Old Geek Invents New Stick 262
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."
Very promising! (Score:5, Interesting)
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)
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)
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)
At my parents' house, Verizon phones get zero coverage, despite three towers being within range.
Power (Score:2)
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)
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.
Re:Very promising! (Score:3, Funny)
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)
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
Re:Very promising! (Score:2)
Re:Very promising! (Score:2)
> 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
Re:Very promising! (Score:2)
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.
Re:Very promising! (Score:2)
Re:Very promising! (Score:5, Informative)
Re:Very promising! (Score:3, Informative)
My comment was not meant to denigrate him or his achievement. On the contrary, I have great admiration for him.
I was just pointing out that the original submitter and the comment I was replying to assumed he was a scientist at URI, when he was not. I also thought the NYT article was interesting enough to be submitted as an additional link.
Re:Very promising! (Score:2)
Ahh yes, but.... (Score:4, Funny)
Re:Ahh yes, but.... (Score:5, Funny)
Re:Ahh yes, but.... (Score:3, Informative)
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
Suggested name... (Score:5, Funny)
Behold! I give you the twelfth-wave design!!
Genetic Algorithm (Score:4, Interesting)
Re:Genetic Algorithm (Score:5, Informative)
The purpose for the Markland antanna is "stealth" - it can turn on and off and re-tune itself on the fly. It is also a directional antenna. The antenna in this story is a smaller form factor for a wide frequency range omni-directional antenna.
Basically they are apples and oranges.
Will we see this at (Score:5, Interesting)
Re:Will we see this at (Score:4, Funny)
Re:Will we see this at (Score:2)
Heh (Score:3, Funny)
Re:Heh (Score:4, Funny)
let it be said: patents at their best (Score:5, Insightful)
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
Re:let it be said: patents at their best (Score:5, Insightful)
So let's hope it's not just a tweak of something that was in QST magazine thirty years ago.
Re:let it be said: patents at their best (Score:5, Funny)
Re:let it be said: patents at their best (Score:2)
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)
Re:let it be said: patents at their best (Score:2)
Re:let it be said: patents at their best (Score:2)
Yet another patent for an anonymous patent portfolio to be used by lawyers as bargaining chips.
Hurrah!
Re:let it be said: patents at their best (Score:2)
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
smart card insertion? (Score:5, Interesting)
Re:smart card insertion? (Score:2)
Re:smart card insertion? (Score:2)
No details of operation (Score:5, Informative)
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?
Re:No details of operation (Score:3, Interesting)
to describe a 2d helix, take a photo of one, concgrats you have one.
its basically a sin wave qith a specific frequency.
Re:No details of operation (Score:3, Funny)
if that was the case everyone would point their satelite dishes in whatever direction and place rocks around it until the signal was strong enough.
Just imagine... (Score:2, Interesting)
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.
Signal Vs Antenna (Score:2)
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
I doubt this will shorten AM towers (Score:5, Interesting)
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?
Re:I doubt this will shorten AM towers (Score:3, Interesting)
They just load the tower at the base and the whole thing radiates!
Re:I doubt this will shorten AM towers (Score:3, Informative)
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
Re:I doubt this will shorten AM towers (Score:5, Informative)
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.
Re:I doubt this will shorten AM towers (Score:5, Informative)
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.
Re:I doubt this will shorten AM towers (Score:4, Informative)
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.
Re:I doubt this will shorten AM towers (Score:5, Informative)
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).
Re:I doubt this will shorten AM towers (Score:5, Informative)
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
Re:Playing with Live Antennas (Score:4, Interesting)
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...
Re:I doubt this will shorten AM towers (Score:2)
Re:I doubt this will shorten AM towers (Score:3, Informative)
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
Re:I doubt this will shorten AM towers (Score:3, Insightful)
Re:I doubt this will shorten AM towers (Score:2)
This could have a very positive... (Score:3, Insightful)
Bandwidth of the antenna (Score:5, Informative)
There are several parameters for an antenna system (receive parameters in parens):
Most compact designs trade bandwidth for performance - the work well at f=NNN.N MHz, but not well at f=NNN.N +
This gets to be REALLY important for wide band systems like CDMA and UWB.
Re:Bandwidth of the antenna (Score:2)
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.
Re:What line of work (Score:2)
I'm afraid I don't have any gear you have designed at my disposal.
While I wouldn't mind purchasing some... we are far too cheap and my budget doesn't include enough for a new juicy spectrum analyzer. (Yeah... I was glancing at them with a stalkeresk look)
A nice newer digital signal counter would be grand too...
However, I could spend all day wanting things
Re:Bandwidth of the antenna (Score:2)
Show me the plots (Score:3, Informative)
Re:Bandwidth of the antenna (Score:3, Insightful)
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
Re:Bandwidth of the antenna (Score:3, Interesting)
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
Re:Bandwidth of the antenna (Score:3, Insightful)
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
I was happy to see... (Score:5, Insightful)
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.
Picture anyone? (Score:2)
Re:Picture anyone? (Score:5, Funny)
I'd love to see a picture of this as I don't know much about antennae.
Here [arxia.com].Pringles mini can (Score:4, Funny)
He expects to get a 10x power boost from metal chewing gum wrappers, and 50x from a microwaved AOL CD!
Re:Pringles mini can (Score:2, Funny)
Communications engineers call this the Knot principle.
let's ask the ladies out there (Score:4, Funny)
That depends (Score:2)
Fractal antennas (Score:4, Informative)
Re:Fractal antennas (Score:4, Funny)
Interesting coincidence (Score:5, Interesting)
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)
Microsoft/IBM can nab this (Score:3, Insightful)
"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,th
Welcome to the US patent Office. Where dreams CAN come true!
Ham response (Score:5, Informative)
Re:Ham response (Score:2)
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)
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...
Sounds like a distributed capacitive hat. (Score:3, Interesting)
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)
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
Laws and Assumptions (Score:2)
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
Why smaller? Lets get better. (Score:3, Insightful)
Re:Why smaller? Lets get better. (Score:3, Insightful)
Prior art? Or innovation? (Score:3, Interesting)
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)
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)
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.
Pardon me for being a little skeptical.. (Score:2)
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
Re:Pardon me for being a little skeptical.. (Score:2)
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
Not trolling, but being reasonably skeptical.. (Score:2)
Re:Not trolling, but being reasonably skeptical.. (Score:2)
Patent Pending? (Score:2, Informative)
Re:Patent Pending? (Score:3, Informative)
Can you say prior art? (Score:5, Insightful)
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
Re:Can you say prior art? (Score:2)
Cheers, Gene
fractal antennas (Score:2)
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?
A Very Skeptical View (Score:5, Informative)
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.
This is probably just hype.... (Score:4, Informative)
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.
Patents before proof (Score:2)
But as I read the article, the guy looks like he wants to make a few bucks from his discovery before providing info/pictures/etc..
Why else would you patent it?
Re:Notes about article and site (Score:2, Interesting)
Most amateurs use way too much power anyway.
KI3J