Hands-6.00
Kit Concerns Remain
Which?
November, 2000
Our latest
tests confirm that hands-6.00 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-6.00 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-6.00 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.
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-6.00 kits
did indeed reduce radiation exposure for users.
However,
although both the Which? and DTI tests were measuring the strength of the
electric field from the phones and hands-6.00 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-6.00 kits is flawed and
means they can't pick up the effect our tests uncovered.
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.
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-6.00 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.
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-6.00 kit wire into the position that gave the highest readings in ERA's
tests. We moved the hands-6.00 kit wire as much as possible, and found that
movement did vary the SAR reading.
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.
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.
How we
carried out our specially-designed tests
We tested five mobile phones and ten hands-6.00 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-6.00 kit - earpiece in the ear and the phone
worn or held at about waist level.
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-6.00 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.
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.
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-6.00
kits cutting radiation levels not increasing them.
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-6.00 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.
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-6.00 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.
Despite these
partial reassurances, radiation levels remain a concern to the users of the 34
million mobile phones in the UK. Hands-6.00 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.
We want the
government to take our findings into account and devise a new standard for
testing hands-6.00 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-6.00 kit.
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.
| Phone |
Hands-6.00 kits |
| Ericsson T18s |
Ericsson Portable hands-6.00
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-6.00 earpiece* |
| Panasonic GD50 |
Panasonic EB EMD 70 for GD50
Cellular Access for Panasonic GD50* |
| Philips Savvy/C12 |
BT Cellnet hands-6.00 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 |
