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Applications and Machinery -> Undersea Cables |
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In the past several years, undersea cables have displaced communications
satellites as the dominant medium for international voice and data
communications. While satellites have become more cost effective in
wireless communications, it's a fact that about 80% of today's international
voice and data traffic moves over cables.
Cables are the dominant medium for voice and data because they do
not share the inherent problems associated with launching and orbiting
satellites. They are immune to solar flares and heavy precipitation
that disrupt satellite communications. And, they are not prone to
security risks. Hundreds of thousands of messages that are carried
simultaneously by cable over a wide spectrum of frequencies cannot
be intercepted. In the rare instance that a cable fails, it can be
hauled-up, repaired, and re-laid undersea.
Thousands of tons of copper are required each year to fabricate the
undersea communications cables needed to conduct the ever-growing
data and voice traffic between the world's trading nations. Although
silica-glass fibers have supplanted copper as the signal-carrying
medium, there's far more copper than glass in the latest cables, some
of which are thousands of miles long.
Copper plays two irreplaceable roles in today's undersea cables: it
encloses and seals the strands of glass against contaminants and carries
power to the series of electronic repeaters that amplify the signals
in transoceanic cables.
The world's largest manufacturing undersea cable plant, Simplex Technologies
of Portsmouth, New Hampshire (parent company is Tyco International
Ltd.), assembles cables in segments up to 70 km (43.5 mi) long in
a non-stop process from strands of fiberglass wrapped around a copper-clad
steel wire core. Copper strip, an inch or more wide and 20 mils thick,
is continuously formed into a tube and welded longitudinally to wrap
the central fiber optic bundle.
Some 4,500 tonnes (5,000 tons) of oxygen-free C10200 copper are used
each year in Simplex's undersea cable. The total annual market for
copper in undersea cables is approximately 13,500 tonnes (15,000 tons)
per year. Two dozen large ships lay the undersea cable. |
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