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Aegis Note: As confirmed in this article, there are difficulties encountered when attempting to use ferrite chokes to prevent phone radiation from being transferred through headset wires. These include frequency considerations, inconsistency under certain operating conditions, and serious doubts about their efficacy as a safety solution.

Ask your Aegis dealer about AegisGuard™ Headset Wire Radiation Shields.

Scientists Believe A Ferrite Choke Clipped To The Wire Of A Hands-Free Set Could Dramatically Lower Radiation
Financial Times
Journalist: Stephen Overell
February 12, 2001

Last August, Patricia Hewitt, minister for e-commerce, gave "unambiguous advice" that hands-free kits for mobiles reduced radiation exposure. Then, in December, the government changed its mind, following a report from the Consumers' Association that said mobiles with hands-free kits beamed 3.5 times more radiation into a user's head than mobiles on their own. Now, it says it does not know.

Until there is better research, government leaflets advise a "precautionary approach". That leaves mobile owners in a quandary. Although there are no proven health risks in using a mobile either with or without a hands-free kit, some studies have found that phones can cause changes in brain activity even within the international guidelines for specific absorption rate - the measurement of the rate at which radiation is taken into the body.

More worrying is the drip-drip of stories that have linked mobiles variously to brain tumours, eye cancer, Alzheimer's disease, memory loss, headaches and even poisoning - with the electrical fields given off by mobiles activating the mercury in dental fillings.

So what is the best thing to do? Most scientists still believe that hands-free kits are significantly better than clasping a phone directly to your ear and question the methodology of the Consumers' Association research. But there is a growing body of opinion that believes the uncertainty means it could be time to incorporate a device called a ferrite choke into hands-free kits to block even more radiation from travelling up the wire.

A ferrite choke looks like what it is: a tiny lump of metal in a plastic case. Ferrite is a magnetic material and chokes clipped around cables are widely used in suppressing unwanted radiation from electronic equipment such as computers and fax machines. Different mobile networks run at different frequencies, which require chokes to be fitted at different points on the hands-free wire. But there is agreement among experts about the principle that ferrite could effectively mop up radiation.

Mike Manning, managing director of SARtest, a leading mobile phone research centre, says: "They (the chokes) will further reduce the radiation going up the wire. The use of a hands-free kit already cuts it down but, given the current social environment, a choke would make it even better."

Simon Best, editor of Electromagnetic Hazard and Therapy, a specialist news service, agrees. "A choke would considerably help stop radiation from going into the head. It is not rocket science. A ferrite choke is a terribly simple little thing."

So why hasn't it been done before? The official position of the Federation of the Electronics Industry on ferrite chokes is that they "work at some frequencies but not at others". Nokia, the phone manufacturer, is even vaguer: "In certain circumstances they can have the effect of reducing radiation but many different factors are involved."

From the point of view of the manufacturers, there is no evidence of a health risk from mobiles, so there is no need for additional safety devices. Yet there are also independent voices who question whether ferrite chokes could ever be a really satisfactory solution.

Dr Gerard Hyland, a senior lecturer in physics at Warwick university, argues that any electronics expert would agree that a ferrite choke on a hands-free kit reduces the amount of radiation going into the head. But he says this is not the fundamental issue.

"A choke would bounce the radiation back towards the handset," he says. "Because many people carry the handset on their person, they would still have surges in radiation on the handset itself. Unless the phone is on a desk or mounted on a unit, it just transports the problem to another area of the body." (Aegis Note: Dr. Hyland is correct. Ask your Aegis dealer about AegisGuard™ LS and XP Radiation Shields.)

That said, the controversy surrounding mobile phones has so far focused on the head. And for people worried about the effects of radiation entering the brain, a hands-free kit with a choke is probably about as close as anyone can practically get to anxiety-light mobile use in the current climate. Other scientific feuds will doubtless follow.

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