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| Mainline
coring tool: Coring tools are
specific to the diametre of cable being used, and are used to
expose the centre copper conductor within the coaxial cable.
The coring tool also removes a portion of the foam medium inside
the aluminum shield to allow connectors to be properly installed.
The tool shown fits onto a standard cordless drillgun. |
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| Mainline cutters: These
are a specialized cutter specifically for coaxial cable. They
are available in various sizes, specific to the diametre of
cable being used. |
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| Centre pin cleaner:
This is used to clean the central
copper conductor in coaxial cable. |
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| Long drill bits:
Useful in installations in houses, these bits will go right
through walls. They are also required for installing messenger
bolt clamps on power poles. |
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| Large Adjustable wrenches:
These are used often in working
on the cable plant in tightening and loosening mainline connectors. |
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| Side Cutters: These
are useful in accurately and cleanly cutting off the centre
pin to the correct length. |
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| Cable end strippers:
These are used in installing connectors
on coaxial cable. Many types are available, both with and without
length gauges. These expose 3/8 " of the center pin, then
1/4 " of the outer shield so that connectors can be properly
fit on to the end of cable and secured. They are generally used
for drop cable only - all cable feeding from the pole to the
home as well as in the home. |
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Crimp tools: These
tools come in sizes specific to the various connectors sizes,
and are used to crimp the compression type of coaxial connector
onto a coax cable. The connectors that are crimped using these
types of tools are usually used for interior purposes only.
They are easier to spin on and off Internet modems. They are
less expensive than compression fittings and tools, however
are not as weather proof.
|
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| Compression tools:
These tools are also used for attaching
connectors to coaxial cable, however they are generally used
for exterior applications. These, and their connectors, are
more expensive than crimp connectors, however they are generally
more water-tight, and generally worth the extra money. |
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| Screwdriver: Most
interior equipment for user installations including house amps,
splitters, etc, are clipped using screw clips. A good screwdriver
is a necessity. |
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| Terminator tool: This
is used to install "terminators" at the end of cable
lines, or where a cable 'tap' needs to be plugged. Terminators
are essentially a 75 ohm resistor which effectively stops the
signal from travelling any further, as well as effectively locking
out that spigot from the tap in order to prevent people from
stealing the signal. |
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| 3/8"
/ 7/16" double ended socket wrench: This is a very
handy tool, as many mainline bolts are 3/8", 7/16",
or 1/2". |
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| Around-pole
climbing strap: This strap is used by qualified climbers
when climbing poles - the double leather strap goes around the
pole and is used as a support. |
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| Climbing
spur: These strap onto workboots and are used by qualified
climbers when climbing poles. |
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| Climbing
belt: climbing belts come as plain belts and as utility
belts, and are used by qualified climbers when climbing poles. |
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Cable: Coaxial
cable comes in many different widths. Generally, the larger
widths are used for the main "trunkline" while medium
widths are used for the "bridger" line, and smaller
widths are used for the feeder lines to subscribers. Cable
comes in waterproof and water-resistant varieties.
Note that mainline cable does not have
the copper braid conductor, simply the outer aluminum shield
as a conductor. |
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| Mainline Pin Connectors:
Used to install devices in mainline. |
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| Splice connector for
mainline: connects two lengths
of coaxial cable. |
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| Solvent: Different
types of solvent may be required to remove the water-resistant
or waterproof gel coating from some coaxial conductors. The
correct type of solvent required will be stated in the information
that comes with the cable or can be provided by the cable supplier.
|
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| Mainline
trunk Amplifier: This type of
amplifier is actually mounted on messenger cable onto which
the mainline cable is spun. It is then connected to the trunk
amplifier. Trunk amps maintain the main signal as an independent
signal from the bridger line signal used to feed subscribers.
|
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Bridger
Amplifiers: All trunk amps
have a bridger amp in them. This is where the bridger line
starts and is re-amped whenever needed by a bridger amp (called,
at this point, a line extender). It is these amps that keep
the signal alive after it has left the trunk line and is being
distributed to cable subscribers.
There should be no more than twenty
of these amplifiers in a row, and they should be kept down
to a minimum where possible after each trunk amplifier. Having
more than this means that the signal degradation may rise.
If more are required, the trunk route may require better planning,
however there will be exceptions to this.
|
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| Return-"reverse"amplifier:
This is necessary for internet connectivity,
as it returns the signal along the coaxial cable, allowing for
two way data communication. |
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Line Extender Bridger
amplifier: This is essentially
a bridger amp without the "trunk" part.
This amplifier looks very similar to the
bridger amplifier above. signal
will only travel a limited distance down a cable. After this,
the signal needs to be re-amplified to be sent further along
the cable. "Line extender" amplifiers perform this
purpose of amplifying the signal, while maintaining signal
quality. |
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| Power Inserters:
A power inserter looks like a splitter,
however, it functions to simply add power to the cable line.
Cable plants require more power as more equipment is added.
Power is suppied by a pole-mounted or pedestal-style power supply.
These types of power supplies will only run a limited number
of devices, so the total amount of power draw of the cable plant
needs to be calculated in order to determine whether additional
power needs to be added. |
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Adapter - This
adapter allows reading of the signal at the seizure screw point
on a service tap. It allows you to take a signal reading directly
from the mainline rather than from the spiggot on the distribution
tap, simply by making contact with the seizure screw inside
the tap. This is in direct contact with the center copper of
the main line cable. Then by also making contact with the tap
housing which is in contact with the outer conductor of the
cable, the signal may be read.
|
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| Negative and positive
traps: These are used to remove
elements from a cable signal. A negative trap removes any frequency
that needs to be removed (for example if the cable provider
wants to block a specific channel or to stop feedback noise),
while the positive trap removes an encoding signal from a specific
frequency that was sent out from the head end. Therefore, the
positive trap works in conjunction with a head end unit. When
the encoding signal is removed, that frequency can be freely
viewed. |
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| Service tap bypass:
This cable allows contact with seizure
screws at both sides of a service tap, effectively bypassing
signal around a tap. This allows replacement of a face plate
of a tap while still providing signal to subscribers farther
down the line. |
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Cable transformer:
This is a pole-mounted transformer
which is always mounted in a weather-proof box. These can
also be used for interior applications, however specifically
designed "interior" transformers are available.
The output is generally 66 volts AC at 15 amps. |
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Distribution or service"taps":
These come in both four-post and eight-post configurations,
and send the cable signal directly to the end users. These
are available in various decibel increments, meaning that
they allow different amounts of signal to "bleed"
or attenuate out of the mainline system.
These 'taps' are configured in three decibel
increments. For example, a four-user tap may be available
in 8dB, 11dB, 14dB, 17dB, etc. An eight-user tap may be available
in 12dB, 15dB, 18dB, 21dB, etc. The farther down a line a
'tap is, the less signal will be available. Taps need to be
chosen appropriately, so that the desired end signal quality
is still achieved with the required number of taps in the
line, and the least amount of "bleed" possible.
For example, suppose a main line has a
signal of 40dB. If an 11dB tap is inserted in this line, then
a signal of 29dB will come out of the service spiggots to
the end users. If a 23dB tap was instead inserted in the line,
only a 17dB signal would come out of the service spiggots.
As is described in the activities and overview
for this module, a cable plant will always be constructed
to facilitate a certain decibel level at the 'tap' service
end. This means that line loss by the foot, (depending on
cable dimension) as well as the set loss values of any equipment
or splices in the line, will need to be added together. These
all factor in to where the cable plan is next amplified.
Top: front view of tap middle: tap with
shrink-wrapped connector installed, and clamp. Bottom: side
view of tap with installation clamp. |
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Messenger Cable:
Used to support all terrestrial cable
types that don't have their own built-in support strand. ( twisted
pair copper, fibre, coax, etc.).
|
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| Lash-on
wire clamp: These are used to secure lashing wire on
to the support messenger. Lashing wire is spun around cable
to secure it onto the messenger cable. |
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| Messenger clamp bolt:
Used to affix messenger cable
clamp to poles. |
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| Messenger clamp: Used
to affix messenger cable to poles. |
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Drop clamp hook:
These are used to support the drop wire
which is attached to a subscriber house. It attaches to the
messenger supporting the mainline.
|
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Drop clamps: Attach
to drop wire either directly or to the support wire provided
on a drop wire so that it can be attached to structure i.e...
subscriber house ,apartment, or messenger. |
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Drop hooks: Used
both at the subscriber installation and at the pole, if the
messenger cable is too low to give enough clearance needed
to secure drop clamps.
|
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Zinc Straps:
These are most commonly used around
poles where there is already equipment mounted for both cable
and telephone. It is not possible to effectively spin lashing
wire here, or in locations where equipment may be periodically
taken down. These straps are strong and removable. |
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Splitters: Bridger
legs feed in many directions, because usually service must be
extended to all areas in a community. Splitters are used to
"split" bridger feeds into more than one feed, to
bring the signal to additional cable feeds to subscribers. the
splitters shown are at the home splitters and not
mainline equip. |
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| Eight-way House or
Apartment Splitter: Divides the
one incoming signal between eight subscribers at one location.
|
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DC Couplers:
These allow for a portion of the
signal in a bridger line to be removed without too much signal
loss at the original bridger leg end. The version shown here
is a user-end DC coupler.
These are used when only a small
amount of
signal is needed at a particular location, so a complete split
in the signal level is not needed. They take a small amount
of signal from the main line without affecting the mainline
signal to any noticeable degree.
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Interior distribution amplifier:
These are used in apartments or installations
where there are multiple users. They have similar qualities
to that of a bridger amp but instead of being
powered by the cable plant itself, they are powered from a wall
AC outlet.
|
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| In home- amplifier:
These are used at the end of
a line installed in a subscriber's building, to amplify the
signal at that location. |
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In-House DC Coupler:
These work in the same way as
mainline couplers. DC couplers are used when a portion of a
signal is required in a different location in a building, however
the additional signal needs to be installed without affecting
the main signal in.
|
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| In-House splitters:
Are used to divide a signal to
multiple devices. |
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In House Three-way
splitter: This takes one cable
signal, and splits it to three devices. The signal comes into
the splitter and out through the other connections - these
come in different configurations, however the installation
directions are usually marked right on the splitters. |
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| Exterior house connection
box: This protective box is installed
on a building exterior when bringing a cable drop to a subscriber. |
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| Terminator: A
terminator is used to stop "leaks" from taps, and
to block out cable (requires a special "terminator"
tool to remove the terminator.) The terminator is also used
at the "end of the line" to stop leaks. |
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| |
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RF Meter with transmitter:
This meter works in both forward and
reverse directions and is used for trouble-shooting a cable
plant. It works in conjunction with a meter in the head end
and allows readings at both ends from at one location.
This allows a technician to see all
signals coming towards him as well as seeing how
well a signal is transmitting back to the head end, (ie. reverse
path)
There are many additional features,
including a spectrum analyzer, complete plant levels in graph
form, and is programmable, which makes it a very versatile
meter. Meters with these sorts of features are also very expensive
|
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RF Meter: This
RF Meter is forward-capable only, which means that it works
well for measuring all downstream signals but is not able to
send back to the head end, which this makes it less helpful
with
reverse-active Internet capable plants.
|
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| Details
on Head-end equipment and dishes can be found in the activity
section under activities 1, 2, and 3:
1
- Cable Plant Design - Overview
2
- "Head End" Overview
3
- Constructing a "head end." |
