such as axial mode helixes
and crossed 90 degree linear arrays produce CP waves where the 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.
I believe that the well known and understood situation of purely synchronous
CP is NOT necessesarily the only form of CP.
Warning... The following may be an invention!
Consider the case of a linear antenna, say a dipole, fed from a feed line
over rotating slip rings, such that the antenna can be rotated while it is
transmitting.
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!
In fact the astute newsreader may note that we need not use a motor to
rotate the antenna. In fact, I can propose several ways of "electronically"
rotating the linear antenna at any arbitrary angular velocity, not
necessarily synchronous with the transmitted frequency and so produce a
so-called non-synchronous CP at any desired rate of rotation.
Clearly, according to Malus Law, the maximum response to the non-synchronous
CP received waves from this 'rotating' antenna contraption would be from a
similarily rotating receiving antenna!
Question?
What would be the response of an axial mode helix antenna or say crossed 90
degree fed dipoles or any other "synchronous" CP antenna to such a
non-synchronous wave produces by a rotating antenna?
Would the response of a syncrhronous axial mode helix be less than that of a
sympathetically rotating receiving antenna?
What?
Thoughts, comments?
-- Pete K1PO
-- Indialantic By-the-Sea, FL
Roy Lewallen
> . . .
> It is commonly understood that polarization of electromagnetic waves may
> be either linear or circular.
Then some education is in order. Electromagnetic waves are elliptically
polarized. The two extreme special cases of this are linear and circular
(with axial ratio of zero -- or infinite depending on your choice of
definition -- and one respectively). There are an infinite number of
other possible elliptical polarizations with different axial ratios.
>
> Linear Polarization (LP):
>
> Of course waves that are linearly polarized may have any arbitrary
> orientation angle (theta) with respect to a reference frame such as the
> earth's surface. For example most common linear amateur antennas
> produce and/or respond to waves of linear polarization, and these
> antennas produce either either horizonally or vertically polarized waves
> depending upon the orientation of the (linear) antenna with respect to
> the earth's surface (ground).
Of course linear polarization can have any orientation, not just
vertical or horizontal. And even those terms lose meaning when away from
the Earth. However, it's often convenient to mathematically separate
waves into two superposed components of horizontal and vertical
polarization.
> As examples; a 1/2 wave length dipole for 10 meters hung at 30 feet
> between two trees of equal height produces a largely horizonally
> polarized wave and, a 2 meter 1/4 wave dipole mounted in the center of
> the roof of an automobile produces a largely vertically polarized wave.
The polarization of the dipole signal will be purely horizontal only
directly broadside. The signal off the ends are purely vertically
polarized, and in other directions neither horizontal nor vertical.
> Of course as electromagnetic waves are propagated throughout an
> environment are never purely orientated and usually contain an ensemble
> of many orientations, because the waves are reflected from the ground,
> trees, buildings, mountains, bridges, moving vehicles, and sometimes
> propogated through moving and anisotropic media such as the ionosphere,
> etc... and so the multiple reflection surfaces at various angles to the
> earth's surface and/or refractions and Faraday rotations will conspire
> to "mix up" the original orientation of the E vector of a purely linear
> transmitted wave and usually produces a quite mixed polarization at
> distance from an emitting antenna.
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.
> Malus' Law {I = Io [cos(theta)]^^2} describes the response of a linearly
> polarized receiving antenna to waves arriving at a polarization angle
> theta relative to the receiving antenna's preferred orientation. i.e a
> horizontally polarized antenna will produce maximum response to
> horizontally polarized waves and a minimum response (zero) to a
> vertically polarized wave and vice versa.
>
> Of course in practice, because of the multipath reflections and
> refractions the 'cross response' is never exactly zero or maximum as
> predicted by Malus Law.
It's also difficult to get the polarizations of the antennas exactly right.
> Just the same it is preferable to have the orientation of a receiving
> antenna 'aligned' with that of a particular transmitting antenna. In
> the HF region it is difficult for hams to "rotate" the orientation of
> their receiving antennas to maximize signal pickup based upon
> polarization, and so most hams are forced to take whatever response
> their relatively fixed antennas produce to the relatively unknown
> orientation of received waves.
There's no advantage at HF of having the antenna orientations the same
if the path is via the ionosphere.
> In military or commercial installations, where money and space may not
> be an issue, either electronically or mechanically derived spatial
> antenna polarization diversity can be utilized to maximize received
> signal strength based upon arriving polarization. Polarization
> diversity receivers...
>
> Circular Polarization (CP):
>
> . . .
> Again Malus Law applies, in an easily applied modified form and so...
> RHCP receiving antennas respond to RHCP waves and LHCP receiving
> antennas respond to LHCP waves. A purely RHCP antenna will produce zero
> response to an LHCP wave, etc...
Interesting. Can you work an example for us? I'm curious as to what you
use for theta in the "law's" equation.
> An interesting effect happens upon reflection of CP waves. An RHCP wave
> reflected from a perfectly reflecting surface returns (is echoed) as a
> LHCP wave!
Only if it strikes the surface directly head-on. Otherwise you get an
elliptically polarized wave. The axial ratio depends on the angle of
incidence and, if the reflector isn't perfectly conducting, on the
impedance of the surface.
> CP propagation is often used in Satellite communications where a
> satellite may use both RHCP and LHCP transmitting antennas on the same
> frequency for communicating independently with two different ground
> stations using R and L CP antennas on the same frequency. CP frequency
> diversity doubles channel capacity!
I think you mean that polarization (not frequency) diversity doubles
channel capacity.
> Yet another common form of CP antenna uses crossed linear antennas fed
> with a 90 degree (Pi/2) phase difference excitation.
>
> As far as I know all currently known CP antennas such as axial mode
> helixes and crossed 90 degree linear arrays produce CP waves where the
> 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.
> I believe that the well known and understood situation of purely
> synchronous CP is NOT necessesarily the only form of CP.
It's the only one which fits the definition. If you choose to rotate the
polarization at some other rate, you should call it something else.
> Warning... The following may be an invention!
>
> Consider the case of a linear antenna, say a dipole, fed from a feed
> line over rotating slip rings, such that the antenna can be rotated
> while it is transmitting.
>
> 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!
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.
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.
> In fact the astute newsreader may note that we need not use a motor to
> rotate the antenna. In fact, I can propose several ways of
> "electronically" rotating the linear antenna at any arbitrary angular
> velocity, not necessarily synchronous with the transmitted frequency and
> so produce a so-called non-synchronous CP at any desired rate of rotation.
>
> Clearly, according to Malus Law, the maximum response to the
> non-synchronous CP received waves from this 'rotating' antenna
> contraption would be from a similarily rotating receiving antenna!
>
> Question?
>
> What would be the response of an axial mode helix antenna or say crossed
> 90 degree fed dipoles or any other "synchronous" CP antenna to such a
> non-synchronous wave produces by a rotating antenna?
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.
> Would the response of a syncrhronous axial mode helix be less than that
> of a sympathetically rotating receiving antenna?
No.
> What?
>
> Thoughts, comments?
Sorry, I didn't find it "mind-blowing".
>
> -- Pete K1PO
> -- Indialantic By-the-Sea, FL
Roy Lewallen, W7EL
Dave
"Peter O. Brackett" <no...@no-such-domain.nul> wrote in message
news:dq-dnZXd6Y0gT6TU...@earthlink.com...
> What would be the response of an axial mode helix antenna or say crossed
> 90 degree fed dipoles or any other "synchronous" CP antenna to such a
> non-synchronous wave produces by a rotating antenna?
the same as for a linearly polarized wave. since the rotation frequency is
much lower than the carrier frequency (unless you are considering elf
transmissions) during any time period consisting of several cycles of the
carrier it would appear stationary to the antenna.
>
> Would the response of a syncrhronous axial mode helix be less than that of
> a sympathetically rotating receiving antenna?
>
it wouldn't matter. now if there were two linearly polarized antennas
rotating such that their polarizations stayed in sync that would at least
reduce the fading caused by one rotating and the other being stationary.
but only if the path between them didn't produce any rotation or
randomization of the polarization, so essentially only for short paths with
no reflective multi-path or other effects. seems like more trouble than its
worth... what would you gain from it anyway?
Peter O. Brackett
Thanks for your well thought out responses.
See my comments below interspersed with snippings of your response.
[snip]
"Roy Lewallen" <w7...@eznec.com> wrote in message
news:F4qdnS9YA_A6daTU...@posted.easystreetonline...
> Peter O. Brackett wrote:
>> . . .
>> It is commonly understood that polarization of electromagnetic waves may
>> be either linear or circular.
>
> Then some education is in order. Electromagnetic waves are elliptically
> polarized. The two extreme special cases of this are linear and circular
> (with axial ratio of zero -- or infinite depending on your choice of
> definition -- and one respectively). There are an infinite number of other
> possible elliptical polarizations with different axial ratios.
[snip]
I agree. My statement was not quite precise.
I should have stated something like, "it is commonly understood that
polarization of waves may be categorized as being either linear or
elliptical, and
in the elliptical category the special case of circular polarization occurs
whenever
the major and minor axes of the elliptical polarization are equal."
[snip]
> Of course linear polarization can have any orientation, not just vertical
> or horizontal. And even those terms lose meaning when away from the Earth.
> However, it's often convenient to mathematically separate waves into two
> superposed components of horizontal and vertical polarization.
[snip]
Agreed!
[snip]
> The polarization of the dipole signal will be purely horizontal only
> directly broadside. The signal off the ends are purely vertically
> polarized, and in other directions neither horizontal nor vertical.
[snip]
Agreed! It is relatively difficult, and perhaps even impossible to arrange
the physical configuration of an antenna such that it emits (or receives)
wave of purely one category of polarization.
In practice though many antennas concentrate a major part of their emissions
in one polariztion form.
[snip]
> 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.
[snip]
> It's also difficult to get the polarizations of the antennas exactly
> right.
[snip]
Agreed!
[snip]
> There's no advantage at HF of having the antenna orientations the same if
> the path is via the ionosphere.
[snip]
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.
[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.
[snip]
> Only if it strikes the surface directly head-on. Otherwise you get an
> elliptically polarized wave. The axial ratio depends on the angle of
> incidence and, if the reflector isn't perfectly conducting, on the
> impedance of the surface.
[snip]
Agreed!
A very intersting optical phenomena to observe is to look at a mirror
through
an optical circular polarizer (polarizer in tandem with a 1/4 wave retarder)
which
renders the "image" of the circular polarizer to be black. i.e. the optical
circular polarizer eliminates the reflection. This technique is widely used
to eliminate reflections from information displays that must operate in high
sunlight with good sunlight readability. High quality high transmissivity
optical circular polarizers are relatively expensive, and so one does not
find such technology applied to consumer displays like computer
monitors, TV sets or IPhones, however optical circular polarizers are
widely used by the military for eliminating sunlight reflections from their
(expensive) information displays.
[snip]
>> CP propagation is often used in Satellite communications where a
>> satellite may use both RHCP and LHCP transmitting antennas on the same
>> frequency for communicating independently with two different ground
>> stations using R and L CP antennas on the same frequency. CP frequency
>> diversity doubles channel capacity!
>
> I think you mean that polarization (not frequency) diversity doubles
> channel capacity.
[snip]
Yep that's exactly what I meant, but my fingers did not type it that way.
Thanks!
[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]
[snip]
>> I believe that the well known and understood situation of purely
>> synchronous CP is NOT necessesarily the only form of CP.
>
> It's the only one which fits the definition. If you choose to rotate the
> polarization at some other rate, you should call it something else.
[snip]
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]
[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.
[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.
[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.
[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!
For did you not state above that a circular carrier wave has a constant
amplitude?
A radio wave with constant aplitude, indeed! Something must be blown!
At zero frequency, how would a constant wave propagate?
This assumption/view that zero frequency wave can propagate is akin to
Cecil's
view that there are no reflections at DC.
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?
Thanks again for your clearly interesting comments and feedback.
More thoughts, comments?
Peter O. Brackett
[snip]
> it wouldn't matter. now if there were two linearly polarized antennas
> rotating such that their polarizations stayed in sync that would at least
> reduce the fading caused by one rotating and the other being stationary.
> but only if the path between them didn't produce any rotation or
> randomization of the polarization, so essentially only for short paths
> with no reflective multi-path or other effects. seems like more trouble
> than its worth... what would you gain from it anyway?
[snip]
A better understanding of circular polarization?
The design of a new polariztion locked loop, akin to a phase locked loop,
but...
More?
.
.
.
Thanks!
Art Unwin
wrote:
> Roy:
>
> Thanks for your well thought out responses.
>
> See my comments below interspersed with snippings of your response.
>
>
> read more »
It was stated above that the purely horizontal polarisation will occur
when the dipole is broadside
This is not correct
Using an optimiser and inserting a one liner where all dimensions are
different allows for the design to conform to Maxwell
laws in their entirety, which means the inclusion of the "weak" force
required for equilibrium
Regards
Art
Dave
"Art Unwin" <Arthu...@gmail.com> wrote in message
news:d8195293-802d-40be...@a12g2000yqm.googlegroups.com...
>the inclusion of the "weak" force
>required for equilibrium
leave it up to art to take a perfectly good premise and insert utter idiocy
into it. next he'll be saying that since the magical levitating weak force
neutrinos are jumping off the antenna at an angle to the element that the
polarization is caused by them. how about it art, can you make your
levitating neutrinos rotate in different directions with left or right hand
circular antennas??
Art Unwin
> "Art Unwin" <ArthurUn...@gmail.com> wrote in message
You can have diversity with respect to all polarizations except
circular
where you only have the choice of one. 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.
One more fool like you on this newsgroup changes little
Art
Dave
>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.
Richard Clark
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!
It is singularly impossible for them to have not included the weak
force - whose total contribution to the resulting -um- results
registers in the 13th digit to the right of the decimal point.
Dismissing this immense revelation is like arguing that a drowning man
is immune from the effects of a drunk pissing into the ocean.
>nor
>will you find any of the existing antenna modeling programs that use the
>weak force.
op. cit.
>which kind of contradicts your whole rant,
That well may be seeing that Ærthur practices a self reinforcing
argument that exhibits that quality of Æquilibrium: damned if you do,
and damned if you do it again.
>you say you believe
>in the modeling programs and that they give results that agree with your
>corrupted weak force model,
A corrupted weak force, the wæk force?
>and yet they don't use the weak force at all...
Of course they do (op. cit.)
>never have, and never will.
Always has and always will (I already said that didn't I? (which is
what op. cit. mæns in Lat.))
>nor can you state where the weak force is
>included in Maxwell's equations,
Ærthur, while rooting in the library stacks of an ancient university
located on the banks of a great (but not grand) lake, he discovered
them in the margins (long neglected as flyspecks on the page due to
their singular characteristic out 13 places to the right). Patents
are pænding, so watch your step.
As we are taxpayers, supporting inventors on the dole, it should be
our full right to be able to examine these hidden documents, but
Ærthur continues to suppress their access.
>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.
The only thing he hasn't explained is the beneficial prosperities of
the color of the color-coded wire. Just as all resistors look the
same except for the colors - and we are all perfectly aware that not
all resistors are the same - hence it is a color thing. (Lest we
diverge into the side topic of wæk resistance, aka Unpedance.)
73's
Richard Clark, KB7QHC
Peter O. Brackett
[snip]
"Richard Clark" <kb7...@comcast.net> wrote in message
news:cpjlj45bvd4329nti...@4ax.com...
> On Sat, 06 Dec 2008 18:46:16 GMT, "Dave" <no...@nowhere.com> 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!
Richard Clark
<no...@no-such-domain.nul> wrote:
>"Reinventing Gravity",
I prefer the original over ersatz.
Roy Lewallen
> . . .
>> 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.
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
Art Unwin
> "Art Unwin" <ArthurUn...@gmail.com> wrote in message
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
Peter O. Brackett
[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]
Richard Clark
<no...@no-such-domain.nul> wrote:
>On Sat, 06 Dec 2008 15:49:26 -0800, Roy Lewallen <w7...@eznec.com> 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. :-/
Roy Lewallen
> . . .
> 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.
I'll quit here, unless you want help with the derivation of the CP E
field amplitude. Best wishes for the success of your innovative creation.
Roy Lewallen, W7EL
AndyS
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
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" <andys...@juno.com> wrote in message
news:faa183b3-9b44-45de...@s9g2000prg.googlegroups.com...
AndyS
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
Roy Lewallen
My previous answers were wrong. Peter's spinning antenna wouldn't
produce a circularly polarized wave (as universally defined) even if it
was synchronous with the wave frequency. As I've said, a circularly
polarized wave has constant E field amplitude; Peter's wave would have a
time-varying amplitude. If it were synchronous, the nulls and peaks
would always occur at the same places in the rotation cycle, so they
would occur at fixed angles relative to a rotational reference point. If
non-synchronous, the nulls and peaks would rotate at the beat frequency.
It seems to me that the way to mechanically generate a circularly
polarized wave would be to rotate a source of *static* E field, for
example, a short dipole with constant applied DC voltage at the
feedpoint. That should produce a circularly polarized wave with the
frequency being the rotational frequency of the dipole. At any point in
space, the E field would change with time, and would propagate, and it
would look exactly like a circularly polarized wave broadside to the
rotation plane.
If the scheme works and radiation is occurring, then power must be going
into the antenna, which in turn means it's drawing current that's in
phase with the applied voltage. When stopped, no current will flow, but
when rotating, it does. So how does the antenna know it's rotating? How
about this -- if you instantaneously move the antenna into some
position, a static E field appears there, and propagates outward at the
speed of light. Closer in than the leading edge of the propagating wave,
the field is static. When we rotate the dipole to a new position, it
moves through the field from its previous position, which induces a
current in it. Hence the current. It's fundamentally a generator, with
the field being in the air.
I'd be willing to bet a moderate sum that if you did apply a DC voltage
to a dipole and rotated it, you'd see an alternating current with a
frequency equal to the frequency of rotation, and a circularly polarized
wave broadside to the antenna. I suspect that the current and the
radiated field increase in amplitude with rotational speed, so you might
have to get it going really fast before you can detect the effects.
Now there's some food for thought.
Roy Lewallen, W7EL
J. B. Wood
Lewallen <w7...@eznec.com> wrote:
> Then some education is in order. Electromagnetic waves are elliptically
> polarized. The two extreme special cases of this are linear and circular
> (with axial ratio of zero -- or infinite depending on your choice of
> definition -- and one respectively). There are an infinite number of
> other possible elliptical polarizations with different axial ratios.
Hello, and that's quite correct, Roy. Having read the OP's statements and
others in this thread I would like to recommend that one step back from
antennas for a moment in order to examine the generation of an ellipse
(representing the locus of points of a rotating E (or H) field. The
parametric equations take the form x(t) = A*cos(2*pi*f*t) and y(t) =
B*cos(2*pi*f*t + phi). (These equations are of the same form that
generate the familiar Lissajous patterns except that for Lissajous the x
and y values differ in frequeny.)
While polarization is a convenient concept in electromagnetic wave
propagaion there's no reason that we couldnt just treat it as the
superposition of two separate Ex (or Hx) and Ey (or Hy) waves. Of course
we have to pay attention to amplitude and phase relationships.
I think investing some time with this math (it's not all that difficult)
will provide one with insight into the concept of polarization and perhaps
head off some misconception. If anyone is interested and has Mathcad,
I've got a worksheet that allows one to vary these parameters, plots the
resulting ellipse (or circle or line) and also calculates ellipticity
(axial ratio) and eccentricity. Sincerely, and 73s from N4GGO,
John Wood (Code 5550) e-mail: wo...@itd.nrl.navy.mil
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337
Dave
> I think investing some time with this math (it's not all that difficult)
> will provide one with insight into the concept of polarization and perhaps
> head off some misconception. If anyone is interested and has Mathcad,
> I've got a worksheet that allows one to vary these parameters, plots the
> resulting ellipse (or circle or line) and also calculates ellipticity
> (axial ratio) and eccentricity. Sincerely, and 73s from N4GGO,
>
All I have to know is that Circular Polarization always helps when one
end of the path is prone to random polarizations, even with the 3 dB
power loss.
christofire
A source of endless coffee-time debates where I used to work! No, the
current into the rotating dipole would be DC and the means of rotation at
the radio frequency would take the place of the 'transmitter'. If the
current were alternating then the radiated electric field would be
discontinuous but it isn't; it has constant magnitude. Between two such
systems separated by many wavelengths, if there were no anisotropic material
around, reciprocity would apply and a means of conveying DC by radio would
be created!
However, intriguing and amusing as this analogy might be I wonder if it
really has any practical value. For real mechanical rotating parts the
frequency would be limited to something rather low like the tens of kHz at
which Alexanderson alternators work, and then the wavelength would be so
long that it would probably be impossible to construct an efficient
radiator*. The quickest moving antenna I've encountered was a commutated
plasma antenna, using a construction similar to a 'dekatron' tube, but even
then the length of the radiator was so small that SHF would be needed to
achieve worthwhile radiation efficiency* and the maximum commutation speed
was limited to a few MHz by the time it takes to establish the plasma at
each step in the commutation cycle.
*(Of course, the conventional principles of radiation resistance vs. loss
resistance may need 'massaging' to bring them into line with the concept of
creating transverse waves by rotating a dipole connected to a battery!)
Chris
Jerry
"christofire" <chris...@btinternet.com> wrote in message
news:qPqdnb02R7Du2qDU...@bt.com...
Hi Chris
I am not smart enough to analyze the effects of rotating a dipole with DC
applied to it, but I have doubts that it would create a "far field". Did
you guys ever figure out how the "DC dipole" generates a Far Field?
Jerry KD6JDJ
Roy Lewallen
>
> A source of endless coffee-time debates where I used to work! No, the
> current into the rotating dipole would be DC and the means of rotation at
> the radio frequency would take the place of the 'transmitter'. If the
> current were alternating then the radiated electric field would be
> discontinuous but it isn't; it has constant magnitude. Between two such
> systems separated by many wavelengths, if there were no anisotropic material
> around, reciprocity would apply and a means of conveying DC by radio would
> be created!
Now that I think about it, you're right -- the current would have to be
DC, so there would be only DC power into the dipole.
Interesting that you and your co-workers thought of and debated this.
I've given it less than an hour of thought since it popped into my head,
so you've had a lot more time to work out the details. Sounds like it
might work something like I described, then.
> However, intriguing and amusing as this analogy might be I wonder if it
> really has any practical value. For real mechanical rotating parts the
> frequency would be limited to something rather low like the tens of kHz at
> which Alexanderson alternators work, and then the wavelength would be so
> long that it would probably be impossible to construct an efficient
> radiator*. The quickest moving antenna I've encountered was a commutated
> plasma antenna, using a construction similar to a 'dekatron' tube, but even
> then the length of the radiator was so small that SHF would be needed to
> achieve worthwhile radiation efficiency* and the maximum commutation speed
> was limited to a few MHz by the time it takes to establish the plasma at
> each step in the commutation cycle.
I can't see where this could possibly be of any practical use. For me it
was simply a mind exercise spurred by Peter's musings, resulting from
wondering just how a mechanical system could be made to generate a CP wave.
> *(Of course, the conventional principles of radiation resistance vs. loss
> resistance may need 'massaging' to bring them into line with the concept of
> creating transverse waves by rotating a dipole connected to a battery!)
Indeed. And it seems there wouldn't be any skin effect, then, with only
DC going to the wire. And what about current distribution on the dipole?
Roy Lewallen, W7EL
Jerry
Hi Roy
I have problems with believing there will be any current in either dipole.
What am I missing?
Jerry KD6JDJ
Roy Lewallen
>
> I am not smart enough to analyze the effects of rotating a dipole with DC
> applied to it, but I have doubts that it would create a "far field". Did
> you guys ever figure out how the "DC dipole" generates a Far Field?
>
> Jerry KD6JDJ
It requires energy to create a far field, since the far field is a form
of energy. I explained why I thought power might be consumed by the
antenna -- current would flow due to coupling with the field still
present from previous positions (although I mentioned alternating
current while Chris correctly pointed out that it would have to be DC).
I don't see any problem with conversion of the DC into AC. It's done all
the time with spinning magnets -- look at the alternator in your car for
example. And in times of yore, RF was generated directly with high speed
alternators. The principle is very similar to, if not exactly the same
as, the scheme I described.
The whole thing is just a mental exercise to help gain a better
understanding of the nature of a circularly polarized field.
Roy Lewallen, W7EL
christofire
Indeed, and I would add that the spinning dipole fed with a constant voltage
appears the same as a stationary dipole fed with an alternating voltage with
respect to any chosen linear polarisation.
I was once told of a method of measuring the radiation patterns of large
installed antennas by 'flying' near to them a small metal rod rotating about
an axis that passes perpendicularly through the middle of the length of the
rod. By detecting, synchronously with rotation of the rod, changes in the
terminal VSWR (or reflection co-efficient for voltage) the near-field
radiation pattern could be assessed (i.e. an impression of the aperture
current distribution) from which the far-field patterns could be derived by
Fourier transform in the normal way (acknowledgement is due to the late Dick
Manton). There is a range of 3D angles over which the axis can vary without
upsetting the measurement. I don't know if this was ever implemented, e.g.
to measure the patterns of a television transmitting antenna - a helicopter
carrying a measuring receiver is used in the far field nowadays.
Chris
christofire
"Jerry" <jerry...@verizon.net> wrote in message
news:YTc%k.643$7I6...@nwrddc01.gnilink.net...
That's understandable.
Chris
Jerry
Hi Roy
When you write "current would flow due to coupling with the field still
present from previous positions", do you submit that more power is required
to rotate a dipole with no DC on it than one with DC on it?
I will respectfully submit that a car alternator doesnt so much spin a
magmetic field as it Rotates the field past a conductor. A car alternator
is a lumpy magnetic field that is spun past stationary coils of wire. There
is no misunderstanding about inductive coupling of close by conductors. My
question related to far field "radiation". I am aware that my understanding
of far Field radiation is very limited, so i dont propose that i have
answers. I do have question about generating a far field by spinning a DC
excited dipole.
Jerry KD6JDJ
Jerry
Hi Chris
Tell me, did you guys ever decide that there would be a far field
generated by the spinning dipole with DC on it? I dont refer to the
inductive field.
Maybe there is no way to separate Far Field from any condition where an
inductive field is generated.
Jerry KD6JDJ
christofire
>
- snip -
>>>
>>> I have problems with believing there will be any current in either
>>> dipole. What am I missing?
>>>
>>> Jerry KD6JDJ
>>
>>
>> That's understandable.
>>
>> Chris
>
> Hi Chris
>
> Tell me, did you guys ever decide that there would be a far field
> generated by the spinning dipole with DC on it? I dont refer to the
> inductive field.
> Maybe there is no way to separate Far Field from any condition where an
> inductive field is generated.
>
> Jerry KD6JDJ
Jerry,
I think you're right - in the far field there is spherical spreading of
power without regard to separate magnetic and electric components that an
antenna, of whatever form, might produce. Of course the radiated power
incident on any surface can be represented by an equivalent value of
electric or magnetic field strength but this is on strict understanding that
the counterpart (magnetic or electric) component is present with the
requisite field strength (E/H = Zo = 377 ohms in free space) and PFD =
E2/Zo.
The answer to your first question is 'yes - hypothetically' there 'would be
a far field generated by the spinning dipole with DC on it' but this
shouldn't be taken as a recipe for some wacky rotating machine. As I
outlined earlier, there is probably little practical application for this
interesting analogy because if it were ever put into practice it would
probably be hopelessly inefficient and transformation of Maxwell's equations
into an inertial frame spinning at the radio frequency is hard, to say the
least! As has been suggested, it's probably best to take the concept no
further than an interesting thought exercise - if you don't understand that,
don't worry, you're not missing much
Chris
Jerry
Hi Chris
Thanks for the reply.
Yeah, I never ascribed any practical use to the "CP by spinning". But,
there are some fundamentally good thoughts generated here. For instance, I
can easily see why two dipoles rotating at the same rate and rotational
direction will couple *nothing*. Thats like trying to receive RHCP with a
LHCP antenna.
I have lived a long time without understanding Poynting and Maxwell
(almost 100 years older than me), I wouldnt want to change that now.
Jerry KD6JDJ
Michael Coslo
> Ærthur, while rooting in the library stacks of an ancient university
> located on the banks of a great (but not grand) lake,
That would be good old Miskatonic U in Arkham?
- 73 d eMike N3LI -
Jerry
Hi Chris
I am having a block in my learning. As I understand it, this would
actually happen if it could be performed.
A spinning dipole would require more power to spin it if it had DC on it
than if it had no DC on it. And, actually, it would require no power to
keep the dipole spinning since there would be that theoritical vacuum around
it. But, once you apply the DC, power would be required to keep it
spinning. That amount of added power would be determined by the amount of
DC applied. Do you confirm that this is true?
My question relates to my ignorance about what there is in the "vacuum" to
cause "drag".
Jerry KD6JDJ
christofire
>
- snip -
>
> I am having a block in my learning. As I understand it, this would
> actually happen if it could be performed.
Yes
>
> A spinning dipole would require more power to spin it if it had DC on it
> than if it had no DC on it.
Yes - as I said, the means of spinning the dipole would be the counterpart
to the 'transmitter'
> And, actually, it would require no power to keep the dipole spinning since
> there would be that theoritical vacuum around it.
If you say so - you're specifying a hypothetical zero-friction system which
is but one of several possible scenarios.
> But, once you apply the DC, power would be required to keep it spinning.
> That amount of added power would be determined by the amount of DC
> applied. Do you confirm that this is true?
Certainly work would need to be done to spin the dipole and create the
outgoing wave by virtue of its rotation. I suppose it follows that the
strength of the outgoing wave would be proportional to the applied voltage
but I'm not certain that a greater voltage would require more mechanical
work to spin the dipole - you may be right but I'm not certain I can confirm
this from what I think I know!
> My question relates to my ignorance about what there is in the "vacuum"
> to cause "drag".
>
> Jerry KD6JDJ
I'm afraid I had taken very little account of causes of mechanical drag. As
noted before, this was a thought experiment - the sort of thing that can
reach a useful conclusion (i.e. 'not likely' in this case!) without
requiring detailed examination of what may be 'second-order' influences.
Chris
christofire
>> My question relates to my ignorance about what there is in the "vacuum"
>> to cause "drag".
>>
>> Jerry KD6JDJ
Just research 'solar sailing' if you want to read about a phenomenon that
involves 'drag' in a vacuum on account of a flux of photons. It's used to
help keep satellites 'on station' whilst saving hydrazine.
Chris
Jerry
Hi Chris
I accept as valid, your statement that the dipole with DC will radiate a
far field when spun. I have a mental block related to questioning what
makes it harder to spin when the DC is increased.
Yes, I do consider the media in which the dipole is spinning creates no
friction. I do wonder what makes it harder to spin when the DC voltage is
increased.
Jerry
Peter O. Brackett
-- Pete K1PO
"Michael Coslo" <mj...@psu.edu> wrote in message
news:ghjsn4$9k6e$1...@tr22n12.aset.psu.edu...
> Richard Clark wrote:
>
>> Ęrthur, while rooting in the library stacks of an ancient university
Peter O. Brackett
[snip]
> I think investing some time with this math (it's not all that difficult)
[snip]
Agreed!
[snip]
> will provide one with insight into the concept of polarization and perhaps
> head off some misconception. If anyone is interested and has Mathcad,
> I've got a worksheet that allows one to vary these parameters, plots the
> resulting ellipse (or circle or line) and also calculates ellipticity
> (axial ratio) and eccentricity. Sincerely, and 73s from N4GGO,
>
> John Wood (Code 5550) e-mail: wo...@itd.nrl.navy.mil
> Naval Research Laboratory
> 4555 Overlook Avenue, SW
> Washington, DC 20375-5337
[snip]
Thanks John!
-- Pete K1PO
Peter O. Brackett
[snip]
"Dave" <da...@dave.dave> wrote in message
news:493d32bc$0$31172$bd46...@news.dslextreme.com...
[snip]
Yep, CP is good!
No matter how it is generated...
-- Pete K1PO
Peter O. Brackett
> 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 ?
Ype that's exactly what would happen!
[snip]
> Is this the sort of principle that you were trying to convey ??
[snip]
Yeah, you've got it man!
[snip]
> 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.....
[snip]
I can see that you did not find that so hard to "grok". Good work man!
Thanks!
[snip]
> This is getting beyond my personal antenna expertise, but I still find
> it
> interesting....... Please pardon my lack of understanding, .... if I
[snip]
Andy! No problem you have it... there is no lack on your part.
Fortunately
you do not seem to be encumbered by convention. Your understanding is
"right on"!
-- Pete K1PO
Peter O. Brackett
[snip]
"Roy Lewallen" <w7...@eznec.com> wrote in message
news:98SdndIksOi97qHU...@posted.easystreetonline...
> Something just occurred to me. I did get to thinking.
>
> My previous answers were wrong.
[snip]
Yep, I thought as much...
[snip]
> Peter's spinning antenna wouldn't produce a circularly polarized wave (as
> universally defined) even if it was synchronous with the wave frequency.
> As I've said, a circularly polarized wave has constant E field amplitude;
> Peter's wave would have a time-varying amplitude. If it were synchronous,
> the nulls and peaks would always occur at the same places in the rotation
> cycle, so they would occur at fixed angles relative to a rotational
> reference point. If non-synchronous, the nulls and peaks would rotate at
> the beat frequency.
[snip]
The problem is... that most "conventional" code and theory, e.g. NEC
does not allow for antennas in motion. These theories and computer
codes/algorithms are based upon a static steady state solution of the
Maxwell/Heaviside equations... i.e. E is a "fixed" phasor rather than
an oscilating waveform.
[snip]
> It seems to me that the way to mechanically generate a circularly
> polarized wave would be to rotate a source of *static* E field, for
> example, a short dipole with constant applied DC voltage at the feedpoint.
[snip]
Hmmm... restricting that dipole to a "static" source is really far too
restrictive. This assumption likely results from the assumption
that E is a sinusoidal steady state value rather than a dynamic
(transient) wave.
[snip]
> That should produce a circularly polarized wave with the frequency being
> the rotational frequency of the dipole. At any point in space, the E field
> would change with time, and would propagate, and it would look exactly
> like a circularly polarized wave broadside to the rotation plane.
[snip]
Yes, but E is not "fixed" in time, it is the magnitude of an oscillating
phasor!
A DC phasor would not propagate. Of course!
[snip]
> If the scheme works and radiation is occurring, then power must be going
> into the antenna, which in turn means it's drawing current that's in phase
> with the applied voltage. When stopped, no current will flow, but when
> rotating, it does. So how does the antenna know it's rotating? How about
> this -- if you instantaneously move the antenna into some position, a
> static E field appears there, and propagates outward at the speed of
> light. Closer in than the leading edge of the propagating wave, the field
> is static. When we rotate the dipole to a new position, it moves through
> the field from its previous position, which induces a current in it. Hence
> the current. It's fundamentally a generator, with the field being in the
> air.
[snip]
Yes that would be the case if the rotating antenna was excited with DC,
however that is not necessarily the general case.
In general the "center" frequency or "carrier" frequency may be any
arbitrary frequency, down to and including DC. Maxwell's/Heaviside's
equations hold for all frequencies from zero (DC) to infinity.
[snip]
> I'd be willing to bet a moderate sum that if you did apply a DC voltage to
> a dipole and rotated it, you'd see an alternating current with a frequency
> equal to the frequency of rotation, and a circularly polarized wave
> broadside to the antenna.
[snip]
Wow! Roy.... you are taking a big risk here. What is the (exact) value of
that
"sum"?
[snip]
> I suspect that the current and the radiated field increase in amplitude
> with rotational speed, so you might have to get it going really fast
> before you can detect the effects.
>
> Now there's some food for thought.
>
> Roy Lewallen, W7EL
[snip]
Agreed! Hey... not many are able to "think outside the envelope", but I
do believe we are getting to the edge...
-- Pete K1PO
Peter O. Brackett
.
.
.
> A source of endless coffee-time debates where I used to work! No, the
> current into the rotating dipole would be DC and the means of rotation at
> the radio frequency would take the place of the 'transmitter'. If the
> current were alternating then the radiated electric field would be
> discontinuous but it isn't; it has constant magnitude. Between two such
> systems separated by many wavelengths, if there were no anisotropic
> material around, reciprocity would apply and a means of conveying DC by
> radio would be created!
Perhaps, but.... the intersting case is when the "center" frequency is
somewhat
higher than DC.
[snip]
> However, intriguing and amusing as this analogy might be I wonder if it
> really has any practical value.
[snip]
T. J. Watson, the early CEO of IBM is reputed to have stated, "I see no real
requirement for more than 7-10 computers in this world!"
[snip]
> For real mechanical rotating parts the frequency would be limited to
> something rather low like the tens of kHz at which Alexanderson
> alternators work, and then the wavelength would be so long that it would
> probably be impossible to construct an efficient radiator*. The quickest
> moving antenna I've encountered was a commutated plasma antenna, using a
> construction similar to a 'dekatron' tube, but even then the length of the
> radiator was so small that SHF would be needed to achieve worthwhile
> radiation efficiency* and the maximum commutation speed was limited to a
> few MHz by the time it takes to establish the plasma at each step in the
> commutation cycle.
[snip]
What if you could electronically rotate antennas at any desried
(practically) high frequency?
Consider, for example phased arrays driven through elecronically controlled
phase shift
networks. Would that work?
[snip]
> *(Of course, the conventional principles of radiation resistance vs. loss
> resistance may need 'massaging' to bring them into line with the concept
> of creating transverse waves by rotating a dipole connected to a battery!)
[snip]
Rotating dipoles do not have to (only) be connected to batteries. They
could
be connected to signal generators operating at 3.765MHz, no?
-- Pete K1PO
Peter O. Brackett
> Hi Chris
>
> I am not smart enough to analyze the effects of rotating a dipole with DC
> applied to it, but I have doubts that it would create a "far field". Did
> you guys ever figure out how the "DC dipole" generates a Far Field?
>
> Jerry KD6JDJ
Jerry... no one on this thread, except perhaps Roy, has restricted the
"frequency" of
the signal applied to said mechanically rotating dipole to be zero, f = 0!!
In fact, in principle,
the frequency of the signal applied to the rotating dipole could be any
desired frequency
selected from the frequency range minus infiinty to plus infinity.
-- Pete K1PO
Peter O. Brackett
[snip]
"Roy Lewallen" <w7...@eznec.com> wrote in message
news:a_adnQoU-bp6x6DU...@posted.easystreetonline...
> Jerry wrote:
.
.
.
> The whole thing is just a mental exercise to help gain a better
> understanding of the nature of a circularly polarized field.
>
> Roy Lewallen, W7EL
[snip]
I agree that it is an exercise to help gain a better understanding of
circular polarization, but...
It is not just a "mental" exercise.
I believe that hhere are practical applications of this phenomena!
FWIW....
-- Pete K1PO
Peter O. Brackett
[snip]
> I will respectfully submit that a car alternator doesnt so much spin a
> magmetic field as it Rotates the field past a conductor. A car
> alternator is a lumpy magnetic field that is spun past stationary coils of
> wire. There is no misunderstanding about inductive coupling of close by
> conductors. My question related to far field "radiation". I am aware
> that my understanding of far Field radiation is very limited, so i dont
> propose that i have answers. I do have question about generating a far
> field by spinning a DC excited dipole.
>
> Jerry KD6JDJ
[snip]
There are many practical examples extant of such "rotating" fields...
Consider the rotating field generated within the stator of a "shaded pole"
electric motor, or perhaps
the roing field of a synchronous electric motor.
However the rotating electromagntic fields of AC electric motors have
conventionally been
synchronized with the frequency (60Hz in North America) of the exciting
waveform. That
commercial application does not preclude applications wherein the rotating
field of an AC
motor is not synchronous with the exciting prime mover. For example,
imagine a motor
wherein the stator magnets are rotated by a separate mechanical device,
bicycle pedals?,
that pulls the rotor around at a frequency not synchronized with the stator
prime mover
excitation. Just because there is no real commerciall application for such
a motor in
today's markets, does not mean that such is not useful for some other
purpose.
Open minds create new applications
-- Pete K1PO
Peter O. Brackett
[snip]
> Tell me, did you guys ever decide that there would be a far field
> generated by the spinning dipole with DC on it? I dont refer to the
> inductive field.
> Maybe there is no way to separate Far Field from any condition where an
> inductive field is generated.
>
> Jerry KD6JDJ
[snip]
If the answer for DC was no, then....
What is your answer for a spinning dipole with 0.0001Hz on it, or say 1,
000, 003.33333 Hz on it?
Food for thought?
-- Pete K1PO
Peter O. Brackett
[snip]
"Jerry" <jerry...@verizon.net> wrote in message
news:CCe%k.663$7I6...@nwrddc01.gnilink.net...
.
.
.
> Yeah, I never ascribed any practical use to the "CP by spinning". But,
> there are some fundamentally good thoughts generated here. For instance,
> I can easily see why two dipoles rotating at the same rate and rotational
> direction will couple *nothing*. Thats like trying to receive RHCP with
> a LHCP antenna.
> I have lived a long time without understanding Poynting and Maxwell
> (almost 100 years older than me), I wouldnt want to change that now.
>
> Jerry KD6JDJ
[snip]
Hey, the shareholders in the pony express company never ascribed any
practical use to the internal combustion engine...
-- Pete K1PO
Peter O. Brackett
[snip]
> A spinning dipole would require more power to spin it if it had DC on it
> than if it had no DC on it. And, actually, it would require no power to
> keep the dipole spinning since there would be that theoritical vacuum
> around it. But, once you apply the DC, power would be required to keep
> it spinning. That amount of added power would be determined by the
> amount of DC applied. Do you confirm that this is true?
> My question relates to my ignorance about what there is in the "vacuum"
> to cause "drag".
>
> Jerry KD6...
[snip]
Roy has got you guys hung up on DC!!!
What is all the magic in DC. DC is just one of a double infinity of
frequency values that
could be applied to a spinning antenna!
This direction of investigation is similar to Cecil Moore's assertion that
there are no
reflections at DC.
There is nothing special about DC, it's just another of the infinity of
excitation
frequencies available.
Hey! Maxwell's/Heaviside's equations do not restrict excitations to any
specific
frequency.
There is no special status assigned to f = 0.0, get over it!
How about f = 0.0000003333 Hz, instead of DC, what then?
-- Pete K1PO
John Passaneau
DC is just AC with a very low frequency. After all you have to turn it
on some time and some day it will turn off.
John Passaneau W3JXP
Dave
out of it... and went back to the books.
In my opinion, no, rotating a plane wave, even at the same frequency that it
is oscillating would not create circular polarization. It would create a
rotating plane wave, but it lacks half of the field components to be
circular. The key is in this quote from ramo whinnery and van duzer's
'fields and waves in communications electronics': "if there is a combination
of TWO uniform plane waves of the same frequency, but of different phases,
magnitudes, and orientations of the field vectors, the resultant combination
is said to be an elliptically polarized wave" (emphasis mine). This is of
course the generalized case of the circular one that would require them to
be of the same amplitude and 90 degrees out of phase as they note a few
paragraphs later.
The key is the 'TWO' that I emphasized. If you trace the E field of a
single rotating dipole that is rotating at the same frequency as the rf
driving it you would still see the E field oscillate in amplitude at the
original frequency. So as it propagated, even though the direction of the E
field would follow a circular path the amplitude of it would change at the
same rate, so there would be nulls in the E field every 1/2 cycle... in a
true circular polarized wave the E field is a constant magnitude, it just
rotates around the axis at the given frequency. you can't get that from a
single dipole no matter how you rotate it since there will always be two
zero crossings every cycle in the E and H fields.
i quickly scanned a bunch of the mail, i'm a bit behind in my reading so
please forgive me if someone already came to this conclusion and i missed
it.
Oh, and i briefly saw something about DC fields... actually i 'think' that
if you put a 'dc' charge on a dipole, lets just separate two charges by some
distance and start them rotating about a common center... that MAY actually
create a circularly polarized wave. but i would consider this a degenerate
case of the general problem. Even if you used an ELF rf signal to drive the
dipole you would get zero fields every 1/2 wave which wouldn't work... with
the pure dc charge you have a constant E field that is rotating, and 2
accelerated charges to make the corresponding H field. I think this works
because there are 'TWO' rotating charges that each contribute to the
resulting wave.
Peter O. Brackett
[snip]
> DC is just AC with a very low frequency. After all you have to turn it
> on some time and some day it will turn off.
>
>
> John Passaneau W3JXP
[snip]
I agree, DC is nothing special... DC is 'just' another frequency!
-- Pete K1PO
-- Indialantic By-the-Sea, FL
Peter O. Brackett
[snip]
"Dave" <no...@nowhere.com> wrote in message
news:blE%k.929$7I6...@nwrddc01.gnilink.net...
>I thought i had myself convinced that it would work, but then talked myself
>out of it... and went back to the books.
>
> In my opinion, no, rotating a plane wave, even at the same frequency that
> it is oscillating would not create circular polarization. It would create
> a rotating plane wave, but it lacks half of the field components to be
> circular. The key is in this quote from ramo whinnery and van duzer's
> 'fields and waves in communications electronics': "if there is a
> combination of TWO uniform plane waves of the same frequency, but of
> different phases, magnitudes, and orientations of the field vectors, the
> resultant combination is said to be an elliptically polarized wave"
> (emphasis mine). This is of course the generalized case of the circular
> one that would require them to be of the same amplitude and 90 degrees out
> of phase as they note a few paragraphs later.
[snip]
Yes! We all know that nothing is really "rotating" in circular
polarization,
rather circular polarization is merely the presence of two separate linearly
polarized waves that are differ in time phase by 90 degrees and mutually
oriented at 90 degrees (space angle) to each other.
A circularly polarized wave excites a linearly polarized antenna equally
well when oriented at any arbitrary angle. In fact a fundamental
"experimental" test to determine if a wave is circularly polarized is to
receive it (measure it) with a linearly polarized 'test' antenna while
the test antenna is rotated. If the signal strength received on the linear
test antenna is the same at all angles of orientation then the received
wave is circular.
Of course, the useful 'discrimination' property of circularly polarized
waves is most evident when they are used with circularly polarized
antennas not linearly polarized antennas. A circularly polarized
wave of a given chirality, will be received at full strength on a
circularly polarized antenna with the same chirality and will be
rejected (null signal) on a circularly polarized antenna of the
opposite chirality. This property provides the most useful
applictions of circular polarization.
[snip]
> The key is the 'TWO' that I emphasized.
[snip]
Yes!
> If you trace the E field of a single rotating dipole that is rotating at
> the same frequency as the rf driving it you would still see the E field
> oscillate in amplitude at the original frequency.
[snip]
Yes, if by 'trace' you mean measure with a linearly polarized antenna.
And you would see exactly the same with "trace' with a circularly
polarized signal.
In other words, there is no difference between the wave generated
by a circularly polarized antenna and a wave generated by a linear
antenna mechanically rotated at the signal frequency.
In each case if you placed a linear receiving antenna in the passing
wave front, and hooked and oscilloscope up to the linear receiving
antenna terminals you would observe exactly the same received signals.
[snip]
> and you would observe the same w So as it propagated, even though the
> direction of the E field would follow a circular path the amplitude of it
> would change at the same rate, so there would be nulls in the E field
> every 1/2 cycle...
[snip]
Yes!
[snip]
>in a true circular polarized wave the E field is a constant magnitude,
[snip]
NO! Unless you are referring to say the root mean square magnitude of
the E field, the actual instantaneous magnitude of the E vector oscillates.
The E field of any electromagnetic wave is never constant
it is constantly oscillating in a plane transverse to the wave direction
at the RF 'carrier' frequency.
[snip]> it just
> rotates around the axis at the given frequency.
[snip]
Yes indeed! In the case of circular polarization, there are actually two
separate phase locked linearly polarized (vector) E fields oscillating at
the same frequency but in simultaneous time phase quadrature and space
phase quadrature.
And, here is the important point...
The 'vector sum' of these two orthogonal waves adds up to give an E
vector that appears to be rotating.
Remember that any vector can be resolved into or synthesized from
the sum of other vectors. For example in two-space any vector
can be resolved into two other perpencicular vectors.
(x, y) = (a, b) + (c, d)
Now (a, b) and (c, d) may be linear, but if they are of the form
a = A cos(wt), b = B sin(wt), c = C cos(wt), d = D sin(wt) their
sum (x, y) will appear to be rotating.
Think of the 'projections' of the spoke of a rotating bicycle wheel!
[snip]
> you can't get that from a single dipole no matter how you rotate it
[snip]
Yes you can, see above.
[snip]
> Oh, and i briefly saw something about DC fields... actually i 'think' that
> if you put a 'dc' charge on a dipole, lets just separate two charges by
> some distance and start them rotating about a common center... that MAY
> actually create a circularly polarized wave.
[snip]
Yes it should, but that's not the particular/specific application or
scenario
that I was originally proposing.
[snip]
> but i would consider this a degenerate case of the general problem.
[snip]
Agreed!
My original point was that there is essentially no difference between the
wave
emitted by a conventional circularly polarized antenna (say axial mode
helix [W8JK], or a turnstyle) and a linear antenna spinning mechanically or
spinning
by electronic scanning means, with angular velocity equal to the carrier
frequency.
My claim is that here simply is no way to determine
the difference by any physical measurement. The emitted fields are exactly
the same.
We know that there are good applications for 'conventional' circular
polarization where the rate of field 'rotation' is synchronous with the
carrier frequency.
I was just wondering if there are any good applications for circular
polarization when the rate of field rotation is not synchronous
with the carrier frequency, and if so, how well one could
discriminate between such waves rotating at different angular
velocities.
Dave
"Peter O. Brackett" <no...@no-such-domain.nul> wrote in message
news:ovednT8NBp3THt3U...@earthlink.com...
no you wouldn't. with the rotating dipole the E field would have zero
crossings every 1/2 wave even as the direction rotates. with a real
circularly polarized wave the E field is a constant magnitude and just
changes direction. if you break down the wave into 2 orthogonal linearly
polarized waves the zero crossings in one line up with the peaks in the
other so the resultant vector magnitude of the E field is a constant... only
the direction changes.
>
> In other words, there is no difference between the wave generated
> by a circularly polarized antenna and a wave generated by a linear
> antenna mechanically rotated at the signal frequency.
yes there is, you are missing 1/2 the wave components.
>
> In each case if you placed a linear receiving antenna in the passing
> wave front, and hooked and oscilloscope up to the linear receiving
> antenna terminals you would observe exactly the same received signals.
Only at multiples of 1/2 wave distances from the transmitting antenna. When
the transmitted peak E field is oriented properly for the receive antenna
you would get a max receive signal. But when you orient the tx antenna so
the max in the tx E field is perpendicular to the rx antenna you get a null.
This pattern repeats every 1/2 wave... again, a real circular signal would
have the 2nd wave component at right angles to fill in those nulls.
>
> [snip]
>> and you would observe the same w So as it propagated, even though the
>> direction of the E field would follow a circular path the amplitude of it
>> would change at the same rate, so there would be nulls in the E field
>> every 1/2 cycle...
> [snip]
>
> Yes!
Ah, so you agree here, but not above... this is the key to the difference.
there are zero crossings of the E field in the rotating plane wave, but NOT
in the circular wave... hence rotating plane waves have nulls every 1/2
wave.
>
> [snip]
>>in a true circular polarized wave the E field is a constant magnitude,
> [snip]
>
> NO! Unless you are referring to say the root mean square magnitude of
> the E field, the actual instantaneous magnitude of the E vector
> oscillates.
> The E field of any electromagnetic wave is never constant
> it is constantly oscillating in a plane transverse to the wave direction
> at the RF 'carrier' frequency.
no, the E field is a constant magnitude in a true circularly polarized wave,
only the direction changes.
>
> [snip]> it just
>> rotates around the axis at the given frequency.
> [snip]
>
> Yes indeed! In the case of circular polarization, there are actually two
> separate phase locked linearly polarized (vector) E fields oscillating at
> the same frequency but in simultaneous time phase quadrature and space
> phase quadrature.
right, there are TWO orthogonal waves... with a rotating dipole you only
have ONE wave whose polarization changes over time. put a circularly
polarized wave through a polarizing filter and you still get a signal no
matter what the orientation. put a polarizing filter in front of your
rotating plane wave and you get a signal that depends on your distance from
the antenna.
>
> And, here is the important point...
>
> The 'vector sum' of these two orthogonal waves adds up to give an E
> vector that appears to be rotating.
Right! But go back to the books and look at that vector sum in detail. the
magnitude of it is a constant, only the direction changes. in a rotating
plane wave both the direction and magnitude change because there is no 2nd
field component to fill in the zero crossings.
>
> Remember that any vector can be resolved into or synthesized from
> the sum of other vectors. For example in two-space any vector
> can be resolved into two other perpencicular vectors.
>
> (x, y) = (a, b) + (c, d)
>
> Now (a, b) and (c, d) may be linear, but if they are of the form
> a = A cos(wt), b = B sin(wt), c = C cos(wt), d = D sin(wt) their
> sum (x, y) will appear to be rotating.
>
> Think of the 'projections' of the spoke of a rotating bicycle wheel!
RIGHT! so take your rotating dipole and look at it from even multiples of
1/4 wave away... lets assume that the max E field from the tx antenna is
when it is horizontal, and min when it is vertical.... remember, the antenna
rotates 90 degrees as the tx rf also goes from peak to zero crossing... so
the zero crossing will always be when the antenna is vertical and the max
will always be when the antenna is horizontal. So, at even multiples of 1/4
wave you see the max E field in the same orientation as when it was
transmitted, horizontal. Move another 1/4 wave away, so now you are at an
odd multiple of 1/4 wave. now that max E field is vertical and the minimum
is horizontal so your horizontal rx antenna sees the minimum field. Without
that 2nd wave at right angles you have a null in the pattern, the 2nd wave
from a real circular wave would fill in that null and you would have a
constant signal amplitude.
>
> [snip]
>> you can't get that from a single dipole no matter how you rotate it
> [snip]
>
> Yes you can, see above.
No you can't, and you agreed with that statement above, you just didn't know
you did.
>
> [snip]
>> Oh, and i briefly saw something about DC fields... actually i 'think'
>> that if you put a 'dc' charge on a dipole, lets just separate two charges
>> by some distance and start them rotating about a common center... that
>> MAY actually create a circularly polarized wave.
> [snip]
>
> Yes it should, but that's not the particular/specific application or
> scenario
> that I was originally proposing.
>
> [snip]
>> but i would consider this a degenerate case of the general problem.
> [snip]
>
> Agreed!
>
> My original point was that there is essentially no difference between the
> wave
> emitted by a conventional circularly polarized antenna (say axial mode
> helix [W8JK], or a turnstyle) and a linear antenna spinning mechanically
> or spinning
> by electronic scanning means, with angular velocity equal to the carrier
> frequency.
>
> My claim is that here simply is no way to determine
> the difference by any physical measurement. The emitted fields are
> exactly
> the same.
yes there is. a polarizing filter or just by moving a linear rx antenna
will tell you which is which.
>
> We know that there are good applications for 'conventional' circular
> polarization where the rate of field 'rotation' is synchronous with the
> carrier frequency.
>
> I was just wondering if there are any good applications for circular
> polarization when the rate of field rotation is not synchronous
> with the carrier frequency, and if so, how well one could
> discriminate between such waves rotating at different angular
> velocities.
maybe it could be used for some kind of distance determination by rotating
at a slightly different frequency than the carrier frequency. that would
create a null when measured from a linear rx antenna that moved along the
line of sight at the difference in frequencies. it may be hard to calibrate
and measure since the tx polarization vs time would have to be known so you
could calculate how much rotation there has been at your location... and it
would of course fall apart if it wasn't line of sight and there were any
reflections.
Jerry
Hi Pete
I dont think a rotating dipole with DC on it will generats a field that
propogates. Your post reads as though you dont think the rotating DC
dipole will producing a propogating Far Field. I read other posts that
seem to indicate that others assume the DC spinning dipole will generate a
propogating "far field". It is sad that I am so lazy that I cannot express
myself using Cross Products. But, I submit that it takes more than rotating
a dipole to produce a propogating far field.
I dont understand where the "Cross H" is generated by a rotating DC
dipole, as required for propogation.
I dont understand why it requires more power to rotate a DC dipole with
increased voltage on it, as required to account for the increased power.
Jerry KD6JDJ
Peter O. Brackett
[snip]
> I dont think a rotating dipole with DC on it will generats a field that
> propogates. Your post reads as though you dont think the rotating DC
> dipole will producing a propogating Far Field. I read other posts that
> seem to indicate that others assume the DC spinning dipole will generate a
> propogating "far field". It is sad that I am so lazy that I cannot express
> myself using Cross Products. But, I submit that it takes more than
> rotating a dipole to produce a propogating far field.
>
> I dont understand where the "Cross H" is generated by a rotating DC
> dipole, as required for propogation.
>
> I dont understand why it requires more power to rotate a DC dipole with
> increased voltage on it, as required to account for the increased power.
>
> Jerry KD6JDJ
[snip]
What is required to generate electromagnetic radiation is any movement of
electric charge such that there exists a rate of change of the positional
acceleration
of electric charge. This can be derived from first principles from the
Maxwell/Heaviside
equations. There is a section in the volume of Feynman's Lectures on
Physics that
discusses this, and I believe that the previous editor of QEX magazine wrote
an
article outlining a derivation of this a year or so ago.
In physics and dynamics the rate of change of acceleration is termed "jerk".
In terms of simple differential calculus, there is position ("x"), there is
velocity
("v = dx/dt") the rate of change of position, there is acceleration ("a =
dv/dt")
the rate of change of velocity, and there is jerk ("j = da/dt") the rate of
change of acceleration. Expressing it in these terms, it can be said that
it
it can be shown from the Maxwell/Heaviside partial differential equations
that govern all of electromagnetics, that radiation occurs when ever
electric
charge is "jerked". i.e. whenever the rate of acceleration of charges
changes
either up or down.
Now in sinusoidal realms, where all the signals are assumed to be of sine
wave shapes, we know from simple differential calculus that differentiating
sine waves results in more sine waves. In other words a sine wave current
comprises electric charges changing position according to a sine waveform,
and so perforce is the velocity, acceleration and jerk of those charges.
Hence
whenever electric current motion follows a sine-like wave there will be
radiation caused by the sinusoidal 'jerk'.
Now there are more forms of acceleration than just sine wave motion.
For example when things have angular motion, there is centrifugal
acceleration, and when things move on a rotating frame there
is coriolis acceleration, etc... and so in general whenever electric
charges are put in motion, the exception being simple motions where
the third derivative of motion is zero, there will be radiation caused
by that motion.
All of the above details are well known to most physicists who study
electromagnetics, from first principles (Maxwell/Heaviside), these 'facts'
are less well known to most (modern) electrical Engineers.
Consequently I find it easy to believe that the mechanical motion of
any body with electric charge on it, be that charge DC or AC is highly
likely to radiate electromagnetic waves.
All of this is difficult, actually impossible, to simulate with NEC codes
like Roy's EZNEC since those analysis codes all assume a simple
steady state fixed sinusoidal regime for the framework in which
the Maxwell/Heaviside equations are solved. NEC does not
provide for the simulation of antennas in motion! And so...
It is beyond the capability of NEC in general or EZNEC in
particular to generate field patterns for rotating dipoles!
Othewise someone (Cecil maybe?) would already have run
a simultation on EZNEC to refute my claims to being able
to generate circular polarization by mechanical rotation.
In other posts in these threads on CP I have asked if anyone
knows of any simulation software (generally would be in the
category called "multi-physics packages" that can adequately
simulate/calculate the fields for rapidly rotating dipoles driven
by sinewaves at arbitrary frequencies. If so I'd like to know.
And I'd like to simulate some of my "theories" just to prove
my assertions.
Actually it may be easier to emulate (i.e. prototype) such
a spinning dipole. In fact one does not have to mechanically
spin a dipole to do this. One can generate the same fields
as a spinning dipole by applying the "right" signals to two
orthogonal linear dipoles. i.e. a synthetic or phased array
beam former, that emits circularly polarized beams of
arbitrary rotation velocity.
Phased arrays can be elctronically scanned or rotated,
this is in fact how most modern STAP radars work, e.g.
Aegis, etc... and so one can electronically rotate emitted
waves in the same way. It's not cheap, but it can be done.
My curiosity is along the lines of if you could find a cheap
way of rapidly spinning an emitting dipole, what new
applications might arise from that.
As far as I can determine, no one has yet done the experiments
that I have been discussing here in these threads.
And so my suggestions/theories are met with comments
like, "It's never been done before, why would you want to do it,
etc, etc... ?
Why do I ask such questions?
Just curious or perhaps I'm just plain stupid!
But no one has yet been able to categorically refute my assertion.
Whenever charge is jerked there is radiation!
Food for thought.
Richard Clark
<no...@no-such-domain.nul> wrote:
>What is required to generate electromagnetic radiation is any movement of
>electric charge such that there exists a rate of change of the positional
>acceleration
>of electric charge.
What a lot of bafflegab. For one sentence movement is named,
described, AND inferred three times; and charge tied to two of them.
Peter, when the ladies say NO to you, they probably have to have it
annotated, indexed, and footnoted before you get it.
73's
Richard Clark, KB7QHC
Peter O. Brackett
[snip]
"Richard Clark" <kb7...@comcast.net> wrote in message
news:8aa5k4ph6336clo13...@4ax.com...
> On Fri, 12 Dec 2008 11:46:47 -0500, "Peter O. Brackett"
> <no...@no-such-domain.nul> wrote:
.
.
.
> Peter, when the ladies say NO to you, they probably have to have it
> annotated, indexed, and footnoted before you get it.
>
> 73's
> Richard Clark, KB7QHC
[snip]
Richard, hey, clearly you have never met me in person. In person I am even
more persuasive than in my often
ill prepared USENET postings, it has been my experience that the ladies
NEVER SAY NO to me!
Heh, heh...
I was an only son, raised in a large family of sisters by my mother who was
often alone since my father was a seagoing
sailor. And so... at a very early age I learned to "convince" the ladies of
the veracity of my assertions and requests.
Long since grown into a man, I'll turn 67 next week, I have polished my
approach to the point that the ladies always
accept everything I say. Heh, heh... Whenever I ask the ladies a question
or state an assertion in my own inimitiable way their
responses are always along the lines of...
"I'll bet you say that to all the ladies" and they invariably end with,
"sure you may, it would be my pleasure, you are such a smooth talker".
[grin]
Smooth talker, sweet talker, what ever works, I say!
On that particular subject there was a "cute" but interesting, entertaining
and amusing two page piece in last month's Esquire magazine
entitled something like, "The Smooth Talker" or "How to be a Smooth Talker".
It was really quite an amusing piece, and apropos to
the current thread.
If you don't get Esquire take the time to look up that piece at your local
library, I'm sure that you will get a laugh or two, I did.
OK, enough of this 'aside', let's get back to the real technical discussion
at hand.
None of the guru's lurking around this particular newsgroup (r.r.a.a) will
deny that whenever electrical charge is "jerked" that photons are emitted.
And... none of the gurus hanging hereabouts will deny that photons can have
'spin'.
The only question remaining is that of the relative quantities of left and
right hand 'spin' of photons in any specific situation where
photons have been 'jerked' lose from the electrical charge and whether the
'spin' is quantized or continuous.
Comments, thoughts?
-- Pete K1PO
-- Indialantic By-the-Sea, FL
PS: Gosh, I've missed this group.... Cecil is fine, but it's just not been
the same since dear Reggie passed. I miss Reg, especially at this time
of year. At least one could easily understand the King's English as written
by dear Reg, and Cecil's English is not that bad for an "Aggie", but
Richard, since your purple prose takes English expression to a completely
different level, you certainly help keep this group entertained. Thanks
for what you do for us all!
Dave
Do you have any hobbies?
Peter O. Brackett
[snip]
> Do you have any hobbies?
[snip]
Technical hobbies, or social hobbies?
Other than kibitzing on r.r.a.a?
Would you believe that I'm a salsa dancing champion? Actually my wife Kathy
(who is a dance genius) and I do a lot of dancing which might be described
as a "hobby" of sorts.
Let me tell you about one of our recent dance escapades.
About three weeks ago my wife and I were in Paris, France, returning from
three weeks in Italy where, among other things, we hiked to the top of
Vesuvius. But that's another story!
All this to say that we stopped over for a night in Paris on our way back to
Indialantic from Naples. We took the opportunity to take in dinner and a
show at the celebrated Moulin Rouge near Pigalle in Paris.
Ouch! That was an expensive evening! It didn't look too bad in Euros, but
when the bill showed up on my Visa statement in US$ it was heart stopping!
Front row seats at the Moulin Rouge, right up against that venerable125 year
old stage, and the multi-course meal with a magnum of champagne was great
and as you will note from the rest of my "story" it turned out to be a
memorable evening!
Kathy and I took the train from CDG airport into the Gare du Nord, and then
we took the Paris Metro over to the Pigalle station leaving time to get lost
at least three times before we got there. Pigalle as you know is in the
center of the "red light district" of Paris. The Moulin Rouge is in the
middle of that district on Monmatre, the dandy's, Princes and Princesses do
not walk along Pigalle to get to the Moulin Rouge like Kathy and I did,
rather they arrive right in front of the door in long black Mercedes
limousines.
Well... at the Moulin Rouge they serve a first class dinner before the show
if you elect to take the dinner and show rather than just the show.
During dinner, a small elegant music ensemble is fronted by a talented duet
of singers, who are sort of the Parisian equivalent of
Edye Gorme and Steve Lawrence, except they sing in French, such songs as
"Chanson d'Amour", etc. as enteratinment for the diners.
During dinner that part of the main stage that later becomes elevated during
the main show is kept at ground level so that people can dance if they wish,
during dinner, and before the main show.
The Moulin Rouge was packed the night we were there and, as usual whenever
there are lots of "observers", there were not many dancers on the floor!
Only a couple of pairs, who had consumed all of their champagne by that time
got up to dance staggered through a few 'slow dance' steps, and so the floor
of the Moulin Rouge looked downright barren.
My wife Kathy suggested that WE get up and dance. As a dance instructor,
you can well imagine that Kathy is not shy about that kind of thing. My
athy always likes
to be the first one out on the dance floor.
Well the small ensemble and the two singers got round to a number with a
certain beat (NC2S) that my wife and
I like and so Kathy suggested that we get up on the Moulin Rouge dance
floor in front of the whole audience that night
and do the Night Club Two Step.
Now for those of you who don't know, the NC2S is a modern dance that was
"invented" by and American,
Buddy Schwimmer of Costa Mesa, CA a few years ago. NC2S is a very elegant
dance done to slower music and is very elegant and quite
unique.
Aside: NC2S is known in the USA but likely not well known in Europe. In case
you are not a dancer, you should know that Buddy Schwimmer
happens to be the father of Benji Schwimmer who won the "So You Think You
Can Dance" show two years ago, and he is also the father of Lacey
Schwimmer who was partnered with Lance Bass on the "Dancing with the Stars"
show this past fall. Lacey and Lance
came in second on the show this year, after that graceful "Brooke Burke" and
her partner Derek Hough.
And so... "there we were", my wife Kathy and I dancing the elegant Night
Club Two Step all alone on the dance floor of the Moulin
Rouge in Paris, in front of an International audience of several hundred
people.
Well... we were surprised! As we danced together to that beautiful slow and
sexy music, all of the dinner "chatter" stopped and all eyes
in that famous 125 year old theatre, were on us as I showcased Kathy's
wonderful dance skills (as the dance partner/leader).
The highlight came as the music ended and we walked back to our dinner
table.
The audience at the Moulin Rouge favored us with a standing ovation!
Apparently they had never seen the Night Club Two Step before!
Unfortunately no one recorded the happenings at the Moulin Rouge that night,
but... for those of you who might be interested to see what the NC2S looks
like
as it is danced, you see an example on You Tube, just click on...
http://www.youtube.com/watch?v=VoyxrEbZpSw
BTW... the Moulin Rouge show after dinner and dancing was spectacular and
well worth the $$$$$.
I suppose that if it were not a 125 year old tradition in Paris that the
Moulin Rouge show mighty be described by Americans as a "high end" Las Vegas
show,
except that... Las Vegas, NV was not even in existence when the Moulin Rouge
started its run 125 years ago!
I'd say that one should really describe Las Vegas shows as pale imitations
of the Moulin Rouge show! [smile]
Guys who are reading this will be pleased to know that not only is the whole
show spectacular, but the show girls at Moulin Rouge are spectacular as
well.
All this to say, Dave.... yes I do have hobbies!
And... I am often "asked to dance"...
BTW.... I highly recommed dance to any man/boy who wants to be closely
asociated with women!
Dave, I'd challenge you to name a hobby for a man that is as exciting as a
hobby where the man gets to hold attractive girls in his arms and run his
hands all over thier bodies for 3-5 minutes at a time and the girls thank
him when it's over and asks him if they could do it again soon?
Ciao!
Richard Clark
<no...@no-such-domain.nul> wrote:
>None of the guru's lurking around this particular newsgroup (r.r.a.a) will
>deny that whenever electrical charge is "jerked" that photons are emitted.
At the risk of being so identified with that villified group, I will
deny that statement (for what it is worth).
>And... none of the gurus hanging hereabouts will deny that photons can have
>'spin'.
That is a fairly short list of what is "not" denied. Why don't you go
further like Gurus refuse to deny:
1. They hate their parents;
2. They stopped beating their wives;
3. The earth is perfectly round;
4. Gussian arrays are the perfect metaphor for radiation;
...
n. and on and on and -heh heh- on.
Peter O. Brackett
[snip]
"Richard Clark" <kb7...@comcast.net> wrote in message
news:gur7k4dpo2qcurlsk...@4ax.com...
> On Sat, 13 Dec 2008 09:41:46 -0500, "Peter O. Brackett"
> <no...@no-such-domain.nul> wrote:
>
>>None of the guru's lurking around this particular newsgroup (r.r.a.a) will
>>deny that whenever electrical charge is "jerked" that photons are emitted.
>
> At the risk of being so identified with that villified group, I will
> deny that statement (for what it is worth).
[snip]
Your denial is not worth to much simply because, as The Bard had one of his
thespian protagonists quote,
"methinks he doth protest too much".
And, so... well, I am afraid to admit that... I don't really know which of
the honored denziens of this
group (r.r.a.a) are the select members of the secret clique of lurkers known
as "The Gurus".
It seems from what you have written above that you deny being one of The
Gurus.
I believe it was Groucho Marx who said, "I wouldn't want to be a member of
any club that would accept
me as a member", and so...
Me?
Hmmm... I not only deny membership in The Gurus, but I actually know that I
am not a member.
Now, if my recollection is correct, Reg Edwards may have known the names on
that secretive list of gurus, but
since Reg has now passed to his reward and, although we have evidence of
Reg's own electromagnetic expertise
in the form of the many programs and web site information he graciously left
for us gratis, there is no evidence
that Reg ever belonged to The Gurus. In fact, I recall Reg indirectly
denying his own membership on many
occasions by referring difficult and sometimes rhetorical questions to "The
Gurus", often answering those
questions himself after much newsgroup discussion.
Apparently Art Unwin has definite knowledge of who The Gurus are, since he
often challenges and castigates
them at the same time. Unfortunately Art would condemn the poor IEEE
because of corrupt behavior, and
so I am not sure that Art is really connected in the electromagnetic world.
All this musing to note that... USENET is a great tool for scientific
discussion, that adheres to the most basic
tennets of "The Scientific Method".
Why, anyone... from freely identified persons, to anonymous posters, may
make whatever assertions and pose
whatever theories they care to, and everyone knows that eventually the truth
will be revealed as those assertions
are examined in the brilliant light of the scientific cross examination that
occurs in these r.r.a.a threads!
Hey! Where's Art when you need him? Art... I've created your opening, now
its your turn...
It's saturday night and I gotta go dancing, the girls are waiting... :-)
-- Pete K1PO
-- Indialantic By-the-Sea, FL
care to and
Richard Clark
<no...@no-such-domain.nul> wrote:
>>>None of the guru's lurking around this particular newsgroup (r.r.a.a) will
>>>deny that whenever electrical charge is "jerked" that photons are emitted.
>>
>> At the risk of being so identified with that villified group, I will
>> deny that statement (for what it is worth).
>Your denial is not worth to much simply because, as The Bard had one of his
>thespian protagonists quote,
>"methinks he doth protest too much".
I didn't think the question had any legs either. D.O.A.
>Apparently Art Unwin has definite knowledge of who The Gurus are, since he
>often challenges and castigates them at the same time.
He is like Septimus who awaits the death of his six brothers before
ascending to the crown.
>Art... I've created your opening, now its your turn...
Stand back then, because you'll find him spitting at you in the chance
of catching me in the backwash.
Art Unwin
wrote:
> Richard:
>
> [snip]"Richard Clark" <kb7...@comcast.net> wrote in message
>
> news:gur7k4dpo2qcurlsk...@4ax.com...> On Sat, 13 Dec 2008 09:41:46 -0500, "Peter O. Brackett"
Peter, there are no gurus on this newsgroup period
When I extended the Gaussian law of statics by making it a dynamic
field
I proved beyond doubt that radiation was via particles and not waves.
David and others denied that you could even bring in the subject of
statics
when discussing radiation even tho it is known that the force between
particles
is part and parcel of Maxwells laws. I might add that many joined him
in this thinking
like lemings. Since that time all of this group have sunk lower and
lower with respect to radio.
All have demanded a definition of equilibrium no less so all are
lacking in science.
They have all denied that mathematically my extension of Gauss results
in the same mathematics
that were arrived at by Maxwell. When I point out that eddy current
( really a field) is the weak
force that Einstein was looking for as he was convinced that
radiation held the clue he was looking for.
Yup they howled at that one too. Ofcourse it was Maxwell who found out
that one of the existing laws by the masters
was not in equilibrium which he then corrected by adding the
displacement current which describes the
action of the eddy current field in lifting and applying spin to a
charged particle. Howls again from all
as this could not be found in any books. Ofcourse this operation in a
macro scale is used daily in scrap
yards for sorting out materials as well as non destructive testing but
again the howls rose again.
So I then told them that maxwell based computor programs account for
all the forces used in radiation
which they could find out for themselves with a optimizer program as
long as the input was not slanted towards a planar design so that it
may be discarded
But then they are self perceived gurus thus don't need to use a
computer as all is already known, ala their books that are more than
50 years old.
I then informed them that one naval base had tipped all their
verticles for better performance by incorporating the weak fork which
also can be confirmed using Maxwells laws. Now I am being considered
and idiot no less. So I then posed the question as to where the
current goes when reaching the top
of a fractional wave antenna and the answers I got was that a closed
circuit is not required for radiation. And this thinking goes on and
on but at no time
has anybody come forward to refute my analysis in anyway, mathematics,
computor programs or what ever.
This whole story reminds me of the Yagi invention that was dismissed
totally by the Japanese intelligensia but embrace by the rest of the
world such that the Japanese never used the Yagi design thru out the
length of the war which was their loss. Peter, all of the above has
been pointed out to this group of self perceived gurus over the past
few years but all has been denied as it is no where in the books to be
read.
When I joined this group more than a decade ago Roy W7EL said he was
going to expose all the old wives tales that floated around including
all the newly touted sciences that were being tossed around but his
silence has been defining while at the same time Snakespere has been
prancing around in his fishnet pants while talking in tongues. Ian is
still demon strating how to solder a connector on coax while the Naval
instructor Woods in Washington
is in total belief that the US navy is using tilted antennas for
superior performance. No Peter, there are no gurus on this newsgroup
as I have one time or another proved that they are nothing more than
talking heads beyond doubt.
As an aside Peter on another subject I have no bone to pick with the
professional societies only the Universities for giving away
information provided by tax payers money and thus was not theirs to
remove from publics eyes
Best regards
Art Unwin.......KB9MZ.......xg (uk)
John Smith
>> ...
> I proved beyond doubt that radiation was via particles and not waves.
>> ...
> Best regards
> Art Unwin.......KB9MZ.......xg (uk)
Actually, that is false ... you could not prove such a thing, unless you
force us to disbelieve our own eyes! To proceed claiming such is only
to invite us to think you daft!
http://www.newscientist.com/article/dn14172?DCMP=ILC-hmts&nsref=news1_head_dn14172
The best you can now argue is that light is composed of a type(s) of
particle(s) which travels as a wave(s); And, still, it seems to possess
both qualities--i.e., behaving both as particles AND waves ... but then,
we already knew that.
Regards,
JS
Art Unwin
> Art Unwin wrote:
>
> >> ...> I proved beyond doubt that radiation was via particles and not waves.
>
> >> ...
>
> > Best regards
> > Art Unwin.......KB9MZ.......xg (uk)
>
> Actually, that is false ... you could not prove such a thing, unless you
> force us to disbelieve our own eyes! To proceed claiming such is only
> to invite us to think you daft!
>
>
> The best you can now argue is that light is composed of a type(s) of
> particle(s) which travels as a wave(s); And, still, it seems to possess
> both qualities--i.e., behaving both as particles AND waves ... but then,
> we already knew that.
>
> Regards,
> JS
John I am confident about my analysis. Scientists have not been able
to explain
anything in radio that procedes at the or near the speed of light or
explain how communication is resolved.
I have provided an explanation that is duplicated in many ways every
day and vindicated by Maxwells equations.
Reviewing the URL you supplied. The photograph is not a simple proof
that it appears to be. Camera pictures are notorious
in fooling people into falible interpretatations. However you can
believe what you want. I would point out that I have melded many
things and aproaches
such that all mesh in a single conclusion None of these separate
aproaches have had any errors pointed out whether it be mathematics or
otherwise.
I am not a programmer so there is no way I could have injected such a
complicated scenario into all the programs now available. Nor could I
have invented the weak force that Einstein was convinced resided in
the analysis of radiation. On the other hand there are many
photographs available of the Lock Ness monster, alien space craft and
alabaster statues with tears coming from the eyes. By the way, compare
different aproaches of resolving radiation analysis and check which
form provides the minimum losses and you will find that planar
antennas just don't measure up versus antennas in equilibrium. On the
other hand if the field of an eddy current is not the weak force that
Einstein forcast or predicted then where and what is this force that
propels a wave, presumably without spin that knocks out what I have
suggested? At the same time does it fit exactgly the jigsaw pussle
that Maxwell left us with the puzzle turned over so the picture could
not be pre determined? And as a finale I see particles occilating
possibly in tandem form that gives the impression that the particles
arenot interconnected in string form but a series of interactions
between particles that operate in their own right als
H2O in molecular but unbound form as with mass
Best regards...... good effort but no cigar. I would aim for best
results at the computer programs or finding the true weak force, or
determining how a electrical wave travels with intelligence or the
center of all proove that the mathematics as applied to gaussian
boundary that is made dynamic under a time varying field DOES NOT
equate with the mathematical laws of Maxwell and last of all that the
term equilibrium has NO PLACE in the laws devised by the masters with
respect to the Universe. I left out the part that a radiater must be
straight as expoused by some pseudo experts in the radio field as well
as to how the addition that Maxwells made to his laws provide the
mathematics for the tilting action on a radiator for minimum lossand
the many other things I have pointed out
My very best regards and best wishes in any endeavor that you wish to
undertake in an effort to proove me in error. There will be some
talking in tongues by the group but I am absolutely positive there
will be no fresh revalations other than just words provided over the
years which have meant nothing
other than the intent to hurt. Goodnight
Art Unwin KB9MZ..........XG....(UK)
John Smith
> On Dec 13, 9:38 pm, John Smith <assemblywiz...@gmail.com> wrote:
>> Art Unwin wrote:
>>
>> >> ...> I proved beyond doubt that radiation was via particles and not waves.
>>
>> >> ...
>>
>>> Best regards
>>> Art Unwin.......KB9MZ.......xg (uk)
>> Actually, that is false ... you could not prove such a thing, unless you
>> force us to disbelieve our own eyes! To proceed claiming such is only
>> to invite us to think you daft!
>>
>> http://www.newscientist.com/article/dn14172?DCMP=ILC-hmts&nsref=news1...
>> ...
> Reviewing the URL you supplied. The photograph is not a simple proof
> that it appears to be. Camera pictures are notorious
> in fooling people into falible interpretatations. However you can
> believe what you want. I would point out that I have melded many
> things and aproaches
>> ...
> Art Unwin KB9MZ..........XG....(UK)
Well, that is simple enough then. You are to have us disbelieve our own
eyes ... good enough, we have that cleared up.
Regards,
JS
Art Unwin
John you can interprete what you want. For me I will await for
somebody
to prove me wrong in the many areas that I have espoused and allow
those that
just want to make nasty remarks go ahead with their agenda. Sooner or
later reason will prevail
and Snakesphere talking in tongues will fade away.. I look forward to
the time that a real guru on radiation
appears on the group to discuss what is salient to the subject
Very best regards
Art Unwin.......KB9MZ........xg (uk)
John Smith
> ...
> John you can interprete what you want. For me I will await for
> somebody
> to prove me wrong in the many areas that I have espoused and allow
> those that
> just want to make nasty remarks go ahead with their agenda. Sooner or
> later reason will prevail
> and Snakesphere talking in tongues will fade away.. I look forward to
> the time that a real guru on radiation
> appears on the group to discuss what is salient to the subject
> Very best regards
> Art Unwin.......KB9MZ........xg (uk)
Now, we approach that time of risking way too much verbiage on way too
little.
Yes, I do trust my eyes. The research done to get that picture was done
by a university; I don't believe the lady, who was head, was out to
reinforce any preconceived ideas/theories. And, I don't believe New
Scientist is a nutter-rag-on-the-fringe; It does push-the-evelope.
THAT is my interpretation; I fear it the only one possible, at this
time. Light and, most-probably, EM (no picture, yet) behaves with
properties BOTH resembling particles and waves. (Thank gawd, at least
something gives us valid reason for argument!)
You can wait for the cows-to-come-home; that research stands; the
picture is NOT a fraud--IMHO. I have no reason to "be nasty"; I simply
believe it to be as it appears ...
I am at a loss for what Shakespeares' stance would be; As you say, may
reason prevail.
My very definition of the meaning of "guru" is "clueless" (in the
context which I have used the word here); Now, you wish to wait for one
of "them?" <scratches-head>
Salient? Change that to logical and I will "look forward" with you ...
now, please, don't "be nasty" ... end-of-story.
Regards,
JS
John Smith
>> ...
> Very best regards
> Art Unwin.......KB9MZ........xg (uk)
By-the-way, a sine wave (such as is seemingly depicted in that picture)
is nothing less than a circle (360 degrees)--"traveling." I don't
believe you were "lost" on that point, but stated here just to make sure ...
Regards,
JS
John Smith
>> ...
> Very best regards
> Art Unwin.......KB9MZ........xg (uk)
By-the-way, a sine wave (such as is seemingly depicted in that picture)
is nothing less than a circle (360 degrees)--"traveling." I don't
believe you were "lost" on that point, but stated here just to make sure
... or, simply, "a traveling circle."
Regards,
JS
Jeff Liebermann
<assembl...@gmail.com> wrote:
>Art Unwin wrote:
>> Sooner or
>> later reason will prevail
>> and Snakesphere talking in tongues will fade away.
>I am at a loss for what Shakespeares' stance would be; As you say, may
>reason prevail.
Shakespeare will have little to say about it. The term "speaking in
tongues" comes from the New Testament:
<http://www.bible.org/page.php?page_id=393>
Also, reason has rarely prevailed. It's usually rationalization,
seduction, politix, or main force that carries the argument. None of
these show any indication of fading away.
How I create circular polarization or simulate a rotating antenna
direction finder. Pretend I'm holding an antenna:
<http://www.LearnByDestroying.com/panorama/jeffl.htm>
When it's done loading, move the mouse around the picture.
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
John Smith
> ...
> How I create circular polarization or simulate a rotating antenna
> direction finder. Pretend I'm holding an antenna:
> <http://www.LearnByDestroying.com/panorama/jeffl.htm>
> When it's done loading, move the mouse around the picture.
ROFLOL!!!
Great! Best laugh I have had on here in quite awhile ...
Thanks,
warm regards,
JS
Jeff Liebermann
<Arthu...@gmail.com> wrote:
>I look forward to
>the time that a real guru on radiation
>appears on the group to discuss what is salient to the subject
Sorry, but the messiah is busy trying to save the multitudes from,
moral debauchery, religious damnation, economic meltdown, global
warming, and the evil oil cartels. Antenna design and theory will
have to wait until all the other evils are dealt with.
Also, guru means "teacher". There are several current and former
teachers that post high quality answers here fairly regularly. If all
you want is a guru, they're readily available. All you have to do is
read, listen, and understand.
Peter O. Brackett
> How I create circular polarization or simulate a rotating antenna
> direction finder. Pretend I'm holding an antenna:
> <http://www.LearnByDestroying.com/panorama/jeffl.htm>
> When it's done loading, move the mouse around the picture.
Cool!
Finally someone with an open mind, good on you...
Lurkers will note that... Jeff is circularly polarized!
Been a while since I was in Santa Cruz. Been a while since I ran SCO...
Thanks Jeff.
JIMMIE
wrote:
> Group:
>
> Warning... this could be mind blowing!
>
> Conventionally electromagnetic wave 'polarization' refers to the relative
> physical spatial orientation of the electric field vector (E) of an
> electromagnetic wave.
>
> It is commonly understood that polarization of electromagnetic waves may be
> either linear or circular.
>
> Linear Polarization (LP):
>
> Of course waves that are linearly polarized may have any arbitrary
> orientation angle (theta) with respect to a reference frame such as the
> earth's surface. For example most common linear amateur antennas produce
> and/or respond to waves of linear polarization, and these antennas produce
> either either horizonally or vertically polarized waves depending upon the
> orientation of the (linear) antenna with respect to the earth's surface
> (ground).
>
> As examples; a 1/2 wave length dipole for 10 meters hung at 30 feet between
> two trees of equal height produces a largely horizonally polarized wave and,
> a 2 meter 1/4 wave dipole mounted in the center of the roof of an automobile
> produces a largely vertically polarized wave.
>
> Of course as electromagnetic waves are propagated throughout an environment
> are never purely orientated and usually contain an ensemble of many
> orientations, because the waves are reflected from the ground, trees,
> buildings, mountains, bridges, moving vehicles, and sometimes propogated
> through moving and anisotropic media such as the ionosphere, etc... and so
> the multiple reflection surfaces at various angles to the earth's surface
> and/or refractions and Faraday rotations will conspire to "mix up" the
> original orientation of the E vector of a purely linear transmitted wave and
> usually produces a quite mixed polarization at distance from an emitting
> antenna.
>
> Malus' Law {I = Io [cos(theta)]^^2} describes the response of a linearly
> polarized receiving antenna to waves arriving at a polarization angle theta
> relative to the receiving antenna's preferred orientation. i.e a
> horizontally polarized antenna will produce maximum response to horizontally
> polarized waves and a minimum response (zero) to a vertically polarized wave
> and vice versa.
>
> Of course in practice, because of the multipath reflections and refractions
> the 'cross response' is never exactly zero or maximum as predicted by Malus
> Law.
>
> Just the same it is preferable to have the orientation of a receiving
> antenna 'aligned' with that of a particular transmitting antenna. In the HF
> region it is difficult for hams to "rotate" the orientation of their
> receiving antennas to maximize signal pickup based upon polarization, and so
> most hams are forced to take whatever response their relatively fixed
> antennas produce to the relatively unknown orientation of received waves.
>
> In military or commercial installations, where money and space may not be an
> issue, either electronically or mechanically derived spatial antenna
> polarization diversity can be utilized to maximize received signal strength
> based upon arriving polarization. Polarization diversity receivers...
>
> Circular Polarization (CP):
>
> Circular polarization describes the condition when an electromagnetic wave
> is spinning or rotating with around its direction of transmission. That is
> the electric vector (E) of a circularly polarized electromagnetic wave is
> rotating with an angular velocity as the wave travels through space. This
> is in contrast to the E vector of a linearly polarized wave which merely
> oscillates in one linear direction.
>
> Just as with linear polarization (horizontal and vertical) there are two
> different distinctly possible orientations for circularily polarized waves,
> these are known as Right Hand Circular Polarization (RHCP) and Left Hand
> Circular Polarization (LHCP). There are actually two well known
> conventions used to label R and L CP depending upon the community of
> interest, namely physics/optics and electrical/electronics. Usually
> electronics folks refer the direction of rotation to the rotation of the E
> vector around the direction of travel from a transmitting antenna, whilst
> the optical physicists refer the rotation of E around the direction of
> travel towards a receiving lens. It's the same as the definition of up and
> down, it's all in the eye of the beholder. Regardless there are two
> orientations for CP
>
> Apparently circular polarization is less commonly known and understood than
> linear (horizontal/vertical) polarization especially among hams.
>
> There exist RHCP antennas and there are LHCP antennas. Perhaps one of the
> easiest forms of CP antennas for hams to understand are the axial mode helix
> antennas first discovered/studied by the great radio astronomer/ham John
> Kraus W8JK. Axial mode helix antennas may be "wound" with either a right
> hand thread or a left hand thread.
>
> Again Malus Law applies, in an easily applied modified form and so... RHCP
> receiving antennas respond to RHCP waves and LHCP receiving antennas
> respond to LHCP waves. A purely RHCP antenna will produce zero response to
> an LHCP wave, etc...
>
> An interesting effect happens upon reflection of CP waves. An RHCP wave
> reflected from a perfectly reflecting surface returns (is echoed) as a LHCP
> wave!
>
> CP propagation is often used in Satellite communications where a satellite
> may use both RHCP and LHCP transmitting antennas on the same frequency for
> communicating independently with two different ground stations using R and L
> CP antennas on the same frequency. CP frequency diversity doubles channel
> capacity!
>
> Yet another common form of CP antenna uses crossed linear antennas fed with
> a 90 degree (Pi/2) phase difference excitation.
>
> As far as I know all currently known CP antennas such as axial mode helixes
> and crossed 90 degree linear arrays produce CP waves where the 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.
>
> I believe that the well known and understood situation of purely synchronous
> CP is NOT necessesarily the only form of CP.
>
> Warning... The following may be an invention!
>
> Consider the case of a linear antenna, say a dipole, fed from a feed line
> over rotating slip rings, such that the antenna can be rotated while it is
> transmitting.
>
> 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!
>
> In fact the astute newsreader may note that we need not use a motor to
> rotate the antenna. In fact, I can propose several ways of "electronically"
> rotating the linear antenna at any arbitrary angular velocity, not
> necessarily synchronous with the transmitted frequency and so produce a
> so-called non-synchronous CP at any desired rate of rotation.
>
> Clearly, according to Malus Law, the maximum response to the non-synchronous
> CP received waves from this 'rotating' antenna contraption would be from a
> similarily rotating receiving antenna!
>
> Question?
>
> What would be the response of an axial mode helix antenna or say crossed 90
> degree fed dipoles or any other "synchronous" CP antenna to such a
> non-synchronous wave produces by a rotating antenna?
>
> Would the response of a syncrhronous axial mode helix be less than that of a
> sympathetically rotating receiving antenna?
>
> What?
>
> Thoughts, comments?
>
> -- Pete K1PO
> -- Indialantic By-the-Sea, FL
"Circular polarization describes the condition when an electromagnetic
wave
is spinning or rotating with around its direction of transmission.
That is
the electric vector (E) of a circularly polarized electromagnetic wave
is
rotating with an angular velocity as the wave travels through space.
This
is in contrast to the E vector of a linearly polarized wave which
merely
oscillates in one linear direction."
Pete, I believe this is your error in thinking,instead of a a
spinning field perhaps it would be better just to few it as a coil
moving towards you with no rotation.
Jimmie
Dave
> oscillates in one linear direction."
>
> Pete, I believe this is your error in thinking,instead of a a
> spinning field perhaps it would be better just to few it as a coil
> moving towards you with no rotation.
>
> Jimmie
Two colocated matched antennas 90 degrees apart electrically, one at a
right angle to the other, will make very nice CP.
Dave
"Peter O. Brackett" <no...@no-such-domain.nul> wrote in message
news:I_adnWk02bhRKNjU...@earthlink.com...
> Jeff:
>> How I create circular polarization or simulate a rotating antenna
>> direction finder. Pretend I'm holding an antenna:
>> <http://www.LearnByDestroying.com/panorama/jeffl.htm>
>> When it's done loading, move the mouse around the picture.
>
> Cool!
> Finally someone with an open mind, good on you...
> Lurkers will note that... Jeff is circularly polarized!
he may be twisted, but hardly circularly polarized!