Hello, all. I came across an article in one of my science mags in which
some researchers had discovered a method to coax more bandwidth out of a
given portion of the EM spectrum by "twisting" radio waves together.
Nothing more technical than that in the article. Well, I managed to
find one the author's papers on the subject online:

http://arxiv.org/pdf/1107.2348v2

If this technique is viable, I'm wondering why it is only now being
contemplated. Note the "twisted parabolic antenna" (Fig. 3A) on p.16.
Of course this makes me want to do some experiments in the ham bands.
(I hope this doesn't turn out to be another CFA-like pursuit).
Sincerely, and 73s from N4GGO,


--
J. B. Wood e-mail:

On Tue, 13 Sep 2011 13:40:37 -0400, "J.B. Wood"
wrote:

Hello, all. I came across an article in one of my science mags in which
some researchers had discovered a method to coax more bandwidth out of a
given portion of the EM spectrum by "twisting" radio waves together.
Nothing more technical than that in the article. Well, I managed to
find one the author's papers on the subject online:

http://arxiv.org/pdf/1107.2348v2

If this technique is viable, I'm wondering why it is only now being
contemplated. Note the "twisted parabolic antenna" (Fig. 3A) on p.16.
Of course this makes me want to do some experiments in the ham bands.
(I hope this doesn't turn out to be another CFA-like pursuit).
Sincerely, and 73s from N4GGO,

Looks like an April fool joke to me.

w.

"Helmut Wabnig" [email protected] --- -.dotat wrote in message
...


Looks like an April fool joke to me.

w.

I had the same thought. Some of the math looked OK -- rather basic
statements of some things we know -- but there were some new terms that put
those little cartoon question marks in the space over my head.

Let's wait and see.

On Tue, 13 Sep 2011 13:40:37 -0400, "J.B. Wood"
wrote:

(I hope this doesn't turn out to be another CFA-like pursuit).

I've been hearing presentations of this stuff for 7 or 10 years now -
optical tweezers.

The "vorticity" can be seen in the graphic headed "Figures at a
glance":
http://www.nature.com/nphoton/journa...TON-201106#/f1

This is not to speculate about applications in the HF where energies
are many, many decades down from visible light. Where light is
tweezing molecules (very small ones), HF would be vastly
imperceptible. It would seem this reference, then, is gratuitous - a
form of authority inflation.

There are curious contradictions found:
"This novel radio technique allows the implementation of, at least in
principle, an infinite number of channels on one and the same
frequency, even without using polarization or dense coding
techniques."
compared with:
"Already with this setup one can obtain four physically distinct
channels on the same frequency by additionally introducing the use of
polarization, in this case independent from OAM. A further
multiplication of a factor five after the implementation of
multiplexing, yields a total of 20 channels in the same frequency."

Soooo. A special vorticity technique that does not use polarization
(even though they describe it as such) and does not use coding, can
demonstrate novel outcomes when paired with polarization and coding
(for which the outcome is fairly well established).

Why isn't this peer reviewed in EM proceedings?

73's
Richard Clark, KB7QHC

On Tue, 13 Sep 2011 17:52:35 -0700, Richard Clark
wrote:

On Tue, 13 Sep 2011 13:40:37 -0400, "J.B. Wood"
wrote:

(I hope this doesn't turn out to be another CFA-like pursuit).

I've been hearing presentations of this stuff for 7 or 10 years now -
optical tweezers.

The "vorticity" can be seen in the graphic headed "Figures at a
glance":
http://www.nature.com/nphoton/journa...TON-201106#/f1

This is not to speculate about applications in the HF where energies
are many, many decades down from visible light. Where light is
tweezing molecules (very small ones), HF would be vastly
imperceptible. It would seem this reference, then, is gratuitous - a
form of authority inflation.

There are curious contradictions found:
"This novel radio technique allows the implementation of, at least in
principle, an infinite number of channels on one and the same
frequency, even without using polarization or dense coding
techniques."
compared with:
"Already with this setup one can obtain four physically distinct
channels on the same frequency by additionally introducing the use of
polarization, in this case independent from OAM. A further
multiplication of a factor five after the implementation of
multiplexing, yields a total of 20 channels in the same frequency."

Soooo. A special vorticity technique that does not use polarization
(even though they describe it as such) and does not use coding, can
demonstrate novel outcomes when paired with polarization and coding
(for which the outcome is fairly well established).

Why isn't this peer reviewed in EM proceedings?

73's
Richard Clark, KB7QHC

Any strong laser beam will trap dust particles and pull them towards
a direction, I do not remember was it towards the light source or away
from it.
I consider that a thermal effect.

The effect is stunning when you see it the first time.
I worked as helper guy for laser shows, and we used Argon lasers
up to 30 watt output. Suddenly some bright spots aligned at the
beam and slowly moved along it. Dust particles in the air,
of a certain size.

w.

On Wed, 14 Sep 2011 08:59:16 +0200, Helmut Wabnig [email protected] ---
-.dotat wrote:

Any strong laser beam will trap dust particles and pull them towards
a direction, I do not remember was it towards the light source or away
from it.
I consider that a thermal effect.

The tweezing is similar to dielectrophoresis and is possibly, but not
probably what you describe. In dielectrophoresis, a normally neutral
molecule (water is such an example) still has an electrical dipole.
The two ends add up to a neutral whole, but in the face of a
non-linear electrical field, the dipole will align along the gradient
and the neutral molecule can be electrostatically steered. It is a
mechanism of fluidic separation done on a scale of what is called "a
laboratory on chip." Panel assays (blood testing for one) are the
goal.

Your 30W narrow beam could present a similar situation.

This, of course, has absolutely NOTHING to do with the claims of
Vorticity.

The Vorticity effect relies on a similar news-flash that arrived here
some months ago about simultaneous reception/transmission on the same
frequency = very critical physical antenna geometries in a
reflectionless environment.

73's
Richard Clark, KB7QHC

"Helmut Wabnig" [email protected] --- -.dotat napisal w wiadomosci
...
On Tue, 13 Sep 2011 17:52:35 -0700, Richard Clark
wrote:

On Tue, 13 Sep 2011 13:40:37 -0400, "J.B. Wood"
wrote:

(I hope this doesn't turn out to be another CFA-like pursuit).

I've been hearing presentations of this stuff for 7 or 10 years now -
optical tweezers.

The "vorticity" can be seen in the graphic headed "Figures at a
glance":
http://www.nature.com/nphoton/journa...TON-201106#/f1

This is not to speculate about applications in the HF where energies
are many, many decades down from visible light. Where light is
tweezing molecules (very small ones), HF would be vastly
imperceptible. It would seem this reference, then, is gratuitous - a
form of authority inflation.

There are curious contradictions found:
"This novel radio technique allows the implementation of, at least in
principle, an infinite number of channels on one and the same
frequency, even without using polarization or dense coding
techniques."
compared with:
"Already with this setup one can obtain four physically distinct
channels on the same frequency by additionally introducing the use of
polarization, in this case independent from OAM. A further
multiplication of a factor five after the implementation of
multiplexing, yields a total of 20 channels in the same frequency."

Soooo. A special vorticity technique that does not use polarization
(even though they describe it as such) and does not use coding, can
demonstrate novel outcomes when paired with polarization and coding
(for which the outcome is fairly well established).

Why isn't this peer reviewed in EM proceedings?

73's
Richard Clark, KB7QHC

Any strong laser beam will trap dust particles and pull them towards
a direction, I do not remember was it towards the light source or away
from it.
I consider that a thermal effect.

Always to the light "source". It is the prove of the wave model of
gravitation.

In the optical tweezers very small bodyies are attracted to the focus point.
After the focus the waves are diverging and works like the Sun.
S*

The effect is stunning when you see it the first time.
I worked as helper guy for laser shows, and we used Argon lasers
up to 30 watt output. Suddenly some bright spots aligned at the
beam and slowly moved along it. Dust particles in the air,
of a certain size.

Wave model of gravitation is proved in space and air.
S*

On 9/13/2011 8:52 PM, Richard Clark wrote:

There are curious contradictions found:
"This novel radio technique allows the implementation of, at least in
principle, an infinite number of channels on one and the same
frequency, even without using polarization or dense coding
techniques."
compared with:
"Already with this setup one can obtain four physically distinct
channels on the same frequency by additionally introducing the use of
polarization, in this case independent from OAM. A further
multiplication of a factor five after the implementation of
multiplexing, yields a total of 20 channels in the same frequency."

Soooo. A special vorticity technique that does not use polarization
(even though they describe it as such) and does not use coding, can
demonstrate novel outcomes when paired with polarization and coding
(for which the outcome is fairly well established).

Why isn't this peer reviewed in EM proceedings?

If I were to hazard a guess, this sounds like another holy grail dream
for the digital folks. Many who just inherently "know" that bandwidth is
infinite and can support infinite data.

Imagine - the entire universe playing Angry Birds at the same time. The
mind boggles!

- 73 de Mike N3LI -

Dear Group: I saw a note in Science News and immediately had the feeling
that it was another scam.
73, Mac N8TT

"J.B. Wood" wrote in message ...

Hello, all. I came across an article in one of my science mags in which
some researchers had discovered a method to coax more bandwidth out of a
given portion of the EM spectrum by "twisting" radio waves together.
Nothing more technical than that in the article. Well, I managed to
find one the author's papers on the subject online:

http://arxiv.org/pdf/1107.2348v2

If this technique is viable, I'm wondering why it is only now being
contemplated. Note the "twisted parabolic antenna" (Fig. 3A) on p.16.
Of course this makes me want to do some experiments in the ham bands.
(I hope this doesn't turn out to be another CFA-like pursuit).
Sincerely, and 73s from N4GGO,


--
J. B. Wood e-mail:


J. C. Mc Laughlin
Michigan U.S.A.
Home:

On reading the paper associated with this claim, it appears that once you wade through the optical and momentum stuff you find that they have set up two transmitters near each other pointed to a common location where they have set up an interferometer. An RF interferometer is two antennas set up with a variable phase adjustment on one leg and both signals fed to a summing junction. Assuming the signal levels are closely matched (reasonable given the similar transmission path geometry), proper phase adjustment causes one of the signals to cancels leaving you with a phase adjusted version of the other signal. Re-adjustment the phase shift causes the other signal to cancel and gives the second signal.
To me this does not signify an new phenomenon it is just a simplified version of MIMO. This is already well understood in the Communications Systems world and is in use in IEEE 802.11N.

This can be technique done with out the fancy split antennas. In fact it has been done many times with simple dipole antennas.

Is this just a case of these physicists finally finding out something that the Communications Engineers have been using for years?