Cabling Infrastructure
CAT 5 cable handles hotel's TVs
System is designed to deliver analog or digital signals over unshielded twisted pair cable.
Network engineer Dale Sennie found a way to deliver high-quality TV reception to guest rooms without having to install coaxial cable.
I saw a big, expensive
disaster coming," says Dale Sennie, who was
in charge of completing the new Sheraton
Baltimore Washington Airport Hotel early
last year. "Nobody wanted a time-consuming,
expensive project pulling coax to every
room. I had to find a better way."
Sennie is a network
engineer for LTD Management Co., Chesapeake,
Va., which built and manages the new
six-story property. He became concerned
after learning the planned MPEG-2 streaming
video system over Category 5 cable would not
be ready in time for the opening-maybe even
long after the opening-which was only a few
months away.
That simply was not
acceptable to a company that specializes in
high-quality hotel properties and customer
services, including high-quality TV
reception for its guests. Complicating
matters further, CAT 5 was the only cable
installed to all 203 guest rooms in the
facility, and all the walls and ceilings
were already in place. Installing a coaxial
cable system at that stage of the project
would have been time-consuming and
expensive.
Sennie took over
construction management of the hotel in
September 2006. About a month later, he
discovered the TV problem, which became one
of the toughest technical challenges he had
encountered since joining LTD in 2003.
The previous construction
manager had specified CAT 5 cabling for a
converged network with voice-over-IP service
to telephones and MPEG-2 streaming video to
TVs. The phone service worked fine, but the
manufacturer of the MPEG-2 media server said
its new product would not be ready for
implementation in time for the hotel's
opening.
The hubs convert unbalanced coaxial
signals into balanced signals, which
then travel on CAT 5 to each guest room.
That is when Sennie
launched a nationwide search for a solution
to the problem, but all he ran into were
dead ends. Finally, he was referred to Tom
Conley at Bulk TV & Internet, which designs
and installs TV systems in hotels,
healthcare facilities, colleges, multiple
dwelling units and other commercial
properties across the country.
Conley recommended a Lynx
video network from Lynx Broadband, a
division of BH Electronics, to solve the
problem. "One of our field technicians had
installed several Lynx systems, which gave
us a nice comfort level (with the product),"
Conley explains.
The solution, compatible
with CAT 5 cable, is designed to deliver
analog or digital television from any source
over unshielded twisted pair cable.
"I was ecstatic when I
found out that I could get this done on CAT
5 cable," Sennie says. "People told me that
I would get a poor signal, interference and
other problems, but that was not the case at
all."
When the hotel opened in
May 2007, all the 42-inch, flat-screen TVs
in guest rooms and public areas of the hotel
worked flawlessly, offering 48 channels.
"The picture was crystal clear," Sennie
says.
The satellite master
antenna television system that was installed
delivers signals via coaxial cable from a
satellite dish to the head-end closet. There
they are remodulated from LNB frequencies to
RF frequencies and sent over RG-11 cable to
amplifiers and Lynx hubs in a wiring closet
on each floor.
The Lynx hubs convert
unbalanced coaxial signals into balanced
signals, which then travel on CAT 5 to each
guest room. A wallplate converter changes
the signal back to coaxial form before
entering the TV. The same network is used
for TVs in the hotel's lobby, lounge and
other public areas.
The system uses 16-port
Lynx hubs to deliver programming to 210 TVs.
Since the hubs can handle up to 256 TVs (16
hubs with 16 ports per hub), the hotel has
the capacity to add more TVs.
Because Lynx delivers
analog RF signals, it does not use any
bandwidth on the network itself. Instead, it
uses the copper wire provided by one twisted
pair within the CAT 5 cable.
Installation of the
satellite and Lynx equipment took less than
a month. The total cost for installing the
system, including the Lynx video network,
was approximately $40,000, according to
Sennie. "This is a fraction of what it would
have cost to tear out drywall, pull coax
through walls and ceilings, then repair
everything," he offers.
For more information
(click here)
BOF for big performance
by David Mazzarese
Today's high-speed
networks are pushing optical fiber into
buildings and closer to the workstation
to carry fiber's high bandwidth to the
end-user. As fiber is installed in the
last mile of these networks, it is
subject to a greater degree of bending,
since it is being installed in smaller
distribution cabinets and more compact
fiber-management systems.
All this is placing
more stringent demands on the
reliability and bend performance of
singlemode fibers than ever before.
These applications have led the industry
to develop new types of fiber optimized
for use in the small spaces found in
these sections of access networks and
enterprise networks.
Specifying the best
of these "bend-optimized" fibers (BOF)
for specific network needs begins with
an understanding of BOF's design and
performance attributes. Important for
the user to realize is that bend
performance is just the first of the
characteristics to look for to ensure
getting the most value.
In fiber
applications, bends can be defined as
deviations from a straight fiber path.
Such deviations can cause light to
scatter and escape from the core of the
optical fiber, resulting in a loss of
signal.
There are two types
of bends. Macrobends are large enough to
be seen by the human eye; they can be
caused, for example, by the routing of a
jumper in a patch panel. Microbends are
microscopic deviations along the fiber
axis; a microbend can result if fiber is
squeezed by the cable buffer or jacket
material as it contracts at low
temperatures. Both types of bends can
result in increased attenuation (loss of
signal).
While bend-optimized
fiber is designed to reduce attenuation
caused by bending, the best value is a
fiber that has bend performance
optimized for the application, to
provide superior optical and mechanical
performance for the life of the fiber. A
bend-optimized fiber should provide top
performance in both microbending and
macrobending, enabling its use in
smaller enclosures and innovative cable
designs. It should be fully compliant
with the new International
Telecommunications Union (ITU) G.657
standard and fully compatible with
standard industry requirements and
procedures for splicing, polishing,
cleaving and connecting.
Other critical
performance characteristics to look for
in a BOF include: full spectrum
attenuation performance from 1,260 nm to
1,625 nm (even in tight bends); zero
water peak to ensure the product is
ready for future bandwidth upgrades; low
splice loss when splicing either to
itself or to the existing fiber base;
and low polarization mode dispersion
(PMD).
The G.657 standard
describes two categories of this fiber
type. Class A fibers are suitable for
use from 1,260 nm to 1,625 nm. These
have tighter dimensional tolerances than
G.652D fibers for improved connectivity.
The attributes of these fibers are
optimized for reduced macrobend loss for
bends as small as 10 mm radius, while
their specifications for attenuation,
chromatic dispersion and PMD remain the
same as those specified in G.652D.
Class B fibers are
suitable for transmission at 1,310 nm,
1,550 nm and 1,625 nm for restricted
distances that are associated with
in-building transport of signals. These
fibers are capable of low macrobend
losses at tight bend radii, but can have
different splicing and connection
properties than G.652 fibers, due to
their varied designs and broad range of
values for mode field diameter.
One of the most critical
considerations is the mechanical
reliability of the fiber under reduced
bends. Be wary of any bend-insensitive
fiber design that allows for bends that
are so tight they threaten the
mechanical reliability of the fiber. Low
loss in a tight bend (e.g, 5 mm to 7 mm
in radius) may look like good
performance during installation, but a
bend this tight could result in a
catastrophic fiber break a few years
after installation.
David Mazzarese is technical marketing manager at
OFS, Sturbridge, Mass.
For more information
(click here)