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By Paul M. Icamina, Special Reports Editor
ALL mobile phones—except satellite phones—use cellular
technology. Thus the term “cell phone” is used interchangeably
with “mobile phone.”
All cell phones use radio waves to transfer
signals to and from the cell phone, and radio waves travel through
the air, which is susceptible to interference.
The signals do not need a clear line of sight
but the more interference, the more reception will be degraded or
eliminated.
The coverage of a service provider is made up of
smaller cell sites to maintain line-of-sight phone-to-phone, each
cell site overlapping other cell sites.
All cell sites are connected to cellular
telephone switches that automatically command the handset and a cell
site to connect as the phone user moves from one cell site to
another.
With a tall cell tower on flat land, it is
possible to get between 50 to 70 kilometers of range. When the
terrain is hilly, the maximum distance can vary from as little as
5km to 8km.
The signal display on the cell phone screen is
the strength of the connection the mobile phone has to the cell
site. Signals depend on proximity to a cell tower, presence of thick
walls and many factors, even weather conditions and the volume of
network traffic.
The cell phone itself may be to blame because of
low battery power that is too weak to send a signal to the cell
site.
Then there are dead zones where cell phones
cannot transmit to a cell site because of hilly terrain, distance,
tall structures and even excessive foliage.
(Devices that claim to improve reception are
unproved. Instead, an external antenna may be installed on the roof
to improve signal.)
A dropped call occurs when communication is
terminated because of a dead zone, the mobile phone is out of range
of a wireless network or the cell site is in overcapacity at the
time of the call.
Or the cell site is not “aware” of a cell
phone trying to connect. When the cell phone cannot find an
alternative cell site to move to and take over the call, the call is
lost.
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