Microtrenching Speeds 4G Fiber Installation

April 2011 Vol. 66 No. 4

The fiber is fed into a box located next to the artificial cactus (or existing street light pole) and from there it connects to a jumper and optical transceiver and amplifier, which terminates at an antenna located inside the node. Like traditional cell sites, a resident makes a call transmitting to the node and then the signal is converted from RF Energy to an optical signal which is then fed to the fiber back bone and to the local service provider. DAS networks enable cell phones, laptops and other wireless devices to take advantage of increased bandwidth for faster Internet and streaming video.

Working for Crown Castle, which owns and manages large cell towers nationwide, Team Fishel is placing hundreds of miles of specially designed HDPE conduit and installing the fiber to feed a DAS network that improves the reception and bandwidth capacity of AT&T's 4G wireless network in the area. “We drill or trench, whichever method is needed to install the conduit, place the fiber and then splice the fiber to activate the antenna system,” Bowen said.

Most of the work, which includes horizontal directional drilling and fiber splicing, has been in Scottsdale, where private home owner associations (HOAs) expect and demand as little disruption as possible to preserve the aesthetics of their neighborhoods.

Upscale work
Working in an upscale HOA called Mirabel, a Team Fishel crew used the new microtrenching attachment for the first time to install about 4,000 feet of conduit between the curb and gutter, where the installation is virtually invisible. The installation “train” consisted of a McLaughlin V500LE vacuum unit out front, followed by a Vermeer RTX550 tractor and the Vermeer MTR12 microtrencher attachment with a conduit reel carrier mounted on the front of the tractor. The trenching crew laid the conduit in the trench after it was cut and vacuumed. Another crew backfilled the trench to complete the installation.

“On that curb and gutter, we cut our microtrench right at the lip of the curb, where the asphalt street butts up against the concrete gutter,” explained Bowen. “We cut the trenches 1¼ to 1½-inches wide and about eight-inches deep, then we installed a conduit developed especially for this application. The conduit is oval in shape and about ½ to ¾ of an inch thick and has two ducts in it that can accommodate cable about the size of a No. 2 pencil lead and contain up to 72 fibers each -- it’s pretty amazing really.