Engineer's Corner
3:00 am
Tue October 15, 2013

TheEC: More Fiber in RIPR's Diet

cox fiber splice tool
Fiberoptic cable splicing tool.
Credit Aaron Read

As all RIPR fans know, we are an NPR member station.  That means we get a lot of our programming from NPR, the BBC, and other providers, via our satellite dish.   The dish is medium-sized as dishes go, but it’s pretty big in real terms: 3.7 meters (12ft) in diameter.   There’s quite literally nowhere to fit a dish that large at our studios in 1 Union Station, so instead it was installed out at our 1290AM transmitter site in North Providence (we still own 1290, but we lease it to Latino Public Radio).

For many years, we’ve relied on a leased circuit from Verizon and Windstream, called a “T-1 line”, to get the audio from the dish’s satellite decoders in North Providence to the studios in downtown.  T-1’s are essentially 24 telephone lines bonded together into one circuit that provides 1540kbps (or 1.54mbps) of data capacity.  It’s a very mature technology, dating back to the 1960’s.

We’ve talked about T-1’s before in TheEC, because this T-1 has become increasingly problematic in the last six months.    I and Verizon have likely traced a major source of the problem to be with the old copper-wire-based cable trunk from 1 Union Station to the nearest “Central Office” for Verizon (Washington and Greene Streets in downtown).   It’s at least two decades old, and probably has water contamination; that’s just a guess, but a good one.   There’s also a Verizon fiberoptic termination point (FTP) in 1 Union Station, but it is also dates back to 1994 and one of the card in the FTP died and couldn’t be repaired (that little escapade took our office phones down for five days a few weeks ago).
 

cox fiber install
Cox installing fiber from the street poles to the 1290AM building.
Credit Aaron Read

The good news is that failure has prompted Verizon to install a new fiber FTP for our building, which is good news on several fronts.  The better news is that, for redundancy, RIPR is also having Cox Communications install new fiberoptic service to both 1 Union Station and the 1290AM site.   The really good news is that the local Cox Central Office is practically across the street from 1290, so we’re first in line on the fiber ring!

Fiber is, generally speaking, a very reliable data transport method.   And it’s very, very common so it’s easy to get service and support for.   A bit pricey, though, about 50% more expensive than the T-1.  But it’s also 3mbps (vs. 1.54mbps) and again, a lot more reliable.

I have to say, though, I have a new-found respect for fiber techs after watching the Cox tech splice in the cable from the street into the new FTP box at 1290.  He has to strip nearly 10ft of 1/2in thick, reinforced cable, down to a tiny 1/4in thick plastic conduit, inside which are 12 actual fiberoptic wires; four of which are used (one to send, one to receive, and a redundant backup for each).  Each wire itself is insulated, and the actual fiberoptic channel inside is no bigger than a human hair.   Each channel has to be stripped, trimmed, and verrrrrry carefully placed in a special device that fuses two channels together, tests the light pass-thru, and then heat-shrink-seals the channels.   It’s demanding, exacting work that takes over an hour to do properly.

We’re still waiting on some special equipment to mate our gear with the new fiber lines, but in a month we should have a lot more fiber in RIPR’s daily diet!  (Ed note: yes that's a terrible pun, and I love it!)