Radio Ham interviewed about Fractal antenna

Heath is absolutely right; There is no place for pseudoscience in ham radio, or fractals for that matter. I will continue to champion the dissemination of real science and describe the advantages that fractals bring, as I have been doing for nearly twenty years.

I am sorry that Heath has apparently run across things that his knowledge base led him to believe is pseudoscience. But keep on pluggin Heath! There is a rich road of knowledge ahead! you might enjoy this summary of the comparison of a 2 element fractal quad compared to an H end loaded one, that played out her. Note that I neither picked, advised, nor modeled here. It was all done by others here. I was happy to clarify vis a vis how antennas are chosen in designs. the summary clearly shows who is better by the comparison. See for yourself!


FRACTAL 2 el compared to End loaded H 2 el
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PARTS NEEDED Fractal only needs bent wire. No coils or matching system like the H.

COMPONENTRY/ECONOMY OF DESIGN Fractal has no parts. slamDUNK!

COSTS Fractal was made for peanuts. H costs likely to be far higher because of its mechanical support system

FRONT TO BACK Fractal 3-5 + dB better F/B

GAIN Fractal has no insertion loss of a matching system or real-world ( QF <<500) coils, so gain likely to be roughly 2 dB higher than 'H'

MECHANICALS/WIND LOAD Peripheral support required by ' H' gives higher torque/wind load

BANDWIDTH If both system allowed to use a matching system, fractal can use multimodes for far wider bandwidth

And, by the way, N3OX finds a 90% efficiency with aluminum wire. shrink the area 4 times. nice added bonus.

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The invariance afforded by fractals in Maxwell's Equations is a real plumb in nature that shows , as one of many examples, exactly why people--with fractals for nerve networks; fractals for airways, fractals for heartbeats; and fractals for blood vessels, need to understand why fractals are an important part of nature and thus an important mechanism for technology. Why, hams have been using fractals for decades! For many, your on the air experience would not have been as rich or rewarding.

I am grateful for the point-out here afforded by this thread. What a wonderful Christmas gift it was!

73 and best to you in 2011 Heath!
Chip W1YW

 

Fractal plumbing

All branching in nature is not fractal.

When the only tool you have is a hammer, everything looks lika a nail.

When the only tool you have is Maxwell's Equations, everything looks like a fractal.

 

Fractals--It does a Body Good

Of course, I am taking the info on fractals in your body from the NOVA show--which is the topic on this thread. There are dozens of scientific publications over the last 3 decades that pointed this out.

Enjoyed that? Be sure to have a look at the two videos showing some new frontiers with fractals:

http://www.youtube.com/watch?v=_JpMJTJXf28

http://www.youtube.com/watch?v=QWd0nEXFnrE

73,
Chip W1YW

 

It was late last night when a friend who'd been following this dropped off his old and tattered October 1999 issue of CQ. After reading the article that KF7BS wrote, I came to the conclusion it was a Herculean effort on his part to build it, but for me, not worth the effort.

Figure 2., on page 22, shows the EZNEC predicted performance. 5.41dBi, and 12dB F/B.

Achieving only 2.41dB more than a simple dipole (one fourth of an S-unit) really isn't worth the effort for me. And, on 10M here in the US, there is no need to worry about undesired signals when working DX. Simply any signal received is desired. Perhaps not so on lower HF bands like 20M with undesireable West Coast noise, but not on 10.

Frankly, a simple 5/8 base loaded vertical or J-pole collinear will equal or outperform it and are very simple to construct. Plus, no rotor's needed. And, they would offer a much more aesthetically acceptable appearance.

It was interesting to note that in his actual construction, he did use aluminum spreaders. Something he didn't model in EZNEC. Not something ANY quad maker would want to do, IMO. So, real performance was probably beneath the model prediction.

There are several ways to physically shrink element dimensions. One could put simple loading coils in the middle of each leg, or shorted stubs as I mentioned earlier.

No need to spend a great deal of time building something with lots of bends and unsupported extensions that could be easily be bent by birds or the wind.

Speaking of that, one of the links K4WGE offered pointed to a somewhat funny, almost paranoid conclusion that a fractal quad had been vandalized. I'd be willing to bet it was Mother Nature personified as a bird or just the wind.........


73.

 

I don't think the courts could handle all of the infringement claims from Belmont, MA.

Flower farmers beware. Your freeway daisies are non-Euclidean fractals.

 

Dude, you need to chill; you've got one hell of a Chip on your shoulder!

 

On that F/B...How about a Number?

BTW Heath, my 2 el from a decade back had a measured gain of at least 3 dB over a dipole-- and a F/B exceeding 25 dB when listening to Europe. The attached NEC plot (courtesy Fractal Antenna Systems,Inc. (c) 1998) shows a gain of (5.41-1.81 = ) 3.6 dB over a dipole (including losses for all antennas) and a F/B of 30 dB. Corner lobes down 18 dB from front . The enclosed caption shows that Gary's somewhat modified version of the design traded off absence of corner lobes for degradation of F/B; he went for 12 dB F/B. Guess he wasnt worried about qrm from the east coast!

Enjoy!

73,
Chip W1YW

 

Always ask: "what are the facts in the case?" ;-)

Nice to meet you Dale. Hope to get down to Tony's for breakfast sometime in March. Say hi to BG if you run into to him for me

Best in 2011,
Chip W1YW

 

Chip, you are comparing a quagi to a dipole. we all know that arrays with parasitic elements will outperform a dipole, and they don't have to be fractal to do that.

 

and see, what does your parasitic array give up? it gives up omnidirectionality, it gives up frequency agility (its a 10 meter beam right?)...so not multiband. What great paradigm shift in performance characteristics are evident in this antenna??

 

Hi Heath!

I am glad you are trying to understand antenna, but you have some effort ahead.

Hams like to use directional antennas because they get higher gain, and can channel out much of the QRM and QRN that comes from directions other than where they wish to communicate with. That means, at the receiver, you hear less 'noise' and more signal. It is commonly the objective of working 'DX'. Basically the antenna is analogous to a flashlight 'beam'.

This design addressed the issue of the smallest antenna that has no components (components are ALWAYS problematic in ham antennas), easy to make ( if you make a jig the sections are made in a few minutes, fit together, and then snap into a frame with snap braces), with a 50ohm match without an ATU or matching system, with excellent gain and front to back, and excellent efficiency. I opted for just the phone band, but the antenna did very well from 28-28.7 in my version. It was optimized for my criteria as a ham ( I used something called an 'objective function', as is the custom in optimization), and those criteria were defined a priori. I needed something very small, and this one was a little over 3 feet by roughly 3 feet. There were several fractal (self similar) solutions. This one looked a bit sturdier, and it sure proved to be. I also looked at, among others, a hex beam, a Moxon, a Pfeiffer quad, various meanders, as well as the H antenna that , by happy coincidence, N3OX suggested here.

The paradigm shift in this case was instituted in 1985, when Landstorfer and Sacher came out with:" Optimisation of Wire Antennas". There, they demonstrated (on matters of interest to hams with their wire antennas)that wire antennas do best when they do NOT have standard Euclidean shapes, and that has since taken branches (pun!) into genetic antennas, fractal antennas, and fractal metamaterials. I strongly recommend that you get a copy.

I am sorry you didnt see the benefits. Perhaps you could look at the table again.

My result was that I could get on 10M and run Europeans. I came 4th in the country in the 2000 10M contest (if memory serves), running low power. My DX on 10M went from the mid 200's to well over 300 countries. I had a blast.

Unfortunately the antenna was vandalized, and we believe it was hams that did so. Between 9/11 and my son growing up, my emphasis has been on commercial antennas, although I do have various fractal antennas I now take in and out of trees. They are totally clandestine and work extremely well--and better than any other options for my application. You'd call them 'disimulation antennas'. Essentially you can't see them unless you are under them.

I'd love you to show me a better antenna that would have met my needs a decade ago. No coaching now: show us how YOU experimented and came up with something new and great--Thats one of the cool things about being a ham.

Please no 'ham porn' armchair NEC antennas...show us a built one.

Wadya got, OM?

 

Heath,

Hams compare their antennas to dipoles all the time, as it is often a useful convention of comparison for gain. Size wise, dipoles are rather large and often prohibitive in many HF/MF ham applications.

I can see by the basic nature of your question that a local Elmer might be helpful. I am sorry I am not nearby.

Bottom line: WHAT PROBLEM ARE YOU TRYING TO SOLVE?

This is the question that you start with in ALL antenna design.

Now: re-word your question with this guidance.

73,
Chip W1YW

 

Adios OM's

Well (waiting)...

I guess not.

73 and FINALLY, best to everyone in 2011. If you hear me on the air stop by and say hello. Thanks to everyone for lookin'.

SK
Chip W1YW

 

Chip, you are your own worst enemy when it comes to selling your ideas.

Of course hams compare antennas to dipoles all the time, nothing in the preceding two posts you made are beyond my level of comprehension (please quit condescending to your audience, it makes you look like a fool). But also, nothing you have offered shows a paradigm shift, a significant advantage over a conventional loaded quagi/yagi type of antenna, and certainly nothing that convinces me to buy into your "product".

As I have stated over and over, there is nothing horrific about using fractals, its a neat concept and I'm sure has its place...but I see no evidence that the entire field of electromagnetics has been turned on its head.

 

And chip, I totally understand why hams use directional antennas (I have one!)...But I also know that this antenna requires the use of a rotor, which is a disadvantage and a sort of compromise in its own right. It requires more mechanical complication, more maintenance, more cost, etc. Nothing comes without a price. Some might even say directionality is a disadvantage in certain situations.

But Chip, you didn't invent directionality. You didn't invent the parasitic array concept. You have fractal-ized an existing technology, and perhaps your claims of performance are true! But there has been a sacrifice in some other parameter as well, without question. No paradigm shift, and in this case, it is somewhat disingenuous to compare to a simple dipole, when comparing to another gain/directional antenna would be much more instructive.