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Technology

New Lighting Technology To Wipe Out Wi-Fi Access? 329

Richard Evans writes "Focus on Broadband Wireless Internet Access has an article [cached by google ] on the potentially catastrophic interference to Communications Users Of The 2.4 GHz Band e.g. Wi-Fi, DECT and Bluetooth by a new lighting technology called RF Lighting."
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New Lighting Technology To Wipe Out Wi-Fi Access?

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  • WTF?!?! (Score:3, Funny)

    by TheDick ( 453572 ) <dick@askadickLION.com minus cat> on Wednesday May 08, 2002 @01:10PM (#3485800) Homepage
    They finally learn, and put a link to the Google Cache, IN THE FUCKING ARTICLE???? I'm so impressed.

    I thought regular fluorescent lighting already fucked shit up, since its not really a steady light (like incandescent) but really flickers on and off REALLY fast. Some guy thought a cool way to basicly broadcast info from these lights was by slightyly altering the timing to transmit data....

    Who needs RF lighting anyway? I'd rather have a wireless laptop/pda.
    • Incadescant flickers on and off too. It's not so prounced, because the tungsten takes time to cool down, but it's there. Connect a light sensor up to an oscilloscope, or those old fashioned 'tell if your record player is revolving at the correct speed' gizomes, and you can see it.
  • nonsense (Score:4, Funny)

    by tps12 ( 105590 ) on Wednesday May 08, 2002 @01:11PM (#3485805) Homepage Journal
    RF lighting is a great idea...just not for humans. While normal "visible" light (like what is coming out of your computer screen right now) consists of tiny waves called "photons." These are the base quantas of light energy. Bizarrely, radio waves consist of the exact same photons, but at vastly different energy levels! Heat also consists of photons, again with different energy or frequency amounts.

    So RF lighting is just normal lighting at a different frequency. A frequency that humans can't even see! Trying to listen to the radio or use wireless networking in the presence of RF lighting would be like trying to watch TV with a spotlight in your face.

    • I thought photons were particles!

      And I think it would be more like watching a TV with a broken tube.
      • I thought photons were particles!

        Actually they're both wave and particle.
        Same thing for electrons.
        Actually all mater is both wave and particle.

        Trust me on this one!

        I hope this clears up all doubts you had.
    • Is that you?
  • Repeater stations (Score:2, Insightful)

    by Keighvin ( 166133 )
    Why not make these play nice and use the lights as repeater stations? Install a recepter on each one, wire'em up to the LAN and have even more ubiquitous access.
  • by Anonymous Coward on Wednesday May 08, 2002 @01:14PM (#3485820)
    If consumers would bother to read the FCC-mandated disclosures that come with all of their new high-tech toys, they would see the following quote:
    It's there, plain as day. If you're mad that somebody nearby is trying to reduce dependence on foreign energy and save the environment by using highly efficient magnetron-powered lights, you have nobody to blame but yourself. There is no substitute for proper consumer education.
    • Yes, I would assume you're right.. "legally" we don't have a right for RF technologies to always work. FCC regulated or not, it comes down to your local area when you're using or considering using wireless phones, WiFi, or other wireless devices. When I was in grad school I was in a building where 2.4GHz was kind of noisy, I expect it was due to science research experiments and a steel-frame building. We just bought antennas and didn't worry about "legal" reasons. Seems everybody is too quick to complain about legality these days.

      I think the real issue is more practical, who buys the technology not knowing that it will heavily interfere with certain wireless equipment. (I'm thinking office environments are the biggest issue) Doesn't the consumer have a right to know things like interference before purchasing a product? After reading the article I personally got the idea that I need to check out the lighting technology and be cautious of where it is installed. That's all, it's an old technique where you just don't buy something if you don't like the side effects.

    • While 100% correct, that is not nessecarily the end of the story. The FCC regulates spectrum for the common good. The use of section 15.5 expanded far beyond the FFC's expectations. The FFC has the *option* to alter its rules to take the current reality into consideration.

      -
    • Well, that is true, but the issue at hand isn't really the rule, but rather corporate america's willingness to use loopholes to do business. In effect, an unauthorized RF source is interefering with an unauthorized RF network (or whatever). Since both are unauthorized, they fall in between the cracks of the Section 15 rule, and therefore, could still be subject to legal action. This could also result in a rewrite of the rules by the FCC to account for such issues (which could be good, or very bad, depending).

      But most importantly, the courts should (don't read will) be very reticent to kill one company's nifty product in production for anothers. And, I believe that satellite radio is an authorized radio service, so if RF lighting does in fact prove to be a source of interference, then RF lighting is going to have a very tough time. Two established providers v. a new an upcoming technology should be an easy one for any court. If satellite is interferred with, then it is almost a sure bet any WiFi equipment will suffer, and the judge, whose kids may surf the web using the WiFi tech, is most likely going to rule in favor of established products.

      Note I'm using the courts in my argument. Due to the FCC's continuing inability to make a decision stand, it is almost inevitible that courts will be involved. Someone will sue someone else in an attempt to force the issue.

    • AC, you must have been modded up as a denial of inteligent conversation.

      First, the article mentions the Section 15.5 rules and considers the issues carefully.

      Second, you are a moron. If you would go visit the company's site [fusionlighting.com] you would see them bragging of 80% efficency of transmision. While that's all well and good, 20% of your juice is a lot to throw away and I would not put these bright little bulbs in the environmentaly friendly catagory. Want clean domestic electricty? Start building nuclear power plants.

      The crux of the problem is the limited and wasteful alocation of specturm by the federal government. Fusion lighting's boast of 80% efficiency came from a 430 MHz transmitter, not a magnetatron operating at the only frequency left open for people to use as they please. There are 69 channels on my TV reciever but only five broadcasters in my town, how about yours? If the FCC alows the abuse of 2.4 GHz it will be to protect conventional telcos, ISPs and large publishers from the freedom of expresion technology can give us. It will be a vastly stupid thing to do, but that's why comercial radio and TV is devoid of anything entertianing or educational.

      There it is, plane as geometry. If you are in favor of wiping out all 2.4GHz comunication instead of allocating more spectrum to the people to use as they please, you have a pin head.

  • by grinwell ( 138078 ) on Wednesday May 08, 2002 @01:14PM (#3485823)
    This article is from July/August 2001.


    The website it cites: Link [fusionlighting.com] is *still* blank at least a year after it was cited.


    The article also goes into very little detail as to *why* this new lighting technology will be either popular nor necessary. It's vaguely referred to as "very high efficiency."


    Summary: Call us when you have real news.

    • The front page of Fusion Lighting is blank, but Google can point you to a promotionalish page on Sulfur Lighting [fusionlighting.com] as well as a Technology Page [fusionlighting.com].
    • and also... (Score:2, Insightful)

      by Schlemphfer ( 556732 )

      Let's see an electric use cost comparison between this RF lighting and fluorescents. It's pretty slipshod that the article didn't bother to address the question of whether this lighting offers significant savings.

      Until it's clear that there are compelling cost advantages associated with microwave lighting, the issue of whether this technology could endanger communications doesn't merit discussion.

    • Earlier today it was the dual-screen laptop. They seem to publish these stories totally uncritically.

      Dudes, if you're that desperate, just regurgitate something from Space.com, Wired News, or the Register.

      This is not a troll.
  • Satellite Radio (Score:3, Interesting)

    by kwishot ( 453761 ) on Wednesday May 08, 2002 @01:15PM (#3485837)
    This article says that Sirius and XM Radio will be effected. That's really bad. Part of the reason it's worth paying for is because of the sound quality...having this happen in it's relative infancy could be realllly bad. I wonder if there's a way to shield these lights...like some sort of compound mixed into/spread on the glass that reduces the RFI. Either that or, as a geek community, we should just hope that this idea doesn't take off!
  • by Neck_of_the_Woods ( 305788 ) on Wednesday May 08, 2002 @01:16PM (#3485843) Journal
    Man with those lights I can grow weed, light my pit of an appartment, completely screw the wireless network the guy next door who has to play mp3's at the highest possible bass level at 3 in the AM!

    Pro's:

    Heat, grows good herb, and kills the wireless network.

    Con's:

    ahhh, shit I forgot...pass that would ya!

  • by cats-paw ( 34890 ) on Wednesday May 08, 2002 @01:16PM (#3485846) Homepage
    I don't know what this lighting is, although I suspect it may be "sulfur" lighting.

    However if it's going to trash your wireless network then the chances are good that you won't even install it in the first place. That takes care of homes and _probably_ office buildings.

    The problem is going to be "public areas" where the lighting is installed to save on electricity costs, and then interferes with ISP's as the article stated. This of course assumes that the lighting is so much more efficient than sodium or mercury vapor that it's worth the expense of installing it in the first place.

    And it's going to take years.

    Far from an ELE.
    • From the specifications, it is indeed a sulfur-based lamp. The major difference is that it uses RF energy, rather than an electrical charge to excite the sulfur atoms to produce light.

      The big advantage is that by using RF energy, they are essentially boosting the efficiency of the bulb. For instance, incandescent bulbs are approximately 2-4% efficient, mercury and sulfur based fluorescent bulbs are about 25-35% efficient. With this new bulb, they are indicating about 70-80% efficiency. These bulbs should also last much longer, as the magnetron device (producing the RF energy) doesn't wear down like electrodes do.

      While to ordinary Joe Consumer, this isn't that much of a big thing, imagine for instance the amount of electricity used by a large city just to keep the lamp posts lit. They would achieve the same amount of light on half the electricity bill.

      Unfortunately, that would mean that every lamp post (so equipped) would become an instant RF source. It would certainly be far too minuscule to cook you, but definitely enough to cause some interference on wireless RF equipment in that spectrum.

  • by jdbo ( 35629 ) on Wednesday May 08, 2002 @01:17PM (#3485853)
    does this mean that I have to re-wire all of my "wi-fi" devices?

    worse, does this mean that I'll have to start referring to them as "wi-wi"?
  • by frantzdb ( 22281 ) on Wednesday May 08, 2002 @01:17PM (#3485859) Homepage
    To prevent interference, RF lights should simply practice exponential backoff for colision avoidance like everyone else in the 2.4GHz range. What's more, the lights would then become an effective network load monitor.

    --Ben
  • by nherc ( 530930 ) on Wednesday May 08, 2002 @01:18PM (#3485865) Journal
    Couldn't the RF Light manufacturer just shield the light fixtures e.g. a Microwave Oven?

    In fact, I would think the FCC would make them, if they had an output over a certain threshold.
    • Couldn't the RF Light manufacturer just shield the light fixtures e.g. a Microwave Oven?
      Microwave ovens aren't shielded any better. (In fact, the RF lamps are nothing more than microwave ovens that heat a quartz bulb with a tiny bit of sulfur in it. The sulfur gets hot, vaporizes, and glows.) The problem is that the magnetrons used in ovens and lamps don't have very good frequency control. Their spectral peak could land anywhere inside the ISM band at 2.4 GHz. Wi-Fi (802.11b) was designed to work around ovens by hopping between a bunch of narrow little bands, the theory being that if you have several microwave ovens in the building there will still be zones that are free of interference.

      That works fine for most buildings. There are only perhaps a dozen ovens at most, and they only run for a few minutes at a time. But there could be hundreds of RF lamps, and they could operate 24X7 in a warehouse environment. The lamps could potentially make the RF environment orders of magnitude more hostile to data service, so that's why people are in a lather over it.

    • Couldn't the RF Light manufacturer just shield the light fixtures e.g. a Microwave Oven?

      No. I saw this thing on Hometime a few years ago.

      Imagine a regular light bulb where the glass part is removable from the base and filament inside. Where the filament normally is there's a wire wrap (maybe more to it than that). The glass part is coated on the inside, with a coating that glows when hit by RF. Put the glass part on the base, it glows. Take it off, it doesn't.

      To shield this, you'd have to put the shielding outside of the light bulb, which would block the light.
  • Whoever has the most powerful transmitter wins. I'm sure Powell Jr. at the FCC loves it that way.

  • by Anonymous Coward
    That's why 2.4 GHz will rapidy become unreliable for wireless LANs.

    Luckily, 5 GHz wireless LAN products (802.11a) are now becoming available (called WiFi-5, I believe). Since they
    do not use the 2.4 GHz frequency range, they will not be affected by this issue.

  • FCC (Score:3, Interesting)

    by Kallahar ( 227430 ) <kallahar@quickwired.com> on Wednesday May 08, 2002 @01:21PM (#3485881) Homepage
    I'm not a big supporter of the FCC (who frequently overstep their bounds), but this is exactly why parts of the radio spectrum need to be regulated. The entire reason that the FCC keeps such tight control is so that companies that invest in radio equipment have some assurance that the guy next door won't simply drown out his signal with more powerful equipment.

    But then again, every time my boss walks by with his cell phone, my monitors fuzz out and my speakers make strange noises from whatever signals the cell phone is emitting...

    Travis
    • I'm not a big supporter of the FCC (who frequently overstep their bounds), but this is exactly why parts of the radio spectrum need to be regulated.

      I agree that the radio spectrum needs to be regulated (like any other common good), but unless my photons are crossing state boundries, why should it be regulated by the federal government?

    • I've got money saying your boss uses a Nextel phone, eh? Nextel uses IDEN instead of GSM/PCS/etc. Noisy. You'll notice your speakers in your car pop every time a call comes in.
  • So basically, Wi-Fi was developed to take part in a area of the spectrum that's licensed to other products. The people who started it knew that this was a potential problem. Granted, this area was a relatively large chunk of the spectrum, but why didn't they realize the possible impact of this interference? It's is much more dangerous to digital communications that other products. Was there really no other place in the spectrum to go? Perhaps find one that the FCC can give exclusive rights to?

    From the article...


    (1) [Each Part 15] device may not cause harmful interference, and (2) [Each Part 15] device must accept any interference received, including interference that may cause undesirable operation.

  • by jsimon12 ( 207119 ) on Wednesday May 08, 2002 @01:25PM (#3485906) Homepage
    • Can someone tell me what this has to do with fusion? What are we fusing? I think fusion lighting is the bright light given off by nuclear explosions. Mixing fusion and lighting is like mixing turbos and lasers.

      We're trying to destroy them sir, but they're evading our turbo lasers.

      I should get a job pointing out the ridiculous. It's my calling.
  • by hackman ( 18896 ) <bretthall@NospaM.ieee.org> on Wednesday May 08, 2002 @01:27PM (#3485925) Homepage
    The article makes a big point out of the collision between the frequency spectrums, however I personally am interested to find out more about the lighting technology that is "high efficiency and RF based". It seems the article kind of missed that explanation, and I can't find much information on it. The lighting's website is down that is referred to, and as far as I know this could be a "made up" problem (by this dude who wrote the article) primarily because it's only a problem if the lighting technology catches on.

    Are the light technology elements mounted in the ceilings like conventional flourescent lights or does it use some kind of a central light-source idea. If it's high-brightness and high-efficiency anyway, the light source could be placed at a central (shielded) location and fiber optics used to distribute the light.

    I'm all for new light technologies, although often flourescent lights are pretty good, there is still a lot of room for improvement. (Time delay to full brightness, hazardous materials, cheap ballasts that buzz, bad fluorescent tubes that put off funny-colored lights) But interfering with wireless spectrums (even unlicensed ones) seems like a bad idea in general... the amount of noise in any spectrum is becoming a serious concern for the design of "robust" wireless technologies.
    • A few years ago I did academic research funded by FusionLighting to improve their product. Without violating any confidentiality agreements, here's a quick explanation of the technology

      The source of light is a gas plasma induced by pulsed microwave radiation. Fluorescent and neon bulbs also use a gas plasma, but they have two electrodes running at 60 Hz. Sodium-vapor and Mercury-vapor arc lamps use plasmas, but also with exposed electrodes.

      These bulbs have no electrodes (so they last _much_ longer) and run at microwave frequencies (2.4 Ghz). Why did they choose this freqency? Just to ruin your wireless connection? No. They needed high power magnetrons (things that generate microwaves) but didn't want to pay military prices. Well there's already a large competitive market for high power magnetrons, it's called the microwave oven.

      The FusionLighting light bulb I worked on was a bit larger than a golf ball and filled with a secret sauce of gases and other stuff. When lit, it was VERY BRIGHT (you absolutely couldn't look right at it) and provided a spectrum of light much closer to sunlight than fluorencent and even incandescent bulbs.

      The light bulb is mounted inside a metal screen box which is the microwave cavity. Light can get out of the metal screen but almost all of the RF stays inside. Actually, once the bulb is on, almost all the energy goes into the bulb (that's why it's so efficient). Apparently, enough leaks out to disturb Wi-Fi etc.

      The downsides of this technology (other than ruining your internet connection) were: [note: it may have evolved since I worked on it a few years ago]

      (1) The bulb plus magnetron was pretty big, very bright, and somewhat noisy. Typical applications were warehouses and gymnasiums, not your home. Example: the Smithsonian Air and Space Museum replaced 88 soldium-vapor arc lamps with a handful of the fusion lighting bulbs. And they were THROWING HALF OF THE LIGHT AWAY by using diffuser tubes that spread it out and kept your kids from going blind when they looked up.

      (2) The bulbs took a few moments to warm up when turned on. During that time, the light was a dim blue-violet color.

      (3) Like sodium-vapor lamps, you couldn't turn them back on as soon as you turned then off. They had to cool down.

      (2) + (3) = No fun if you forget the keys and then run back in to find them in the dark.

      I was working on (2) and (3), as well as improving the efficiency, which would lead to a smaller size. We made some progress on all counts.
  • by 4of12 ( 97621 ) on Wednesday May 08, 2002 @01:30PM (#3485941) Homepage Journal

    Why get all in a lather about RF lighting?

    If solid state lighting [sandia.gov] takes off we'll get great efficiency and no 2.4 GHz spectrum pollution.

  • by noahbagels ( 177540 ) on Wednesday May 08, 2002 @01:32PM (#3485954)
    This article is utter garbage!!!

    The first link (off-site) from the article referred to, in fact the makor of said "RF-Lightning-Craptacular VC-Money Whoring" company has a "our website is under construction" on it.


    C'mon people - stop posting obvious flamebait articles at the highest level. This was a freakin waste of everyone's time.
  • Seeing as this technology uses tiny microwave emitters to excite sulfur ions what effect would it have on pacemakers? If they have to sheild it for pacemakers and stuff then shouldn't the effect be minimal or seeing as the 2.4 ghz area is open can they just dump as much radiation as they want into that spectrum? I mean I don't see problems when I use my 2.4ghz cordless of WiFi laptop when my microwave oven is running, so shouldn't the lights be sheilded to the same standard?
  • Who would want them? (Score:2, Interesting)

    by gunnk ( 463227 )
    If the RF lights get shielding on them then we don't have to worry about them interfering with network devices too much.

    Then again, if they DON'T get shielding they'll never sell. Try telling your employees that you are going to replace all the lights in their workspace with lights that spew radiation at the same frequency that their microwave uses, but without the shielding! Sure, the output would be WAY below a microwave, but who wants to sit under a bank of them eight or ten hours a day from now until retirement?
  • by stormcrow969 ( 458071 ) on Wednesday May 08, 2002 @01:36PM (#3485976)
    The company I used to work for did the very first large scale (non-test) installation of their lighting products in the US. It sounded like an awesome product. It would provide MORE light for LESS power with LESS maintenance.

    We installed a HUGE area with this stuff (took many months to do the install). A year later we ended up yanking every bit of it out. Why? Well, there were SEVERAL technical problems with these things that they hadn't worked out. The short version of how they work is that they irradiate a glove with some sulfur in it with microwaves and turn it into a glowing plasma. Well, that stuff is a bit hot, so you have to continuously rotate the 'bulb' This rotational part breaks, so the light breaks.. the reflectors can't stand the heat, etc.

    so don't worry.. they are in bankruptcy... :)

    • they irradiate a glove

      Sounds like an expensive system. Is that why Michael Jackson only had the one?
    • OK so we don't need to worry about THIS one, but what about the next one?

      I think the larger issue here is that the huge installed base of communications equipment which operates in the 2.4GHz band is not legally protected from interference, and it could be only a matter of time before some widespread technology comes along which renders all 2.4 comm devices useless because of this loophole.
  • by Animats ( 122034 ) on Wednesday May 08, 2002 @01:36PM (#3485977) Homepage
    Prototypes of this "sulfur lamp" technology are in place at two public places in the Washington, D.C. area [doe.gov], the front of Department of Energy headquarters and the Gallery Place Metro station. So get down there with your Wi-Fi equippped laptop and see what the situation is.

    This looks like a niche product. It's not even clear that Fusion Lighting is still in business. Their web site is essentially defunct. Their web site used to have [archive.org] some nice pictures of glass bulbs and more info, but now [fusionlighting.com], it's just a starter page.

  • All this talk about interference between WLAN and Bluetooth is more or less rubbish in my experience. Both at work and at home, I work every day with both Bluetooth and WLAN at the same time and I've never had any problems or slowdowns of either one. On my laptop, I have both and both are enabled at all times - no problems, ever. At work, just two rooms over from mine, people code Bluetooth code every day with several Bluetooth devices, some of which are experimental. The same office space has a WLAN network and nobody ever complains about interference.. *shrug*
  • power issues (Score:3, Interesting)

    by OpenMind(tm) ( 129095 ) on Wednesday May 08, 2002 @01:45PM (#3486041)
    It seems unlikely to me that these things will be all that catastrophic in their effects. To be power-efficeint light sources, each bulb will have limited power with which to generate interference. To be power-efficient enough to make a difference in this market, this technology should probably consume <10 watts for the equivalent of a 60-watt light bulb. Considering that most of that energy will be going into visible light, it can't be a very strong signal source. Even in large installations like gas stations, where many such small sources would exist, the effect should fall off quickly. Don't use them in your home, and your wireless LAN should be safe.

    The reason the satelite radio providers are running scared is that these things are mainly slated for use in street lights. Since cars tend to drive under street lights, and car users are the big market for satelite radio, someone's business model will have to give. Even small intereference feilds can be a big problem if they interupt your line of sight, particularly with high frequencies.
    • To be power-efficeint light sources, each bulb will have limited power with which to generate interference.

      You are completely missing the energy scale. A gas station using these for exterior lighting would probably run a few hundred watts. 1% of a few hundred watts is a few watts. Communication devices are measured in milli-watts. It's kind of like looking for stars during the day.

      -
  • by Spazmania ( 174582 ) on Wednesday May 08, 2002 @01:56PM (#3486104) Homepage
    The article is rather light on details about how exactly the lights are going to interfere.

    2.4ghz is special in that its the resonance frequency of the water molecule. That's why microwave ovens operate at that frequency: vibration = heat.

    So how exactly are these folks going to sell a product which emits high wattages at that frequency? Sitting under one would be like sticking your head in a microwave.

    Answer: They're not stupid enough to sell a product that is like sticking your head in a microwave. Some critical facts are missing here.

    The wireless stuff isn't particularly dangerous since its emitting at such a low power: well under 1 watt where the typical microwave emits at up to 1000 watts. And the spread spectrum technology does a good enough job of ignoring noise that the technology works despite the leakage from those ovens. If the wireless stuff does OK in the presence of leakage from 1000 watt Microwave Ovens, it'll do fine in the presence of other safe 2.4ghz devices.
  • One thing that strikes me about all of this is that places that install high efficiency lighting are probably companies of various kinds. These same places will generally also purchase things like wireless networks (802.11b is all over the place now from gas stations to big companies). If a company finds that their new lighting system will disrupt day to day business, I doubt they'll invest and this will be bad news for Fusion Lighting since 802.11b was there first.
  • Perhaps someone could answer a question for me that I've always wondered about.

    Exactly WHY are devices, such as the 2.4 GHz Part 15 devices mentioned in the article, required to accept all interference? What is gained by not allowing products to be [shielded] from unwanted interference/RF signals?
  • I've been wondering about this for a while. Why is that people seem to be so unconcerned about frequencies that operate in their microwave to cook food, but are perfectly willing to put handsets that operate at similar frequencies right next to their head, or laptops that use Wi-Fi in their laps? I know it is based off of different power outputs, but still some of these we use for hours at a time. It hardly seems safe.

    Now lights with a potential solution being offered of going up to the 5 GHz spectrum for communication devices.

    Amateur radio operators I plead with you (since I am one, but am not active enough to remember some of this stuff) to provide info on use of various handsets at high frequencies next to your head.
    • Why is that people seem to be so unconcerned about frequencies that operate in their microwave to cook food, but are perfectly willing to put handsets that operate at similar frequencies right next to their head, or laptops that use Wi-Fi in their laps?

      I think there's a typo there somewhere, but I can't figure out exactly where.

      Microwaves cook food. My head is not food. So why should I think that microwaves will cook my head?

      • I'm sure there's a typo. ;)

        You head may not be food, but as far as a microwave is concerned... if you put your head in one, it would cook just like food. It's that whole contains water thing.
    • I'm not an RF expert, but I'll tell you why I personally don't worry. The 2.4GHz band was set aside as an ISM band precisely because it is very well absorbed by water. Which is how a microwave oven works. The several hundred watts of microwaves emitted inside of the oven will bounce off the metal walls until they get absorbed by something. Usually this is your food. Or more accurately, the water in the food. Which is why it heats it up so well.

      You don't want to be around the output of a microwave oven for precisely the same reason you don't want to stick your hand on the stove when it's on. You'll get burnt, plain and simple. With microwaves, you could actually get burnt on the inside. Most internal organs don't like extra heat. Witness how little of a fever you have to have before it becomes life threatening.

      Now, back to wireless devices. The power output of your typical 802.11b device is between 30mW and 100mW. A typical microwave oven will produce up to 1000W of power. 10,000 times the power of your wireless card. Can the output of your wireless card or phone heat up your head? Of course. Will it heat it up enough to matter? Not likely.
  • by leighklotz ( 192300 ) on Wednesday May 08, 2002 @03:07PM (#3486587) Homepage

    When I was a kid, I had a set of encyclopedias of the sort that were parodied in Science Made Stupid [oz.net] a wonderful book [amazon.com] if you don't have it.

    Anyway, one illustration that stuck with me was a drawing of a man at home at a desk, reading a book. In the background are baseboard radiators with little squiggly lines coming out of them. The caption reads "In the future we will save energy in home heating by using microwave radiation to heat, people but not the furniture." This article on microwave lighting reminds me a little of that picture.

  • by Picass0 ( 147474 ) on Wednesday May 08, 2002 @04:05PM (#3486959) Homepage Journal
    Ah Yes! Another loving spoonful of alarmist hype! One company has a technology that conflicts with Wi-Fi and I'm to believe that companies with a vested interest in wireless are going to let this happen!

    Wolf! Wolf!
  • Things that transmit in the 2.4Ghz ISM band have to follow the rules. It may be unlicensed, but it's not without rules.

    Power levels would have to be within tolerance, as would stray EMI from the units, as would a lot of other things.

  • I don't really think this is going to take off. We already have tons of diffrent ways to emit light. I doubt the cost diffrential of these lights would really be less then the loss from not being able to use 2.4ghz devices.

    I mean it's not like everyone is going to go out and get rid of their old lights.
  • Evidence? (Score:2, Insightful)

    by dmiller ( 581 )
    I don't see any evidence of why this would be so catastrophic. I can't imagine why a lighting system would be using anything but a narrowband transmission, whereas all the communication technologies use spread-spectrum techniques to avoid exactly this type of narrowband interference.

    Secondly, the RF lighting seems to be targetted at industrial applications (e.g. lighting warehouses and factory floors) without the need to run cables - *exactly* the same market for RF comms technologies and for exactly the same reasons. The RF lighting people are the new entrant, so if *they* don't interoperate then they'll be the one seeking chapter 11 :)
  • ...but what about the effects of the RF lights?

    What happens when a nearby gas station installs RF lighting... and all 802.11b devices and 2.4 GHz cordless phones for a mile in diameter stop working?

    Is this total FUD or is it grounded in facts about these lights? Personally I don't like the idea of RF lights that would interfere for miles. I woudl think they'd need suficiently more power to make light than a cel phone or 802.11 card ( > 4W?). A previous post mentioned that 2.4GHz is the resonant frequency of water. There is some water in gasoline. Sooooo.....gas stations are going to begin randomly exploding?

    If my microwave doesn't kill my cel phone connection, it must be shielded prety damn good (it's a big ass 1500W). How come they can't just shield the lights and eliminate the problem?
  • They've done it again: "New Lightning Technology to Wipe Out Wi-Fi Access". Well, no shit. Lightning will wipe out pretty much every computer component it touches.

    Focus, focus.....oooohhhhh, lighting.
  • I've heard this before. This was going to put us all out of business when I was at Metricom in '96.

Remember the good old days, when CPU was singular?

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