http://nomasts.org.uk/index.php?opti...=50&Itemid=116
A familiar piece of misinformation quoted by mobile phone operators is
that the emissions of a mobile phone mast are comparable to that of only a
60W light bulb, and thus equally harmless. Quite apart from the fact that
the light from a 60W light bulb can be harmful to a person with
photo-sensitive epilepsy, if it is flashed at an appropriate rate, the
comparison is solely based on intensities and neglects three important
points:-
1. The fact that more than one carrier signal is usually transmitted from the mast. Thus, the figure of 60W must be multiplied by the number of carriers that are actually transmitted in any particular case; in order to minimise inter-carrier interference, however, this number is restricted typically to 4 at the most, so the total output wattage can be a high as 240W.
2. Beams from the mast, however, are not emitted uniformly in all directions (as happens with light from a light-bulb), but are instead concentrated in specific directions, the degree of directional focusing being quantified through the so-called ‘gain’ (G) of the antenna, even omni-directional types, typical values of which, in the case of GSM, range from about 40 to 60. If we use an optimistic figure of 30 the so-called ‘effective isotropic radiated power (EIRP), given by the multiplying Power by Gain – is 1800W, which is further increased to 7.2kW if 4 carriers are transmitted – a value that is 120 times higher than the 60W quoted! The maximum EIRP value permitted by law is 1500W per carrier, whilst the maximum number of carrier signals is 16 (at 1800MHz) and 10 (at 900MHz); in practice, however, the number of carriers is usually restricted to 4 at the most, for the reason mentioned above.
3. The comparison neglects the all important frequency dimension, in
particular the difference in the frequency that characterises the visible
light from the light bulb from that which defines the radiation to be
(invisible) microwave radiation. For whilst the output from such a bulb
is, during the day, completely negligible in comparison with visible light
of natural origin – i.e. that from the Sun – this is not so in the
case of the microwave radiation emitted by a phone mast antenna day and
night, which, several hundred of metres away, is typically 10 billion
(1013) times higher than the microwave radiation that is emitted by the
Sun at the same frequency. Accordingly, the emissions of mobile phone
masts have caused an enormous (and relatively sudden) alteration in the
natural environment (at this frequency) from that in which life on Earth
has, over a very much longer time, evolved. The impact of this altered
environment on biology is further enhanced by the high coherence of the
mobile phone radiation. [11]