Networking

Peter Cochrane's Uncommon Sense: Mobile myth busting

What's true and what isn't?

Ever wonder if your mobile phone is really killing your brain cells? Or why you can't use it in hospitals and on airplanes? Peter Cochrane takes on the top myths about mobile technology.

It is hard to recall a technology that has been so universally enjoyed and at the same time so vilified as the mobile phone. Perhaps as proof of its popularity, I have noticed what superb urban legends have risen up around the device and mobile technology in general.

The first is the notion that mobiles are cooking your brain with radio waves.

Despite all the evidence to the contrary, we have groups and individual zealots dedicated to proving mobile phones are dangerous. But most users don't seem to be unduly worried. For a change, common sense seems to have overcome irrationality and hysteria and the world's population employs mobile technology as they might use a pencil.

We have been using mobile devices for over 50 years - since World War II - with power levels ranging between 50MW and 50W. And there have been no positive or confirmed detrimental effects on the brain so far. However, the number of lives saved by instant communication on the move is in the many thousands. So the equation of benefit to potential risk seems to be approaching infinity.

Let me assure you that this is not true of all technologies that we have accepted and use everyday without a second thought. Power tools, automobiles, microwave ovens, electric fires and toasters are but a few of the most common risks we encounter.

The second urban legend: recently I spent quite a bit of time in hospitals and medical facilities with signs asking people not to use their mobile phones for fear of interfering with medical equipment. Considering that the equipment was designed to be used in a public place, I thought the risk of interference was extremely unlikely but like everyone else I complied. And who wouldn't?

It was with some amusement and curiosity that I soon observed that all the wards and many of the offices I visited were equipped with cordless phones. These devices emit a steady 5W no matter how far they wander from their base. In contrast mobile phones emit at most 0.5W. Next I observed that many of the staff - janitors, administrators, nurses and doctors - used their mobile phones throughout the hospital.

What magic technology prevents the staff cordless and mobile phones from interfering with medical equipment? None! They all obey the same laws of physics and cordless devices are actually far more of a threat than my mobile. So what's going on here? I suspect that most hospitals have done deals with phone companies to get a slice of the lucrative patient-relative communications traffic. Telephones on the wards and in the rooms charge 10 times the normal per-minute cost of a standard landline call.

Another mobile-free zone I regularly visit is the airliner, the site of the third urban legend I will take on. Without exception, mobile phones must be turned off during airplane flights. This sounds sensible but I cannot find a single incident of confirmed interference and problems - just a lot of scare stories and rumour. Even more interesting, I am writing this after taking a flight on which a new Wi-Fi service was being tested. The 2.4GHz 0.1W radiation for the Wi-Fi equipment is sure to be equally or even more risky for aircraft systems than a 0.9GHz 0.5W signal from a mobile.

A quick calculation reveals that a modern airliner travelling at cruise altitude and anywhere under 300km per hour would be seen by a mobile phone station as the plane crosses contiguous cells. Now Doppler shift will cause a GSM mobile phone to lose signal lock at around 170km per hour. So any user of a mobile phone - air to ground - would experience a lot of dropped calls for a significant percentage of cell coverage.

But it gets worse. The terrestrial mobile networks were never designed to cope with the rapid cell-to-cell handovers presented by passenger airlines, let alone the concentration of mobile phone users they usually transport.

So I wonder if there has been a deal between mobile providers and airlines that resulted in the in-flight telephones that charge $2.50 per minute. Though I must say, in all my years of flying I have only witnessed two people use seat back phones on an aircraft.

How many brains have been fried, patients killed and airplanes crashed by mobile phones? I can't find any numbers or solid evidence to answer these questions. I suspect the answers are zip.

One thing I can tell you: if you are concerned about the use of mobiles on aircraft, just consider the engine management and safety systems in your car the next time you phone home on the freeway. They are as equally susceptible to inference as those on an airplane.

Drafted at the Berlin Marriott Hotel, rewritten on Kiawah Island NC and despatched to silicon.com via the Washington Hilton business centre LAN.

About Peter Cochrane

Peter Cochrane is an engineer, scientist, entrepreneur, futurist and consultant. He is the former CTO and head of research at BT, with a career in telecoms and IT spanning more than 40 years.

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