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Technology

Spark Gaps and Ultra Wide Band Data Transmission 182

Posted by timothy from the bathing-in-data dept.
Embedded Geek writes: "It sounds like the revenge of Marconi, but Scientific American has a story about the use of spark gap technology for Ultra Wide Band (UWB) data transmission to send data at 100 to 500 Mbps across short distances (five to ten meters). As with every new technology, 'engineers expect these UWB units to be cheaper, smaller and less power-hungry than today's narrowband radio devices,' but there might be some truth to the hype. The secret appears to be the lack of a carrier wave, allowing use of wide swaths of the spectrum for transmission (the few comments I read at the FCC site referenced in the article addressed spectrum allocation)." Read below for a few more links, too.

"The article pitches the technology as a challenger or succesor to Bluetooth and 802.11a. There are several commercial companies investigating the technology (Aetherwire, Multispectral, and others are cited in the article) and Intel has a paper cited in the article. Spin off applications from the components needed to make this technology work might include a GPS style system accurate to one meter and a radar technology that would allow seeing through walls for construction, rescue, and (ahem) law enforcement."
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Spark Gaps and Ultra Wide Band Data Transmission More

Spark Gaps and Ultra Wide Band Data Transmission

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  • Because of the short pulses (Score:5, Insightful)

    by BiggestPOS ( 139071 ) on Thursday April 18, 2002 @06:07PM (#3369019) Homepage
    These are supposed to look like noise to anything else transmitting. Since they spread the signal around a LOT of specturm, they are generally just raising the level of background noise.... What happens when enough of these devices get out there, and the noise floor rises to equal Everest?

      • MY ERROR 1/3000 of a cell phone Hair Dryer (Score:5, Interesting)

        by JohnDenver ( 246743 ) on Thursday April 18, 2002 @06:30PM (#3369172) Homepage
        1/3000 of a cell phone.

        Ultrawideband communications systems would share the same problem except that they deliberately operate at power levels so low that they emit less average radio energy than hair dryers, electric drills, laptop computers and other common appliances that radiate electromagnetic energy as a by-product. This low-power output means that UWB's range is sharply restricted--to distances of 100 meters or less and usually as little as 10 meters. For well-chosen modulation schemes, interference from UWB transmitters is generally benign because the energy levels of the pulses are simply too low to cause problems.

        A typical 200-microwatt UWB transmitter, for example, radiates only one three-thousandth of the average energy emitted by a conventional 600-milliwatt cell phone.
        • Yes, but that cell phone will be radiating almost all of its energy on a set frequency, with harmonics etc 60db or more down, so it has very little pollution. 3db equals a halving of power, go figure, but at 600mW, even 40db suppression of 'sproggies' means much less than 0.125mW is radiated spuriously. Sounds like this thing polutes...

    • Re:Because of the short pulses (Score:2, Informative)

      by Anonymous Coward
      Cringely already had a good article about this. It can be found here [pbs.org].

    • Microwatts (Score:1, Redundant)

      by Alien54 ( 180860 )
      A typical 200-microwatt UWB transmitter, for example, radiates only one three-thousandth of the average energy emitted by a conventional 600-milliwatt cell phone.

      So it seems that these are very very low powered.

      I mean, Microwatts?

    • Wow! Now I can transmit 50-100 MBPS over 5 to ten meters! At only several times the cost of 100 MBPS ethernet and over a shorter distance!
      • Well, it's wireless, and you may be able to daisy chain through multiple devices (e.g. repeaters) to go longer distances. Also, this is probably a battery powered technology. Pricing depends more on how many of these devices get built, and it's potentially quite a cheap technology in fact.
        • Well, it's wireless, and you may be able to daisy chain through multiple devices (e.g. repeaters) to go longer distances

          Wouldn't it be easier to just have a high speed ethernet connection? This is about as expensive as 802.11B but only goes a few meters. You would have to have a lot of reapeaters.
          • I think wireless is easier to deploy- no drilling, no unsightly cables, you can use your laptop on the same lan, it covers a wider area, and ad-hoc connectivity is easier.

            There's nothing wrong with ethernet though. Its just more cumbersome. Potentially faster, 100 or 1000 M if you need that. But mostly, I find I don't. The only time I thought this would be useful was for a huge compile I was working on (115+ M bytes). There, not having 100M ethernet to my file server costs me about 3 minutes on a ~10 minute link; I was using 10 base T. But I don't think that's such a common thing.

    • Re:Because of the short pulses (Score:4, Informative)

      by n9hmg ( 548792 ) <n9hmg@hotm a i l . com> on Thursday April 18, 2002 @06:56PM (#3369352) Homepage
      Did anybody else think this was an illogical spot in the article?

      Ironically, the more challenging technical problem appears to be finding ways to stop other emitters from interfering with UWB devices. This area is one in which narrowband systems have a decided advantage--all such systems are fitted with a front-end filter that prevents transmitters operating outside their reception bands from causing trouble. Unfortunately, a UWB receiver needs to have a "wide-open" front-end filter that lets through a broad spectrum of frequencies, including signals from potential interferers. The ability of a UWB receiver to overcome this impediment, sometimes called jamming resistance, is a key attribute of good receiver design. One approach to improving jamming resistance is to install so-called notch filters that attenuate those narrow parts of the spectrum where interference is known to be likely. Another protective measure that has been developed would be to use automatic notch filters that seek out and diminish the signals of particularly strong narrowband interferers.

      First: part of the point of a plain UWB system is that you ignore interference by looking for your signal in ALL of the freqencies you use, at the same time. If a pulse shows up across enough of the range, it's probably good, and if it's actually a blast from another UWB source (a light switch, perhaps?), that's what error correction's for.
      Second: there's the issue of ignoring interference. I suppose that at these ultra-low ERPs, they could be exempt, but as they're using bandwidth allocated to other services, they've got to meet Part 15, part of which specifies that they must A)not cause interference to licensed services, and B)accept interference from licensed services.
      Like I said, they meet the first one pretty well, but part of the second one is to force awareness on the user of the Part 15 device that they're conflicting.
      • The problem is that real RF devices do not behave like ideal RF devices. In particular, the wideband amplifiers (or receive detectors if there are no amps) can be saturated by a single frequency of high enough power. In that case, the system is unable to do the time-domain filtering because the desired signal is highly attenuated. In a receiver, this phenomenon is called "blocking".

        Furthermore, the lower power the receiver uses, the more sensitive it is to blocking, and the UWB applications many have been talking about are would require low power consumption.

    • I am not an engineer, but...

      Wouldn't it just decrease the average transfer rate of each of the devices (and fuck with any non-uwb device using that spectrum)?

      They're talking about it only being really short-range though. Unless you're like, on a convention floor or something, full of UWB phones, I doubt you'd get unworkable numbers of them close enough together to be a problem.
  • Sounds very much like the old SSB (single sideband) systems I used to play around with in my CB days :) But seriously, why would anyone *need* such high speed transfers at 5-10 meters?
  • .. to mention Tesla!

    • Re:Let me be the first.. (Score:1, Offtopic)

      by Anonymous Coward

      What IS the obsession with Tesla by certain people? Yeah, he was a bright guy who discovered a few interesting things. But he was also a crackpot who made made a lot of very stupid mistakes in his theories.

      He is NOT underrecognized. Deal with it.

      • Your statement about Tesla sir is verry ignorant, and perhaps should you have paid more attention to his work/patents you would have noticed that even the most modern PC's have his inventions in them (IE electromotor, ALTERNATING CURRENT (AC) Transformers in your power supply....). And yes he made many bad mistakes in his life...while in germany working for edisons german subsidiary Eddison promised him 20 000$ (at that time!)to move to US and finish some work on his patents, upon completition Edison said: " We had no legal contract, welcome to America..and live with it". So his only problem was that he never acually worked on his image nor did he have thirst for money to charge thousans for kis inventions. Please make more informed judgement next time.
        • Jesus fscking Christ, some people just need to be shot in the head. Tesla WAS a genius, the fact was that he got screwed over too many times. If he had more business sense, his accumulated wealth would make Gates look poor. Westinghouse had a deal going with him for $1 per hp generated by his electric motors, westinghouse started to go poor so Tesla ripped up the contract.
          Tesla wanted to transmit power and allow people free use of it but his financer (J.P.Morgan) realised that he wouldn't be able to make a profit off of it so he canned the funding (part of the reason was that Tesla had previously told him that he wanted the money to build a global communications network but was building a facility to transmit power instead).

          Every day your life is affected in some way by Tesla-tech. AC in all its forms for starters and then even the ignition coil in your car is Tesla-tech, as is the flyback transformer in your TV/CRT.

          Then there was his research on 'scalar' waves, these were standing EM waves. I thought this was fantasy, but I did some calculations the other night and they work:
          Start with four sine waves of different frequency, a,b,c and d
          Multiply a and b and c and d
          Then add the two resultant waves:
          (a * b) + (c * d)
          Now plot them, but have the four waves changeing as if you are watching a window of the transmission, have a few cycle of each on screen and change phi so they move.
          The moving vector waves, when computed together to form the scalar wave will have an interesting effect. A scalar wave will be created that has nodal points in free space and have a varying amplitude. It is a bit ricky to explain without images but you have enough info to do that yourself.
          Some of the claims regarding scalar waves have yet to be proven to me, I still have some experimentation to do (I do B of C, no CS at this uni. campus so all in free time) to justify these facts to myself, but it is claimed that scalar waves can propagate FTL and it is possible to modulate the speed. Also when two scalar waves are combined, they recreate a vector wave, I proved this to myself last night. The theory goes that if you can send out two scalar wave at different speeds and with a suitable time separation, you can cause them to re-create a vector wave at a certain point and somehow be able to receive that vector wave at full power (fan-fscking-tastic for wireless networking). This can also be used to generate EMPs at a distance, create force-fields (Tesla shield) or create fantastic explosions (Tesla's death ray). Tesla claimed to have caused the Tunguska explosion with early experimentation on this.
          For more info on scalars do a Google on Tom Bearden.

          Just my $0.0106 (Aussie dollar picking up!)
    • Yes Nikola Tesla should be credited with the invention of acuall notion-idea of transmission of data (IE morse code) wirelessly. There are many conspiracies and quasi theories bit a couple of years ago evidence has been produced that supports Tesla as the inventor of wireless telegraphy, whereas marconi was the first to publish/patent it and therefore get all the glory. What nobody mentioned is that Tesla has also Built an apparatus for wireless transmision of ELECTRICITY as well (think of earth being GND and air being AC...im not too familiar with the pysics of it but i saw a demo a year ago in tesla museum...it was acually pretty cool, they gave us a neon light, turned the generator in and on it went) :)

      Just my 2
      • Yes, and about 5 thousand watts were being broadcasted in almost every direction just to do 3 watts of lighting. It's emmensely inefficient. Fun, and interesting. But impractical beyond belief.
        • Yes i realise the inefficiency of that, but why do u think they have those little Tesla coils in Red Alert? To KFC people! On a more serious note, there are 2 companys that are trying to fix the the problem, one is concentrating on loss of efficiency, while the other is trying to invent a fusion generator so that they would get unlimited power, and not be forced to rack their brains out by trying to fifure out how to curb inefficieny..i will post the URLS as soon as i find them
  • What is the benefit when the applicable distance is so short?

    • anything that currently has a docking station or plug could use this and get rid of a lot of user confusion.

      Maybe you will only have to plug in a single power cord to the next iMac.
    • > What is the benefit when the applicable distance is so short?

      The first thing that comes to mind is wireless heads-up displays for wearables. Some bogus math:

      1024x768 * 32bit * 80Hz = ~2Gb/s

      Throw in some compression and other cleverness, and you should have no trouble fitting it in the 500Mb/s they mention. Enjoy streaming digital video from your belt pack to your ultracool retinal scanning shades (or whatever).
      • double that for two eyes, but then again what yo said is bogus. Consider that almost all the time almost all the screen stays constant even the simplest forms of compression would be able to narrow that.

        But what even more siginificant is that couple this technology and Moore's Law you can have the entire device into a not too bulky pair of glasses within a couple of years.

      • Re:silly question (Score:3, Interesting)

        by man_ls ( 248470 )
        IIRC, Matrox has released a wireless monitor.

        No, this is no joke. It's a wireless monitor...don't know the frequencies, but it is limited to 800x600 resolution 16-bit color because anything more than that and there isn't enough bandwidth.

        I don't know what technology its using though, but the limited range and large resolution mean it probably isn't this.
    • No ... not really that silly ...

      The article mentioned spacial density. It's short so you can pack more people using it into a smaller space. If you were to crank up the power, you would walk over others using the same "frequency" which would be about everyone else using the thing.

      Also, the higher the frequency, the more you get into the microwave bands ... you really don't want to be putting out 200 watts of power to everyone around ... they'd get cooked!

      Since it covers such a broad spectrum of radio, many things can/will be affected if this was in the lower portions of the radio spectum. That's why its limited to 5 - 10 GHz ... for now ...

      If this was allowed at about 80MHz, you wouldn't be able to listen to radio ... all you would hear would be static. In fact the article went on to say that you need several Gigahertz of bandwidth. This is a LOT!

      For instance CW (Morse code) ... you need to seperate conversations by about 50 Hz ... minimum. Stop and think about how many conversations you could get in ....

      Go up to AM and it gets a bit broader about 5 kHz minimum ... with FM being the "widest" of the bunch ... upto about 10 kHz minimum.

      • you're forgetting power (Score:1, Insightful)

        by Anonymous Coward
        The power level on this is ridiculously silly low. You mentioned 200 watts, well you're off by a factor of 1000 if that's what you were mentioning.. Of course 200 watts at the 2-3 Ghz range would fry you. But 200 milliwatts is absolutely nothing. No effect. No effect on radio, on television, on cell phones, on nothing.
        • Actually ... if you would have read the article ... it was 200 MICROwatts ...

          A typical 200-microwatt UWB transmitter, for example, radiates only one three-thousandth of the average energy emitted by a conventional 600-milliwatt cell phone.

          This is another reason that the range is only ~5 to 10 meters.

          The point I was attempting to make, but appeared to fail at, was the reason you want short distances and power levels for 5 to 10 GHz transmitters with several GHz of bandwidth.

          Sort of the shotgun approach instead of a rifle.

  • replenish the ozone while you're at it (Score:1, Funny)

    by Anonymous Coward
    I love the smell of ozone in the morning.

  • Intel looking to fabricate UWB radios on CMOS (Score:4, Insightful)

    by JohnDenver ( 246743 ) on Thursday April 18, 2002 @06:15PM (#3369072) Homepage
    Think about it: Short-wave radios fabricated on a chip that are capable of 100-500 Mbits/sec.

    1. Your PDA would be your CPU + Memory
    2. You could put your harddrive in your coat pocket.
    3. When you walk towards a monitor, you could wirelessly dock to it or the neighboring keyboards/mice.

    This is actually an old article, but I honestly believe if Intel gets this right, UWB is going to be HUGE.

    Here's another article:
    http://zdnet.com.com/2100-1105-840393.ht ml

  • Is anyone else worried about the fact that this increases background noise radiation across the entire spectrum? Won't this cause a massive health risk?

    If the world was filled with these devices then background (full spectrum Gaussian) radiation would be high enough to kill us all, equivalent to having a cellular+microwave+xray+gammaray transmitter constantly switched on stapled to our foreheads, bathing us endlessly in radiation. UWB gives us a dose of everything

    Then again maybe small doses of gamma radiation are good for us, errr maybe they keep our DNA repair system primed or something? I mean small amounts of chocolate's good for us so.. why not gamma rays + xrays?

    Well at least it's not as bad as cosmic radiation or neutrons I suppose, but today's narrowband transmissions at least use (to our puny knowledge) frequency ranges that don't kill us.

    • This is about radio frequencies, not fucking gamma rays. Why don't you get your hand off your dick for 5 minutes and look for some info on EM transmitters. Do you honestly believe that the same device could transmit frequencies across the ENTIRE FUCKING EM SPECTRUM?! Take a Physics 101 class and get back to me.
      • just a friendly reminder.
      • Why don't you get your hand off your dick for 5 minutes and look for some info on EM transmitters.
        After you... Don't want a sticky keyboard, eh? I thought so.
        I like petting kittens.
        I don't want you to get my cat sticky either.
        Do you honestly believe that the same device could transmit frequencies across the ENTIRE FUCKING EM SPECTRUM?!
        I thought that was the "miracle discovery", ah well I guess it's ultrawideband << totalband instead of merely ultrawideband < totalband. The military is already looking into this stuff [defenselink.mil], apparently it can see through walls and the ground.

        Both narrowband and UWB can be harmful against lots of stuff, quoting US military sources [af.mil],

        an official from the U.S. Army's Space and Missile Defense Command stated that recent scientific advances in radio frequency (RF) weapons technology by several states raise significant concerns. Broadly speaking, these weapons use high power microwave energy, in either narrow or wideband form, to disrupt or destroy the high-density metal oxide semiconductor devices that are used in modern computers and sensors.....


        Current technology has produced a 25-gigawatt ultra-wideband source, a 100-gigawatt UWB device is anticipated within a year, and finally, travelling wave devices are also being explored for UWB applications
        A 100 Gigawatt UWB pulse is.... Not gonna be good for my sperm count. How does it sound to you? Oh yeah, it's transient so are you volunteering? Looks like lots of research is being done [roke.co.uk] below 6GHz, hmmm that frequency spread should be mmmmmkay. This link [doc.gov] has the real nitty gritty, symbol rates and all that. Can someone gimme my PhD already?
        • Well we're not talking about military applications here. No shit a 100Gw UWB pulse isn't going to be good for you, neither is a 1Mw pulse from a laser. That doesn't mean the background glow from a city full of streetlights is going to burn holes in you does it? Didn't think so. Anyways, if you conflate radio transmissions with gamma ray transmissions you have already proven yourself an idiot. No PhD for you; it's grade 10 Physics all over again.
          • No shit a 100Gw UWB pulse isn't going to be good for you, neither is a 1Mw pulse from a laser. That doesn't mean the background glow from a city full of streetlights is going to burn holes in you does it? Didn't think so
            <Budweiser Frog>True, true</Budweiser Frog>
            Anyways, if you conflate radio transmissions with gamma ray transmissions you have already proven yourself an idiot. No PhD for you; it's grade 10 Physics all over again.
            Whoa, dude, did you do your grade 10 at Area 51 or Los Alamos? Last time I looked UWB sub-nanosecond pulses weren't on any curriculum. Strictly, there's nothing stopping UWB from operating in the gamma regions. If that's not UWB then it must be UWGXP (Ultra Wideband Gamma Xray Pulse) or something, you'll need to ask some MBA marketing guy.

            Seriously does anyone know what a UWB pulse looks like in the frequency domain? Would it look like a square wave with a sharp cut-off point at 6GHz? This is what I figure, as a peak would imply a carrier-esque signal. I got drunk and missed the lecture about Bessel functions, so is this to do with that?

            • Strictly, there's nothing stopping UWB from operating in the gamma regions.

              The fact that UWB operates only in the RF range and gamma rays are completely on the opposite side of the EM spectrum does, indeed, put a stop to that.

              A band as wide as you're thinking of would encompass heat and visible light as well, which would be really silly for no-LOS wireless.

    • Re:Problem (Score:2, Insightful)

      by PiGuy ( 531424 )
      Why should it be a problem? Driving a car doesn't pose a health risk, and those sparks go off 3000RPM*V6=18000 times a second.
      And our narrowband transmissions /do/ pose health risks - 30kHz to 300kHz (correct me if I'm wrong) is extremely dangerous to human organs, but is widely used for shortwave radio. Cell phones operate on microwave frequencies, and both of the above transmit 100s of watts and go 100s-1000s of miles; this spark gap goes all of ten feet; I see no health risk unless you touch it...
      • You may want to check your math there. ((3000RPM/60 seconds per minute)*6 cylinders) / 2 revolutions per spark in a 4-stroke engine = 150 sparks per second.

    • Re:Problem (Score:2, Informative)

      by Pass_Thru ( 79608 )
      No, I don't think the problem is a health one, but as has been pointed out, I think it will up the background noise level, meaning that other users of the rf spectrum will have less chance of using weak signals as they will be lost amid the higher noise levels. Ask any amateur radio enthusiast about computer/cordless phone noise etc, and other man made interference.

      Radio HAMS are to radio like we are to computers, they see the problems before most people have heard of the cause. Marconi spark transmitters can have a vast range, due to HF emmisions ( a Marconi spark transmitter made the first America-England transmission), OK these things are going to have a bandwidth limitation, but people use 3ghz ++ too, If these devices become common, then services on these microwave bands will suffer to some extent.

      Best mitigating circumstance is that amateur/professional microwave stuff is going to be using highly directional antennas, which will help keep signal/noise ratio high. There will I think be a detrimental effect though overall.
    • Is anyone else worried about the fact that this increases background noise radiation across the entire spectrum?

      no.

      Won't this cause a massive health risk?

      no.

      UWB gives us a dose of everything

      no.
    • Is anyone else worried about the fact that this increases background noise radiation across the entire spectrum? Won't this cause a massive health risk?

      No.

    • Welcome to Power Class. (Score:1, Insightful)

      by Anonymous Coward
      Does no one actually know what a milliwatt is? It is one ten thousandth (1/1000) of a watt. Does everyone know what a watt is? Well it's 1/1000th of the power consumed by your typical microwave. So what do these two multiplied together give?

      (1/1000) * (1/1000) = (1/1000000)

      One millionth! So unless you have one million of these fucking devices within 10 meters of each other, you're not going to have anything even coming close to the power of your average microwave.
  • The secret appears to be the lack of a carrier wave, allowing use of wide swaths of the spectrum for transmission
    This is not really a secret, and is the reason why Morse Code (CW) and Single Sideband use narrower frequency ranges and make better use of available power. Using AM or FM modes, while offering greater fidelity, is a less efficient use of bandwidth.
    • S/N is the signal-to-noise ratio, W is the bandwidth, C is the (theoretical maximum) data capacity.

      It's easier to get capacity by raising the bandwidth consumption than by raising the power level, since the S/N is inside the logarithm. Then a virtuous circle gets started, because you can drop power level, which means someone nearby can operate without having you interfere with them, which means more people can each have whatever data rate C turns out to be.

      This is really just a radical extension of spread spectrum radio.
    • Even more efficient modulation techniques can be found at this PSK31 site. [psk31.com]

  • IANA Explosives Expert but... (Score:5, Funny)

    by Anonymous Coward on Thursday April 18, 2002 @06:18PM (#3369098)
    "...For example, rather than picking up recorded movies at the video store, we may end up downloading films using a portable mass-storage unit and UWB wireless transmission while filling the car up at the fuel pump..." The whole spark gap transmiter + gasoline fumes seems bad for some reason.

    • I'm not either, but considering the location of a cars catalitic converter, and exhaust system, I would expect that an explosion at a gas station is not possibal.

      I don't know the exact values, but gasoline needs about a 5% concentration of fumes before it can explode, which I would assume is deadly in itself. Considering gas stations are outside, I don't think an explosive combination is possibal.

  • Not a Panacea (Score:2, Interesting)

    by Anonymous Coward
    This is not a panacea. While using a wider bandwidth does allow for the use of less power, Shannon's theorem still holds so there is a limit to how much the power can be reduced. And yes, with UWB, just like with spread spectrum, other signals contribute to the "noise" so as more people use it the overall performance will degrade. The proponents of this technology often "overlook" these facts when pushing it.
  • Don't spark gap transmitters cause a great deal of interference across all radio bands? I thought they were outlawed or something for that very reason. Unless they've come up with a way to prevent that, isn't that going to be an issue?
    • Yes they do. The few time I was at a hamfest that demo it, it took a special FCC temp license to run the station. And they did not run it long.

      Back in the old days ( 1960~ 1980 ) when car ignition were not shielded and mechanical you had a dickens of a time trying to shield the system so you could use a radio. Knew every braded supply place in 40 mile rage to build shielding for it.

      Hum. Some where I still have a 1969 Japanes Imae Corvet car with a spark gap generator as the transmiter for the car. No battries needed for the transmiter. Simular to a one button afare with Go-Left-Right-Stop sequency. It did work.

      We basicaly have these now. They are called PC. ;)
    • Don't spark gap transmitters...

      yes, they do. fortunatly no one except the headline writer is proposing to use spark gaps. the story started by mentioning hertz and his sparkgap demos, and i guess the headline writer didn't read any farther than that.
    • Heh, reminds me of a story that one of the venerable old EE's here loves to tell. Again and again and again...

      He was in Nevada back in the 50's working on ECCM (electronic counter-counter measures... jam-proof radar, basically) for the Air Force, and they were testing out the system in the field. And on an intermittent basis, their radar would just be totally washed out with noise... better than the military's best countermeasures could produce. Suspicious, the Air Force tracked down the source...

      To an old geezer out in the middle of nowhere using a 1900's era DC arc welder.

      That thing put out noise "from DC to light," as the story goes. They tried to buy the welder from the man, but he wouldn't sell it for any amount of money.

  • Anyone who's ever installed a decent radio in an old car knows that the ignition system causes a lot of noise, even the article states this. For this reason i seriously doubt the usefullness of this as a transmision device because the noise is not just on one band, but on many, very many. It's the same way on some comutator motors. So, unless your willing to give up all other radio capabilities this product is not for you!
    • Having installed dozens of decent radios in cars, I can assure that if you were getting noise, it was your installation and not the cars breaker-point ignition system causing the problem. The more decent the radio in fact (I don't mean Kraco, I'm talking like Nakamichi- okay maybe not Nak but Eclipse, Sony Mobile ES, or Alpine) the better it rejects noise UNTIL you have a bad ground on your radio or a crappy old antenna.

      Of course, it doesn't hurt to have a ground strap running from your firewall to your hood either.
  • But isn't this the same thing as this? [slashdot.org]
  • quote: ...and a radar technology that would allow seeing through walls for construction, rescue, and (ahem) law enforcement."

    Finally, I can see just what the heck my apartment neighbors are doing to make all that friggin racket 24/7! And I get to nuke them with the radiation at the same time? Say it ain't so! (sniff) I'm sooo happy!!!! (sniff)

    Great, so now instead of the DEA flying overhead with thermal imaging equipment to check for heat coming from a grow room, all they have to do now is drive by and point a camera at your place and see how much your plants are growing every day. (Tell me it's not gonna happen...)

    • I think you're refering to this quote:
      These pulses give UWB wireless the ability to discern buried objects or movement behind walls, capabilities that could be important for rescue and law-enforcement missions

      So in essence you might be able to see that your neighbors are moving, but it would not be like completely removing the wall.
      • I know, I was just illustrating the point of intrusive technology in our lives and the fact that if I can come up wth applications like that so quickly, think of what people with real brains could do with it. Intrusive technologies are already around us and it's not going to get better. Check out 'Body of Secrets' by James Banfield about the CIA and see how fast they adapt technology for less than honorable purposes...IMHO
  • The Science Museum in London has the only Spark Gap Transmitter licence in the UK. You can press a button to transmit a message using the spark, to a receiver across the corridor.

  • Pulson and Aetherwire are great companies in field (Score:4, Informative)

    by Thagg ( 9904 ) <thadbeier@gmail.com> on Thursday April 18, 2002 @06:47PM (#3369277) Journal
    Two companies that have been pioneers in UWB are Pulson [pulson.com] and Aetherwire. [aetherwire.com]

    Pulson (and its predecessor company, Time Domain) has been desparately trying to commercialize this technology for radio communication for years. More than five years ago they demonstrated a few-milliwatt UWB radio with 100-mile range. They have mostly been held back by patents taken out by Lawrence Livermore. Livermore claims to have invented all of this stuff, and has been rediculously rough on licensing. Also, the FCC has been unclear until very recently on how it would license UWB.

    Aetherwire has attempting to use UWB technology to build localizers, basically extremely short range, extremely low-power peer-to-peer short-range version of GPS. The localizers would all cooperate at keeping track of where the other ones were within a few hundred meter radius. If you've read A Deepness in the Sky by Vernor Vinge, it's all about localizers.

    Now that the FCC has cleared the way, I expect to see tremendous progress in UWB. It's going to revolutionize many fields, from radio to positioning to radar.

    thad
    • I think Time Domain is still the name of the company and Pulson is the trademark name of the technology. If they did change the name of the company the sure haven't changed the signs on the buildings. I work next door to them. It's really interesting to see the test equipment in the parking lot. Lots of really strange shaped devices.
  • "While traveling on planes or trains, people could enjoy streaming video input or interactive games..."

    Yeah, I think I want a buch of spark gap generators on a plane with me. The streaming video will be good for that time when we're taking off and landing and they make me turn off all electronics including my PDA to reduce (possible) navigation interference.

    Granted, I don't think most electronics put out enough RF interference to cause problems, but why chance it? What if the transmitter get kicked, droped, jostled, or otherwise "detuned"?

  • No a magic technology. (Score:5, Insightful)

    by 3flp ( 172152 ) on Thursday April 18, 2002 @06:53PM (#3369322)
    This is just a different method of sharing spectrum among different users. The currently used methods are pretty good. They have been under development for about 100 years. The Rf spectrum is a limited resource. The amount of information that can be transmitted over the spectrum is limited by Shannon's theorem (read his 1949 paper). This limit can't be increased. What UWB does is spreading its information over really wide bandwidth, raising the noise floor for everybody else. If there are enough UWB transmitters around, they will interfere with each other to the point of uselessness. Also, this will f**k up every other user of the Rf spectrum. In addition, with UWB, the spectrum can't be managed by assigning different frequency bands to different entities. Everyone jsut uses all of the spectrum all the time. The strongest transmitter wins. Sounds like this technology has a good chance of being approved in the US...
  • Reading this article I got an interesting idea. For this system to work it seems that you have to sample at an extremely fast rate. Given that, why couldn't you use the same hardware interface along with a DSP to extract signals of much lower frequencies, i.e.: Using FFT extract an FM signal. It would seem that we are at the cusp of being able to use one device to fulfill most of your all RF needs.
  • In a sparkgap transmitter the spark is used to excite oscillations in a tuned circuit which is coupled to the antenna. The Q of the tuned circuit is made as high as possible so as to minimize the bandwidth. Unfortunately it is not practical to make the Q high enough to prevent radiation of broadband (not wideband) noise and harmonics. However, the energy in the noise and harmonics is wasted. It is a narrowband transmitter that just happens to be rather inefficient.
    • [A sparkgap transmitter] is a narrowband transmitter that just happens to be rather inefficient.
      Exactly. The article's assertion that UWB is similar to spark gaps is ludicrously wrong. A spark gap is simply a low-gain amplifier, connected to a dissipative resonator. It's exactly like a quartz crystal oscillator, just much lower quality.
  • As I understood it from when i last read up on this it was to do with having monocylcic pulses spread across the entire frequency range, and the analogy to a spark gap is a pretty poor one.

    A spark gap interferes with the entire radio spectrum - using it to send only one bit of data.

    UWB sends very brief signals over the entire radio specturm but jamming no part of it for any more than a tiny fraction of a second. Even then power output can be so low that to conventional radio a UWB transmission will fade into background noise.
    • UWB sends very brief signals over the entire radio specturm but jamming no part of it for any more than a tiny fraction of a second.

      That is not correct. A filter (which is present in any conventional radio) will delay and expand the signal to match the filter's own pulse response. This will result in output pulse being wider and lower in amplitude, but with the same energy. Basically, any receiver subjected to UWB will receive whatever signal it was designed to receive, as defined by its filters and the demodulator.

      As I understand it, from all EE points of view, UWB is evil.

  • Imagine the near future when these things proliferate.

    You're living in an apartment building listening to an "ordinary" radio one evening. Suddenly, hideous whining and crackling proceeds to interrupt every station you could receive before. The entire FM and AM bands are trashed with this sound.

    Your TV (not yet connected to cable) with rabbit ears - same story.

    You pick up the portable phone to call the apartment manager, and your phone gives off that two tone beep that indicates either that your portable can't sync with the base unit because 1) your phone's battery is dying or 2) there is too much ambient interference.

    Oh... you suddenly figured it out. The computer geek next door just got one of those new UWB networks set up.

    The point: the quality of life for certain pastimes will take a dramatic nosedive... yet another way that your fellow man can make your life miserable without even breaking a sweat. Any sort of radio equipment will have to be used well away from most buildings.

    I know, they will set "thresholds" of acceptable power for these things. The problem is, there are many legitimate uses for sensitive radio equipment, such as shortwave, or non hardwired TVs or radios.

    What an IDIOTIC idea. It basically erases 100+ years of progress in electronics.
    • Yes, you MUST forget those PAST technologies for the sake of consumerism, or call it progress. Analog shortwave must be sacrificed for a variety of economics reasons; the Media giants no longer want analog transmission. Never mind it's inherent simplicity and beauty, it is destined to be all DIGITAL; on a chip and mostly undecipherable except by the handful of chip engineers who make it happen. Capacitors and Inductors, Transistors and Valves, given over to algorithms.

      how sad a time to be involved in (Electronics) technology, and I am not normally a Luddite.
      Send me back to the 40's.
  • Do you know how bad this stuff is?

    You might think you can live with this stuff, but it wrecks it for everyone else. The FCC (and other international Frequency management agencies) has been trying to reduce the ammounts of noise in the EM spectrum for years, that includes your noisy drills, mixers, and other noisy equiptment, and you want to make the noise worse? This stuff could make the difference from hearing your favorite FM station 50kms away from the transmitter, down to 20-30kms away. (That's with 3db signal loss through noise)

    I don't know if anyone here might have heard of AM radio, but if you've ever listened to it, and you hear that occasional car going past making clicking noises is really low level. What your talking about now is whenever someone has one of these devices going, it will have the effect of dropping the station your hearing, watching, or even talking to, under the noise. So you'll now drive past someone past thier fancy UWB devices, and all your precious data connections (eg. CDMA) drop without a second thought, fm station will drop out, etc, etc... Image if your neighbour in an appartment block was using his reguarly?

    Solution? Yes, simple, there is tonnes of bandwidth available you short range use all over the place, hey, there's even gigs of bandwidth available above 10Ghz, put a carrier on this, and transmit your data! Or, even, use infra red, there's atleast a few meg of bandwidth there (I've heard of tests of distances as much as 50kms).

    Oh, and if your interested in this UWB stuff, then don't even think about security, the only way to keep you stuff partially secure would be Spread Spectrum, which needs to be managed on a set of frequencies.

    • What your talking about now is whenever someone has one of these devices going, it will have the effect of dropping the station your hearing, watching, or even talking to, under the noise.
      Do you have a link power budget analysis to support this, or are you talking out of your ass?
      Oh, and if your interested in this UWB stuff, then don't even think about security, the only way to keep you stuff partially secure would be Spread Spectrum, which needs to be managed on a set of frequencies.
      Baloney. No modulation scheme provides any security whatsoever. If you want security, you have to use cryptography.
  • In times like these we must ask ourselves one very important question: How will this affect... Al Frankin?

  • How much bandwidth could they get out of the spark plugs in an average V-8 engine? Enquiring minds want to know...

  • Wonder when the quantium concept will replace this stuped idea. By having two particles tangles and by changing one it affect the other then you have one heck of a radio! This is an effect that has been proven. In effect a direct connection that is not a direct connection. It turns into basic net tech without the noize and mess that UWB will create. The only way UWB will work is dump the current stuff ( all radios from 60hz through microwave ) and make everthing, communication, data whatever switch over completly. Hum. Wonder if using Teslar thinking these devices could live off of the noize generated by other devices? Self powered devices you cant switch off?
  • Here's a comment [slashdot.org] I made earlier this week about wardriving and the X10.

    It's all about scope, if you dont want your TV talking to your next door neighbours TV, you shield your house by building a faraday cage into the walls, check the link because anything else I type would be redundant.
  • The popping sound would drive me mad...
    Also, try this experiment. Get an electric drill with a trigger switch wo| a detent (physical click) at the start of the trigger's throw.
    Hold it up to a radio (AM), and quickly pull the trigger, from full-off, to full-on. The radio will start popping.
    Now imagine this on a sensitive, microwave array, listening for 300mW 20km away, instead of your 50,000 watt station.
  • Scientific American now sounds like Popular Mechanics. "Ultrawideband wireless technology should make possible an entirely NEW CLASS OF ELECTRONIC DEVICES and functions that would change the way we live." Sigh. Reality check time.

    First off, how much use is there for high-speed radio links that span 5 to 10 meters? It's not enough for an office network. It's not even enough to get a TV signal to the back bedroom.

    Most of the claimed applications sound very similar to those claimed for Bluetooth. Remember Bluetooth? Besides, do we really need half a gigabit for PDA synchronization?

    What this is really about is a spectrum grab. The RF spectrum is full of underutilized channels which use obsolete technology, like AM television. You could probably put a spread-spectrum cell phone system right on top of a TV band and all TV viewers would see is a little more snow, if anything. But the TV industry would howl.

    All the hype about "ultrawideband" is to allow putting spread-spectrum signals (which is what ultrawideband signals are) on top of other channels. Initially, the proposals are for very low power levels, but once the technology is deployed, there will be pressure to allow higher power levels, even if it degrades the old-technology channels a bit. The ultrawideband stuff will have lousy range until the power levels increase.

    Think of this as a political migration path to an all-spread-spectrum world. Judge it in those terms.

    • The RF spectrum is full of underutilized channels which use obsolete technology, like AM television. You could probably put a spread-spectrum cell phone system right on top of a TV band and all TV viewers would see is a little more snow, if anything. But the TV industry would howl.

      Remember, analog TV is going away by 2006. Then you'll have DTV channels delivering 19Mbps ATSC transport streams, either delivering 1 HD program, 4 standard definition programs, or various multiplexes of HD/SD and datacasting (for example, KLAS-DT was sending out a 1 Mbps Windows Media stream during the recent NAB convention).

      Moreover, all current TV operations in channels 52-69 will be moved to the "core" channels 2-51, and the extra spectrum will be made available to other services.

      Interference to DTV doesn't cause snow, you either don't see it (with bit error rates below the FEC correction) or it makes the picture go out (with higher bit error rates).
  • We all use the same band to talk to and hear each other.

    But we only receive those who are sending from locations near to us.

    --Blair
  • Some time ago /. mentioned this story [discover.com] about inventor Larry Fullerton, who spent 25 years developing radio burst technology in his backyard lab. His company, Time Domain, is listed in the Entrepreneurs box of the SciAm article. It's nice to see 2 things happening: 1) the technology has not disappeared, and 2) one of the original pioneers is actually getting a piece of it.

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