Passage 1. How Mobile Telephony Turned into a Health Scare
The technology which enabled mobile phones was previously used in the kind of two- way radio which could be
found in taxis and emergency vehicles. Although this was a great development, it was not really considered mobile
telephony because it could not be used to dial into existing phone networks. It was
known as simplex technology,
operating on the same principles as a walkie-talkie, which required that a user press a button, meaning that only one
person at a time could talk.
Simplex meant that there was only one communication frequency in use at any one time.
The first mobile phones to connect to telephone networks were often installed in cars before the hand-held version
came on the market and the revolution in mobile technology began. The first generation of mobile phones (called 1G)
were large, heavy and analogue and it was not until the invention of the second generation (2G) in the 1990s that
digital networks could be used. The digital element enabled faster signalling. At the same time,
developments in
battery design and energy-saving electronics allowed the phones themselves to become smaller and therefore more
truly mobile. The second generation allowed for text messaging too, and this began with the first person-to-person
text message in Finland in 1993, although a machine-generated text message had been successfully sent two years
earlier.
None of this would have been possible without the development of duplex technology
to replace the relatively
primitive simplex technology of the first phase of mobile communication. In duplex technology, there are two
frequencies available simultaneously. These two frequencies can be obtained by the principle of Frequency Division
Duplex (FDD). To send two signals wirelessly, it is necessary to create a paired spectrum, where one band carries the
uplink (from phone to antenna) and the other carries the downlink (from antenna to phone).Time Division Duplex
(TDD) can achieve the same thing, but instead of splitting the frequency, the uplink and downlink are switched very
rapidly, giving the impression that one frequency is used.
For mobile telephony to
work to its fullest potential, it needs to have a network through which it can relay
signals.This network depends on base stations which send and receive the signals. The base stations tend to be simple
constructions, or masts, on top of which are mounted the antennas. With the rapid increase
in demand for mobile
services, the infrastructure of antennas in the United Kingdom is now huge.
Many thousands of reports have appeared claiming that the signals relayed by these antennas are harmful to human
and animal health. The claims focus on the fact that the antennas are transmitting radio waves in microwave form. In
some ways, public demand is responsible for the increase in the alleged threat to health. Until quite recently,
voice and
text messages were transmitted using 2G technology. A 2G mast can send a low-frequency microwave signal
approximately 35 kilometres. Third generation (3G) technology allows users to wirelessly download information from
the internet and is extremely popular. The difference is that 3G technology uses a higher frequency to carry the signals,
allowing masts to emit more radiation. This problem Is intensified by the need to have masts in closer proximity to
each other and to the handsets themselves. Whatever danger there was in 2G signals is greatly multiplied by the fact
that the 3G masts are physically much closer to people.
Government authorities have so far refused to accept that there is a danger to public health, and tests carried out by
governments and telecommunications companies have been restricted to testing to see if heat is being produced from
these microwaves. According to many, however, the problem is not heat, but electromagnetic waves which are found
near the masts.
It
is believed that some people, though not all, have a condition known as electro-
sensitivity or electro-
hypersensitivity (EHS), meaning that the electromagnetism makes them ill in some way. The actual health threat from
these pulsed microwave signals is an area which greatly needs more research. It has been claimed that the signals
affect all living organisms, including plants, at a cellular level and cause symptoms in people ranging from tiredness
and headaches to cancer. Of particular concern is the effect that increased electromagnetic fields may have on children
and the fear is that the negative effects on their health may not manifest themselves until they have had many years of
continued exposure to high levels. Tests carried out on animals living close to this form of radiation are particularly
useful because scientists can rule out the psychological effect that humans might be exhibiting due to their fear of