archive: Re: SETI Fwd: Fractal Antenna Distance Record Set

Re: SETI Fwd: Fractal Antenna Distance Record Set

Fractenna@aol.com
Tue, 22 Dec 1998 05:04:17 EST

In a message dated 12/21/98 11:23:23 PM Eastern Standard Time,
MarcusJohn@aol.com writes:

<< From the business news wire, courtesy of our good friend Nathan 'Chip'
Cohen:

John Marcus.

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Subject: Fractal Antenna Distance Record Set
Date: Mon, 21 Dec 1998 09:57:15 EST
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Fractal Antenna Distance Record Set

FT LAUDERDALE--(BUSINESS WIRE)--Dec. 21, 1998--Fractal Antenna Systems,
Inc. today reported that after a five month shakedown, a `ham' radio antenna
has shown that small things go great distances. In this case, a small fractal
antenna.

Fractals are a family of geometric shapes that repeat their pattern over
a variety of size scales.

Nearly 1/4 the regular size of a conventional Yagi-Uda dipole beam, the
fractal beam consists of two folded dipoles bent into fractal shapes. Each is
about 1.5 meters on a side, a tiny fraction of the 10 meter wavelength
employed for the radio contacts.

Dr. Nathan Cohen, CTO of the company, radio astronomer, and assiduous
radio amateur, has used the fractal Yagi on top of a short tower to make
thousands of radio contacts all over the world from the company's R&D
facilities in Massachusetts. In doing so he has set a new record--the small
fractal antenna easily made contact with dozens of stations in Europe--using
only 1 watt. Contacts with stations in Palau, Papua, and many other exotic
Pacific locations were accomplished successfully with only 2 watts.

As a point of reference, typical cell phones use about one watt of power
to accomplish local transmissions to cell sites.

At a stretch of over 5000 miles per watt, the fractal antenna has gone a
long way. Cohen pioneered the field of fractal antenna elements after hearing
a conference talk by Benoit Mandelbrot, the fractal mathematician founder, in
1987. First publicly reporting his results in 1994, and publishing the first
article in 1995, Cohen has started a field with internationally recognized
significance, and research teams in many countries, as well as the United
States. Cohen has recently been recognized for this accomplishment by being
appointed a finalist in the 1998 Discover Awards for Technological
Innovation,
as reported in the July issue of that magazine.

Downplaying the novelty of the distance record, Cohen nonetheless
stressed the lessons learned from it. " The fractal Yagi antenna proves
extremely efficient and high in performance, irrespective of its diminutive
size." Cohen added, " no discrete electronic parts or matching units were
used
or necessary. This is a `plug and play' antenna."

Although Fractal Antenna Systems, Inc., does not sell ham antennas, it
has made details available on its patent pending design for experimentation
by
hams. Its commercial, proprietary fractal antenna designs are predominantly
at
cell phone frequencies and higher, where they comprise tiny etched circuit
boards rather than the bent wires of the ham antenna. Details are available
on
its web page at http://www.fractenna.com.

CONTACT:

Fractal Antenna Systems, Inc.

Phil Salkind, 617-489-8824

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Hi John--

I appreciate you mentioning this but unfortunately there is minimal overlap
with SETI:-( I have kept Rob Dixon abreast of these developments but he hasn't
followed through; I offered to help the SI out with some fractal feeds last
March (at cost I might add) but like everything else I present to them, it
goes nowhere. Ergo I have stopped talking with them at all. I am sure I am not
unique in this experience.

I do like to remind people that fundamentally this is a 'ham grown' technology
and this particular piece seemed a fun one to get some ham radio kudos in.

Scientifically there has been a breakthrough in understanding the role of
fractals in electromagnetics; that is manifest in a manuscript submitted
recently, which I can talk about when its accepted--and off list:-)

I do get on 10M with this antenna and generate pileups--and I'm not talking
contests. Just regular everyday 10M stuff. Here's a nice 5 minute snip of my
log on 10M sideband, beginning on 12:52 UTC and ending 12:57 UTC on 6 Dec
1998:

2W0AQP
HB9DDS
DL8BTL
LA7JBA
G3TKK
FB1BON
EI5EV
LA9EX
RU3FM
S57MVD
RA3DX
RA3DKE
LA9BX
G3ENX
G4YXB
OH3DF
LA2NCA
HA5BWW
I8LCM
SP7MOQ
IK2ODD

I realize the rate is very, very high; obviously I am doing 'W7RM'-like
operating with signal reports only. I am sure that being posted on the DX
clusters in Europe helps.

The antenna is not doing anything out of the ordinary as an ANTENNA. What IS
unusual is how well it works for its small size and simplicity feed.

73
Chip N1IR