Coaxial drop cable is the stuff of legend. Like other
legends, plenty of myths develop over time about the product, its preparation
and performance. I’m a huge fan of the show, “MythBusters,” so let’s bust a few
drop cable myths right here.
Myth 1 – The
denser the braid, the better the shielding.
Braid density is one factor that impacts drop cable
shielding, but it’s not the only one.
Coaxial cable is both a precision radio frequency (RF) waveguide and a
mechanical structure. If the mechanical structure is compromised, the RF
performance will be as well. Heavily
braided cables can negatively impact shielding as the braid structure works
against the bonding and tape layers during handling, installation or
environmental flexure. It can also make a cable stiffer and more difficult to
properly prepare for termination. Decades of engineering at CommScope have
taught us that an optimized braid working in tight alignment with advanced
tapes and bonding provides the best shielding under any installation and
handling conditions. Our F677TSVV-XP
is just such a cable, with a 77 percent braid that outperforms 90 percent braid
(and even quad shield).
Myth 2 – LTE interference
requires a different shielding design.
LTE interference is certainly a prevalent issue today,
and one that is well understood by CommScope.
We see and understand best
practices from both sides – wireless and wireline. Bottom line, LTE is a potential interfering
wireless signal, at a set of frequencies. The same shielding techniques that
have evolved over decades protect against LTE.
What is the biggest culprit when shielding is
compromised? Experience suggests it is
the connector interface, so proper cable preparation is paramount. Would you be surprised that there are myths
about termination too?
Myth 3 – Snip off
the center conductor so it “looks right.”
Modern drop cable stripping tools are designed to provide
a center conductor length of 5/16”, as recommended by the Society of Cable
Telecommunications Engineers (SCTE). Connector nuts can vary in height, so the
5/16” length may look different with different connectors. If cut off, the conductor risks being too
short, and may cause electrical anomalies during temperature changes. Remember, drop cable is both a waveguide AND a
mechanical structure. Components can
move, and 5/16” (not ¼” or “eyeballed”) is the best length to ensure solid
connectivity in any temperature. Trust
Myth 4 – Using a
connector or plier to “round out” the cable helps ease insertion force.
Argh… where do I start?
Proper tools, in good condition and with sharp, fresh blades, will
produce a well-rounded cable end ready for termination. The outer foil must be removed (and can be
automatically with CommScope
XpressPrep), and the braid must be folded
back along the jacket in an even distribution.
A stiff plastic brush or fingertip can accomplish this. Using a metal
tool of ANY sort can damage components, cut braids and lead to potential connector
failure and truck rolls. CommScope has offered training and videos to
assist in this procedure for decades, and we have NEVER recommended a metal
tool or shortcut using anything as a tool.
Myth 5 – I’ve been
using this tool for 20 years and…
I have a screwdriver in my drawer that is bent 45
degrees. Why? I used it for the wrong purpose. I keep it to remind myself never
to do that again! The SCTE has
prescribed prep lengths for coaxial cable. To achieve this prep, tool
manufacturers make tools specific for the cable. Use the right tool, with the right blade, for
the job. Are your tools 20 years old? Replace
them! Old blades, or the wrong blade,
can damage the cable end. If you see braids on the ground, change the tool or
blade. Don’t allow a $2 blade to create
several $100 truck rolls!
Have you heard other myths that might put your subscriber
experience at risk? Share them here, and let’s bust them all. Reliable and
repeatable coaxial drop cable terminations are critical to network performance.
If you avoid the myth trap, your connections can be truly legendary.