Turning Hardline Coax into Fiber Conduit

What if you could replace your old hardline coax with fiber without having to pull it down from poles or dig it up? Technology from Kabel-X is designed to do exactly that.

Since its U.S. debut at the SCTE’s Cable-Tec Expo in June, Kabel-X has been drawing attention. CT Senior Technology Editor Ron Hranac included the company in his Expo Show Picks column, and now several cable operators are examining the idea.

Kabel-X Executive Vice President Darin Clause said the company is involved in talks and trials with several MSOs, of which he was at liberty to disclose only Bresnan Communications.

"The feedback has been very positive," he said.
How it works The Kabel-X system allows the removal of the center conductor and dielectric from hardline coax, leaving the sheath in place to serve as a mini-conduit for fiber or other cabling.

A patented engineered liquid is pumped into the existing cable between the dielectric and the sheath/jacket, then one end is capped, and the cable is pressurized to distribute the liquid. The liquid breaks the bond between the sheath and dielectric so the dielectric and center conductor can be pulled out as one unit.

The residual liquid serves as a lube for pulling in the new cable. The process can be used with both foam and air dielectric, Clause said, in aerial, buried duct, and direct-buried applications.

"In essence, what we’re making is a new duct," he said. The company has successfully pulled up to 1,100 feet, but Clause added that this was "not a hard spec" – that’s just the longest they’ve tested so far.

There are no special requirements for the fiber used, Clause said, so long as it will physically fit inside the cored-out sheath. Neither is timing or installation method critical: "Pulled or blown, doesn’t matter," he said.

The company’s business model is to sell or lease the technology to cable operators and/or contractors, Clause said. They don’t generally do the pulling themselves, though they could if a customer really wanted that. Challenges Part of the process’s appeal is the potential to install fiber without arduous permitting hassles.

One senior engineer at a major MSO offered qualified praise: "It may indeed hold promise for cable systems in cities where obtaining construction permits has become difficult."

But there’s a rub, he added: The permitting authority might not want to play ball. "A … problem is whether the folks that issue construction permits would let (it) be classified as maintenance of existing plant that has no impact on the easements and therefore not requiring a construction permit. That determines the real value of this approach."

Cost is another question. Clause said there are many variables, but that an operator could expect 40-60 percent savings over conventional methods in places where trenching, boring or overlashing would be too expensive.

– Ron Hendrickson

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