OSP Expert: Don McCarty

A Hitch in the IoT


In 2019 I see the IoT expanding at an alarming rate, and I project that the infrastructure will fail to keep up with the demand. More things are communicating with more things over the wired infrastructure, the wireless infrastructure, fiber infrastructure, and, yes, the coaxial cable infrastructure. If there is a disruption of any of the infrastructures, then the IoT is affected. Any down time on any of the 4 structures will have both immediate and long-term effects on the IoT.  Concerns Network reliability is all important. My concerns are many.  My first concern is the oldest copper infrastructure which…

Using the earth-gradient test set when fault locating in buried plant


Around 1976, a fine gentleman by the name of Tom Lathrop, then with Bell Labs, invented the earth-gradient method of fault locating. Using a transmitter, an earth contact frame, and a receiver, transmitted voltage differences are detected and shield-to-earth or conductor-to-earth faults are exactly pinpointed in buried plant. Two test sets were manufactured by Western Electric, one for cables, one for drops. And finally, the difficult world of buried fault-locating was made simple. Several manufacturers build similar devices, and they all use the same principle as Tom’s sets. Today’s earth-gradient test sets work on any cable or drop that is…

Troubleshooting the Copper Network


When Test Sets Do Not Perform to Expectations — Field technicians have a multitude of test equipment that is used to identify and locate faults in the copper network. Many of the test sets have multi-function features. If the fault or faults in the cable are resistive in nature, such as unwanted shorted and grounded cable pairs or crossed battery from other cable pairs in the same compliment, the test set has a resistive fault locate function (RFL) and a Time Domain Reflectometer (TDR) function to help you locate these problems. If the fault or faults in the cable are…

Repair of Your Wounded Copper Infrastructure


In an earlier column we discussed the proactive process of finding single pair faults in the copper infrastructure rather than moving the customer to another cable pair to restore service. This proactive approach of finding and fixing single pair faults will resolve problems in 95% or more of your copper infrastructure customers, and quickly gets them back in service. Additionally, adhering to this process can support identifying other potential pedestal and terminal problems that can be repaired before customer service is affected. The other 5% of service interruptions occur in bad sections of cable, both aerial and buried, in the copper…

High Voltage Transmission Lines Over a CO/Hut


I recently received an email from Aaron, a manager of an independent telephone company, discussing the effect of high voltage lines on telephone equipment. He stated that a power transmission company is proposing to build a transmission line adjacent to one of his existing telephone buildings. From the proposal drawings it appears the lines will be within 100’ of the building, and could possibly go directly over the building. It is an unmanned building, but they have copper and fiber equipment and distribution at this location. He asked me if I foresee problems from electromagnetic interference and, if so, is…

Moisture Diffusion in Underground Pulp Cable Networks


During a phone call, a cable maintenance supervisor from a large metropolitan area described a cable maintenance problem he had been recently encountering when qualifying pulp cable pairs for power pairs. When testing any cable pairs for potential power pairs, the pair must test less than 10VAC tip to ring, tip to ground, and less than 3VDC tip to ring, tip to ground, and ring to ground. The insulation resistance must test greater than 100 megohms tip to ring when applying 500VDC to the pair with an electrical insulation test set, and greater than tip and ring to ground when…

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