If you can read this, either the style sheet didn't load or you have an older browser that doesn't support style sheets. Try clearing your browser cache and refreshing the page.

(Discover)   Some favor expanding the radio spectrum to increase available bandwidth. This guy proposes twisting radio waves like corkscrews to create subfrequencies, which would create 100x more bandwidth with the current spectrum   (discovermagazine.com) divider line 43
    More: Cool  
•       •       •

2906 clicks; posted to Geek » on 26 May 2012 at 12:53 PM (2 years ago)   |  Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



43 Comments   (+0 »)
   
View Voting Results: Smartest and Funniest

Archived thread
 
2012-05-26 11:22:55 AM
Artist's depiction:

i.imgur.com
 
2012-05-26 11:31:39 AM
What kind of madness is this?

Next thing you know they will be proclaiming that the world is round
 
2012-05-26 11:37:22 AM
I'm on a wireless connection right now

/and I fail to understand how Fark could get any more twisted
//without being 4chan
 
2012-05-26 11:43:10 AM
So, this is just a different type of multiplexing? Or am I confused on the concept?
 
2012-05-26 12:05:59 PM

Gonz: So, this is just a different type of multiplexing? Or am I confused on the concept?


I figure this is playing with phase and polarization of the signal. Which isn't exactly new.
 
2012-05-26 12:09:00 PM
/jumped the gun there

Addendum:

I could be wrong though. The article was vague enough that I'm just guessing..
 
2012-05-26 01:03:50 PM
As long as Clear Channel is not involved, then I'm for it.
 
2012-05-26 01:09:50 PM
clear channel looking for a way to license and or dominate this
 
2012-05-26 01:10:08 PM
Twisted radio frequencies will cause 100x more cancer in children.
 
2012-05-26 01:12:35 PM
Great, now I'm going to have to start making my foil hats with a corkscrew pattern.
 
2012-05-26 01:17:54 PM

PvtHike: Gonz: So, this is just a different type of multiplexing? Or am I confused on the concept?

I figure this is playing with phase and polarization of the signal. Which isn't exactly new.


That. I am not excited.
 
2012-05-26 01:18:06 PM
by Edwin Cartlidge
From the October 2011 issue; published online October 10, 2011

And I'm pretty sure it's a repeat.
 
2012-05-26 01:19:44 PM
And every got-damned one of these new stations will run "Get the Led Out" at 7 pm local time.
 
2012-05-26 01:28:54 PM

Cthulhu_is_my_homeboy: Great, now I'm going to have to start making my foil hats with a corkscrew pattern.


Make sure you hat corkscrews in the opposite direction from the radio waves.
 
2012-05-26 01:35:27 PM
Go to Europe and see how broadcast digital tv works there.

Then come back to the US and compare broadcast digital here.

It ain't about more channels. It's about more revenue at the cost of poorer reception.
 
2012-05-26 01:37:52 PM

dahmers love zombie: Artist's depiction:

[i.imgur.com image 458x229]


I think I may have just become more stupid by trying to figure out what the fark that picture was referencing. Gene Ray is definitely insane!
 
2012-05-26 01:40:38 PM

PvtHike: I figure this is playing with phase and polarization of the signal. Which isn't exactly new.


The article explicity says this is fundamentally different from polarization. I wouldn't use "twisting" to describe phase modulation, so that's out.

What it appears to be, based on the linked wiki article, is a more complex shape than a simple wave.

<physics>
If you take a typical radio wave, and trace out lines of constant electric and magnetic potential, you will see that the lines trace out a wave shape (i.e., sine wave). There will be crests and troughs. Electric and magnetic waves will form right angles to the direction of motion, and if the electric waves only go in a single direction the radio wave is polarized. This much we all know. The thing is, the wave shape radio waves take is a solution to Maxwell's equations for the simple bounday conditions seen in typical antennas (that is, a single emitter rapidly changing voltage). But it's not the only solution to Maxwell's equations. You can set up antennas with more complex boundary conditions, and you can produce radio "waves" that look nothing like waves. Talk of phase and polarization might not even make sense.... In this case it looks like they are combining superpositioning a helical shape onto a traditional sine wave shape, each one at a different frequency. Presumably it's possible for a receiver to distinguish and filter both independently. Which, if successful, and there are no unintended consequences, would essentially square the bandwidth available. Very cool possibility.
</physics>
 
2012-05-26 01:57:37 PM
Still costs money to upgrade to it, right? Then VZW will be the only one to get it. And they will torture you for it.
 
2012-05-26 02:45:05 PM

aerojockey: PvtHike: I figure this is playing with phase and polarization of the signal. Which isn't exactly new.

The article explicity says this is fundamentally different from polarization. I wouldn't use "twisting" to describe phase modulation, so that's out.

What it appears to be, based on the linked wiki article, is a more complex shape than a simple wave.

<physics>
If you take a typical radio wave, and trace out lines of constant electric and magnetic potential, you will see that the lines trace out a wave shape (i.e., sine wave). There will be crests and troughs. Electric and magnetic waves will form right angles to the direction of motion, and if the electric waves only go in a single direction the radio wave is polarized. This much we all know. The thing is, the wave shape radio waves take is a solution to Maxwell's equations for the simple bounday conditions seen in typical antennas (that is, a single emitter rapidly changing voltage). But it's not the only solution to Maxwell's equations. You can set up antennas with more complex boundary conditions, and you can produce radio "waves" that look nothing like waves. Talk of phase and polarization might not even make sense.... In this case it looks like they are combining superpositioning a helical shape onto a traditional sine wave shape, each one at a different frequency. Presumably it's possible for a receiver to distinguish and filter both independently. Which, if successful, and there are no unintended consequences, would essentially square the bandwidth available. Very cool possibility.
</physics>


I'm suddenly reminded of the book "Contact". "Hey, looks like we're getting a video message here. Wait, there's FM encoded under it. Holy crap, it also contains polarization modulation, and PCM...fark me."
 
2012-05-26 03:25:32 PM
Yay, so 100 times more stations playing Green Day and Nickelback incessantly...

Although, I see this has already been covered.
 
2012-05-26 03:33:23 PM

aerojockey: In this case it looks like they are combining superpositioning a helical shape onto a traditional sine wave shape, each one at a different frequency. Presumably it's possible for a receiver to distinguish and filter both independently. Which, if successful, and there are no unintended consequences, would essentially square the bandwidth available. Very cool possibility.


I dunno. I never made it to antenna theory, but it looks to me like at best you can double your bandwidth -- in effect, you're modulating the E and M fields separately, but each one is still bound by the Shannon limit. It seems like you're trying to cram arbitrary amounts of information into what boils down to a phase shift, and as far as I can tell, bandwidth doesn't work that way.
 
2012-05-26 04:14:24 PM

jfarkinB: aerojockey: In this case it looks like they are combining superpositioning a helical shape onto a traditional sine wave shape, each one at a different frequency. Presumably it's possible for a receiver to distinguish and filter both independently. Which, if successful, and there are no unintended consequences, would essentially square the bandwidth available. Very cool possibility.

I dunno. I never made it to antenna theory, but it looks to me like at best you can double your bandwidth -- in effect, you're modulating the E and M fields separately, but each one is still bound by the Shannon limit. It seems like you're trying to cram arbitrary amounts of information into what boils down to a phase shift, and as far as I can tell, bandwidth doesn't work that way.


From what I've read up on it, it's more than just a phase-shift. In fact, I don't think a single-dimensional complex variable would be sufficient to describe the signal. It's closer in idea to a hologram where you're not just encoding the magnitude of the light, but a second variable (in holograms it's direction, here it's angular momentum or twist).

Shannon limits still apply, but they are 2D limits, not 1D.
 
2012-05-26 04:14:59 PM

jfarkinB: I dunno. I never made it to antenna theory, but it looks to me like at best you can double your bandwidth -- in effect, you're modulating the E and M fields separately, but each one is still bound by the Shannon limit. It seems like you're trying to cram arbitrary amounts of information into what boils down to a phase shift, and as far as I can tell, bandwidth doesn't work that way.


I am not the biggest electromagnetic expert, but I don't how one could modulate E and M separately. Doesn't the electric field completely determine the magnetic field? Maybe that's only true under simplifiying assumptions.

However, from what I read (briefly), I'm not getting that modulating E and M separately is what's happening here. It seems like a complex electric field (helix-shaped) is being used, which can't be generated with a simple antenna.
 
2012-05-26 05:00:51 PM
The Navy's been pranking around with OAM modulated laser designators for years. I also seem to recall something about someone or other using OAM modulated microwaves in radar to sort through pesky jamming devices. Somewhere.
 
2012-05-26 06:06:07 PM

aerojockey: PvtHike: I figure this is playing with phase and polarization of the signal. Which isn't exactly new.

The article explicity says this is fundamentally different from polarization. I wouldn't use "twisting" to describe phase modulation, so that's out.

What it appears to be, based on the linked wiki article, is a more complex shape than a simple wave.

<physics>
If you take a typical radio wave, and trace out lines of constant electric and magnetic potential, you will see that the lines trace out a wave shape (i.e., sine wave). There will be crests and troughs. Electric and magnetic waves will form right angles to the direction of motion, and if the electric waves only go in a single direction the radio wave is polarized. This much we all know. The thing is, the wave shape radio waves take is a solution to Maxwell's equations for the simple bounday conditions seen in typical antennas (that is, a single emitter rapidly changing voltage). But it's not the only solution to Maxwell's equations. You can set up antennas with more complex boundary conditions, and you can produce radio "waves" that look nothing like waves. Talk of phase and polarization might not even make sense.... In this case it looks like they are combining superpositioning a helical shape onto a traditional sine wave shape, each one at a different frequency. Presumably it's possible for a receiver to distinguish and filter both independently. Which, if successful, and there are no unintended consequences, would essentially square the bandwidth available. Very cool possibility.
</physics>


That's what I get for reading something when I'm supposed to be sleeping.
 
2012-05-26 08:09:59 PM
TFA is about as informative as the stupid picture that goes with it. Is this circular polarization? If so, it isn't new. Unfortunately, AFAIK, the technique works only with a focused beam, not an omnidirectional antenna. Have the boffins invented a new kind or radio wave, having observed such a thing near a black hole, or have they reinvented circular polarization, having skipped that lecture in physics class.
 
2012-05-26 08:12:20 PM
This is what, when ham radio operators do it, gets their licenses revoked for using horizontal and vertical polarization at the same time. CQ magazine had an article on someone who tried it, with a mechanical spinning antenna rotating at the transmitted wavelength.
 
2012-05-26 08:36:23 PM
No dittybopper? I was sure he would have been here...

/cant speak RF
//article was interesting to me in the way that a newspaper is interesting to a monkey
 
2012-05-26 09:42:25 PM

This About That: Is this circular polarization? If so, it isn't new.


Nope, although it sort of sounds like it the way TFA tries to describe it.

Here , I believe, is the original paper.

This is a bit more informative.

Pictures...

Polarization is an effect of spin angular momentum, the orbital angular momentum affects the shape of the wavefront. Picking that out is oddball, and the antennas are so far pretty freaky for radio, it requires a lot of optical crap for optics unless you're really clever. The Navy wants to use OAM to designate hundreds of inbound targets distinctly with a laser so that they can release a "flock" of laser-guided countermissiles, each able to isolate the OAM state that designates their particular target. That's to keep clumps of the counter-armament from attacking a single incoming target. The way you do that is light-heartedly still secret, I'm almost afraid to google it.

For radar, it allows you to do some really nifty things as far as picking out info about the reflections.

There's also some side applications involving secure communications that depend on not only the nifty OAMness of it, but also that most ways you produce OAM specific photons automatically gives you an entangled pair, that may be true for every way you do it in order to satisfy conservation laws, I'd have to think about it.
 
2012-05-26 10:03:46 PM

erewhon: Nope


Thanks. That makes more sense than TFA, although no easier to visualize. It seems to be juuuuust beyond the border between "yes, I can see that" and "yeah, but it's all quantum physics-y".
 
2012-05-26 10:13:51 PM

This About That: erewhon: Nope

Thanks. That makes more sense than TFA, although no easier to visualize. It seems to be juuuuust beyond the border between "yes, I can see that" and "yeah, but it's all quantum physics-y".


It IS all quantum physic-y, and it's not that intuitive, or they'd have discovered it before 1992 or whenever it was. Hm. If you were a test dipole floating in free space, circularly polarized light would make you want to spin, while orbitally polarized light would make you want to make little tight circles around the beam axis center. Maybe spin too.
 
2012-05-27 12:38:46 AM

Mofo_Jones: And every got-damned one of these new stations will run "Get the Led Out" at 7 pm local time.


... and Mandatory Metallica at 8
 
2012-05-27 05:25:46 AM
It's not new and has been demonstrated already.

We've been doing this with Optical wavelengths for years, seems natural to extend it to radio if it all works fine.
 
2012-05-27 05:10:50 PM

The WindowLicker: No dittybopper? I was sure he would have been here...

/cant speak RF
//article was interesting to me in the way that a newspaper is interesting to a monkey


Just saw it. Been busy putting up a pool.

Oh, and circular polarization isn't illegal. You wouldn't get your ham ticket pulled for essentially usinga rotating dipole.
 
2012-05-28 01:11:54 AM

TasyRadiSkull: It's not new and has been demonstrated already.


That's a recent article about the same researchers. Seems pretty new to me.
 
2012-05-28 01:20:31 AM
It's been done (although relatively new) with lasers. It's a lot newer with radio, although there's been some very preliminary radar work.
 
2012-05-28 08:15:41 AM

Mrtraveler01: As long as Clear Channel is not involved, then I'm for it.


Yeah, well, that probably is actually a serious problem with this or any similar idea: My experience in broadcast lobbying tells me that any channel proliferation scheme that major broadcast incumbents (NAB and NPR, chiefly) perceive as a threat to their hegemony is certain to face aggressive resistance. NAB and NPR both pulled out all the stops in their opposition to low power FM for this reason. (Back in '98, I sarcastically described this as 'content interference' -- the threat posed by small-time broadcasters who serve their listeners better than larger ones, which has been a growing problem since national ownership caps were eliminated in '96.)

The existing FM band could be tripled right now, within the same range, with existing technology. A few tweaks, and we could probably expand it twentyfold of current usage. Neither of those ideas has gained any traction, and I firmly believe it's specifically due to resistance from major incumbents.

I'm confident that this guy's engineering math is good, Unfortunately, I fear that any proposal to increase the number of channels -- by any method at all -- must also take into account the very unfortunate political math.

As the saying goes, this is why we can't have nice things.
 
2012-05-28 08:23:07 AM

This About That: TFA is about as informative as the stupid picture that goes with it. Is this circular polarization?


FTFA: "Note this type of wave-twisting is fundamentally different from the better-known circular polarization of light."

TFA is more informative if you read it and not just look at the pictures. This is science, not porn.
 
2012-05-28 08:25:20 AM

SwiftFox: This is what, when ham radio operators do it, gets their licenses revoked for using horizontal and vertical polarization at the same time. CQ magazine had an article on someone who tried it, with a mechanical spinning antenna rotating at the transmitted wavelength.


You can actually do any damn thing you want, as long as you get an STA to do it. And prudent and patient people do.

I don't feel sorry for broadcasters who get in trouble. If you're that stupid, lazy, incompetent, or arrogant, we don't need your ass on the air. There are millions more to choose from, and some of them are sure to be better.
 
2012-05-28 09:41:24 AM

Sylvia_Bandersnatch: I'm confident that this guy's engineering math is good, Unfortunately, I fear that any proposal to increase the number of channels -- by any method at all -- must also take into account the very unfortunate political math.


For broadcast radio, I'm afraid you're right, although I see things like the DTV transition (one current channel gets replaced by several, all run by the same incumbent, but transmitting different content) as a possible alternative.

But while broadcast content is loud and hard to miss, it nearly disappears into the noise when compared to the amount of stuff (I hesitate to say "information") transmitted via cell, 802.11x, and other bidirectional wireless. That's where I'd hope this could make a difference. I mean, if cellular carriers can increase their per-cell capacity by a factor of 10, surely they might be tempted to throw us a 2x or 3x increase in our data caps. For a nominal surcharge, of course.

I'm still at a loss how you'd deal with multipath effects on this. But after reading erewhon's link (thanks, BTW!), I realize that I'm hopelessly over my head here. I'll have to entrust it to the army of little Teslas that modern EM theory and hardware is enabling.
 
2012-05-28 10:14:42 AM

jfarkinB: Sylvia_Bandersnatch: I'm confident that this guy's engineering math is good, Unfortunately, I fear that any proposal to increase the number of channels -- by any method at all -- must also take into account the very unfortunate political math.

For broadcast radio, I'm afraid you're right, although I see things like the DTV transition (one current channel gets replaced by several, all run by the same incumbent, but transmitting different content) as a possible alternative.

But while broadcast content is loud and hard to miss, it nearly disappears into the noise when compared to the amount of stuff (I hesitate to say "information") transmitted via cell, 802.11x, and other bidirectional wireless. That's where I'd hope this could make a difference. I mean, if cellular carriers can increase their per-cell capacity by a factor of 10, surely they might be tempted to throw us a 2x or 3x increase in our data caps. For a nominal surcharge, of course.

I'm still at a loss how you'd deal with multipath effects on this. But after reading erewhon's link (thanks, BTW!), I realize that I'm hopelessly over my head here. I'll have to entrust it to the army of little Teslas that modern EM theory and hardware is enabling.


My point is validated by your observation: Incumbents are perfectly happy with channel proliferation when it benefits them. Not when it doesn't.

From my perspective, increasing the number of channels per existing incumbent -- which DTV does -- indisputably increases the volume and variety of content, but without any meaningful expansion in the number of independent voices it represents very little improvement for the public at large. Seriously, would you prefer there to be twenty times as many different radio stations owned and operated by different people, or twenty times as many Clear Channel stations?

Major incumbents have actually argued that increasing the number of 'formats' under the *same* owner, merely by channel (in this case, ownership) proliferation was a real gain for listeners (or, by hypothetical extension, viewers). Does anyone really believe that? If I can now get Clear Channel country, Clear Channel sports talk, Clear Channel news talk, Clear Channel talk, Clear Channel rock, Clear Channel easy listening, and so on, am I really better off as a listener, consumer, and citizen?

Why this matters: In a democracy like ours, channels of information are absolutely critical to a voting public making informed decisions. Why should media be subject to special oversight and regulation, more than, say, lumber? Because media, unique among all industries, manufactures democracy itself. How well informed we are as a voting populace depends very greatly on the quality of the information we get. For maximum benefit, we need as many *different* and competing voices as possible -- not more voices from the same few sources. To the extent that any change in our media does not increase the total number of voices -- or worse, reduces it -- we are impacted as citizens in our democracy. And how would you expect to be told about such a threat?
 
2012-05-29 05:06:59 AM
I was told there'd be no deep fundamental analysis on the nature on the key mechanisms of self governance.
 
2012-05-29 11:48:05 AM
If we could only have a cautionary tale of screwing with radio frequencies...

www.best-horror-movies.com
 
Displayed 43 of 43 comments

View Voting Results: Smartest and Funniest


This thread is archived, and closed to new comments.

Continue Farking
Submit a Link »






Report