fractals and HDTV antennas
 

Hi:

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.

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

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

Yours,

JLG

fractals and HDTV antennas
 

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

Hi:

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.

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

-sigh-

Any? Yes.
Many? No.

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

They work about as hard as Bernie Madoff worked.

The most enthusiastic fractal supporters here are those who never
built any, couldn't show you a design if they were forced to google
for one, and pound their breast about how modern inventors are reviled
in their own neighborhood. The most successful merchant who has dared
post here would sue you if you tried to make your own.

What's inside them?

Wire (metal). Same as any antenna.

What makes you ask?

73's
Richard Clark, KB7QHC

fractals and HDTV antennas
 

"John Gilmer" wrote in message
net...
Hi:

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.


That might be true. There's certainly material on the www about research
into fractal antennas that can be Googled, such as
http://ceta.mit.edu/pierb/pierb14/07.09030802.pdf


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

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


As you may realise, terrestrial broadcasting provides a large margin for a
lot of households which makes it possible to receive good signals in some
areas using a dead sheep. Consequently indoor television antennas are sold
in a variety of styles and, at some locations, some of them work - even if
they have meagre electrical characteristics. Unfortunately, there is a
tendency for unqualified folklore to arise about antennas that appear to
work (in particular circumstances). The DVB-T system used in Europe is
particularly resistant to multipath distortion, which helps.

Some book-sized efforts contain a PCB bow tie in front of a plane reflector.
In others, the shapes of the elements are fiddled around with like
http://www.instructables.com/id/How_...DTV_DTV_plus_/

Chris

fractals and HDTV antennas
 

Wow. Been a while. Last time I saw or wrote anything here about fractals was
over ten years ago, and someone in the group threatened to sue me/everyone
who was not a supporter of the technology.

I do know that I have seen mention of this technology relative to hand held
ATSC receivers for mobile video (cel phones, etc)

GeorgeC


"John Gilmer" wrote in message
net...
Hi:

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.

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

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

Yours,

JLG

fractals and HDTV antennas
 

"John Gilmer" wrote in message
net...
Hi:

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.

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

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

Yours,

JLG


Heh heh....just sitting here recalling the GFW (Great Fractal War) on this
newsgroup a few years ago.
Where is Chip when we need him :)

fractals and HDTV antennas
 

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
Skype: JeffLiebermann AE6KS 831-336-2558

fractals and HDTV antennas
 

John Gilmer wrote:
Hi:

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.

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

I recall a 10 meter fractal antenna. Strange looking thing. Disappeared
some time ago from the web.

It's interesting that they call fractals "technology". Any of us could
generate a usable fractal, and form some wire along that pattern, and
make something. "Fractal" is no more technology than is "dipole".

There is a fellow who used to post here who has a company that makes
such antennas. When I first came to this group, there was a war winding
down. I never had any problems with the guy, but whoeeee the arguments
were running hot.

But on the antennas themselves, they work, but they are not a substitute
for a lot of other high performance antennas. All antennas are
compromises, and Fractal ones are all about getting an antenna into a
small space. The are mostly UHF also. That ten meter antenna was the
exception, not the rule. HF? Imagine a 160 meter Fractal. No matter how
it's done, it's still going to be big. If you have a small box running
at UHF, you might think about putting a fractal (or it's cousin, a small
random pattern antenna) in it. But if you want to run 80 meters in a
small yard, there are better ways of doing it.

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

Define work. 8^) *Real* close to the stations? then probably. As for
what's inside, if there was any design at all, probably a dipole cut for
the approximate frequency. But that's a guess. IMO they are a wast of money.

- 73 de Mike N3LI -

fractals and HDTV antennas
 

On Wed, 30 Sep 2009 09:43:33 -0700, Jeff Liebermann
wrote:

Myth number one:
Yep. The advantages of fractal antennas are small size and wide
bandwidth.

73's
Richard Clark, KB7QHC

fractals and HDTV antennas
 

On Wed, 30 Sep 2009 13:31:22 -0400, Michael Coslo
wrote:

I recall a 10 meter fractal antenna. Strange looking thing. Disappeared
some time ago from the web.

Same page for ten years now:
http://www.qsl.net/kb7qhc/antenna/fr...sket/index.htm

73's
Richard Clark, KB7QHC

fractals and HDTV antennas
 

Richard Clark wrote:
On Wed, 30 Sep 2009 13:31:22 -0400, Michael Coslo
wrote:

I recall a 10 meter fractal antenna. Strange looking thing. Disappeared
some time ago from the web.

Same page for ten years now:
http://www.qsl.net/kb7qhc/antenna/fr...sket/index.htm

Ahh, I didn't know about your page. The one I was thinking about had an
actual picture and construction ideas.

So you're in the Puget Sound area? I used to stay in Poulsbo fairly
often. Spent some evenings at the "Sons of Norway" club there. Coslo is
a good old Norwegian name! 8^)



- 73 d eMike N3LI -