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"Stealth" Plasma Antennas

ScuttleMonkey posted more than 7 years ago | from the no-you-see-it-now-you-don't dept.

Communications 169

eldavojohn writes "There's a new antenna that consists of plasma and essentially vanishes when you turn it off. While it may seem to not have many uses in the commercial world, it is very important to military personnel who risk detection or for anybody wishing to avoid signal jamming."

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Prediction (-1, Flamebait)

Anonymous Coward | more than 7 years ago | (#21329253)

This will be used to kill sand niggers.

The more it kills the better.

Thats what you get for making your women cover their faces.

God is punishing you with American weapons.

Re:Prediction (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#21329309)

It's not that there's really that many people that think like this that gets to me, it's that we have so many socially retarded fuckwits who troll like this over and over and over and nothing happens.

Will someone start pulling out the fucking ban hammer on ip ranges? Or do you not really care what slashdot becomes?

Re:Prediction (0)

Anonymous Coward | more than 7 years ago | (#21329367)

you just made something happen by replying in the first place

Re:Prediction (0)

Anonymous Coward | more than 7 years ago | (#21329381)

> Will someone start pulling out the fucking ban hammer on ip ranges?

Just plain doesn't work. You could ban 9/10ths of the internet and still have tards with open proxies via compromised machines in every single remaining IP range.

Re:Prediction (0, Offtopic)

nuzak (959558) | more than 7 years ago | (#21329569)

Blogs have moved to open proxy block lists. Then again, implementing that would entail slashdot's development actually accellerating beyond two new features per decade.

Re:Prediction (0)

Anonymous Coward | more than 7 years ago | (#21329489)

You are the reason Slashdot trolls are so pathetic. If you and your kind weren't so "serious business" about every little thing then there would be room for creative trolling.

Re:Prediction (0)

Anonymous Coward | more than 7 years ago | (#21329613)

the internet, serious business

Re:Prediction (2, Funny)

larry bagina (561269) | more than 7 years ago | (#21329533)

Thats what you get for making your women cover their faces.

Rosie O'Donnell much?

Re:Prediction (1)

Trogre (513942) | more than 7 years ago | (#21330671)

I know what those words mean, but that phrase didn't make any sense.

Re:Prediction (2)

renegadesx (977007) | more than 7 years ago | (#21329785)

If you have seen Britney Spears face reacently, maybe those "sand niggers" as you like to call them maybe on to something

Re:Prediction (-1, Flamebait)

Anonymous Coward | more than 7 years ago | (#21330615)

I hate muslims. I think mecca and medina and all those muslim shitholes should be nuked. Fuck mohammed. Piss on him. Nuke them to hell.

Of course, as a ham radio operator... (0)

Anonymous Coward | more than 7 years ago | (#21329255)

... my neighborhood-association rules already prohibit stealth plasma antennas. :(

Not if you fly if from a stealth-plasma flagpole! (5, Funny)

wsanders (114993) | more than 7 years ago | (#21329357)

(Sorry ham radio nerd humor.)

Disguise it as a stealth-plasma flagpole and proudly fly a red-white-and-blue flaming sheet-o-plasma flag! Has the added advantage of shocking the hell out of any pot-smoking hippies who try to burn it!

Re:Not if you fly if from a stealth-plasma flagpol (1)

PayPaI (733999) | more than 7 years ago | (#21330217)

Wouldn't the flag already be technically burning? Hippies, 1 You, 0

Re:Not if you fly if from a stealth-plasma flagpol (0, Offtopic)

ScrewMaster (602015) | more than 7 years ago | (#21330575)

Regarding your sig, Give a man a fish and you have fed him for today. Teach a man to fish, and he'll say "WHERE'S MY FISH, YOU IDIOT?", I like this one too: "Share your fire with a man, he'll be warm for a night. Set him on fire, and he'll be warm for the rest of his life."

Um... Light Saber,,, Hello? (0)

Anonymous Coward | more than 7 years ago | (#21330081)

Who the hell cares about using it for an antenna, when there are millions of aspirant Jedi to sell this to?

Use the force, beyotch!

How does a disappearing antenna help? (4, Insightful)

explosivejared (1186049) | more than 7 years ago | (#21329275)

How does having the antenna "disappear" effect it's ability to circumvent jamming? The article is apparently being slashdotted as I type this, so I'm just curious.

Re:How does a disappearing antenna help? (4, Informative)

another_neophyte (1050364) | more than 7 years ago | (#21329299)

The article briefly claims the plasma attenna can be adjusted to react to the jamming. Independent feature of the ability to disappear.

Re:How does a disappearing antenna help? (1)

pudding7 (584715) | more than 7 years ago | (#21329327)

Yeah, I don't get that either. And the tube the gas is in is still around.

Re:How does a disappearing antenna help? (1)

renegadesx (977007) | more than 7 years ago | (#21329813)

Your colen?

Re:How does a disappearing antenna help? (5, Informative)

TaeKwonDood (1171129) | more than 7 years ago | (#21329365)

Because it's a plasma antenna, it's tunable on the fly. No jamming tech ( though it will surely follow ) works on every f at once. The invisibility is just because it shuts off so then is basically inert.

Re:How does a disappearing antenna help? (1)

explosivejared (1186049) | more than 7 years ago | (#21329379)

What are we talking about jamming? Radio, microwave, what?

Re:How does a disappearing antenna help? (2, Funny)

Anonymous Coward | more than 7 years ago | (#21329581)

Strawberry...or possibly grape

Re:How does a disappearing antenna help? (2, Funny)

Mincer Lightbringer (979840) | more than 7 years ago | (#21329825)

Raspberry!
There's only one man who would dare give me the raspberry: Lone Starr!

Re:How does a disappearing antenna help? (1)

JensenDied (1009293) | more than 7 years ago | (#21329849)

RADAR TECH.: I'm having trouble with the radar, sir.
HELMET: What's wrong with it?
RADAR TECH.: I've lost the bleeps, I've the lost the sweeps, and I've lost the creeps.
HELMET: The what?
SANDURZ: The what?
HELMET: And the what?
RADAR TECH.: You know. The bleeps, the sweeps, and the creeps.
HELMET: That's not all he's lost.
RADAR TECH.: Sir. The radar, sir. It appears to be... jammed.
HELMET: Jammed? Raspberry. There's only one man who would dare give me the raspberry. Lone Starr!

Re:How does a disappearing antenna help? (1)

djasbestos (1035410) | more than 7 years ago | (#21329675)

Still, if you are transmitting voice on let's say 150 Mhz and someone is transmitting a high pitched whine (taking up more bandwidth, thusly...16khz or so) at a higher amplitude than your voice transmission, it's gonna get cruddy. Even FM gets F!'ed up by this. Then again, all you have to do is change frequencies, but I don't see where attenuation comes in handy for defeating a broadband jammer.

Same principle would apply to airborne data transmission, I would think. Correct me if I'm wrong, I only renewed my license for the hell of it because I am a bad ham and the internets is more fun than my HT :(

Re:How does a disappearing antenna help? (1)

lordofwhee (1187719) | more than 7 years ago | (#21330261)

Well of course a transmission on the same frequency with a higher amplitude is going to mess with yours, IT'S MORE POWERFUL. I odn't see what this has to do with the topic at hand...

Re:How does a disappearing antenna help? (1)

LiquidCoooled (634315) | more than 7 years ago | (#21330555)

I do.
There is no rule which says "when jamming, ensure you only jam the frequencies being used by your enemy".
You want to stop the signal any way you can, and if a high pitched scream does the job then so be it.

Re:How does a disappearing antenna help? (1)

megaditto (982598) | more than 7 years ago | (#21331151)

So, jump your frequency. They can't jam the entire spectrum at once, you know.

Re:How does a disappearing antenna help? (3, Informative)

The FNP (1177715) | more than 7 years ago | (#21329389)

Antennas are not stealthy. They have a radar signature, but glass has a minimal radar signature. So the tube should not be as non-stealthy as attaching a chunk of metal to an otherwise stealthy piece of equipment.

--The FNP

Heat signature? (1)

grantek (979387) | more than 7 years ago | (#21329657)

Isn't plasma hot? ie:
1. Shoot radar-guided missile
2. Shoot heat-seeking missile
3. ???
4. Kaboom!

Re:Heat signature? (3, Insightful)

mapsjanhere (1130359) | more than 7 years ago | (#21329835)

Yes - and no :)
The gas is hot, but at very low pressure. So the amount of energy transmitted to the glass container surrounding it is minimal, and could be further reduced by active cooling. So the second your incomings are detected and the antenna shuts down it becomes invisible to both the RF and infrared seeker.

Hides by Glowing in the Dark? (1)

billstewart (78916) | more than 7 years ago | (#21330049)

I don't quite get the usefulness of this thing either - when it's turned on, there's bright glowing plasma, and when it's turned off, even though it doesn't have a long metal piece, it still has a lot of metallic support machinery, plus it's a glass tube that you need to haul around carefully instead of a metal antenna or rubber ducky that you can bang into things.

Re:Hides by Glowing in the Dark? (1)

MadnessASAP (1052274) | more than 7 years ago | (#21330751)

You can fabricate some pretty sturdy pieces of glass that you could beat a person to death with, It's going to cost you a fortune but thats hasn't stopepd the military yet. If I remember correctly glass in theory is stronger then steel it's just that during the cooling process many micro fractures form in it.

It can't! (1)

EmbeddedJanitor (597831) | more than 7 years ago | (#21329753)

If it is performing as an antenna then it will have the same RF characteristics as a physical antenna and so must be open to jamming.

Re:How does a disappearing antenna help? (5, Informative)

Chrononium (925164) | more than 7 years ago | (#21329799)

One very simple way to counteract jamming is to note that the jammer is not omnipresent. That is, the jamming source is often only present in a small radian-angle of the antenna's radiation sphere. Therefore, you can counteract jamming by configuring your antenna to place a null in the direction of the jammer (i.e. ignore the annoying little kid) and radiating elsewhere. Alternatively, if you know where you want to either transmit a signal or receive a signal, you can create a beam to point in that direction by reconfiguring your antenna. In both cases, it is usually standard practice to use an array of antennas. This invention (and no, it's not really a new idea, but perhaps the engineering makes it more reliable or easier to manufacture than in the past) allows you to place a large antenna array on an aircraft without permanently increasing the RCS of said aircraft, since the antennas only exist when you charge up the plasma. A large antenna array can create a narrow beam and place several nulls using conventional technology. All of this stuff exists today, so these plasma antennas just need to replace metal antennas and away you go. The really interesting application of these antennas could actually be to create 3D reconfigurable antennas using DC-magnetic fields (kind of like a CRT, but with more magnets).

An old idea (2, Interesting)

Anonymous Coward | more than 7 years ago | (#21329801)

This is an old idea. Look in Kraus, Antennas, Third edition. Section 21-29. Also see patent 6657594. The point is the RCS of the antenna is lower when the plasma is off, they efficiency of this type of antenna isn't that high.

Re:How does a disappearing antenna help? (1)

omeomi (675045) | more than 7 years ago | (#21330265)

How does having the antenna "disappear" effect it's ability to circumvent jamming?

I'm a bit foggy how it "disappears". Last I checked, you need some type of container to shape plasma into a cylinder, so while the plasma may disappear, the giant glass tube presumably will still be there...and why does the author keep calling plasma a gas? Yes, you get plasma by superheating a gas. You get gas by heating liquid. Doesn't make gas the same as liquid. Plasma isn't the same as gas either.

Re:How does a disappearing antenna help? (1)

Nefarious Wheel (628136) | more than 7 years ago | (#21331347)

Hmm... boiling a gas to get a plasma. Interesting meme.

Now if only we could make (-1, Troll)

Anonymous Coward | more than 7 years ago | (#21329295)

the niggers disappear.

Non Slashdotted Link (5, Informative)

eldavojohn (898314) | more than 7 years ago | (#21329315)

When I submitted this story, I submitted the story from PhysOrg [physorg.com] and I'm not sure why they changed the link. That poor blog didn't stand a chance. I guess they must do that to more randomly distribute their news sources or make it look like they aren't playing host to some PhysOrg worker trying to generate more traffic. Oh well, enjoy a usable link anyhow.

Re:Non Slashdotted Link (1)

explosivejared (1186049) | more than 7 years ago | (#21329353)

Much appreciated, but still the physics seem a little weak. I still am not getting how changing the composition of the antenna will prevent jamming. Both articles fail to articulate this very well.

Re:Non Slashdotted Link (1, Interesting)

Anonymous Coward | more than 7 years ago | (#21329513)

Greetings,

      It doesn't really prevent jamming, though it does give them a variable antenna, by tuning the plasma, thereby improving their ability rapidly change radio frequencies etc. This give them the ability to reduce the affects of single band jamming and even some multi-band jamming. It actually seems pretty clever, though, I really fail to see it's battlefield value as there will be a tremendous amount of heat given off by the plasma field. Now shipboard and some amored cav uses, I can see, but they have the ability to shield/mask the heat emissions.

Re:Non Slashdotted Link (1)

secPM_MS (1081961) | more than 7 years ago | (#21329461)

You can view it as an electrically switchable conductor. Turn the power on and you have a conductor. Turn it off and you get an insulator. The problem is that it takes power to maintain. As long as you have adequate power, you can make a conductor. If you have lots of power, you can ionize atmospheric pressure air, but we do mean lots of power. At low pressure, you need less power, but you have the corresponding issue of fragility of the supporting structure, which must be both strong and insulating.

An alternate way would be to take a metallic antenna and break it up into a lot of short segments, which you would wire together with electrically controlled switches. If the switches are off, it would appear as a lot of isolated pieces of conductor with a much smaller signal crossection than the full antenna when they are engaged. If you are worried about the antenna survival in a high power environment, you would use gaseous switches rather than the smaller and cheaper solid state devices.

Mod Parent Up (1)

explosivejared (1186049) | more than 7 years ago | (#21329697)

So good idea in theory, but hard to put into practical terms. I then guess the large power constraints and the fragility of the plasma are what's keeping this from commercial use. I know there was a post about cell phones using this. When thinking about powering the plasma I guess that gets thrown out the window.

Re:Mod Parent Up (2, Insightful)

secPM_MS (1081961) | more than 7 years ago | (#21329913)

I assume that the technology would be more useful in radar sources, where you could do a short term illumination of a target and then turn it off. A sensor trying to pick up the antenna when it was not powered might well have a significantly harder time than with a traditional antenna.

TFA - From The Original Link (1)

TubeSteak (669689) | more than 7 years ago | (#21329473)

The original link works for me

'Stealth' Antenna Made Of Gas, Impervious To Jamming
Submitted by News Account on 12 November 2007 - 2:58pm.
Physics

A new antenna made of plasma (a gas heated to the point that the electrons are ripped free of atoms and molecules) works just like conventional metal antennas, except that it vanishes when you turn it off.

That's important on the battlefield and in other applications where antennas need to be kept out of sight. In addition, unlike metal antennas, the electrical characteristics of a plasma antenna can be rapidly adjusted to counteract signal jamming attempts.

Plasma antennas behave much like solid metal antennas because electrons flow freely in the hot gas, just as they do in metal conductors. But plasmas only exist when the gasses they're made of are very hot. The moment the energy source heating a plasma antenna is shut off, the plasma turns back into a plain old (non conductive) gas. As far as radio signals and antenna detectors go, the antenna effectively disappears when the plasma cools down.

Picture:
http://www.scientificblogging.com/files/plasma%20antenna.jpg [scientificblogging.com]

This prototype plasma antenna is stealthy, versatile, and jam-resistant. Credit: T. R. Anderson and I. Alexeff

The antenna design being presented at next week's APS Division of Plasma Physics meeting in Orlando consists of gas-filled tubes reminiscent of neon bulbs. The physicists presenting the design propose that an array of many small plasma elements could lead to a highly versatile antenna that could be reconfigured simply by turning on or off various elements.

- T. R. Anderson and I. Alexeff
2007 APS Division of Plasma Physics annual meeting
November 12, 2007

So uhh.. how does this prevent jamming?
Because you have a broader range of frequencies to hop?

Re:TFA - From The Original Link (1)

BosstonesOwn (794949) | more than 7 years ago | (#21329743)

FINALLY !!! One step closer to getting a working light saber !

Wonder if this works for wifi antenna. Would make it easier to see the people stealing my neighbors wifi signals.

Re:TFA - From The Original Link (0)

Anonymous Coward | more than 7 years ago | (#21330363)

Dunno... But if I were in some location where spying could be a problem, I'd keep better tabs on who is doing any repairs or replacement of flourescent lighting fixtures.

Also this could be great for a communications center for an intelligence outpost in an urban environment. The police or counterintelligencia would be looking for the antenna equipment. All the while never realizing that the tubes backlighting the big laundromat sign are broadcasting all the precious data.

Re:Non Slashdotted Link (1)

TaeKwonDood (1171129) | more than 7 years ago | (#21329523)

I submitted this link but it says 'pending', so maybe they liked your writeup and my link. It's mashably terrific. I think we could all live without a physorg monopoly for one day.

Are you confused? (1)

The FNP (1177715) | more than 7 years ago | (#21329319)

If it helps with signal jamming, I want it integrated into my cell phone! What do you mean it doesn't have commercial viability?

--The FNP

Re:Are you confused? (0)

Anonymous Coward | more than 7 years ago | (#21329515)

I would love to have this on a cell phone. I know just what to call it too a "light saber". Catchy, I think I might market that. Hollywood might like it. Perhaps I'll feature it in a movie for the initial advertising.

Re:Are you confused? (0)

Anonymous Coward | more than 7 years ago | (#21329651)

"If it helps with signal jamming, I want it integrated into my cell phone!"

So would all the loud bastards that insist on using their phones in crowded movie theaters, public transit etc..

Re:Are you confused? (1)

ILuvRamen (1026668) | more than 7 years ago | (#21329919)

If it can be used as a lightsaber I'll take it on my cell phone otherwise I'd prefer not to burn my hair lol. Isn't that the real story here. If they can focus plasma into a limited beam, how could they not saber-ize it?

Is that a plasma antenna in your pocket... (1)

kybred (795293) | more than 7 years ago | (#21331127)

If it helps with signal jamming, I want it integrated into my cell phone! What do you mean it doesn't have commercial viability?
Hopefully it won't go active when you receive a call while your phone is in your pocket!

Re:Are you confused? (0)

Anonymous Coward | more than 7 years ago | (#21331247)

sorry, all your airwaves are belong to us.

Not News (3, Informative)

Anonymous Coward | more than 7 years ago | (#21329341)

I read this in new scientist years ago:

http://www.newscientist.com/article/mg16422141.000-now-you-see-it---.html [newscientist.com]

yeah (0)

Anonymous Coward | more than 7 years ago | (#21329399)

Even the dept is the same, lazy mods.

TFA (3, Informative)

DumbSwede (521261) | more than 7 years ago | (#21329405)

'Stealth' Antenna Made Of Gas, Impervious To Jamming Submitted by News Account on 12 November 2007 - 2:58pm. Physics

A new antenna made of plasma (a gas heated to the point that the electrons are ripped free of atoms and molecules) works just like conventional metal antennas, except that it vanishes when you turn it off.

That's important on the battlefield and in other applications where antennas need to be kept out of sight. In addition, unlike metal antennas, the electrical characteristics of a plasma antenna can be rapidly adjusted to counteract signal jamming attempts.

Plasma antennas behave much like solid metal antennas because electrons flow freely in the hot gas, just as they do in metal conductors. But plasmas only exist when the gasses they're made of are very hot. The moment the energy source heating a plasma antenna is shut off, the plasma turns back into a plain old (non conductive) gas. As far as radio signals and antenna detectors go, the antenna effectively disappears when the plasma cools down.

This prototype plasma antenna is stealthy, versatile, and jam-resistant. Credit: T. R. Anderson and I. Alexeff

The antenna design being presented at next week's APS Division of Plasma Physics meeting in Orlando consists of gas-filled tubes reminiscent of neon bulbs. The physicists presenting the design propose that an array of many small plasma elements could lead to a highly versatile antenna that could be reconfigured simply by turning on or off various elements.

- T. R. Anderson and I. Alexeff 2007 APS Division of Plasma Physics annual meeting November 12, 2007

Re:TFA (1)

QuantumG (50515) | more than 7 years ago | (#21329459)

So what's you're saying is that this conversation is no longer fiction:

Radio Operator: Sir! I can't get through to base!
Officer: damn, they must be jamming our transmissions! Try inverting the phase polarity!
Radio Operator: That did it! I have communications.. here..
Officer: General, the enemy is capable.

Re:TFA (3, Insightful)

Brandon30X (34344) | more than 7 years ago | (#21329563)

These antennas sound interesting, reconfigurable and all that, but I am guessing that their noise performance must be awful. And I mean electrical noise not audio noise for those out there who are confused. Usually in an RF system you want as little noise up front as possible, and noise goes up with temperature. So this is an antenna made of very hot plasma as the very first element in the receiver system.

I could be wrong, I didnt RTFA.

-Brandon

Re:TFA (1)

ForTheLoveOfCats (1188201) | more than 7 years ago | (#21331043)

It would seem to me that an antenna made of hot anything would be inherently noisy. Noise is usually the limiting factor in receiveing weak signals, so great care is taken to preserve signal captured by the antenna without introcducing noise. This is why Low Noise Amplifiers (LNAs) are used at the front end of a receiver system, very near the antenna. THe idea is to introduce as little noise as possible while the signal appearing at the antenna is amplified to a level that the subsequent electronics can process it and extract information. Thermal noise is found in all (practical) systems, and is the primary parameter that limits the distance a signal of a set amplitude can travel and stil be received. It sets the "noise floor". Thermal noise, also known as Johnson Noise, is proportional to temperature. Check out... http://en.wikipedia.org/wiki/Thermal_noise [wikipedia.org] If the antenna is a high temeprature ionized gas, isn't it goign to be noisy? That would seem to limit its practical uses.

Heat & Light vs Wire? (0)

Anonymous Coward | more than 7 years ago | (#21329423)

So instead of worrying about being jammed, you have to worry about heat seeking missiles. If you are in some place where a single wire will give away your location, I think the heat and light would be easier to notice than the wire.

Re:Heat & Light vs Wire? (2, Interesting)

mangu (126918) | more than 7 years ago | (#21329763)

If you are in some place where a single wire will give away your location, I think the heat and light would be easier to notice than the wire.


The light is easily taken care of, just paint it black. The heat released is about the same as a fluorescent bulb, much less than a human being emits.


As for detecting the wire, an antenna is resonating at a specific frequency, and that can be detected easily with very simple equipment [wikipedia.org] . That how most anti-shoplifting devices work.


I think the main use for these plasma antennas wouldn't be for a soldier in an open battlefield, but for covert operations instead. The idea is to make it harder for the enemy to find if someone in a crowd is carrying a concealed radio.

But what about sound? (1)

nick_davison (217681) | more than 7 years ago | (#21330623)

If George Lucas taught us anything, it's that these things should make a whum, whum noise as they're moved around plus a kind of white noise crackling whenever they hit things.

That's hardly unobtrusive in a crowd.

Re:Heat & Light vs Wire? (1)

mrex (25183) | more than 7 years ago | (#21329787)

Aircraft have been dealing with the problem of heat signatures produced by engines for a long time. Will this antenna really get as hot as the engines on an F-22?

Re:Heat & Light vs Wire? (2, Interesting)

mapsjanhere (1130359) | more than 7 years ago | (#21329957)

The real application for this might be in space. It's very hard to hide your satellite from the incoming kill vehicle if you have a huge antenna deployed. This technique could actually project a "ghost antenna" just off the satellite, and since this is not horse shoes, close does not count.

Lots of problems with this article (4, Informative)

compumike (454538) | more than 7 years ago | (#21329425)

In a normal antenna, electrons in the metal slosh up and down, accelerated by the electromagnetic fields that it's receiving (or transmitting). In this case, I could use the same description: electrons slosh up and down, driven by the EM fields.

The idea that this could lead to a reconfigurable antenna is a bit farfetched, as it would require that the driving bias electrodes be able to totally float at RF frequencies. Just like a neon sign, or a fluorescent light, you're going to have to keep a large voltage across these to get them to light, so it'll be tricky to use it as a receiving antenna in particular.

Take a look at another project, Talking Lights [talking-lights.com] . This uses conventional fluorescent lights (hey, a plasma!) with a modified ballast to transmit data at serial-link speeds.

The "jam-resistance" doesn't make any sense. If it can receive signals, it can receive signals, period. At the point of the antenna, the desired signal and the jamming signal have already been mixed. The antenna itself can't help you out. (Clever frequency-hopping or other schemes can, though.)

--
Microcontroller kits for the digital generation. [nerdkits.com]

Re:Lots of problems with this article (1)

TheThiefMaster (992038) | more than 7 years ago | (#21330213)

Or using multiple antennas so you can do a spatial analysis of the signals.

Do it right, and you end up receiving the signal you want, and knowing exactly where it is being transmitted from, while also receiving the jamming signal and knowing exactly where THAT is from.

Re:Lots of problems with this article (1)

computerchimp (994187) | more than 7 years ago | (#21330275)

I think the article was written as an executive summary, its not going to give many details.

Will it provide jam resistance? Yes. Through, as you said, frequency hopping schemes. The antenna will morph to shift its frequency response, perhaps it will have better directional abilities too. Its an executive summary, the audience does not care how it will do it just that its a promising use of the technology.


The idea that this could lead to a reconfigurable antenna is a bit farfetched

obviously some smart guys have worked on the problem and have come up with something worthwhile. Your insight of the hurdles that may have lay in the way are certainly worthy of causing discussion. CC

Glass Tubes? (1)

FrankSchwab (675585) | more than 7 years ago | (#21329427)

OK, so you don't have a big metal antenna...Instead, you have a big structure built out of evacuated glass tubes resembling Neon tubes.

And you're going to take this out on the battlefield?

Now, the concept of changing the resonant frequency of the antenna by activating different individual elements is kinda cool, but this doesn't look stealthy at all.

/frank

Re:Glass Tubes? (1)

KiloByte (825081) | more than 7 years ago | (#21329605)

It is stealthy against antenna-detection tools which operate on EM spectra quite different from visible light.

It's kind of how a stealth bomber is quite easy to notice if you just look upward -- it is made to fool radar, not human sight.

I remember these things..... (5, Informative)

DavidKlemke (1048264) | more than 7 years ago | (#21329431)

Back in my university days I had the pleasure of being taught by a physicist turned engineer who was actually working on one of these things. The trouble with traditional antennas is their giant radar footprint and traditionally they solved this problem by flopping the antennas up and down when they needed to send signals. Not the most graceful solution so they started looking for alternatives. We had one of the prototypes of these things in the plasma instrumentation lab and it was pretty adept at sending some small signals. The great thing about them is their tunability. Just like any kind of woodwind instrument if you change the length of the tube (imagine a giant piston that's got plasma in it) you change the resonant frequency. My lecturer referred to it as playing the plasma trombone. Good to see these things finally making their way through to practical uses. I was always hoping my crazy lecturer's tinkerings would be used someday.

Combat viable? (2, Interesting)

djasbestos (1035410) | more than 7 years ago | (#21329491)

The pic from TFA looks a bit dainty for combat use. I think a whip antenna is probably still more reliable and has a smaller radar signature for short range communication (IE a couple dozen miles). And the big ones, well, there's no hiding them.

Plus that whole bright and hot thing tends to attract the attention of certain guided missiles and sensor systems...not good! Maybe if they paint the glass or something...at least the light problem is solved.

Re:Combat viable? (0)

Anonymous Coward | more than 7 years ago | (#21330475)

The heat problem, as you mentioned, is an even bigger danger. There are plenty of next generation weapons in development by the US and other powers that take advantage of cheap infrared sensors to home in on individual scale heat sources, so anything which generates extra heat, unless absolutely necessary, is already at a serious disadvantage for consideration in combat use, even if it comes with some other advantages.

Doesn't exactly Disappear, not in free air. (2, Insightful)

DumbSwede (521261) | more than 7 years ago | (#21329499)

I reposted the article just above. The picture shows a glowing u-shaped florecent tube. By "disappear" I believe they just mean large radar return. Such materials are called PECs in radar parlance (Perfect Electrical Conductor). You will still be able to see the tube visually.

In related speculation, I wonder if you could use the ION beam from a space probe's thruster (assuming Ion Drive of course) as an antenna. Of course since it wouldn't be parabolic or very directional it might be of limited use.

don't forget stalkers (0)

Anonymous Coward | more than 7 years ago | (#21329511)

this nice college girl next door is sooo pretty, but i'm too shy to talk with her, i want to listen her conversations and avoid go to jail, sounds nice, where can i buy one kit?.

Switch now! (2, Funny)

maciarc (1094767) | more than 7 years ago | (#21329537)

Everyone should go out an buy a new plasma antenna before they switch on Feb 17, 2009. After that, your old metal ones will have to have an adapter to work.

I am sure they are real hard to detect (1)

DarkOx (621550) | more than 7 years ago | (#21329555)

Yup totally undetectable, its not like the enemy has the equipment to spot the infrared thrown of by gas heated to super high energy levers or anything. So much harder to see then a metal pole.

Noise Temperature (0)

Anonymous Coward | more than 7 years ago | (#21329645)

Mmmmmmm...Hot Plasma. This antenna is going to have an amazingly high noise temperature. (Interpretation: it's sort of like trying to use your cell phone right next to an arc welder...that's bad.)

Not Physically Stelthy (1)

nurb432 (527695) | more than 7 years ago | (#21329653)

If it needs glass tubes to work, its not like it will just 'dissapear', and would be a lot more fragile than a metal one. That might be ok for light use, but stick it out in the battlefield and i dont see it holding up for long.

Might work disguised as a neon 'eat at joes' lamp for undercover work..

It also mentions needing several 'segments' to prevent jamming. Couldn't this also be done with more traditional antennas?

Re:Not Physically Stelthy (1)

Ash-Fox (726320) | more than 7 years ago | (#21329751)

and would be a lot more fragile than a metal one
Pretty sure they have very tough glass out there.

Re:Not Physically Stelthy (1)

nurb432 (527695) | more than 7 years ago | (#21329817)

Still, size per size, metal would be more sturdy in combat.

You dont see cannons made out of Lexan ( yes i know thats a polymer.. ).

I've experienced something like this (0)

Anonymous Coward | more than 7 years ago | (#21329791)

We were having no luck using an HF radio positioning system. We noticed that everywhere we went in the nearby town we could hear clicking in loudspeakers. We asked one of the locals about it and he told us it was caused by a large military radar. These guys were cranking out so much power that they were creating their own ionosphere (ie. plasma). All the other signals in the vicinity were being absorbed and reflected. You could certainly use this effect to create a large reflector using physically small equipment. For long range radar, the biggest thing is the reflector and that makes it not very portable. This could solve that problem.

plasma interference (1)

drakyri (727902) | more than 7 years ago | (#21329815)

This might have a small physical cross-section on radar, but I'm not sure that's enough to compensate for the plasma... ...I work in an electronics lab, and occasionally we use a sputtering system - which generates a ball of plasma to transfer ions from one surface to another. Anyway, point being, when we do this, the guys next door, who do a lot of RF measurements, go absolutely nuts - because we've just screwed all of their instruments and currently-running measurements. (Incidently, between them and the plasma is an inch-thick steel chamber at near-vacuum, plus a thinner steel layer and a reasonably thick wall.) So sure, it may not look like much when it's off, but it's like a giant pillar of electromagnetic flame when it's on. Still worth it?

Re:plasma interference (0)

Anonymous Coward | more than 7 years ago | (#21330017)

I have seen this come and go in the antenna field. Question is what noise level does this gas inject on the received signal. I have seen this idea from multiple plasma physicists, but never from anyone with an Antenna Engineer on staff. Then one must think about a power source for the antenna. Electrodynamics and hence antenna design is much complicated than these plasma physicists give it credit. As the commenter above noticed, there exists a large spectrum created by arcs sometimes used to create plasma (a gas which is so full of energy the electrons do not orbit an nucleus in an 'a priori manner'). So now, knowing the dynamics of gas and inherent electromagnetic noise that must be associated with plasma (this is just going on personal thought process, so if someone has a reliable measurement / research source - reliable meaning from multiple sources and repeatable using acceptable equipment - I would love to read it) it is a wonder that the antenna can have an acceptable dynamic range for any meaningful operation (yes applying dynamic range to an antenna due to it being an active device in this situation).

This idea is wonderful, but I have not seen enough good research to prove its viability at this point in time.

As far as stealth, that is very VERY doubtful considering that plasma is a high energy gas (what type of signature does a fluroesent light give off, anyone ever used a corona-cam??!! This thing must be ejecting millions of photons and hence corona-cams should be able to pick it out readily.)

Publish or perish (0)

Anonymous Coward | more than 7 years ago | (#21329883)

Things must be a perishing there....

As someone who designs antennas for fun, This thing would be useful as a transmitting antenna only. The broadband white noise this thing will kick out will easily mask any incomming signal. Furthermore, the noise this thing produces will stand out like a sore thumb for a HARM (High speed Anti Radiation Missle) missle.

Can we apply the stupidity filter to this one as a field trial?

Real World Uses (1)

Nom du Keyboard (633989) | more than 7 years ago | (#21329901)

But can I use it for filesharing, and just disappear when the RIAA comes sniffing around?

Well (1)

Microlith (54737) | more than 7 years ago | (#21330067)

I am a heat-seeking missile so I am really getting a kick out of these replies...

I think they're forgetting something... (1)

immcintosh (1089551) | more than 7 years ago | (#21330103)

Sure, it's hard to spot when you turn it off maybe... does that make up for the fact that it looks like it glows like a goddamn spotlight when it's turned on, or am I missing something?

Seems a tad misleading (2, Funny)

Tinman_au (1004053) | more than 7 years ago | (#21330105)

The plasma is contained in a glass, neon light, like tube.

I was picturing a 30-40' foot long spear of flaming hot plasma death that you could turn on your enemies to turn them into smouldering piles of charcoal....and radio in to mom at the same time!!!

Re:Seems a tad misleading (1)

StellarFury (1058280) | more than 7 years ago | (#21330291)

No lightsaber for you.

The plural of "Antenna"... (1)

Peet42 (904274) | more than 7 years ago | (#21330195)

...is "Antennae".

Auto Electronics (2, Funny)

Doc Ruby (173196) | more than 7 years ago | (#21330357)

antenna that consists of plasma and essentially vanishes when you turn it off. While it may seem to not have many uses in the commercial world,

Everyone who parks their car in NYC and other hostile environments wants an antenna that vanishes when you turn it off. Plasma probably wouldn't jam after a year of use like a retractable antenna, and might even clean the snow off your car, including the pile burying you from the street plows.

Pay no attention to the huge glowing neon tube... (1)

dpbsmith (263124) | more than 7 years ago | (#21330425)

Well, the "stealth" antenna in the article is a huge, glowing tube. According to the article, the antenna is indeed made of "gas-filled tubes reminiscent of neon bulbs."

I wouldn't call an neon sign "essentially vanishes" when it's turned off.

There's no indication in the article that they can generate the plasma without a confining tube, but even if they could, like the Cheshire cat's grin without the cat, it would still be pretty conspicuous when it's on.

Reminds me of an old cartoon in Computerworld, back in the days when corporations had just standardized on IBM PCs and tried to prevent people from bringing in Macintoshes. An IT inspector is saying to a flunky "Desk, chair, filing cabinet, large glowing chef's hat--nope, no Macintoshes here."

Re:Pay no attention to the huge glowing neon tube. (1)

aXis100 (690904) | more than 7 years ago | (#21330513)

Did you think that maybe they might put the neon antenna inside an opaque container? Also, the "stealthy" part refers to it's ability to hide from antenna detectors, not physical inspection.

Noise Figure (0)

Anonymous Coward | more than 7 years ago | (#21330459)

Plasma antenna? I'd love to know it's Noise Figure.

makes me think (0)

Anonymous Coward | more than 7 years ago | (#21330527)

a vacuum also conducts electricity .Maybe not as well.could they use a vacuum?
Vacuum tubes are cool because some of the stuff they do is still hard to do with semiconductors.

Interesting idea ... (1)

ScrewMaster (602015) | more than 7 years ago | (#21330601)

sounds like it might find application in the area of phased-array radars.

It is stealthy (4, Insightful)

Dan East (318230) | more than 7 years ago | (#21330867)

Metallic antennas are excited by EM radiation (radio waves) of a proper wavelength. In turn, the antenna will re-radiate (transmit) a tiny bit of that energy, although very weakly, which can be detected. This is totally passive, which is how it is possible to build a passive repeater by simply running a wire between two directional antennas. It is also the general principal of how RFID tags work.

The stealth of this antenna is that it is non-metallic and will not react to EMF when switched off. It has nothing to do with how big the antenna is, or what color it is, or whether or not it emits light, which are all things people have been speculating about.

Dan East
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