Wednesday, July 20, 2011
Mobile phones employ intelligent power management to limit the amount of radiation they produce during a call. That is to say they reduce their transmitted signal strength during a call to conserve battery life and minimise the amount of pulsed digital microwave radiation that goes into the user. Normally about 70% of the radiated energy is absorbed by the user, so distancing oneself from one's mobile phone significantly reduces exposure, especially from the near-field radiation that extends about 15 cm from the in-built antenna. Use of the phone's loudspeaker capability, a shielding pouch or using an external antenna significantly reduces the radiation absorbed by the user.
In rural areas the nearest applicable base station can be 15 or more Kilometres away. That means the phone has to work at maximum power in order for the call not to be dropped. When you hold your mobile phone to your head, the distance from the phone to your brain is about 15mm. Compare this to the distance to the mast at say 15 Kilometres (15,000 metres). At a million to 1, no wonder then that the radiation would rather go into your head and brain, which is mostly water and fat, rather than through the less conductive atmosphere all the way to the mast. The same mobile phone power management dynamics apply in multi-story car parks, buildings clad with foil shielding in their insulation, buildings glazed in energy efficient glass, elevators and similar places where signals have difficulty penetrating.
For the first few seconds after pressing 'send' or 'off-hook' when a call is made or received, mobile phones use a separate data channel to communicate with masts in range to connect the call most efficiently and at an audio quality level that is acceptable. The data channel operates at full power and it is this primarily that transmits during the call setup. Once the call is connected, only then does the dynamic power management become effective. So if you must hold a mobile phone to your head, waiting those few seconds before holding the microwave transmitter to your head makes a big difference to the amount of signal your head and brain have to soak up. As we all know, the head not only contains the brain but also a lot of other useful though, for many, somewhat mysterious stuff that is nevertheless essential to quality of life. Two of these structures which everyone can see are the eyes. That is, everyone who has not suffered cataracts or other form of vision degeneration and loss of vision. The eyes are particularly high in water content.
What would your prospects be if you lost your mental faculties? What would your prospects be if you lost your ability to see? Close your eyes for just a second or two and think about the risks you are taking regularly holding a mobile phone to your head. From noticing some initial visual disturbance to total cataracts can take less than a year even if you are not especially exposed. How would you feel today knowing you may have seen the spring, a blue sky or your child's face for the last time? The size and placement of the eyes in your skull result in microwaves from a mobile phone held to your temples being ducted by the bones of the cranium preferentially to the eyes. Add to that the eye's propensity to absorb electromagnetic radiation (that's what light is) then the risk to the eyes should be of much greater concern to mobile phone users.
You could say mobile phone users appear to have been kept in the dark over risks to their eyesight.
Simply encouraging the debate over mobile phone and wireless safety to concentrate on cancer risks ignores the many other adverse consequences to which the world's 4.5 billion mobile phone users are potentially exposing themselves each day.