It is an old industry thing that you need 1 km cables and may test specs just boilerplate that into the spec. Back when semiconductors were much slower, in the days when OTDRs were invented, I am sure deadzones were that large.
My Inno OTDR has a dead zone of 80 cm. My Viavis have a dead zone of 65 cm. (event dead zones, the attenuation dead zones are at about 2.5m). Using 1 km launch cables just make short measurements all that harder to see and measure accurately. From: Mike Hammett Sent: Thursday, September 10, 2020 10:51 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] My solution I think the manufacturer recommends a certain length of launch cable to get the most out of their product. I'd use whatever they recommend. ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP -------------------------------------------------------------------------------- From: ch...@wbmfg.com To: af@af.afmug.com Sent: Thursday, September 10, 2020 11:31:33 AM Subject: Re: [AFMUG] My solution I have mixed emotions about 1 km launch cables. Most splicers these days have a dead zone that is in the range of 1 meter. I have a 3 meter launch cable and it makes it really easy to dilineate C.O. connector and splice loss vs anything else. If I had a 1 km cable then a C.O. connector or splice may be at 1.010 meters. Also, I set everything up for feet not meters. Go 'merica! -----Original Message----- From: Seth Mattinen Sent: Thursday, September 10, 2020 10:20 AM To: af@af.afmug.com Subject: Re: [AFMUG] My solution On 9/10/20 08:42, Mark Radabaugh wrote: > > As far as testing - plug in the OLT and see what the reported signal > levels are. Compare them with the acceptable levels and the number on > the other customers on that ONT port. If signals out of line first > clean the connectors, then break out the optical power meter and check at > the NID to see it the issue is inside or outside. If it’s outside check > and clean the connector at the pole/handhole if there is one. If you > still can’t find it you can break out the OTDR, though keep in mind the > OTDR probably isn’t going to tell you much about the pigtail. It’s very > difficult to see much of interest on an OTDR near the launch point, and it’s > hard to see anything when the pigtail splice is 3’ from the pigtail end. > Probably easier to just replace the pigtail if you think the splice might > be screwed up. Add a 1km launch spool. -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -------------------------------------------------------------------------------- -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
-- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
