Mel; You are absolutely right. I should have been more specific in my description of the problem.
On Thu, Jan 31, 2019 at 1:27 PM Mel Beckman <m...@beckman.org> wrote: > Fletcher, > > I don’t think that’s true. I find no specs on fiber dB loss being a > function of ambient temperature. I do find fiber optic application data > sheets for extreme temperature applications of -500F and +500F > (spacecraft). You’d think if temperature affected fiber transmission > characteristics, they’d see it in space. > > What you likely were seeing was connector loss, owing either to improper > installation, incorrect materials, or unheated regen enclosures. > > Insertion loss (IL) failures, for instance, in the cold are a direct > result of cable termination component shrinkage. That’s why regen and patch > enclosures need to be heated as well as cooled. > > All fiber termination components have stated temperature limits. As > temperatures approach -40F, the thermoplastic components in a > cable's breakout, jacketing, and fiber fanout sections shrink more than the > optical glass. Ruggedized connectors help somewhat, but the rule is that > you can’t let optical connectors and assemblies get really cold (or really > hot). > > A typical spec for a single-mode OSP connector is: > > Operating -30C (-22F) to +60C (+140F) > > The range for the corresponding Single Mode fiber is: > > Operating -55C (-67F) to +70C (+158F) > Storage -60C (-76F) to +70C (+158F) > Installation -30C (-22F) to +50C (+122F) > > All professional outside plant engineers know these requirements. So if > you’re seeing failures, somebody is breaking a rule. > > -mel > > > On Jan 30, 2019, at 3:05 PM, Fletcher Kittredge <fkitt...@gwi.net> wrote: > > > Cold changes the transmission characteristics of fiber. At one point we > were renting some old dark fiber from the local telephone company in > northern Maine. When it would get below -15%-degree F the dB would get bad > enough that the link using that fiber would stop working. The telephone > company was selling us dark fiber because regulation required them to. They > refused to give us another fiber nor inspect/repair. They took the position > they were required to sell us fiber, not working fiber. > > > On Wed, Jan 30, 2019 at 11:41 AM Mark Tinka <mark.ti...@seacom.mu> wrote: > >> For anyone running IP networks in the Midwest, are you having to do >> anything special to keep your networks up? >> >> For the data centres, is this cold front a chance to reduce air >> conditioning costs, or is it actually straining the infrastructure? >> >> I'm curious, from a +27-degree C summer's day here in Johannesburg. >> >> Mark. >> > > > -- > Fletcher Kittredge > GWI > 207-602-1134 > www.gwi.net > > > -- Fletcher Kittredge GWI 207-602-1134 www.gwi.net