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News

Fractal Antennas, Hype or Hope

By Dan Romanchik, KB6NU

 

QRZ.Com currently has a very interesting item on fractal antennas (http://forums.qrz.com/showthread.php?t=277623). While the idea of applying fractals to the design and construction of antennas has been around for quite some time, very few hams have actually built them, and there are currently no companies building commercial fractal antennas for the ham radio market. The question, of course, is why?

Those that are hyping fractal antennas—most notably W1YW, CEO of Fractal Antenna Systems—claim several advantages. These advantages purportedly include wider bandwidth and smaller size when compared to traditional antennas, such as verticals and dipoles. Those that are trying to debunk these claims contend that this is all just hogwash, and that there's no real scientific basis for these claims.

One thing that's confounding this debate is that there have been very few articles published on the topic. For commercial reasons, W1YW has made his articles unavailable. He says that he will be publishing something real soon now, but there is nothing definite at this point.

There is at least one article on the Internet that describes the construction of a fractal antenna for amateur radio use. "FYI:FYQ: Another look at the Fractal Quad Yagi" (http://www.scribd.com/doc/18788401/FYIFQY) was published in the October 1999 issue of 73 magazine. It describes the construction of a two-element, 10m antenna. Like most 73 articles, it's not incredibly technical, though, and doesn't really contribute to the technical debate, except to demonstrate that physically small antennas can be made using fractal design.

The PDF contains several photos of the antenna. It's a crazy contraption that looks relatively difficult to build. So difficult, in fact, that it makes me wonder if it's even worth it to try building one. After all, 10m antennas are not really all that big or all that difficult to build to begin with.

Even more interesting than the antennas are the personalities on both sides of the debate. The QRZ.Com discussion quickly devolved into a flame war, with neither side scoring a knockout.

Personally, I think the brouhaha is much ado about nothing. It seems to me that it's been demonstrated that you can build antennas using fractal design techniques. They are physically smaller than traditional antenna designs, but you really don't get something for nothing. Overall, they don't have as much gain as yagis or quads, and they're more complex to build.

My opinion on this is that if W1YW can build antennas that radiate a signal and can sell those antennas to someone, then more power to him. In the end, his company will live and die by how well, his antennas work and how much they cost when compared to antennas from other companies.

As for me, I think I'll stick with the more traditional HF antennas. If I need to make my antennas smaller, I'll use loading coils or designs such as the Moxon. I may not be on the bleeding edge of technology, but I'll certainly avoid a lot of headache trying to figure out who's right.

=======================

When not avoiding flame wars on QRZ.Com, Dan, KB6NU, operates CW on the HF bands, writes and publishes license exam study guides, and teaches ham radio classes. You can find his ham radio blog at www.kb6nu.com.

Solar Data

29 May 2017 2008 GMT
SFI: 75
SN: 20
A Index : 51
K Index : 3 / No Report
X-Ray : B1.2
304A : 105.3 @ SEM
Ptn Flx : 1.16e-01
Elc Flx : 2.55e+02
Aurora :  2 / N = 1.99
Mag (Bz) :  4.5
Solar Wind : 370.0 km/s
Band
Day
Night
80M - 40M
Poor
Fair
30M - 20M
Fair
Fair
17M - 15M
Poor
Poor
12M - 10M
Poor
Poor
Geo-Magnetic Field : UNSETTLD
Noise : S2-S3
foF2 : 5.0
Solar Data provided by hamqsl.com