- Contrary to previous assumptions, hands-free mobile phone
kits can significantly boost the brain's exposure to radiation, according
to new research conducted by British consumer research magazine Which?
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- The new findings confirmed claims that the magazine first
published in April that using hands-free earpieces could more than triple
the brain's exposure to radiation compared to a conventional mobile phone
call. That original report was dismissed in August by the British government,
which commissioned research that showed the kits did cut exposure levels.
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- The independent lab conducting the test took thousands
of measurements to explore what was causing the changes in EMF emissions.
It found that one critical factor was the distance between the top of the
phone's aerial and the ear.
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- But consumer magazine said the methodology used in the
government research was flawed. They found that the shape of the test rig
used in the government tests made it impossible to get the hands-free kit
wire into the position that gave the highest readings. According to the
report:
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- We have found two possible explanations for this. First,
the design of the SAR test rig doesn't replicate how someone would normally
use a hands-free kit. Most importantly, the wire couldn't hang down straight
- as it did when we took the highest readings in our other tests. Second,
we found that the SAR test system looks for the point in the head where
there is the highest level of radiation - and gives a final reading for
only this area. But we found that kits and phones emit the highest levels
of radiation in different places: kits emit most at the ear; phones emit
most at the user's jaw and cheek.
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- The new research confirmed that hands-free kits could
act as an aerial that channeled radiation to the ear.
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- The level of emissions depended on the distance between
the tip of the phone's aerial and the earpiece, which varied according
to how the phone was held. The government tests did not allow for this,
Which? said. According to the magazine's editor:
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- Öit'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.
Scientists agree that electromagnetic radiation from mobile phones warms
brain tissue, some strains of mice have developed cancer in tests in Australia
and Finland and that others become disorientated.
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- Which? said the kits could cut emissions by 10 to 90%
in some positions.
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- In other positions they could increase them by a factor
of up to 3.5. One reason that the government's tests did not show this
increased exposure is that they used only one position which did not allow
the wire to hang straight down, Which? said.
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- Not surprisingly, mobile phone maker Ericsson played
down the new findings in a public statement.
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- Which? said it was impossible to recommend a "safe"
position for holding a phone. Both short and long distances between the
aerial and the earpiece produced increased emissions, with only a short
length in the middle generating lower emissions than conventional mobile
phone calls. They recommend that "if you're concerned, the most important
safety-first advice is to keep the number and duration of calls to a minimum,
whether you use a phone with or without a hands-free kit."
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- To see the original report:
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- http://www.which.net/campaigns/handsfree/hfkits.html
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- Hands-Free Kit Concerns Remain, says Which? Our latest
tests confirm that hands-free kits can indeed increase the radiation from
mobile phones. Following the tests in this controversial area, our conclusion
and message to consumers remains: don't rely on a hands-free kit to reduce
the amount of radiation emitted from a mobile phone. Previous Which? tests
In April, Which? published the results of tests on a variety of mobile
phone devices, including two hands-free kits. We reported that both kits
emitted more radiation than a mobile phone alone. In both cases, these
emissions were three times higher than those generated by the phone. These
findings surprised us - we had assumed that the kits would cut emissions.
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- DTI tests Our findings were reported worldwide. In response
to UK concerns, the Department of Trade and Industry (DTI) commissioned
its own tests on kits. Made public in August, these tests seemed to give
contradictory results to ours. On the basis of this report, the government
advised that hands-free kits did indeed reduce radiation exposure for users.
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- However, although both the Which? and DTI tests were
measuring the strength of the electric field from the phones and hands-free
kits at the head, the DTI was using a different type of test called a specific
absorption rate (SAR) test. We think the way these tests are carried out
on hands-free kits is flawed and means they can't pick up the effect our
tests uncovered.
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- As the DTI published its report, we were midway through
our latest round of testing. We wanted to see whether we would find the
same results as in April if we used more phones and kits in different combinations.
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- The Latest Which? Tests Topline results Mobile phones
emit low-level radiowave radiation - also known as radiofrequency (RF)
radiation. We found that all the hands-free kits in our latest tests could
lower the level of these RF emissions. However, just as in April, we found
that they could also increase RF emissions, this time by anything from
50 per cent to 250 per cent - an increase of up to three-and-a-half times.
The critical factor ERA Technology Ltd, the independent lab we used for
our tests, took thousands of measurements to explore what was causing the
changes in RF emissions. It found that one critical factor was the distance
between the top of the phone's aerial and the ear (distance 'd'). And in
many of the positions that are likely when a kit and phone are worn in
normal use, the probe inside our test head detected higher emissions from
the kits than when the phones alone were held against the head.
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- SAR test limitations We also carried out some SAR testing
at the same laboratory used by the DTI. We found no positions where the
kits gave higher readings than the phones. But we also found that the shape
of the SAR test rig made it impossible to get the hands-free kit wire into
the position that gave the highest readings in ERA's tests. We moved the
hands-free kit wire as much as possible, and found that movement did vary
the SAR reading.
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- There is another important difference between ERA's tests
and SAR tests. ERA measured the radiation from the kits and phones at the
same place - inside the head at ear level. With SAR tests, the probe moves
around inside the test head and the equipment picks out the area where
the reading is highest. With the kits, this was again at the ear. But with
the phones, it was at the jaw and cheek. So, unlike our ERA tests, SAR
tests don't automatically give a reading for radiation emissions from phones
at the ear.
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- We think the standard that SAR tests phones have to go
through should be extended to include this so that kits and phones can
be compared properly. We also think more research is needed to investigate
whether there are differences in the effects of RF radiation emitted at
the ear (close to the brain) and at the cheek and jaw.
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- Click here for a SAR test set up diagram
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- How we carried out our specially-designed tests We tested
five mobile phones and ten hands-free kits - two were suitable for each
phone. Our tests were devised to reflect the position in which people normally
use a phone with a hands-free kit - earpiece in the ear and the phone worn
or held at about waist level.
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- We used a probe inside a dummy head to measure radiofrequency
radiation emissions. First we measured the emissions with just the phone
handset next to the ear. Then we measured them with the hands-free kit
earpiece in the ear and the phone at about waist level. From this position,
the scientists moved the phone up and down so that they varied the distance
between the tip of the phone's aerial and the earpiece (distance 'd').
They took readings for thousands of different positions.
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- We found that this distance 'd' determines how much RF
radiation the earpiece emits. The maximum emissions occurred when 'd' was
between 40cm and 47cm, and again between 58cm and 75cm, depending on the
kit being tested. Between 47cm and 58cm the emissions fell again so that
they were lower than the levels from the phones. In the positions where
the kits were giving higher readings, they were between 46 per cent and
259 per cent higher than the readings from the phones. In the positions
where they were cutting emissions, the scale of the change was less marked
- anything from 8 per cent to 97 per cent.
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- Click here for a diagram of the set up for our specially
designed tests
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- Exploring SAR tests We also carried out some specific
absorption rate (SAR) tests which use a moving probe to measure the radiation
absorbed in a liquid-filled dummy head. We wanted to explore why this type
of test has so far only shown hands-free kits cutting radiation levels
not increasing them.
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- We have found two possible explanations for this. First,
the design of the SAR test rig doesn't replicate how someone would normally
use a hands-free kit. Most importantly, the wire couldn't hang down straight
- as it did when we took the highest readings in our other tests. Second,
we found that the SAR test system looks for the point in the head where
there is the highest level of radiation - and gives a final reading for
only this area. But we found that kits and phones emit the highest levels
of radiation in different places: kits emit most at the ear; phones emit
most at the user's jaw and cheek.
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- The health question The real issue that concerns people
is whether mobile phone radiation will damage their health. Currently there's
little evidence that it causes health problems, but neither has research
given it the all clear. In a report in May, the Department of Health Independent
Expert Group on Mobile Phones concluded that exposure to RF radiation within
government guideline levels doesn't cause adverse health effects. And all
the readings we took in our tests - whether from hands-free kits or from
phones - were within these guideline levels. But the group added that there
may be other effects at or below these levels which warrant further research.
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- Despite these partial reassurances, radiation levels
remain a concern to the users of the 34 million mobile phones in the UK.
Hands-free kits were originally thought to reduce radiation - but our tests
show that, while they can cut levels, they can also increase them. This
depends on the phone, the kit, your height and where you position the phone.
Unfortunately, there's no way that an individual can work out the best
position for them to minimise the effect.
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- We want the government to take our findings into account
and devise a new standard for testing hands-free kits. But remember: if
you're concerned, the most important safety-first advice is to keep the
number and duration of calls to a minimum, whether you use a phone with
or without a hands-free kit.
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- ERA Technology Our tests were carried out by ERA Technology
Ltd, an international consulting company. ERA has a broad range of specialist
knowledge in electrical, electronic and radiofrequency technology built
up over 80 years. It also has extensive expertise in electromagnetic compatibility.
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- Phone 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
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