Independant Expert Group On Mobile Phones
RECENT STORY ...
According to a recent Daily Mail front cover headline:
'HANDS FREE' PHONE SHOCK
Hands free kits for mobile phones can actually increase radiation exposure ....
.. tests for the CA's Which? magazine have found that two kits - one for a Philips Savvy phone and another for an Ericsson - tripled the radiation level going into the head. While the watchdog did not have time to test other kits, it believes the results would be similar.
Daily Mail, Tuesday, April 4, 2000
A simple CSC test-
The Creative Science Centre has recently tested (6 April, 2000) an Ericsson SH888 and a 'standard' hands free kit. Using the wavemeter described in the associated web page we clearly measured a signal from the mobile phone antenna but were unable to measure any signal from the hands free wire or earpiece. This suggests that, for the above phone at least, the headlines might be a little missleading.
However the situation maybe more complex than it first seems. The earpiece fits very close into the ear and so is much closer to the brain and ear than the standard mobile phone. The radiation field strength is sensitively dependant on the distance from the radiation source (although the exact strength is complex to calculate very near to the radiation source) and increases greatly as the distance decreases. It may be that although we have not been able to actually measure any field with our very simple meter, even a small field might actually represent some risk.
Of course other handsfree kits may radiate more than our test case. If this is so the radiation might be passing from the phone itself down the outer wire (the screen) of the handsfree wiring. A simple inductor fitted near to the socket of the hands free kit might solve this problem. As a first attempt at addresing this problem we might be able to make a simple inductor actually from the earpiece cable itself; wind about four or five turns of the wire (nearest to the socket) around a finger to form a coil, remove the finger and tape up the coil to stop it unwinding. Some experimentation might be needed in the 'coil' design to reduce capacitance between the turns of the coil (Note: ferrite cores which are often used for these type of inductors might not work at these frequencies). This make shift inductor should a) reduce radio frequencies from entering the mobile phone and b) reduce any that might be transmitted from it.
It is also possible that the hands free lead itself may act as a receiving antenna (picking-up signal from the mobile phone antenna) and lead to re-radiation (into the ear for example). One would have thought that this is likely to be quite small because the cable is unlikely to be resonant, and also that it is some distance from the antenna.
for further information on mobile phones click below:
Are mobile phones safe ?
to go to the absorption meter click below:
ARE MOBILE PHONES SAFE ? - Some interesting articles:
RADHAZ, Brian Collins, Electronics World, Oct 2004, P.30-36
Radiation Hazard, special issue Elector Magazine, June 2005
For a good over view of the work done on the short term effects of mobile phone radiations see The New Scientist Article :
Get your head round this ... SPECIAL INVESTIGATIONS, MOBILE PHONES,
The New Scientist, 10 April 1999, page 20-25
see also The New Scientist web site:
I will try to add more documents / articles as they come up.
THE CREATIVE SCIENCE CENTRE
University of Sussex, JPH 01
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