Cell Phones -- Unsafe At
What Speed?
ZD Net News
Journalist: Jane Wakefield
October 27, 2000
Motorola says its earlier
comments on the radiation safety of newer, faster mobile phones were wrong,
but declines to explain why.
Motorola says a New Scientist
report on GPRS radiation safety was wrong, but declines to explain why.
Mobile manufacturer Motorola is
backtracking on recent comments by its spokesman suggesting that GPRS, the
high-speed successor to Global System for Mobile Communications (GSM), might
have to be made slower in order to stay within radiation absorption
guidelines.
Motorola Marketing Manager
Rainer Lischetzki recently told New Scientist that implementing GPRS at the
speeds its marketing division has hyped -- between 27Kbps and 86Kbps -- could
cause a phone to overheat. He also said such speeds could push a phone's
microwave radiation beyond European guidelines on the energy that can be
absorbed by the brain.
But Motorola (NYSE: MOT) now
says the New Scientist report was at fault, claiming that Lischetzki is not
"qualified" to discuss GPRS issues despite the fact that he is
Motorola's technical marketing manager for GPRS.
ZDNet's request for an
interview with Lischetzki was refused. According to Mark Durrant, Motorola's
director of communications, the company is not prepared to risk "another
inaccurate report."
Instead, Motorola has issued a
statement conceding that, "Whilst the initial GPRS phones that enter the
market may not operate at their highest theoretical data speeds, that fact is
not related to the issues raised by New Scientist." Motorola offers no
explanation about why higher speeds will not be available.
However, the Department of
Trade and Industry (DTI) confirmed that higher speeds could be potentially
dangerous. "It is conceivable that GPRS devices ... could produce
exposures above the levels specified in the Council Recommendation," said
a DTI spokesman.
Simon Mann, technical spokesman
for the National Radiological Protection Board (NRPB) agrees, saying that
although mobile manufacturers will have to observe regulations governing the
emissions from mobile phones, it is "entirely feasible" that some
GPRS mobiles, particularly those at the top end of the market, could tip over
the (emission) limits."
The
issue is speed
The issue revolves around whether or not GPRS mobile phones will operate at
the speeds mobile manufacturers are touting. Typically, GPRS mobiles are hyped
as transferring data about three to five times faster than current mobiles,
although consensus suggests these speeds are exaggerated.
Analog mobile phones have a
transmitter that is on all the time when making a call, with one phone having
exclusive use of one radio channel. GSM phones share channels, with up to
eight phones taking turns to transmit short bursts of data on a single
channel. This means that although a GSM phone has a maximum power output of
two watts, in practice it transmits an eighth of that -- quarter of a watt,
maximum. This can, and frequently is, reduced still further.
To save battery life and to
increase the number of phones that can be handled by the system, the mobile's
power is automatically adjusted to the minimum necessary to keep a reliable
link with the base station.
GPRS uses exactly the same
system, but to increase the amount of data transferred a phone can use more
than one slot. Thus a three-slot GPRS link, carrying about 30 to 40Kbps, will
use a maximum of three-quarters of a watt. This is roughly the same as an
analog phone used for a single voice call, but as with GSM, the power levels
will often be lower than the maximum, especially in areas with many base
stations or few buildings.
Average power levels are
further reduced because GPRS is a packet-based system: The transmitter is only
on when data is being sent and is idle otherwise. A file transfer from the
phone to the base station will make the transmitter work at full tilt;
keystrokes or Web browsing will only fire up the transmitter occasionally,
reducing the average power output to a few milliwatts.
When ZDNet eventually got to
speak with Lischetzki, he said confusion over what speeds GPRS would actually
run at were damaging both for Motorola and for the mobile industry in general
and that his comments about the safety of GPRS mobiles were misconstrued. He
offers no clarification on theses comments.
Motorola's refusal to answer
questions was condemned by the Consumers' Association. "Given the concern
among consumers about health issues and mobile phones, I think Motorola's
actions are unhelpful," said a spokeswoman. She added: "Clarity is
needed on these issues. It's a topic of concern for many consumers."
