Radiation concerns about mobile hands-free kits

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The latest research by Which? confirms that levels of radiation inside the head can be increased by mobile phone hands-free kits by up to three and a half times.

There is currently no agreed international standard for testing mobile phone hands-free kits. Which? wants more research to be done in this area and is urging the UK Government to press for a new European standard specifically for hands-free kits.

Following publication of its controversial findings in April this year, Which? commissioned more research to determine whether this effect was found in other phones and hands-free kits and to investigate apparent differences between its test results and others.

“The results of the latest tests show that for all the hands-free kits tested in positions that people would normally use them, the level of radiation emissions can increase significantly. The highest increase was three-and-a-half times. We also found that by changing the position of the wire, we were able to reduce emission levels. These results indicate that the picture is more complicated than the DTI suggested in August.

Which? found that with the kit wire hanging straight down, the critical factor in determining radiation emissions, is the length between the earpiece and the mobile phone antenna.

Which? was also able to uncover a potential solution to the higher levels of emission. Having carried out some preliminary testing, we found that fitting ferrites (metallic / ceramic compounds designed to absorb electro-magnetic fields) on the hands-free kit wire below the ear seems to reduce the levels of radiation into the ear. Which? wants the mobile phone industry to carry out further research in this area.

Hoping to identify why different tests (SAR* tests) indicate that hands-free kits reduce radiation, Which? also carried out this type of test at the same laboratory used by the DTI. We discovered problems in the way some SAR test rigs are erected for tests on hands-free kits, including that the wire cannot hang straight down – as in normal use – in positions where we found maximum emissions.

Another important difference between the Which? tests and SAR tests is that the maximum SAR reading from a mobile phone appears at the cheek and jaw, but the maximum SAR reading from a hands-free kit appears at the ear. The Which? tests take both readings inside the head in line with the ear. Because radiation may affect the tissue in the brain differently from the tissue in the cheek and jaw, Which? wants to see further research carried out.

There is no agreed international standard for testing mobile phone hands-free kits. Which? wants more research to be done to set a standard and urges the Government to take this latest research into account to arrive at an agreed protocol.

Helen Parker, editor of Which? said:

“As in our earlier tests, it’s clear that consumers can’t rely on hands-free kits to reduce radiation emissions at the brain from mobile phones.

“Although these kits can reduce radiation, they can also increase it significantly, depending on where you position the phone and kit. Unfortunately, there is no way that consumers can work out the best position to reduce radiation.

“We were able to reveal some good news for mobile phone users – ferrites fitted to the wire just below the ear seem to reduce radiation. So we’re looking to the hands-free kit manufacturers to carry out further research and – if they are proven to work – then incorporate ferrites into hands-free kits.

“Our latest tests are the first to investigate the reason for the different results for mobile phone hands-free kits tests, and we want our results to inform the study of radiation from mobile phones and the development of a specific international standard for testing hands-free kits.”

ERA Technology, an independent consultancy with expertise in electromagnetics, conducted the tests for Which? Chris Perks, commercial director of ERA, said:

“Our test results for Which? have shown that it’s possible to simulate situations where measured emissions from hands-free kits differ from results of other tests. This suggests that the range of tests may need to be extended to account for the changing ways in which mobile phones are used.”

Which? published results of tests on two hands-free kits that found the kits tripled radiation into the ear (Ring of Truth, Which? April 2000).

The DTI published a report on 8 August which stated that hands-free kits reduced exposure to electromagnetic fields.

Which? tested the following phones and hands-free kits:
Ericsson T18s
Ericsson Portable hands-free
Orange kit mains libre*
Nokia 3210; Nokia headset for 3210
Hama headset for 3210*
Nokia 5110; Nokia Headset HDCGP 51/61/71
Telcom Personal Hands-free earpiece*
Panasonic GD50; Panasonic EB EMD 70 for GD50
Cellular Access for Panasonic GD50*
Philips Savvy/C12; BT Cellnet hands-free accessory kit for Philips Savvy
Telcom Personal hands-free earpiece

* These kits are not available in the UK, but were tested for comparison with European Consumer organisation tests.

*SAR (Specific Absorption Rate) tests measure the rate of energy that is absorbed, or dissipated in a mass of dialectic materials, such as the biological tissues.

Because some SAR test rigs do not allow the wire to hang straight down as it would in normal use, the crucial vertical difference of the wire between the earpiece and the antenna cannot be taken into account. Even the SAR tests carried out by the Australian Consumers’ Association, which taped the wire to the test body, did not explore the variation of the distance of the wire.



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