May 8, 2019
Power Influence and Balance —
While I always find Don McCarty’s articles to be very informative and spot on, in his article in the May issue of ISE magazine, I think there could have been a better way to describe the relationship between power influence, noise metallic and (pair) balance. While what Don said is true: “Circuit noise (noise metallic) and power influence are interrelated, each being dependent upon the other to form acceptable balance”, I think the better way of explaining this would be as follows:
“Power influence and balance (pair quality) are interrelated, each being a contributing factor to circuit noise (metallic noise).”
Pair balance is what should direct the technician to work on a metallic issue with the cable pair or look at cable shield grounding and bonding in the exposed cable plant. From my experience, a balance of 60 or below would mean a physical issue with the cable pair, while a balance greater than 65 would have me looking at cable shield grounding and bonding to reduce power influence. A balance between 60 and 65 can be the most difficult as it could be either a metallic issue or a power influence issue causing the customer’s noise.
A case in point would be a customer’s line which has a power influence reading of 87 dBrnC, a noise metallic reading of 24 dBrnC which gives this circuit a balance of 63. Is this noise from high PI or from a physical problem on the cable pair? It could easily be either one, or both could be contributing factors.
I whole-heartedly agree with Don that multiple circuits should be tested to help determine if it’s just the reporting customers circuit having issues or if the noise problems are affecting all of the customer in the cable. This will also help the technician in deciding how to proceed with his repairs.
Annex C in the 2018 update to IEEE 1137 contains some very good information for trouble shooting noise metallic issues in copper cable facilities.
Daniel Ashton, Sr ICEP Engineer
Hello, Daniel — It is obvious to me that you have years of experience in the field helping maintenance solve noise mitigation problems not only in the voice grade arena but also in the bandwidth arena. If field technicians take your comments to heart they will be able to determine if the reason the circuit failure is a cable pair problem, a bonding or grounding issue, or an associated power issue. I am not a noise mitigation expert, but you are. I enjoy all reader letters, but particularly from those who have different experiences or views from mine. Thank you for taking time to provide excellent insight. – Thank you for writing in, Don.
May 18, 2019
The OSP and Life
Mr. McCarty, I thank you for still educating techs about the OSP. I started following your articles in OSP magazine in 1998 when I came out of retirement and was hired by BellSouth. I didn’t need the job, but was too young to retire and needed to stay busy, and I always wanted to be a Phoneman.
My background is in electronics and wireless communications, and what you were writing about made total sense. While a lot of my co-workers couldn’t understand a fourth of what you were writing, it gave me a very huge one up when I first went into ADSL in 1999, and after I moved to Specials in 2000, where xDSL bonded, HDSL2, and HDSL4, were becoming the norm for Highcaps and Ethernet over copper.
Your shared knowledge allowed me to have a very enviable position as craft, with management, and while that was understood by some of my co-workers, I was hated by others for it. Too bad for them.
Thank you, Wayne, for your faithful readership. Receiving feedback is the best compensation for my life’s work. As with any career, there are professional, dedicated managers and technicians who take difficult problems as a challenge to find and share the answers. You are an example of a dedicated employee who believes in life-long learning and the value of creating strong customer relationships. While I no longer train on location, I am here to support technicians on the phone and by email. When I don’t have the answer, I almost always have relationships with expert sources who can help; we almost always can find solutions — or have a great time trying! Keep up the good work. Best, Don.
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