Fort Collins Connexion FTTH Construction – Part Four

Inside this small splice enclosure, a 24 fiber, gel-filled cable is terminated.

A 24-count, gel-filled fiber cable is terminated inside this small splice enclosure. The splice enclosure is then placed inside the underground vault to await connections to drop fibers to people’s homes.

Welcome to part four of  my blog post on the construction and installation of the Fort Collins Connexion municipal broadband fiber network. In part three, we looked at the installation of service at my friend Collin’s house. In part four, we’re returning to my neighborhood and documenting the final construction steps before service goes live on my street.

January 30, 2020 – Splice Trucks in My Neighborhood

splice-truck

Technicians unroll the fiber cables from the vault before bringing them into the van to splice together.

On Thursday, January 30, 2020, contractors for Connexion were splicing fiber cables together to connect the fibers distributed throughout the neighborhood back to the fiber distribution hub (FDH) for the area. One technician worked at the vault across the street while another technician worked at the vault directly in my cul-de-sac.

At the Splice Vault on Our Cul-De-Sac

24-count-gel-fiber

24-count gel filled fiber mounted in a small splice enclosure. The 6 fibers that will feed the houses on my cul-de-sac are routed to the top; the 18 unused fibers to the bottom. The slots will hold the fusion splices connecting to the drop fibers.

A fiber cable runs from the vault across the street to the vault on my cul-de-sac. Inside the vault on my cul-de-sac are four pieces of conduit. One conduit contains the fiber cable from across the street. The other three smaller conduits are empty. The three empty lengths of conduit run to three flower pots distributed in front of about ten houses.

When someone orders service, a drop fiber is buried from the house to the flowerpot. The fiber is then pulled through the conduit in the flower pot up and into this vault. Inside the vault the drop fiber will be fusion spliced to the existing distribution fiber that runs through the larger conduit and across the street.

The splices are protected using a waterproof splice enclosure and a splice tray. The splice tray is shown in the photo above. The technician disassembled the splice enclosure and fed the fiber cable from across the street into the bottom of the splice enclosure. When houses subscribe to service, their drop fibers will be fed up into the bottom of the splice enclosure too.

This particular fiber cable was a 24-count, gel-filled cable. The technician removed the outer sheath of the fiber cable exposing the gel and 24 individual fibers. He used some isopropyl alcohol to remove the sticky gel from the fibers then placed the fibers into the races on the tray.

The 24 fibers were divided into a group of 18 and a group of 6. The 18 fibers were placed in the bottom of the tray (left side in photo). These fibers are not connected to the network and will not be used for service.

The remaining 6 fibers were placed in the top of the tray (right side in photo). These fibers will be spliced to the fibers that connect to the houses on our street. The space in the middle will hold and protect the individual splices when the time comes to install the drop fibers.

splice-vault

All sealed up and waiting for the drop fibers. The larger conduit holds the distribution fiber. The three smaller empty conduits go to the flower pots in front of our houses and will hold the drop fibers. All the tracer wires are grounded in the vault.

Remember that I wrote earlier that there are about 10 houses served by the conduit and flower pots out of this vault? There’s only six fibers allocated for connections to service though. Connexion is betting that not everyone will subscribe to service.

If more than six houses subscribe, technicians will have to reallocate and re-splice fibers from the splice vault all the way back to the fiber distribution hub to accommodate the extra houses. This is unlikely to happen.

After routing the fibers in to their raceways, the technician closed the splice enclosure and placed it into the vault as shown in the photo above. The splice enclosure is waterproof and will protect the exposed fibers and splices inside.

The orange wires in the vault are tracer cables used to locate the conduit and fiber underground. If you look closely, you can see that they’re tied to a ground rod in the side of the vault. The red tape on the fiber cable indicates that fiber cable runs toward the headend. Blue tape is used on fibers that run toward subscribers. Finally, the technician closed the vault.

At the Splice Vault Across the Street

144-count-jacket-removed

Meanwhile across the street in the splice truck, another technician exposes the fibers in the distribution fiber. He’ll carefully pull out six of the fibers from this larger cable and splice them to the six used fibers feeding into the vault.

Meanwhile across the street, a technician had the job to splice the six allocated fibers from the vault in the cul-de-sac into the 144-fiber cable running through this vault and through the neighborhood. The splicing is done inside the splice truck to provide a dry, clean, controlled work environment for the equipment, fiber, and operator.

The fibers before and after fusion splicing.

The fibers before and after fusion splicing.

Inside the vault are two fiber cables. The first cable has 144 fibers. It comes into the vault, some extra cable is coiled up, and then it leaves the vault. It is a continuous piece of cable. The second cable has 24 fibers. It begins at this vault and ends at the vault on my cul-de-sac. This is the situation shown in “Before Splicing” in the diagram above.

The technicians job is to carefully pluck out six fibers from the 144 fiber cable, cut them, and splice them to six fibers of the 24 fiber cable running to our cul-de-sac. The first step in the process is to pull the outer protective sheath off the 144 fiber cable and pull a section of it into the splice enclosure. The 144 fibers are carefully placed into raceways inside the splice enclosure. Unfortunately, I don’t have photo of this.

The 24 fiber cable is then stripped and pulled into the splice enclosure. The 24 fibers are run around raceways as well. After all the individual fibers are in their raceways, the technicians pulls 6 fibers from the 144 fiber cable and cuts them. He then uses a fusion splice machine to splice these 6 fibers to the 6 fibers allocated to our cul-de-sac. This leaves 6 fibers in the 144 fiber cable and 18 fibers in the 24 fiber cable headed towards everybody’s houses orphaned. This is depicted in the “After Splicing” section of the diagram above.

fusion-splice

The distribution fiber contains 144 fibers. He’ll roll up the ones that don’t need to be spliced into the splice tray on the workbench in the previous photo. He’ll then use a fusion splicer similar to this one to splice the 6 fibers to our vault into the cable.

The fusion splicer automatically aligns the ends of the fibers then applies heat using an electric arc to fuse them into a single continuous piece of glass. A separate heater at the back of the machines shrinks heat shrink tubing to protect the splice.

When the splice truck drives off there will be continuous pieces of fiber from the vault for the drop fibers on our cul-de-sac to the fiber distribution hub (FDH) at the edge of the neighborhood. Inside the FDH, fibers from up to 32 homes are combined using a passive optical splitter into a feeder fiber.

The feeder fibers then run to an OLT at a fiber hut co-located at an electrical substation. From there, it’s redundant 100 Gbps fiber to core routers and to the Internet.

splice-vault-2

Managed to get a quick photo of the assembled very large splice enclosure before they closed the vault and drove off. There’s two 144 fiber cables and a 24 fiber cable coming out of the bottom of the enclosure. Red tape points toward FDH/CO. Blue tape points toward houses.

When the technician is done splicing the cables, the splice enclosure is sealed, the fiber is coiled up, and everything is placed in the underground vault. In theory the fiber on my street and in my cul-de-sac now connects all the way back to the electrical substation where the fiber hut containing the OLTs is located.

February 15, 2020 – A Bit More Splicing

Splice truck at the corner of Skimmerhorn and Overland Trail. The grey above ground cabinets in the lower right are Comcast equipment. All the Connexion equipment is located in underground vaults.

Splice truck at the corner of Skimmerhorn and Overland Trail. The grey above ground cabinets in the lower right are Comcast equipment. All the Connexion equipment is located in underground vaults.

I was riding my bike today and noticed another splice truck at the intersection of Overland and Skimmerhorn. I believe this is where the fiber from the electrical substation and fiber hut enters our neighborhood and where our fiber distribution hub is located.

This splice truck is a bit fancier than the previous splice truck. It has a window that’s just big enough for the splice enclosure to fit through. Inside that window is a smaller window that’s just big enough for the fiber cables to fit through. And inside that smaller window is a chunk of foam to keep the cold air outside the truck.

March 2, 2020 – Fiber Locates

Oops. Looks like they misplaced or forgot to install some conduit.

Oops. Looks like they misplaced or forgot to install some conduit.

Earlier this week someone painted hot pink lines along one of the fiber routes on my street then today a technician showed up to locate the existing conduit and fiber. It looks like they may have forgotten to run a length of conduit in the neighborhood. To see if they had or not, a technician located the existing fiber and conduit coming out of a splice vault across the street.

Connecting the locator signal generator to the tracer wires in the conduit.

Connecting the signal generator to the tracer wires in the conduit.

To locate the fiber, the technician opened the splice vault and disconnected the tracer wires from the ground rod inside the vault. He then connected the leads from a 3M Dynatel 2550 locator transmitter to the tracer wires and a temporary grounding rod placed next to the vault. In the photo above, the red wire and red clip connects to the orange tracer wires. The black wire and black clip connect to the temporary grounding rod which is mostly buried in the dirt and gravel.

fiber-locate-2

Close up of the 3M Dynatel 2550 locator.

The transmitter injects a radio signal on to the tracer wires. The radio signal can then be picked up using a radio receiver carried by the technician. The radio receiver has a highly directional antenna that can determine the precise location of the tracer wire underground and by extension, the location of the buried conduit it is inside. The locator radio receiver looks very similar to the beacon receiver for the Ditch Witch directional drilling equipment.

Using the radio receiver to locate the tracer wire and, by extension, the conduit and fiber.

Using the radio receiver to locate the tracer wire and, by extension, the conduit and fiber.

The technician starts at the fiber vault then works his way outward for each one of the conduits. He slow moves the receiver over the area where the conduti is located. Every time the radio receiver records a peak signal, he marks the ground with orange paint. In the world of utility locates, orange paint is used to mark communication cables. If you look closely at the photo, this technician does a lot of communications utility locates because his boots are orange.

March 3, 2020 – More Locates

Fort Collins Utilities did some electrical and water locates around the vault today. Looks like their could be more drilling on our street.

Fort Collins Utilities did some electrical and water locates around the vault today. Looks like their could be more drilling on our street.

Fort Collins Utilities showed up today and marked the location of the electrical and water lines in the vicinity of the vault across the street. This is the same location where the hot pink lines were painted and fiber locates where done earlier in the week. My guess is we’ll see some directional drilling work and some additional conduit put in the ground this week or the next.

Someone came around and installed bolts in the corners of the other vaults in the neighborhood.

Someone came around and installed bolts in the corners of the other vaults in the neighborhood.

On another note, they’ve finally installed bolts to secure the lids of the splice vaults.

March 4, 2020 – More Directional Boring

Yep, sure enough. Crews came back out on Wednesday and installed another piece of conduit on the north side of Michener Drive between Dixon Creek and Beaver Ct. With the new conduit, they’ll need to pull more fiber and redo some of the earlier splice work. In theory, construction in our neighborhood was finished on January 31, 2020. Given the current slow rate of subscriber additions and the number of neighborhoods in line for service ahead of us, I don’t think the additional work will delay when service is offered to our houses.

March 17, 2020 – A Splice Truck is Back

Today they patched in the fiber they initially forgot to install late last year.

Today they patched in the fiber they initially forgot to install late last year.

Today a technician in a splice truck showed up and spliced the new fiber in the new conduit into the network. There should now be two 144 strand cables and two 24 strand cables spliced together in the splice enclosure. I didn’t get close enough to confirm given the state of the world today.

 March 19, 2020 – Snow and a Tent

Technicians use a small popup tent while they work on the fiber in the fiber vault across the street.

Technicians use a small popup tent while they work on the fiber in the fiber vault across the street.

Technicians came back again today to do more work on the fiber and splice enclosure in the vault across the street. This time they brought a small popup tent to let them work more easily in the cold, wet snow.

March 25, 2020 – City Inspectors and Asphalt Repairs

City employees were driving around the neighborhood inspecting the fiber installation today.

City employees were driving around the neighborhood inspecting the fiber installation today. Unlike most of the other trucks and equipment I’ve seen in my neighborhood in the past, these vans are owned by the city.

Today, city employees (not contractors) were driving around the neighborhood inspecting the fiber installation and doing their final quality control checks. This is the last step before the city accepts ownership of this portion of the network. The city employees also said this fiber is lit which means it is, in fact, connected all the way back to the OLT’s in the fiber hut at the substation.

Finished asphalt repair of a hand hole dug four months ago.

Finished asphalt repair of a handhole dug four months ago.

Also this week, contractors were going around the neighborhood doing final repairs to the handholes crews had drilled in the road and sidewalks over the past few months. The photo above shows a completed repair to a handhole dug in the asphalt in front of my drive way.

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