COFFEE shops and cafes across Britain are set to become focal points for wireless connections to the Internet. You鈥檒l just walk in with your laptop and log on. The idea has already taken Silicon Valley by storm, but the service will further concern campaigners in Britain worried about the proliferation of microwave radiation sources.
British Telecom (BT) says it will install 4000 microwave antenna 鈥渉otspots鈥� in high street cafes and on payphones over the next three years. Anyone within 300 metres of an antenna will be able to log on to the Net, providing their laptop is fitted with a suitable wireless networking card. Companies who鈥檝e shown an interest include a chain of high-street coffee shops and a motorway cafeteria business.
BT says its IEEE 802.11 wireless networks will work at 2.4 gigahertz, a microwave frequency already used for industrial and medical instruments. And recently the Bluetooth system, which allows electronic devices to communicate, started using the same frequencies.
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While there鈥檚 no evidence that microwaves like those from mobiles pose any risk to health, recent research found that the radiation has non-thermal effects on animal cells (快猫短视频, 9 February, p 4).
Alasdair Philips of Powerwatch, an independent watchdog that monitors electromagnetic field issues, says of BT鈥檚 hotspot idea: 鈥淚鈥檇 worry most about people who work long hours close to a transmitter.鈥� Customers in coffee shops tend to use mobiles a lot in any case, so the radiation from the new network won鈥檛 make much difference, he says. Staff will be exposed for much longer. But as with cellphones, there鈥檚 no evidence that such low-power microwave radiation presents any threat to health.
Andrea Vocale, who is development manager for wireless technology at Cisco Systems鈥攐ne of the companies working with BT to set up the networks鈥攕ays the 50-milliwatt transmitters pose no risk. 鈥淭here may be a perception of risk. But concern over mobiles is UK-specific, and the wave of concern is going down.鈥�