K1DFT Antenna: Revolutionary or Not?
Dr. Barry Johnson (W4WB)
on
September 13, 2004
View comments about this article!
As you may recall, the University of Rhode Island's Department of Communications/News Bureau issued a press release on June 2 reporting the development of a new and revolutionary antenna technology by Rob Vincent (K1DFT) who is a Physics Department employee at the University and is the developer of the technology. They further reported the antenna design has been submitted for patenting. The new design claims to dramatically reduce antenna size while improving efficiency and maintaining broad bandwidth. See the full press release at:
http://www.uri.edu/news/releases/?id=2659
Not much was known or disclosed about Vincent's design or experimental methods and results. Last weekend, two seminar hours were devoted at the Boxboro Hamfest for Vincent to discuss his antenna. I was not able to attend, but several folks that did related to me their impressions of his presentation and the demonstrations (one being a comparison to the G5RV at the on-site station). In short, they were underwhelmed.
After a week since Boxboro, there seems to be a dearth of reports on Vincent's presentation, design, or demonstration at Boxboro after all the buildup for the great revelation prior to Boxboro.
Is the reason for this lack of comments about Vincent's presentation, etc. simply that the antenna was seen to be such a non-starter, no comments are required ... or what? After all the articles in the press (including the NY Times) prior to Boxboro, it seems that there should be more press coverage now that he gave the presentation.
As it once was said in those famous TV commercials years ago ... "Where's the beef?"
73,
Barry W4WB
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K1DFT Antenna: Revolutionary or Not?
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by W4RK on August 23, 2004
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I just read the press release referenced in W4WB's posting and agree that it is extremely general, without much detail. If the 15 meter version is 18" tall and the antenna looks like a flagpole, it must be a flagpole for a doll house. Not trying to be critical, since there really isn't enough information to criticize. It would, however, be great to have even some general comparative results with a reference antenna. If anyone has additional information about this antenna, please share it. Things that seem too good to be true generally are just that.
Thanks in advance and 73,
W4RK
Nashville, TN
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K1DFT Antenna: Revolutionary or Not?
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by WIRELESS on September 13, 2004
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About every 10 years someone announces a new miracle antenna and then nobody ever hears about it again.
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K1DFT Antenna: Revolutionary or Not?
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by N3EVL on September 13, 2004
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There is a web page showing what appear to be the slides presented at Boxboro:
http://www.uri.edu/news/vincent/boxboro_files/frame.htm
I understand that one or more versions of the antenna had been sumbitted for independent testing at a respected facility - it sure would be nice to see the results of this study.
73, Pete, N3EVL
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K1DFT Antenna: Revolutionary or Not?
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by K6SBA on September 13, 2004
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Barry,
In the current issue of WorldRadio, the notorious "Kurt N. Sterba" skeptically weighs in on this antenna.
73 de K6SBA
David in Santa Barbara
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RE: K1DFT Antenna: Revolutionary or Not?
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by W8JI on September 13, 2004
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The really scarey part of this is a university seems to have gotten behind the project. The good part is it isn't a university known for excellence in engineering. This is a sad testimony of where we are heading with technology.
It's been known for a long time that radiation resistance of a monopole is a direct function of current distribution over distance, and the maximum possible change change is a ratio of 4:1 when going from triangular to uniform current.
This antenna does not even go to uniform current like an antenna with a large hat would do, so it never acheives maximum efficiency for a given ground loss!!!
The whole thing is hyped all out of proportion. Similar things have been done years ago with CB antennas, and the results are nothing special. It'll all go away like Fractals, the CFA, the CTHA, the E-H antenna, and the rest of this sort of nonsense.
73 Tom
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K1DFT Antenna: Revolutionary or Not?
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by W4WLZ on September 13, 2004
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Bummer,
I just bought about 150 feet of 12 gauge ladder line and 350 feet of number 12 solid antenna wire.. What can I do with it now ??
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K1DFT Antenna: Revolutionary or Not?
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by N4JAH on September 13, 2004
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From the slides and specs, it looks to me like a coil shortened St. Louis Vertical. Nothing very revolutionary about that. There is sufficient info in the slides to build one, though.
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RE: K1DFT Antenna: Revolutionary or Not?
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by KK7SS on September 13, 2004
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IMHO...
Add a loading coil at the center of a vertical whip (like a Hustler mobile antenna) to a helical wound whip (like a Hamstick/Valor/ProAm) and I think you have the K1DFT antenna...
Revolutionary ... I think not!
Evolutionary... perhaps !
Dave KK7SS
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RE: K1DFT Antenna: Revolutionary or Not?
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by K6AER on September 13, 2004
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An interesting and well crafted news release regarding the antenna. It is an odd mixture of junk science, ancient history and vague biography. Great for the general public consumption and obviously who ever is funding this project in the academic system. As Tom, W8JI mentioned, the ground losses for this antenna would render this antenna one food chain above a light bulb with no where near the bandwidth. About the only claim I did not see was the expected weigh loss you’ll get buying one of this.
Put up antenna range results and comparisons to a real reference antenna. Then I might listen.
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RE: K1DFT Antenna: Revolutionary or Not?
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by WB2WIK on September 13, 2004
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We have a "skunkworks" operation creating a new, very shortened fan dipole. Can't divulge the results just yet, but we're encouraged enough that we've applied for a federal grant at least equivalent to the one awarded for tracking the snail darter years ago.
America's a great place for research.
WB2WIK/6
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K1DFT Antenna: Revolutionary or Not?
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by KE4ZHN on September 13, 2004
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It always amazes me at how many people try to change the laws of physics. Short antennas work...but very poorly. No amount of "hocus pocus" will make this thing much better then a leaky dummy load.
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RE: K1DFT Antenna: Revolutionary or Not?
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by KG5JJ on September 13, 2004
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I worked with a commercial antenna design engineer in the late '70s. He always spouted "Aperture is Everything".
73 KG5JJ (Mike)
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RE: K1DFT Antenna: Revolutionary or Not?
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by KI7YY on September 13, 2004
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The claims for this antenna remind me of the fellow in the early 80's who had perfected the perpetual motion machine.
Anyone who believes these claims should be re-tested.
73, Kirk, KI7YY
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RE: K1DFT Antenna: Revolutionary or Not?
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by N0TONE on September 13, 2004
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Basically, it's a twist on where you put the loading in a short antenna. As W8JI didn't quite say, top-hat loading gives the highest radiation resistance of any loading scheme for a given length. All other loading schemes are a compromise down from the top hat. The benefit of high radiation resistance, as W8JI said, is that higher radiation resistance antennas operate at better efficiency, for a fixed ground system loss resistance.
The biggest disappointment to me is the caliber of the presented material. It is riddled with spelling and grammatical errors, and the graphics are not well-notated, so you are often not at all certain about what you are seeing. The overall caliber of the style of communications is typical of junior high school student, not a graduate student.
My guess is that K1DFT has something that is patentable, and that the Univeristy showed some interest in it, but his presentation materials have NOT been peer reviewed, or reviewed by any Univesity Team at all. The University probably would not like this low caliber of presentation being out there with their name on it.
However, with my criticism out of the way, I do want to commend K1DFT for at least making some attempt at antenna experimenting and modelling. His measurements of the current distribution show that he has some knowledge about the relationship of measurable parameters and real world performance.
His usage of on-ground radial systems shows that he has not yet performed any in-depth study of ground systems.
AM
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RE: K1DFT Antenna: Revolutionary or Not?
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by KC8VWM on September 13, 2004
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I can improve your antenna radiation efficiency by 30% !
Firstly; - Hair Tonic - Stop using it on your head and try coating your antenna wire with it. Improves your antenna's velocity factor by 2. Works best on antennas constructed with "capacity top hats."
Injecting WD40 in your coax will not only reduce corrosion and thus prevent loss of signal due to the effects of water. It also prevents coax from cracking due to expansion freeze thaw cycles too!
Soak your coax in suntan lotion. This will improve the water resistive characteristics of your feedline. In addition, this will provide for marked improvements in the coax cable UV radiation resistance factor. Using specific brands marked with UV/25+ or better will ensure your audio output will remain above 25 U/V and also helps to improve your S-units to the East by a factor as indicated on the last 2 digits of the products UPC code.
Tip: You can improve the signal output of a dry piece of string, by making it wet!
Truely, this recent revolutionary discovery defies the laws of physics. Recently, research grants are being provided by the government to further study this fascinating phenomenon! I suspect that future NASA experimental probes will spotlight dry string as the "next communication medium." Rumor has it that they are going to partner with the Campbell's company on the project. ... More on this later.
Hams Make First Long Distance QSO Record Without Any Antenna's Attached!
(Sep 8, 2004) -- AP News, Newireton, CB.
Hams have been reported to have the first long distance moonbounce QSO without any antennas attached to their stations. John, N0CAL of California has reported a contact of over 25 miles to another station using a combination of moonbounce and HF sky wave propogation ....while repotedly using nothing more than a dummy load attached 75 feet away on a high loss feedline array system connected to an elaborate grounding bar.
"It was so exhilerating to make this contact" said N0CAL, "I bought my dummyload at Unicorn Radio at the recommendation of the LRRA handbook which is available on the LRRA website for $$$$$$.!"
... True Story
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RE: K1DFT Antenna: Revolutionary or Not?
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by W3JJH on September 13, 2004
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As Scotty says, "Ye cannae change the Laws of Physics!"
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RE: K1DFT Antenna: Revolutionary or Not?
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by W3JKS on September 13, 2004
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Well, my new fractal fan antenna can beat this new fangled thing.
It all started when my new MFJ Enterprises fan antenna fell off the Big Brown Truck and was run over...
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K1DFT Antenna: Revolutionary or Not?
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by KE2IV on September 13, 2004
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My Goodness!
What is going on here with all you skeptics?
Clearly this gentleman has finally re-discovered the long lost and lamented Hoakes Antenna. It's the long lost Holy Grail of aerials for which many have searched and none have heretofore found.
I was suprised to hear that URI waited until June 2nd to announce this revolutionary re-discovery. Usually such press releases are issued on April 1st!
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RE: K1DFT Antenna: Revolutionary or Not?
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by N3EVL on September 13, 2004
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I tend to agree with N0TONE's comments. I was able to attend the discussion at Boxboro and must admit to being a bit disappointed with the overall presentation. Based on the hype, I was expecting something a bit more quantatative, less qualatative: if the antenna was as good as the hype was suggesting, then there should have been the hard math to back up the claims - this was missing.
However, the design did get positive reviews from the those who had been assisting with testing the various antennas (including on-the-air real use in QSOs). This makes me ask what they were comparing against and how the comparisons were made - once again, hard, independent, verifiable evidence is needed.
It may be the case that for those of us that are geographically and geometrically challenged, such an antenna may be a reasonable compromise but I have seen nothing so far that suggests the design is revolutionary.
With respect to the design details, I am curious - when does a helix become a loading coil and a loading coil become a helix? These two items appear to be key to this design; what is the quantatative difference between these types of inductances?
Having said all that, it's still a vertical - and the golden rule still applies: Verticals Radiate Equally Poorly in All Directions!
Pete
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RE: K1DFT Antenna: Revolutionary or Not?
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by K3BU on September 13, 2004
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Here is some hype in "trade" magazines:
http://www.thefeature.com/article?articleid=100798
http://in.tech.yahoo.com/040605/139/2dhn2.html
http://www.eet.com/at/lae/news/showArticle.jhtml?articleId=21401977&kc=6384
http://www.gizmodo.com/archives/uri-employee-develops-hot-stuff-antenna-technology-015760.php
in this press release bu URI
http://www.uri.edu/news/releases/?id=2659
>>"The Holy Grail of antenna technology is to create a small antenna with high efficiency and wide bandwidth," explains Vincent. "According to current theory, you have to give up one of the three—size, efficiency, or bandwidth—to achieve the other two."
After decades of experimentation, combined with a 30-year engineering career and Yankee ingenuity, Vincent has invented a revolutionary antenna technology. The distributed- load, monopole antennas are smaller, produce high efficiency, and retain good to excellent bandwidth. And they have multiple applications.<<
This is what I posted on Antenna NG after seeing the presentation on the "magic" or "miracle whip" antenna:
>>Howdy NGers,
I was curious about another "miracle" short vertical, being subject of great
interest, patent by Robert Vincent and Physics dept. of University of Rhode
Island. I got up at 4 am, drove to Boxboro ARRL convention and eager to see
what are we missing.
Not much!
Giveaway was opening statement something like: how to make shortened antenna
with more gain (compare to what? I guess light bulb :-)
In the "theoretical" portion of the presentation audience was told that current
across the helical coil decreases away from the feed point, while across
loading coil it stays constant. Due overcrowding of "inventor" I did not
persist in breaking through and asking for enlightenment.
Author claims more gain (familiar), better bandwidth (doesn't get it why) and
small size (of course). Showing measured graphs with current and phase
distribution along the radiator. Works very well! (Many stations worked.)
He showed how to measure current at the antenna using ferrite pickup
transformer way up the antenna and cables to the instrument (handsomely
detuning and distorting the measurements).
I suspect that "broad bandwidth", (SWR 2:1) was achieved thanks to losses in
the coils and dielectric, as "confirmed" by his statement that coils were fried
when power was applied.
What is it? Basically helically wound coil starting from the base, about half
way up the radiator, then piece of straight tubing, than loading coil, then
tubing and in some case top hat (works better :-). Matching to 50 ohms is done
by picking tap at the base, few coil turns up. That is 3D version.
He showed some "2D" versions, having "coils" made of basically coil formed as
hairpin loops instead of classic solenoid, also the loading coil. So kind of 2D
- 3D antenna :-)
I wanted to make a bet that my single loading coil loaded vertical would cream
the "miracle", but there were so many worshippers paying compliments to the
inventor, that I resigned not to stay for the second hour of lecture how to
build it.
I saw no trace of any modeling, just experiments using wrong tools.
So brace yourselves for another "miracle" in the arsenal of "very small and more
efficient antennas". It should be a hit with CBers and other suckered users.
So that's it (oh, no chokes in the feedlines), I hope U of RI is proud of this
breakthrough, I can sleep well now. Back to DR1.
Yuri, K3BU
with more info that could have saved lotsa experimenting at
http://www.k3bu.us/loadingcoils.htm
<<
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RE: K1DFT Antenna: Revolutionary or Not?
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by KC8VWM on September 13, 2004
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Build your own:
Plan A)
http://www.dsokids.com/art/tin%20can%20telephone.jpg
Plan B)
http://www.qsl.net/vk5br/EHAntenna20_40.htm
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RE: K1DFT Antenna: Revolutionary or Not?
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by KC8VWM on September 14, 2004
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Protect that EH antenna with this revolutionary lightning protection device:
http://totallyabsurd.com/lighteningribbons.htm
Don't go to another field day event without one of these amazing inventions!
http://bumperdumper.com/
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RE: K1DFT Antenna: Revolutionary or Not?
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by W6TH on September 14, 2004
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It is a surprise of how many will believe and buy.
Wait till you hear about my 3 inch radiator that will outperform the 3 element yagi antennas. What is holding me back is the Gov't won't let me buy any gold.
.:
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K1DFT Antenna: Revolutionary or Not?
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by AC7ZG on September 14, 2004
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Hamstick with loading coil in the middle of a top stinger....
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RE: K1DFT Antenna: Revolutionary or Not?
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by N0TONE on September 14, 2004
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I think we're being a little harsh. There is nothing silly about the antenna. The only silliness is calling it "revolutionary". The inventor has some interesting ideas on a different way to build a loaded vertical. Actually, one problem that always remains with a center-loaded whip is how to finally manage the impedance match to 50 ohms. By replacing the bottom straight portion with a helical winding, he has created an impedance-matching transformer that can be made to work by selecting the correct tap on the helix.
The typical ham would use a center-loaded whip, and then some auto-tuner feeding the base. THe auto-tuner would have losses. Compared to this situation, this antenna with the helical winding at the bottom enabling a transformer match, WOULD be more efficient.
AM
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RE: K1DFT Antenna: Revolutionary or Not?
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by KQ6XA on September 14, 2004
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K1DFT is hereby invited to enter his best 20 meter antenna in the HFpack Antenna Shootout in 2005.
For more info on the shootout:
http://www.hfpack.com
Bonnie KQ6XA
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RE: K1DFT Antenna: Revolutionary or Not?
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by N6AJR on September 14, 2004
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fan dipole for ever..........
http://www.hamuniverse.com/multidipole.html
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RE: K1DFT Antenna: Revolutionary or Not?
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by N6AJR on September 14, 2004
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Don Johnson of DK3 fame has done this years ago. you mount the base of his antenna to ground. it has a 7 or 8 turn built in impeadence match built in the shell of the antenna and it is adjustable too from 10 meters to 80 mobile.. read his book, check out the dk3
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RE: K1DFT Antenna: Revolutionary or Not?
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by W5HTW on September 14, 2004
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I have no time for this antenna. I'm still trying to perfect my 3500 watt propane-powered, electric start, generator that fits in a shirt pocket. I have managed, so far, to put the injector into my pocket. A bit more, work, though, and I'm sure it will be a great Field Day device. Coupled with a 24 inch 20 meter monobander on my helmet (to replace the 2 meter antenna) and a superscript (yes, there's that word, except I probably need to do subscript) 706-XXXS (for triple X small) mounted on my belt buckle, I shall soon be totally emergency radio ready. I'm fastening a counterpoise to my left boot.
Ed
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K1DFT Antenna: Revolutionary or Not?
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by AE6JX on September 15, 2004
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Looking at the presentation I have a few remarks....
I used ex CB firesticks and skinny sticks on 10m FM 20 years ago, they had the same construction.
Feed impedance is the sum of radiation resistance, ohmic losses and ground losses. So if you use thin wire, have a rotten ground you can kid yourself you have a high feed resitance, especially if you use a transformer, but all you get is a lot of loss and so low efficiency, but a wide bandwidth. I particularly liked (or not) the helically wound magnetic loop antenna. These are normally made with large diameter Cu or Al pipe, to get the ohmic losses down. After experimenting with these, I am skeptical as to their efficiency, however replace the low loss tube with skinny wire, that should really mess them up.
In good conditions HF can cover great distances on small power, so the proof of this pudding is not in the eating.
cheers.........Adrian
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RE: HPpack antenna shootout
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by N0TONE on September 15, 2004
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Bonnie,
I looked at the web page you referenced. It took a lot of clicks, and there was a whole lot of text. In the end, I didn't have time to read through the whole thing, but I gather you're making some sort of received signal strength meausrement at relatively close range. I have questions, so many queestions...
1) Do you somehow differentiate between antennas that are intended to be low angle radiators versus high angle, other than having separate categories for vertical and horizontal polarization?
2) Do you place intentional NVIS (aka cloudwarmer) radiators into a special category?
3) Have you correlated your near-field measurements with far-field? In other words, have you attempted a shoot-out with the receiving sites located, for instance, at 100, 1000 and 10,000 miles away?
I have often thought about doing such antenna comparisons, but in the absence of any correlating evidence, I decided that for my needs, the effort was not justified. I'm a DXer and simply wasn't certain that easily-accomplished near-field measurements would correlate particularly well with a given antenna's ability to successfully launch a low-angle wave.
Looking forward to your reply,
AM
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Stinky Pinky
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by KA4KOE on September 16, 2004
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"We have a "skunkworks" operation"
You're right....something smells to high Hades around here.....
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RE: K1DFT Antenna: Revolutionary or Not?
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by OLDFART13 on September 16, 2004
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by KQ6XA on September 14, 2004
K1DFT is hereby invited to enter his best 20 meter antenna in the HFpack Antenna Shootout in 2005.
For more info on the shootout:
http://www.hfpack.com
Don't you mean 11 meter shootout?
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K1DFT Antenna: Revolutionary or Not?
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by AE9L on September 16, 2004
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Revolutionary, NOT.
I was just looking at the slide show and noticed something familiar. This technique has been used for years on mobile fiberglass whips.
The Mark Antennas HeliWhip series with was marketed to hams from the early sixties on used this method. It was a continuosly load F.G. whip but was different than its competition by the fact that the windings started at the bottom with a small matching section then went on to a "helical" section of wider spaced turns, and finally to a loading coil section which was wound to resonate the antenna. This configuation gave the Heliwhip a wider bandwidth and higher effciency than the competition.
Unfotunately the Heliwhip is no longer manufactured, Mark Antennas became Anixter Mark and finally Mobile Mark which I work for. The CB and Ham lines were sold a few years ago..
Jerry AE9L
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RE: K1DFT Antenna: Revolutionary or Not?
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by W8JI on September 16, 2004
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RE: K1DFT Antenna: Revolutionary or Not? Reply
by N0TONE on September 14, 2004 Mail this to a friend!
I think we're being a little harsh. There is nothing silly about the antenna. The only silliness is calling it "revolutionary". The inventor has some interesting ideas on a different way to build a loaded vertical. Actually, one problem that always remains with a center-loaded whip is how to finally manage the impedance match to 50 ohms. By replacing the bottom straight portion with a helical winding, he has created an impedance-matching transformer that can be made to work by selecting the correct tap on the helix.
The typical ham would use a center-loaded whip, and then some auto-tuner feeding the base. THe auto-tuner would have losses. Compared to this situation, this antenna with the helical winding at the bottom enabling a transformer match, WOULD be more efficient.
>>>>
None of that is true NOcall NOtone.
If the helical section changes the impedance, by definition it must have substantial current from the area above the inductor to ground.
If it has that, it robs the antenna above the coil of current and reduces efficiency.
The only way to increase base impedance with a series component is to add series loss resistance.
73 Tom
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RE: K1DFT Antenna: Revolutionary or Not?
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by OLDFART13 on September 16, 2004
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A little antenna that may be appropriate for some situations: Yes.
Revolutionary: NOT!
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RE: K1DFT Antenna: Revolutionary or Not?
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by OLDFART13 on September 16, 2004
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To Jerry AE9L,
Sorry I didn't mean to steal you NOT! You had it first. I change mine to:
Revolutionary: I don't think so!
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K1DFT Antenna: Revolutionary or Not?
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by K8NQC on September 16, 2004
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I for one will wait and see. So often I have seen new things come along that amaze those of us who always think that we already have tried everything. I remember when the "shoe phone" was just a comedy prop. Back in those days we scoffed at using antennas like full-wave horizontal loops. Today those sky warming loops are putting some of the best signals on the HF bands.
When I look at the theoretical patterns of short dipoles, they are only down a fraction of a db from a half-wave dipole. In fact, if we shorten the dipole all the way to a tiny point, the pattern is only down 2.14 db (the isotropic pattern.) The math does not rule out the idea of a K1DFT antenna working. The problem is one of finding how to make it work within practical limitations. I like the thought of a member of our fraternity coming up with such answers.
I also think that such an antenna would be very valuable. One would be foolish to share too many details before the value from such a find is well secured. After that is done, it needs to be presented for peer review. After that, we amateurs could experiment with the design for our non-profit projects.
Hams love to play with antennas. Let's wish each other success.
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RE: K1DFT Antenna: Revolutionary or Not?
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by K1YDA on September 17, 2004
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Hey yahoo W3LPL is a University of Rhode Island
EE grad class of 68 and you are an edcuational snob.
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RE: K1DFT Antenna: Revolutionary or Not?
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by K1YDA on September 17, 2004
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Hey yahoo W3LPL is a University of Rhode Island
EE grad class of 68 and you are an edcuational snob.
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K1DFT Antenna: Revolutionary or Not?
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by WA2JJH on September 17, 2004
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Skunk works? What is this antenna for black ops or something! Where is the smoking dude from X-files?
I will stick with my paper clip antenna feed with 20,000 feet of RG-174.
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RE: K1DFT Antenna: Revolutionary or Not?
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by N0TONE on September 18, 2004
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W8JI,
I dare say you mis-read my comment. I did not say that the helical winding in series raised the impedance. I said that it allowed him a convenient method for creating a transformer. He feeds the antenna via a tap on the helical winding, and the bottom of the helical winding is grounded.
I agree with you - the helical winding, as a series element, is not impacting the impedance of the antenna.
AM
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RE: K1DFT Antenna: Revolutionary or Not?
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by KC0BUS on September 19, 2004
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My word! Everyone is so cynical! I challenge someone to just try and make one and finally put their money where their mouth is.
KC0BUS,
Scott
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RE: K1DFT Antenna: Revolutionary or Not?
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by W4WB on September 19, 2004
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I did many years earlier Scott ... it was called a dummy load. ;-)
Seriously however, I heard from a friend that attended Boxboro and who witnessed the testing of Vincent's antennas at the hamfest station. As I understand, there was an antenna located at each corner of an aluminum plate about 3' on each side. This assembly was located fairly near the base of the tower that had a beam mounted upon it. The hamfest station also used a G5RV hung between lamp posts in the parking lot. The radio used was a FT-1000MP as I understand (this radio's S-meter is generally rather well calibrated).
On 17 or 20 m (not sure which band was used), the beam was reported to provide 1.5-2 S-units BETTER reports than the G5RV. Vincent's antenna performance was around 4 S-units BELOW that of the G5RV. Vincent was reported asked if he would like to move the antenna assembly away from the tower base to mitigate interaction between them. He reportedly replied that his antennas don't suffer such interactions. (It has been my experience that the more efficient an antenna, the more it "interacts" with nearby metal objects. On the other hand, a dummy load is rather insensitive to such interaction.)
In addition, it was not evident that Vincent used any means to eliminate common-mode currents on the coax outer shield. Perhaps this is really the primary source of the emitted radiation.
As I mentioned above, it is common to see more interaction between an antenna's environment as its radiation efficiency increases. For example, I have a number of motorized antennas that I can mount onto my Blazer. The Yaesu ATAS-100 is relatively insensitive to parking near a metal building while the Hi-Q-80/5-RT (5" diameter coil) is quite sensitive. On the other hand, the signal reports on 40 m are about 4 S-units better with the Hi-Q.
If anyone has tested any of Vincent's antennas, please share your observations and your test methods. Improper test methods can lead to incorrect conclusions.
73,
Barry W4WB
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RE: K1DFT Antenna: Revolutionary or Not?
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by NN6EE on September 20, 2004
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The antenna is REVOLUTIONARY??? Hmmmm!!!
I remember back in the 70's when our country was experiencing the Arab "Oil-embargo" and some brilliant individual developed a revolutionarily NEW carburator that would give American automobile engines the ability to get 100 MPG!!! YAH RIGHT!!!
False hopes spring eternal don't they!!!
Jim/ee
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RE: K1DFT Antenna: Revolutionary or Not?
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by N1EY on September 20, 2004
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I had thought URI was a good
school for engineering.
What did K1MAN graduate from URI
or something?
Bill
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K1DFT Antenna: Revolutionary or Not?
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by KF6RRR on September 27, 2004
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Vincent has posted a slide presentation showing his antenna design at: http://www.uri.edu/news/vincent/boxboro_files/frame.htm>
A friend said of Vincent’s demonstration / talk at the Boxboro, MA convention that the latter’s antenna performed at 20 dB below the level of a G5RV!
He noted that Vincent’s design had been discussed a lot on the Tower Talk reflector, (see this article and search there for others): http://lists.contesting.com/archives//html/Towertalk/2004-08/msg00331.html
He reported that W8JI has provided a technical model which explains why Vincnet’s design does not work well.
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K1DFT Antenna: Revolutionary or Not?
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by KE6BBP on May 15, 2005
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as pointed out in Kurt Sterba's World Radio Feb edition, this is not new just an expansion of a earlier radio whip that had a lower coil winding, a long lead up and a top load coil. This one is just a big version for 160 meters and for quite a bit of power . Now all you "exspurts" go build one and some one take it to a recognised test range and do near and far field (10 wave lengths away) testing, then we can see if this is a good one. In the lecture it was said it was patented, wel no listing or preliminary fileing shows up. Also a claimed copyright, not at the copright office, where's the proof ??
'
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