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[IP] more on Bead 'slashes mobile radiation'



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Date: Tue, 25 Jan 2005 06:37:55 -0800
From: Joe Pistritto <jcp@xxxxxxxxxxx>
Subject: Re: [IP] Bead 'slashes mobile radiation'
To: dave@xxxxxxxxxx
If your readership wants to try this for themselves, you can get "split" cores that actually clamp over a cable. (the best thing to do is to run the cable through a number of times, the inductance goes up as the square of the number of windings).. The smallest "split" cores are fairly large for things like phone headsets but i found one that's not *too* big at Universal Radio. 

<http://www.universal-radio.com/catalog/misc/amidon.html>http://www.universal-radio.com/catalog/misc/amidon.html
Amidon makes a large number of these cores that amateur radio people use to reduce RF (at much lower frequencies generally than cell phones). However i dont see why they wouldn't work for cell phones as well. (although the required core size is much smaller at those frequencies).
The core you want is the Amidon 2x31-1428p2 - this is a little over an inch long and 3/4 inch in diameter. There might be smaller "clamp on" ones, but i havent found them. If you wanted to cut the cable and solder, you could use a much smaller core to achieve the same effect. Universal sells this one for $3.75 + shipping. 

David Farber wrote:


------ Forwarded Message
From: Dewayne Hendricks <mailto:dewayne@xxxxxxxxxxxxx><dewayne@xxxxxxxxxxxxx>
Reply-To: <mailto:dewayne@xxxxxxxxxxxxx><dewayne@xxxxxxxxxxxxx>
Date: Tue, 25 Jan 2005 03:14:18 -0800
To: Dewayne-Net Technology List <mailto:dewayne-net@xxxxxxxxxxxxx><dewayne-net@xxxxxxxxxxxxx> 
Subject: [Dewayne-Net] Bead 'slashes mobile radiation'

  Bead 'slashes mobile radiation'

Radiation from hands-free mobile phones can be reduced to virtually
zero by a simple tiny magnetic bead which costs a few pence, a
government adviser says.

  Professor Lawrie Challis said clipping a ferrite bead on kits stops
the radio waves travelling up the wire and into the head.

  He called on the mobile phone industry to start using them "as
standard".

  The beads, which often measure less than 1cm in diameter, are commonly
used to stop data interference in computers.

  Professor Challis, who is chairman of the Mobile Telecommunications
and Health Research Programme, told BBC News: "There is no evidence yet
that mobile phones are harmful to health but people have not been using
them long enough for us to be sure.

  "Using a ferrite bead effectively reduces emissions to the head to
zero but as yet manufacturers do not put them on hands-free kits."

  And Professor Challis, who was also on the Stewart committee which
looked into mobile phone safety in 2000, added: "I am not sure why, but
I wish they would. They could use it as a marketing technique, you
would think they would like to promote it."

  While studies have shown hands-free kits reduce radiation, emissions
still travel up the wires on the outside and are absorbed by the head.

  The beads work by absorbing these "unintentional" emissions.

  Wires

  Dr Stuart Porter, of the department of electronics at the University
of York, said he agreed with Professor Challis's comments.

[snip]

  Story from BBC NEWS:

<http://news.bbc.co.uk/go/pr/fr/-/1/hi/health/4203077.stm>http://news.bbc.co.uk/go/pr/fr/-/1/hi/health/4203077.stm

  Published: 2005/01/25 08:27:20 GMT


Archives at: <http://Wireless.Com/Dewayne-Net>
Weblog at: <http://weblog.warpspeed.com>


------ End of Forwarded Message


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