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Old Geek Invents New Stick 262

Posted by michael
from the can-you-hear-me-now? dept.
the morgawr writes "According to the EE Times and Science Blog, a scientist at University of Rhode Island has developed a new type of antenna design that, by increasing the efficiency, performs as well as the convential quarter-wave design but is only 1/3 as large."
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Old Geek Invents New Stick

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  • Very promising! (Score:5, Interesting)

    by erick99 (743982) * <homerun@gmail.com> on Friday June 11, 2004 @08:52AM (#9396671)
    From the article:

    To check his theory, Vincent analyzed and compared the current profiles, output power and a score of other standard tests for measuring antenna performance. All measurements were in reference to comparative measurements made on a quarter-wave vertical antenna for the same frequency, on the same ground system and same power input. "I was able to increase the current profile of the antenna over a quarter-wave by as much as two to 2.5 times," said Vincent.

    As a ham (amateur radio operator) this sounds like a very exciting development. I would like to see more "real life" testing in a variety of settings. Still, the idea of an antenna that can be reduced in size by that much (2/3) comes in very handy on the low bands where it's not uncommon to use several hundred feet of wire (Usually into a tuner).

    Happy Trails!

    Erick

    • Re:Very promising! (Score:5, Interesting)

      by ejdmoo (193585) on Friday June 11, 2004 @08:57AM (#9396706)
      As a user of all things gadgety and all things wireless, I can't wait to have this on my cell phone ! It could improve battery life or reception (depending on how it's calibrated).

      However, this brings up a question...is this a design that scales to something as small as a cell phone?
      • Re:Very promising! (Score:5, Interesting)

        by josecanuc (91) on Friday June 11, 2004 @09:03AM (#9396757) Homepage Journal
        The great thing about antenna design and RF theory is that all of the design happens in the mathematics domain, so all designs are infinitely scaleable. The only hitch may be in manufacturing, since small designs can be affected by molecular structure (or at least moreso than larger designs...)

        The articles did mention that it could be used in the frequency bands that cell phones use, so you're in luck!

        And actually, it would improve BOTH battery life and reception, since receiving a signal doesn't require any more or less power based on the antenna or incoming signal strength (excepting preamps). All other things being equal, if you decrease the transmit power, increase the antenna gain (which gives a gain for both receive and transmit), then you use less power overall, but can output an equivalent signal.

        Improved reception is an unrelated (to power consumption) bonus.
        • Re:Very promising! (Score:2, Interesting)

          by Short Circuit (52384)
          I'm not sure how the system is normally supposed to work, but you might want to be careful of cell towers fighting over a given phone.

          At my parents' house, Verizon phones get zero coverage, despite three towers being within range.
          • by bsd4me (759597)

            With most cell phones, especially CDMA, power is very carefully controlled. I seriously doubt that an increase in antenna efficiency would cause problems with current installations. Basically, the phone would just input less power to the output PA and get the same EIRP. On the receiving end, it would just look like a better connection. Cell phones already know how to deal woth signals from multiple basestations.

          • Re:Very promising! (Score:3, Informative)

            by dubious9 (580994)
            It is more likely that your deadspot is the result of those towers not being Verizon or of multipath scattering, in which the surrounding environment causes the cell signal to interfere with itself. Modern cell placement is very careful, and the hw/sw used there is almost positively able to overcome "fighting" over a given phone.

            Adjacet base towers use different frequencies to resolve exactly this kind of problem. The cell phone should be able to pick which one is best.
        • Actually from what the article says power usage would actually be limited by the antenna, whn he cranked up the power on his to full power he melted it.
          of course we'll probably see a few cell phone designers screw up and over power the antenna and melt the phone into someones head.
          • Re:Very promising! (Score:3, Informative)

            by Theaetetus (590071)
            Actually from what the article says power usage would actually be limited by the antenna, whn he cranked up the power on his to full power he melted it.

            Article also says that that antenna was of a limited-power design (maybe he used cheap and small 28-gauge wire, or something?) In any case, it says he refined his design after that.

            -T

        • Actually there will be little gain for most modern cellphones since basically none of them use a tradition whip antenna. In fact some have no aparant antenna because they use a fractal antenna built into the PCB of the controll board!
      • > I can't wait to have this on my cell phone ! It could improve
        > battery life or reception (depending on how it's calibrated).

        I didn't check in detail, but the article talks about antenna SIZE,
        not power efficiency. That is, your cellphone might be smaller but
        still have the same battery life.

        Also, cell phones usually work with smaller than 1/4 lambda
        antennas anyways. Here is an example:

        http://www.ee.kent.ac.uk/research/resproject.as p ?p roject=75
    • I would be interested to know how is this different from commerically available "helix" antenna.

      I've being told the reason that the Navman GPS [navman.com] uses a helix antenna for their clip-on iPaq GPS. I have seen their engineer disassmbled one unit a while ago (2-3 yrs). The antenna is like a few wires glued on a piece of flexble plastic sheet. The sheet is rolled up to form a helix before placing into the enclosure.
    • For smaller gadgets, couldn't this mean an extra boost to battery life beyond the obvious? After all, if you have a small antenna which is more effecient, doesn't this mean less power has to be spent on things like amplifiers and noise filters? Granted, I'm sure you'll still need to filter, but with a better signal, doesn't that mean less filtering because of a better signal. Likewise, less amplifaction required because you can pull in a stronger, better signal?
  • by BlueCodeWarrior (638065) <steevk@gmail.com> on Friday June 11, 2004 @08:52AM (#9396674) Homepage
    Can it be adjusted to fit on top of my tinfoil hat?
    • by Anonymous Coward on Friday June 11, 2004 @08:57AM (#9396713)
      Yes, but you'd look like a Teletubby...
    • Re:Ahh yes, but.... (Score:3, Informative)

      by demachina (71715)
      Here [af.mil] is a cool antenna which wont fit on top of your tinfoil hat but you will want to be wearing a tin foil hat or actually a full body suit if you encounter one.

      Its the U.S. military's latest Active Denial System developed by Raytheon scheduled to start trials this fall. Its a millimeter wave beam weapon designed for non lethal crowd "control". Volunteers at Raytheon subjected to it described it as "unbearably painful, saying they felt as though their bodies were on fire". It should put an end to any u

  • by Anonymous Coward on Friday June 11, 2004 @08:55AM (#9396690)
    "performs as well as the convential quarter-wave design but is only 1/3 as large"

    Behold! I give you the twelfth-wave design!!
  • Genetic Algorithm (Score:4, Interesting)

    by dustmote (572761) <fleck55&hotmail,com> on Friday June 11, 2004 @08:57AM (#9396698) Homepage Journal
    How does it compare against that bizarre antenna developed by genetic algorithms that we saw a story on a few months ago? Or am I comparing apples and oranges here?
  • Will we see this at (Score:5, Interesting)

    by Allen Zadr (767458) * <<moc.liamg> <ta> <rdaZ.nellA>> on Friday June 11, 2004 @08:57AM (#9396700) Journal
    Will we see this at next year's WiFi Shootout [wifi-shootout.com]?
  • Heh (Score:3, Funny)

    by xSquaredAdmin (725927) on Friday June 11, 2004 @08:57AM (#9396704)
    Once again, it's been proven that it's not how big it is, but how well you use it.
  • this is patents at their best: the little guy innovates, and becomes the not-so-little guy in reward

    that should be the purpose of patents, to protect the little guy who innovates

    let us hope that we can back to this world, a world where patents reward innovation, instead of suppress it

    it is a delicate balance, but there are hordes of ip lawyers and corporate whores out there who are hard at work, having sold their conscience, hard at work warping the balance in the direction of those who don't deserve to be rewarded for suppressing true innovation like this
    • by AndroidCat (229562) on Friday June 11, 2004 @09:03AM (#9396752) Homepage
      Hopefully it is innovative. A lot of people have played around with antennas over the years, especially amateurs trying to fit a big antenna in a small space. I'd be surprised if no one has tried something close to it.

      So let's hope it's not just a tweak of something that was in QST magazine thirty years ago.

      • by AliasTheRoot (171859) on Friday June 11, 2004 @09:12AM (#9396812)
        I just hope he hasn't taken a 30 foot antenna and bent it every 12 inches then wrapped ductape around it.
      • So let's hope it's not just a tweak of something that was in QST magazine thirty years ago.

        Then he patents the tweak because that's what made an idea that didn't work (nobody is using it) to an idea that did work.

        My father was issued the third patent on variable pitch propellers. The key difference between his design and the first two designs was his worked and the first two didn't.

      • Prior Art? (Score:2, Informative)

        by AndroidCat (229562)
        I'm sure that there must be something close to his design on the ARRL site. [arrl.org] After mulling it over coffee, I thought of the endless "hide your loaded helix antenna as a flagpole!" QST articles over the years. (Yeah, most flagpoles have coax cable running to the house. No one will suspect a thing!) D'oh, most of the articles are members only.
      • My thoughts exactly. What the article failed to mention was that an antenna can have any size, it's all a matter of tuning. At a quarter wave, it's intrinsically tuned and any straight wire will do. For different lenghts, one needs inductors and/or capacitors to tune it. From the description there, I think what he did was to design some sort of helicoidal antenna. It might be a new design in some details, but hardly revolutionary, helicoidal antennas have existed for decades.
    • ... and the patent will benefit the university he was working at.

      Yet another patent for an anonymous patent portfolio to be used by lawyers as bargaining chips.

      Hurrah!
    • Unfortunately, it would seem that in a world such as this, with patent law combined with large corporations with deep pockets, "the little guy who innovates" never stands a chance. Look at what happened to Philo Farnsworth. RCA broke him in spite of his patents on televison, and he died bitter and unrecognized for his innovation. It was only decades after his death that his role was properly recognized. The situation is far worse now than it was in Farnsworth's day. It will only be a matter of time before t

  • by bobba22 (566693) on Friday June 11, 2004 @08:58AM (#9396719) Journal
    "With the new helix design, Vincent has built a prototype 7-GHz antenna that he claims is indistinguishable from a quarter-wave antenna in all but its size. "Because the new design is completely planar, we could crank these out using thin-film technologies," Vincent said." Sounds like the answer to radio -powered smart cards ios just around the corner?
  • by AliasTheRoot (171859) on Friday June 11, 2004 @08:59AM (#9396727)
    All i could see is that it is a 2-dimensional helix, so it's likely to be directional, if radio waves aren't hitting it on the perpendicular they will miss.

    The other thing I saw was that you tuned the antenna for a frequency with components - does this mean potentiometers or does it mean scrapping it and buying another 2d helix tuned to the specific wavelenghth?
  • Just imagine... (Score:2, Interesting)

    by wolf31o2 (778801)
    ...being able to pick up radio from Atlanta while in Charlotte. Then again, knowing how the electronics industry is, we would instead get smaller antennae that get the same reception, versus same-sized antennae with greater reception.

    I still wouldn't mind seeing these in cars. My only question is if this can work with cars tha have "in windshield" antennae, such as mine.

    • Yes, but that's assuming that the source signal actually reaches your destination antenna. Having an antenna of the same size but better reception might allow you to better pickup existing signals, but radio signals also have a falloff point (different for AM/FM) and penetration ratio.

      I don't know about Atlanta radio, but the signal itself still have to reach Charlotte well enough for the antenna. Also, for an in-windshield antenna, you could probably just get a portable antenna and re-route the hookup fr
  • by Punchinello (303093) * on Friday June 11, 2004 @09:01AM (#9396737)
    And those 300-foot tall antennas for the 900-KHz AM band that dominate skylines would have to be only 80 feet high, with no compromise in performance, using Vincent's design, he said.

    Hmmm... I am no expert, but I thought those AM towers were tall so the antenna could be placed at the highest possible altitude. The radio transmitters in the Philadelphia, PA area are also located in the highest place in the region geographically.

    I think the actual antenna is attached to the top of the tower. It's not the entire tower. Can someone help me out here?

    • Many old AM transmitter stations used the whole tower as the antenna, simply because the wavelength at such low frequencies was so long it would be impractical to stick a 200 ft. antenna on top of a 200 ft. tower.

      They just load the tower at the base and the whole thing radiates!
      • Many old AM transmitter stations used the whole tower as the antenna, simply because the wavelength at such low frequencies was so long it would be impractical to stick a 200 ft. antenna on top of a 200 ft. tower.

        Um, all AM transmitter stations use the whole tower as the antenna. Actually, they also use the ground as the antenna, too - half the radiator is above ground, and the ground plane acts as the other half of the radiator. And since you need a good ground plane, a 200' antenna on top of a 200' towe

    • by ONOIML8 (23262) on Friday June 11, 2004 @09:10AM (#9396794) Homepage
      No, you're thinking of the VHF FM band...that is exactly the case there.

      On the AM radio band the tower IS the antenna. What you see sticking up in the air is usually insulated from ground right at the base, the part you see is actually hot. Therefore the tower itself radiates and is engineered to be a certain height as part of antenna design.

    • by Air-conditioned cowh (552882) on Friday June 11, 2004 @09:13AM (#9396818)
      "I think the actual antenna is attached to the top of the tower. It's not the entire tower. Can someone help me out here?"

      Long (LF) and medium wave (MF) antennas usually are the entire tower because of the low wavelength. For VHF (e.g. FM radio) and TV the antenna is much shorter so it is at the top of the tower.

      One way to tell if it is not obvious is to look at the steel support ropes. If they are broken along their length with insulators then it is probably a long wave or medium wave antenna. The steel rope is broken in this way to prevent the wire being long enough to become a significant and undesireable part of the antenna.
      • by W2IRT (679526) <pjd@panix.com> on Friday June 11, 2004 @09:42AM (#9397008) Homepage
        One way to tell if it is not obvious is to look at the steel support ropes. If they are broken along their length with insulators then it is probably a long wave or medium wave antenna. The steel rope is broken in this way to prevent the wire being long enough to become a significant and undesireable part of the antenna.

        An even easier way to tell is look where it's installed and how many towers there are.

        "AM" radio (actually, MF broadcast) transmitter sites are almost exclusively found in low, wet, marshy land in order to maximize their groundwave coverage and to get a good counterpoise (RF ground).

        Not just that, but many "AM" transmitter sites -- though certainly not all, however -- encompass a number of similar towers in an array, not just one or two. This is done in order to direct their signals in certain directions and to null out their signals in other directions (since MW broadcast signals carry over somewhat great distances after dark).

        VHF Broadcast ("FM") and television trnasmitters, on the other hand, are located on high towers on the highest ground available. VHF and UHF are line of sight, hence the higher the better.

        As previous posters have stated, "AM" transmitting antennae are the towers themselves. Using the equation 468/f (MHz), a quarter wavelength for 1000 kHz is 468 feet high! VHF antennae, on the other hand, are MUCH shorter and are mounted atop supporting towers.

    • by div_2n (525075) on Friday June 11, 2004 @09:27AM (#9396891)
      As others have noted, the tower is the antenna. The output line coming from an AM transmitter is fixed directly to the tower. Usually this is not fixed at ground level to avoid killing a passerby. RF waves WILL arc and kill. Also, if you are feeling especially depressed and want to cause yourself bodily harm, walk up to a hot AM tower barefoot and grab it.

      As it says in the article, wet (and salty which I didn't know) ground is best for transmission. AM towers are often set in a group of three and set in low lying wetlands (near water especially). If you look closely, you will see that the only thing perched on top would be the strobes (if applicable).
      • AM towers are often set in a group of three and set in low lying wetlands (near water especially).

        Just to add... since the entire tower is the radiator at AM frequencies, the multiple towers are used for directionality... just like in VHF and UHF (and cell) frequencies, multiple antennae are usually mounted on the towers (though it's tough to see individual antennas since they're usually placed either 1/4-wave or 1/2-wavelength apart... in VHF that would be about 6-10 feet).

        So anyways, several AM towers in a straight line (like WEEI, 4 towers south of Boston, or many others - there's a 6-tower set just west of NYC) yield a sort of figure-8 pattern, with the lobes pointed in the same direction as the line of towers... usually an easy way to tell the direction to the nearest big city. There are also directional patterns that aren't so easy, like one of my sites, WRNI in Rhode Island, which has 4 towers, set in a sort of Y shape. 3 are used during the day for one pattern, and one of them turns off and a different one turns on a night for a different pattern.

        -T

      • by Phrogman (80473) on Friday June 11, 2004 @01:50PM (#9400008) Homepage
        "As others have noted, the tower is the antenna. The output line coming from an AM transmitter is fixed directly to the tower. Usually this is not fixed at ground level to avoid killing a passerby. RF waves WILL arc and kill. Also, if you are feeling especially depressed and want to cause yourself bodily harm, walk up to a hot AM tower barefoot and grab it."

        When I was in the Canadian Military I was a Radio Operator. We had a standard practice of informing the operator not to key the antenna when changing the HF antenna on the top of the truck - usually in fact the person doing so went in and physically checked the antenna was disconnected at the set end. Then you went on the roof and unscrewed the antenna and screwed in the new one. If someone forgot the middle step - and the operator keyed the antenna - you would see the person touching it get lobbed a good 10-15 feet off the top of the truck by the shock and it might or might not kill them or at least severely injure them. Only saw this happen once, and the guy wasn't hurt, he got up and was ok in a few seconds - although the operator was hurt shortly thereafter :)

        10,000 watts is not a good thing to run through the body...

    • I'm no expert either, but I don't think 80 is a third of 300.
    • No, in then usual cases, the whole tower is the antenna. This is because at the am band, wavelengths are in fact quite long.

      Also, as much as possible is usually done to reduce the skywave portion of the radiation and confine it to the ground wave that goes out toward the horizon as oppose to shooting off into the sky, to either go forever in the daytime, or to be reflected back many hundreds of miles away by the changes in the night sky ionization layers, and wrecking havoc with another local station also
    • Keep in mind that lots of radio is line of sight so, higher means better sight in hilly areas, not forgetting that tall buildings can also cause problems. Thusly, I can't imagine tall towers going anywhere anytime soon.
  • effect in the radio industry, where finding areas to put antennas is difficult due to population density, FAA regulations, etc. A more compact unit could be placed on taller buildings, essentially broadening the area that the signal could reach in urban areas.
  • by wowbagger (69688) on Friday June 11, 2004 @09:03AM (#9396755) Homepage Journal
    I wish the linked article had shown some VSWR plots of the antenna vs. conventional designs - I'm betting this antenna has a very narrow bandwidth.

    There are several parameters for an antenna system (receive parameters in parens):
    1. VSWR bandwidth - this is the range of frequencies over which the antenna will correctly accept the signals, rather than reflecting them to the transmitter (in receive, the range of frequencies the antenna will properly couple to the receiver.). For a fixed-frequency system (like a radio station) this is less of a concern, for a frequency agile system like a cell phone this becomes more of a concern - if some of the cell channels are out of the bandwidth of the system operation will suffer.
    2. "Gain" of the antenna - technically no antenna can radiate more power than it receives from the transmitter (deliver more power than is available in the environment). However, if you are talking to a system "over there", any signals not going over there are wasted - thus an antenna that focuses the signal in the desired direction provides gain. The article implies a gain consistent with a dipole, but there are other antenna designs that provide even more gain than that.
    3. Radiation angle - this is the set of directions from which the RF will radiate from the antenna (be accepted by the antenna), and is linked to the gain of the antenna. For example, a phone should have a radiation angle as close to 0 degrees (toward the horizon) as possible - signals radiated at, say, 45 degrees are unlikely to hit a tower and are just being radiated into space.


    Most compact designs trade bandwidth for performance - the work well at f=NNN.N MHz, but not well at f=NNN.N + .yy MHz.

    This gets to be REALLY important for wide band systems like CDMA and UWB.
    • Yeah....

      However, for a cut antenna this would be great. Given the antenna's I lug around when doing spot checks or trying to determine if a given tower is in an acceptable range... I really wouldn't mind this design so much.

      I'm surprised someone hasn't said they want a beowolf cluster of these.

      Me... I just want a cut quad of these.
    • Supposedly, he didn't sacrifice bandwidth to get the smaller size - in fact, that's a central point of the article: he's apparently found an answer to the "bandwidth, size, efficiency, pick two" problem.
      • Show me the plots (Score:3, Informative)

        by wowbagger (69688)
        Again, I'd like to see the plots. Extraordinary claims require extraordinary proof, and three simple plots - VSWR/freq, radiation pattern in XY, radiation pattern in YZ - would go a long way to answering my questions.
    • The aricle specifically states that it has high bandwidth.

      It is nice to see people questioning basic assumptions. When I was in university, we were told that there was a hard limit on the amount of data that could be transferred over a standard phone line -- that was 1200 baud, hence 1200 bits/second.

      Antenna design has had basic assumptions about it for years. It is only when you start to question those assumptions that you move forward.

      de VE9MKS
      • It is only when you start to question those assumptions that you move forward.

        That only works when you question those assumptions intelligently. Let me give an example. By the 1920's it was well known that noise power was proportional to bandwidth. Progress in radio reception quite naturally followed the path of narrowing bandwidth (from early spark-gap systems that had poor selectivity and on to elaborate tuned LC circuits). Armstrong, when developing FM, wasted years trying to get good signal-to-noi

    • I'm betting this antenna has a very narrow bandwidth

      My thoughts exactly. The trade-off you mention was proven from Maxwell's equations in 1947, when everyone's interest was in making small vehicle-mount antennas in the HF bands. (The proof, though, makes some assumptions about ground planes & such.) I can't remember the reference, but I think it was published in the Proceedings of the IRE.

      Applying techniques like these (fractal antennas, frequency selective surfaces, artificial magnetic conducto

  • by mobiux (118006) on Friday June 11, 2004 @09:04AM (#9396759)
    That the University of Rhode Island and the Physics dept were made beneficiaries of the patent.

    I can see this generating alot of revenue, and people (corporations) that may try to rip this off.
    At least they will have a vested interest in fighting for the patent.
  • I'd love to see a picture of this as I don't know much about antennae.

  • He found that by using those pringles mini cans, he could get similar reception to that of a regular-sized pringles can.

    He expects to get a 10x power boost from metal chewing gum wrappers, and 50x from a microwaved AOL CD!
    • It's been scientifically proven that for this to work you also need 30 metres of string attached to either end, and just everso slightly under 30 metres of distance between the transmitter and receiver.

      Communications engineers call this the Knot principle.
  • by Jrod5000 at RPI (229934) on Friday June 11, 2004 @09:07AM (#9396773)
    c'mon, i don't care what you say... if it's 1/3 as large no woman on earth would believe it performs as well! :p
  • Fractal antennas (Score:4, Informative)

    by rutger21 (132630) on Friday June 11, 2004 @09:08AM (#9396784)
    Well, nice, but is it better than fractal antennas [fractenna.com], i.e. Sierpinski [ucla.edu] antennas?
  • by Insurgent2 (615836) on Friday June 11, 2004 @09:12AM (#9396810)
    I was just reading about something like this just last night.
    I'll bet it ends up working on the same principle that Bill Beatty [amasci.com] is talking about when he got to thinking about why it is that an atom can absorb light so readily even though the size of the atom is such a small fraction of the wavelength.
    Relevent articles:
    Energy sucking antenna [amasci.com]
    On the Possibility That Electromagnetic Radiation Lacks Quanta of Any Kind [amasci.com]
    Nearfield coupling and tuned circuits [amasci.com]
  • For Rural Areas... (Score:3, Interesting)

    by StacyWebb (780561) on Friday June 11, 2004 @09:13AM (#9396820) Homepage
    ..this will be great, living in the stix has it's advantages and disadvantages (disadv-no cable broadband , adv - can see the stars at night) Disadv -Having to rely soley on Direcway for broadband. This will open the doors also to companies wishing to move to the rural areas.
  • IBM, Cisco, Microsoft or any other tech company can steal this patent by filing something akin to the following.

    "A Method for reducing the size of radio antennae by a quarter using new design UNDER THE CONTROL OF A SOFTWARE DRIVEN DEVICE."

    Remember, even if someone else has patented,invented,used,implemented,sold,issued,tho ugh and/or showed it to you first, if you jack it up to a computer, then you've got a patent pal! Now no one can connect a computer to this device without giving you money! Yippie!!

    Welcome to the US patent Office. Where dreams CAN come true!
  • Ham response (Score:5, Informative)

    by tetranz (446973) on Friday June 11, 2004 @09:18AM (#9396842)
    I wish them well but FWIW, it got a skeptical response on this popular ham site qrz.com [qrz.com]
    • I wish them well but FWIW, it got a skeptical response on this popular ham site

      I'd wait for more details. Hams, like slashdotters, are long on opinions but frequently short on actual knowledge.

      "The article is a bit short on detail, it seems very unlikely that an antenna only 18" high is going to perform as well on 15 meters as claimed." - i.e. "it can't work because its never worked before"

      -T

    • Re:Ham response (Score:5, Insightful)

      by Lumpy (12016) on Friday June 11, 2004 @10:24AM (#9397385) Homepage
      that is because it goes agains all antenna and RF theory.

      Granted, I have seen antennas that defy logic until you really understand how they are working.... the Discone antenna for example... but this one still is baffling and the lack of details increases the skeptical thoughts... no explination at ALL on how it works, no theory explained other than "i did this... no you cant look at it!" responses...
      • Granted, I have seen antennas that defy logic until you really understand how they are working.... the Discone antenna for example... but this one still is baffling and the lack of details increases the skeptical thoughts.

        It sounds like a cross between a capacitive hat and a rubber-ducky style helix.

        A capacitive hat lets you expose the lower part of the 1/4 wave half-dipole (where most of the current is) then cut off the end. The remaining current goes into the capacitive hat and doesn't contribute to t
    • Re:Ham response (Score:3, Interesting)

      by Cthefuture (665326)
      Yeah, as a ham myself I have to agree with the "snake oil" theory.

      Antenna design is a lot like cryptographic algorithm design. That is, a lot of extremely smart people have tried and failed. Often once their work is out in the public for a larger community to examine the flaws start to show through.

      Like crypto design, antenna design is mathematically provable. However, it's complicated enough that it's damn near impossible for one person to cover all the bases and make something that really meets all t
      • Unfortunately, we often confuse physical laws and longstanding assumptions. Sometimes it is one of those over-the-shoulder questioners who can tell the difference.

        This could well be snake-oil. Anyone recall the CB craze of the '70s and the antennas that were sold to the gullible?

        Hams will certainly question, but if there is validity in the design, you can bet that it will be improved and made functional. The only despicable response is to say "It is impossible, and I don't want to hear another word abo
  • by PMuse (320639) on Friday June 11, 2004 @09:28AM (#9396902)
    Smaller is nice, but if we build a cell phone with a DLM the same size as the antennas in current models, can we get 3 times the reception?
    • Actually no. The size of the antenna correlates with the frequency. A three times larger antenna would work well on signals three times the original wavelenght. You need gain for better reception.
  • by pa3gvr (548273) on Friday June 11, 2004 @09:37AM (#9396959) Homepage
    Although the articles are a bit thin on specs my gut instinct tells me it will be similar or an improvement the EH antenna. Link to definition (pdf) of EH antenna [eh-antenna.com] Link to (pdf) how to build an EH antenna. [eh-antenna.com]

    I hope that despite of the patents the design will be made available for amateurs to use and experiment with.

    These kind of innovations just show that Amateur Radio is still alive and can contribute in the advancement of radio.

    Amateur Radio also still works for emergencies [arrl.org].

    73 de Sjaak, W4RIS ex-PA3GVR
  • not possible (Score:5, Interesting)

    by pcmanjon (735165) on Friday June 11, 2004 @09:39AM (#9396976)
    Hmmmm.. a 'ham' making new antenna discoveries...sounds familiar:-)

    It is not physically possible to attain a moderate Q or low Q, thin monopole --antenna-- which is 15-18 inches on 21 MHz and is efficient. This is not a statement against K1DFT, or anyone else. It is a statement of fact, based on the physics of very electrically small antennas, and many years professionally devoted to pursuing such issues. K1DFT has apparently pursued a path long since traveled by many others, and not only myself.

    Occasionally, in some form factors, it is possible to trade efficiency for gain, but this is too short for that. And so much for bandwidth.

    Great care needs to be taken to remove multipath effects in the measurement of gain, and greater care needs to be taken in equating measured comparitive gain with actual antenna efficiency. Based on this anecdotal report, there is no evidence presented that such issues could be removed in the measurements.

    Radiation resistance results from an antenna's sampling portions of radiating waves. A short antenna samples a small portion of the wave--and not from the peak, unless the electrical length is 1/4 to 1/2 the wave or more. Multiple current maxima do help increase radiation resistance. Efficiency is derived from the ratio of this radiation resistance to the total resistance--which includes ohmic losses. Distributed discrete loads are moderately lossy, and one would require load Q-factors of 1000 or more to attain even moderate Q antennas with high efficiency.

    The optimization of distributed loads in monopoles is an old technology, recently aided via genetic algorithms. I recall, for example, some good work on this approach published in 1996 by Boas et al. Before that, R.C. Hansen made fundamental efforts into such understanding, as well as others. MATLAB is also a poor tool for this, because it is difficult to assess losses properly.

    Another concern is: what is radiating? In some cases, ground planes (counterpoises) do, indeed, radiate in the far field and are thus part of the antenna. The monopole 'antenna' is often a loading mechanism in this case, and contributes little to the radiation. There are commercially used 'antennas' that are 1/10 th the height of a 1/4 wave or less; are broad/multiband/ and so on. This is not new. They are used in wireless LAN; RFID; and cell phones; and many other places.

    Many here are aware of my efforts in fractal antenna technology--which started in a similar radio amateur vein. Although I applaude continued efforts into antenna experimentation through ham radio, I must confess that my educated opinion is that nothing new has, or will be, attained by such efforts. The state of the art is often not public, and far outstrips what is commonly available in, for example, amateur radio publications. I would enjoy being wrong, however. In fact, I'd get a great kick out of it.

    It's sure fun to read about though, and experimenting is fun to do.
    • Re:not possible (Score:4, Informative)

      by pcmanjon (735165) on Friday June 11, 2004 @09:41AM (#9396996)
      It should be pointed out that the inventor mentioned in the news release is listed in the Unversity's directory as a "Technician". That is, he is not one of the Physics Department faculty. So I think it highly unlikely that any government funding is involved, or that it will be published. Looking at their website which lists their research programs, in fact, there is no mention of anything having to do with antennas. So in all likelihood this is a bootleg or personal effort, not an official University project. That is not necessarily mean it's bogus - I haven't seen the details myself - so I'm just pointing out that if it does turn out to be nonsense, we should not condemn the Physics department for it!

      I am a physicist myself, currently doing materials research for the Navy. From time to time throughout my career, I have been approached by "inventors" with various ideas. I always give these schemes due consideration because, as another poster mentioned, one should keep an "open mind". But mainly because, even if the idea as a whole is nonsense, there may be elements of it that worth something.

      There is a pattern. Almost all of the "inventions" that have been presented to me for evaluation and endorsement have made remarkable claims about "efficiency" approaching 100% -or in some cases exceeding 100%. This always turns out to be due to the inventor not recognizing and accounting for all the losses in the system, or making bad assumptions about efficiency being equal to some other factor (there are a few hams, for example, who mistakenly equate SWR with efficiency). There is another pattern to this sort of thing - that is, when I point out the error, they almost always accuse me of not having an "open mind" and I sometimes get a lecture from them about "paradigm shifts" or Einstein or Tesla and so on. etc. Then sometimes they proceed to harass me for months with minor variations of their idea. I always wonder why, if I don't have an "open mind" and am part of the entrenched establishment, why do they work so hard to try to get my endorsement!

      Some of these have been pretty interesting ideas that have taken up to a week to study. Some of have been utter nonsense. I was even approached once by someone who claimed to have found some "particles" left behind by aliens who had abducted him, and he wanted me to "analyze" them. Well, I did an analysis and identified it to be a chuncks of Hartz hamster food. But that's another story.

      I can't say whether the antenna inventor in this case might have approached someone in the physics department about this antenna, and if he did whether he was turned away, and if so, why.

      Just suggesting that (1) we should not condemn the idea outright until we get some first-hand information on what the guy actually claimed - press releases don't necessary mean anything, and (2) if it's nonsense, it is not necessarily reflective of the University's research quality.
  • While I'm not an antenna physicist, I've been a ham radio operator since 1958 and have built and used a LOT of antennae. I've discovered that there are trade-offs. I will be very interested to see how this pans out and hope that it is, indeed, a break-through.

    Here are some of the reasons for my skepticism. An antenna that is smaller will inherently intercept less of the signal when used for reception. It's called capture area. When used for transmission there are usually reductions in efficiency due to inc
    • In the professor's blog, he mentioned that when he increased power to 100 watts at 21 MHz, the antenna melted. That means that energy, instead of being radiated, was converted to heat, AKA lost efficiency.

      And for those people who like reading things in context:

      "After examining the molten matter, Vincent wasn't discouraged. This was only a small model and not designed to handle much power. The part of the antenna that failed proved to be the key to the design. After analyzing the failure, Vincent realize

      • Sorry if you felt that was out of context. I know from a lot of practical experience that adding "Loading" to antennas means adding inductance to compensate for reduced length. Adding inductance means adding coils which are inherently lossy, both resistively and dielectrically. The loss can be mitigated by using larger conductor and better dielectric materials as insulation, but there are obvious physical limitations to that and, in addition, the effect of increasing the "Q" reduces the useable bandwidth. F
        • I think there is some loss there - he mentions that the power output is the same, the size is drastically reduced, and the bandwidth is "good to excellent"... That says that the bandwidth is reduced, but maybe not as badly as previous trials have done. Also, since he's saying that the design is 80-100% as efficient as the 1/4 wave radiators, I see a somewhat higher VSWR, plus a somewhat tighter bandwidth as the trade off... Which means you probably won't want to use this on your 10kW AM torch, but you might
  • Patent Pending? (Score:2, Informative)

    by Cmdr TECO (579177)
    No, not another patent flamefest. Just that I wanted more details than the articles provide, but I can't seem to find the application [uspto.gov]. Anyone else wanna try?
    • Re:Patent Pending? (Score:3, Informative)

      by Compulawyer (318018)
      Nor will you find the application. If the time limit has not been reached, it has not been published. If he is not filing outside the US, he can opt-out of publication until the patent issues.
  • by Almost-Retired (637760) on Friday June 11, 2004 @10:03AM (#9397190)
    From the simplistic description given, this design has hundreds of thousands or prior art examples already sold in the marketplace, and has had for maybe 45 years.

    Most any CB'er that wasn't running a full 1/4 wave stick on the roof of his car, and getting it mangled by driving thru any overpass with less than 14 feet of clearance, was using a shortened antenna of this design. They were also a bit narrowband, having extreme difficulties in getting 1.3/1 or better vswr performance over the 40 channels of the cb band.

    They alsa radiate a disproportionate amount of their power well above the horizon, reducing the gain in the real world.

    New? Yeah, somewhat like me, I'll be 70 in a few months.

    I suspect that there are, or were (some having gone on to that big retirement party in the sky held for failed companies or merged into oblivion entities) plenty of patents that will prove prior art, if the patent office wasn't too understaffed and lazy to search for them. Avanti & HiGain are just 2 names that come to mind.

    Scuse me while I chuckle at yet another of the patent offices incompetant blunders.

    Cheers, Gene
  • This is all fine and dandy--
    but when are we going to be able to buy the fractal antennas [fractenna.com] we heard about a few years ago. They were supposed to be the bomb, and I wanted one for TV, but they don't seem to sell any consumer models. What up with that?
  • by AB3A (192265) on Friday June 11, 2004 @12:49PM (#9399116) Homepage Journal
    Groan. This is not as unique as most would have you think.

    First, most PCS phone antennas don't have to be shortened. The wavelength is such that it's not hard to get 1/4 wave across your typical portable phone. It's a mere 4.1 cm.

    Just so that most of you understand, a monopole antenna is really half of a folded dipole. It has a wire going up and then it goes back down the pole to a field of radials. It has a characteristic impedance of half what a folded dipole would be --about 150 ohms.

    In contrast, a normal quarter wave vertical has a characteristic impedance of about 37 ohms (assuming a very good radial system).

    Now, remember the part about heating up the antenna? The reason it happens with very short vertical antennas is because there is a current node right there at the base feedpoint. Even a small amount of resistance will generate heat. As you shorten the antenna the characteristic impedance drops. For anything less than a tenth of a wave long, it can drop to less than an ohm. At that point, ANY antenna resistance, even the normal resistance of copper or silver, becomes very relevant. If someone were to use a superconductor, it might make a very big difference.

    So a shortened vertical isn't such a good deal. We use them because sometimes that's all we can afford to install on a mobile system. This is why most hams who operate on longer wavelength bands try to locate the loading coil closer to the middle of the antenna. It gets the loading coil away from the worst of the current node, reducing i^2r losses, and increasing efficiency.

    Now, take the monopole: The current node is near the top of a quarter wave monopole, not the bottom. We still need a loading coil, however, so that we can match the impedance to something we'd expect a transmission line to have. If we shorten the monopole, we move the current node. The key is to move the current node away from the loading coil, because loading coils don't radiate well.

    Thus, what this designer has done is to distribute the loading coil of a shortened monopole so that he avoids the current node.

    There are problems, however. First, you still need an effective radial system. Without one, you simply won't have anything that radiates worth a damn. Second, while coil Q factor is less relevant where it stays away from the current node, it still has to be damned good. Further, the current node at the top needs to have very good surface conductivity.

    Finally, no matter what, a shortened vertical antenna will have a shortened bandwidth, proportional to how much the antenna itself is shorter than a regular 1/4 wave. TNSTAAFL.

    Don't misunderstand, a short antenna doesn't have to be inefficient. However efficiency is not the same thing as gain. Short antennas can not have much gain. That's a matter of physics and mathematics. And the shorter an efficient antenna gets, the less bandwidth it can cover. Despite the steady parade of publicists, that's the reality. Don't buy any snake oil, folks... This isn't really that novel.
  • by tiger99 (725715) on Friday June 11, 2004 @04:53PM (#9402024)
    .... like all other similar claims over the years. Even if a short antenna is resonated correctly, which is standard practice, and seems to be what is being claimed here, and if it reaches 100% efficiency, it is not as good as a long antenna, because both the bandwidth and the directional properties are necessarily inferior.

    The "gain" of an antenna comes purely from directional effects, in a transmitter, which is easier to understand, more of the radiation goes out near the horizontal, where it is useful, the apparent gain in receive mode is identical due to the reciprocity theorem. In any situation involving electromagnetic radiation, such as light, or even pressure waves such as sound, the directional properties are always limited by the dimension of the antenna, loudspeaker, lens, etc, in the case of a verticle monopole you really need height to get lots of low-angle radiation, for the same reason that radio telescopes of high angular resolution have several dishes spread out over a great distance, sometimes hundreds of miles. It is also why a 15 inch PA loudspeaker will give, on axis, maybe 102dB at 1 metre with 1 watt input, while an 8 inch hi-fi speaker may give only about 80dB. even though both are equally well made and have had similar attention to loss mechanisms. Likewise the best searchlights have large-diameter lenses....A human eye is large in comparison to the wavelenght of light, so it can resolve lots of detail, the eye of an insect can distinguish only vague impressions of light or colour. There are lots more examples.

    Some years ago, the Crossed Field Antenna, which purported to be even smaller, made similar claims, backed up by real-life tests.... I am sure that Google will find lots of references, so why does every AM broadcast station not use one? Maybe 10 to 20 feet high, not too heavy, no expensive materials, yet do you ever see them? Again, it was correctly resonated, but it did not have the height.

    In any case I am sure there will be a very large amount of prior art on this one, a fair proportion of CB antennae for instance use loading coils and helixes in just about every combination imaginable. The current distribution of monopole antennae has been widely studied for many years. I would like to see a picture of the thing, to see what, if anything, is new.

    Also, the microwave end of the spectrum has no need of smaller antennae, no mobile phone I have seen in recent years has had an external antenna at all, and you can only make a phone so small.. You have to hold the thing, after all. If it is not entirely self-supporting in air, dielectric losses will be serious.

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