On Wed, 30 Sep 2009 00:46:28 -0400, "John Gilmer"
wrote:

A month or so ago I say a PBS piece on fractals. The piece claimed that
the "technology" is used to make the antennas for cell phones.

Yep. The advantages of fractal antennas are small size and wide
bandwidth. These are the prime requirements for cramming an antenna
inside a tiny cell phone. Making it work for 800/1900Mhz cellular,
2.4GHz Bluegoof and Wi-Fi, and possibly for TV, FM, WiMax, etc, is not
easy.

Have any amateurs used "fractal technology" to form their antennas?

Not intentionally, although many antennas (and towers) somewhat
resemble a fractal, especially when they crash to the ground. Same
with some "low visual impact" cell towers. To the best of my
knowledge, hams are not cramming broadband radios into packages the
size of cell phones.

Also, I note that "they" market HDTV antennas that are about the size of a
book. Do these things work? What's inside them?

Sure. So do rabbit ears, clip leads, and coat hangers. If you're in
a strong signal area, almost anything will work, including a fractal
antenna. However, if you're in a weak signal area, or are plagued by
reflections, the more traditional designs are more useful.

(Disclaimer: I've never built a fractal antenna).


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
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