Why? Many Questions Answered

A mobile phone is essentially a two-way radio, like a CB set,
transmitting and receiving wireless radio-frequency signals
However, while a CB set is what’s known as a “simplex”
device (i e , two people can communicate at the same time
but only one person can talk at a time), a mobile phone is
described as a “duplex” device (i e , it uses one frequency
for transmitting and another for receiving, enabling people
on either end of the line to talk and listen simultaneously)
The radio signal from the phone is transmitted through
the air to the antenna of the nearest base station, which
contains equipment designed to emit radio transmissions
and passes the signal to the
network and then to its destination Each base station covers an area of about ten square
miles, known as a “cell,” which is why mobile phones are
called cell or cellular phones

Mobile phone signals can reach only limited distances,
which is why an intricate network of cells is needed to connect
people at greater distances and why mobile phones
don’t work in remote areas that have no base stations Each
base station has a finite capacity to receive and transmit signals,
and highly populated areas usually have a higher number
of base stations to cope with the large number of users

The reason why a mobile phone can be used while driving
for many miles is because the signal moves from one
base station to the next so that a number of base stations,
and their cells, are utilized



Mobile phones contain low-power transmitters and low-
mass lithium-ion batteries that store a lot of power, two
factors that enable them to be very small and light