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CommScope Drop Cable User Manual

Page 11

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Coax Selection Considerations - Shielding and Environment

Once you’ve determined which cable answers your need for signal over distance, you need to determine the type

of cable you’ll need for the installation environment.

For areas of possible RF interference, (pager antennas or other visible

problem as outlined in Section 3.1, or if there is a history of customer comments

concerning interference from ham radios, etc.), consider using a Tri-Shielded cable

(foil/60% braid/foil) shield. The extra layer of foil provides additional protection

against high-frequency RF signals at little additional cost. Super-Shield (Quad) cables

(foil/60% braid/foil/40% braid) provide optimum protection against RF interference.

For aerial installations, select a messengered cable (also called a figure-8 cable) with a polyvinyl chloride

(PVC) jacket. The messenger wire is a steel wire that is webbed together with the coax. This wire supports the coax

- under no circumstances should subscriber access coax be run without a messenger or lashed to a wire.

For buried installations, select a polyethylene-jacketed cable with MigraHeal

®

flooding compound to prevent

moisture ingress in case of damage. Article 830 considerations (see page 13.3 and Buried Installation 6.1) make

the use of cable pre-installed in conduit (CommScope’s ConQuest

®

) very attractive.

For cables that transition from outside to inside (from the ground block to the inside connection), select

a CATV cable for residential use, or select a CATV or CATVR cable for commercial buildings.

For commercial installations, CATVR riser and CATVP plenum cables are required in certain circumstances.

A riser-rated cable may be run vertically between floors; plenum cables are designed for use in air-handling

spaces, such as the area above a hung ceiling. General purpose cables (CATV) may be run horizontally within or

along walls and in raceways - they cannot transition between floors.

For locations where salt or other aerial corrosives may be a problem, CommScope offers two

aerial cable anti-corrosive treatments for braid shields: BrightWire

®

, a dry treatment that chemically combines with

metal components to protect against corrosion (and improve DC loop resistance); and APD (Amorphous Polypro-

pylene Drop), a non-flowing polypropylene flooding compound.

Tri-shielded

cables offer

excellent RF

protection at

reasonable cost

Cable

Selection 3.2

Indoor/Outdoor and Shield Selection