We use EXFO otdr's on some spans that are 160km and we can get it down to the metre.
On Tue, Aug 27, 2024 at 7:07 PM Josh Luthman <j...@imaginenetworksllc.com> wrote: > Don't you document where your splices are? If you see your splices every > 33k and see it's broken 1 mile from the last splice it should be pretty > obvious, no? > > On Tue, Aug 27, 2024 at 6:26 PM <ch...@go-mtc.com> wrote: > >> Magical device called a fusion splicer. Our reels were typically 33,000’ >> >> >> *From:* Josh Luthman >> *Sent:* Tuesday, August 27, 2024 3:51 PM >> *To:* AnimalFarm Microwave Users Group >> *Subject:* Re: [AFMUG] fiber patch cables >> >> I don't see how you have a 50 mile span. Even if you get 80k reels >> that's 15 miles. >> >> On Tue, Aug 27, 2024 at 5:19 PM <ch...@go-mtc.com> wrote: >> >>> When you have spans up to 50-75 miles at times, you have to use longer >>> high power pulses. There is a lot of variability in velocity of >>> propagation, earth temperature, splice slack loops, fiber twist. 1 mile >>> error over 50 miles is only 2%. You can easily be off by several thousand >>> feet. You can’t just go dig. You have to go to the closest splice point >>> and test again, even then if you it show the fault 2000 feet away and you >>> dig at 2000 feet you may be off by 20 feet or more. I have been doing this >>> for decades. Takes lots of digging to actually find it. >>> >>> *From:* Josh Luthman >>> *Sent:* Tuesday, August 27, 2024 3:01 PM >>> *To:* AnimalFarm Microwave Users Group >>> *Subject:* Re: [AFMUG] fiber patch cables >>> >>> A mile?! IDK how that's possible. Every time we turn a new splitter on >>> the sequentials and OTDR are within a few feet - we lose a couple of feet >>> in butt splices and our sequentials end up wrong. Every new reel gets >>> tested on delivery and it's right on. >>> >>> When we had a broken fiber (ants) it was right on the case. When we had >>> a broken fiber (ribbon got knicked with installation) it was between two >>> cases. >>> >>> On Tue, Aug 27, 2024 at 3:48 PM <ch...@go-mtc.com> wrote: >>> >>>> Wow, sometimes looking for gopher damager over 20 miles I have been off >>>> a mile. >>>> >>>> >>>> >>>> *From:* Josh Luthman >>>> *Sent:* Tuesday, August 27, 2024 1:30 PM >>>> *To:* AnimalFarm Microwave Users Group >>>> *Subject:* Re: [AFMUG] fiber patch cables >>>> >>>> So far every time we've used the OTDR it's been accurate within 1 foot. >>>> >>>> On Tue, Aug 27, 2024 at 12:55 PM Trey Scarborough <t...@3dsc.co> wrote: >>>> >>>>> The only thing you have to worry about with shorter cables is the >>>>> reflection. In some instances with dirty connector at just the right >>>>> connector you can get reflection back in to the transmitter that can cause >>>>> errors, the tx to shut down or premature failure. This is very uncommon >>>>> with LR 10G and less optics and can be prevented from making sure you have >>>>> clean connectors. Check the RX and TX levels and make sure you don't have >>>>> excessive loss. With 100G its a little different story due to the combined >>>>> power of multiple channels, but still can be prevented by cleaning >>>>> connectors, but in some instances Ive had to use attenuation when mixing >>>>> different vendor optics. >>>>> >>>>> The using no launch on an OTDR most automatically calibrating OTDRs >>>>> will work without one. Your results can be off though. Most of the lower >>>>> cost ones are also lower powered and have less of an RX sensitivity so >>>>> they >>>>> don't suffer as much from the reflections interfering when testing. I can >>>>> test all day long with my little otdrs without one, but my long range >>>>> 200k+ >>>>> units I have to have a minimum of a 1k spool on it or you see ghosts. They >>>>> will show up as repeating events at even intervals. Not something you will >>>>> see on shorter runs either. >>>>> >>>>> >>>>> On 8/26/24 4:31 PM, Ken Hohhof wrote: >>>>> >>>>> I should note that apparently I used to do this with direct attach >>>>> cables (DAC) but I think that was a pain, one more thing to stock and to >>>>> bring with for projects. Whereas I’d always have boxes full of SFPs and >>>>> fiber patch cords. >>>>> >>>>> >>>>> >>>>> *From:* AF mailto:af-boun...@af.afmug.com *On Behalf Of *Josh Luthman >>>>> *Sent:* Monday, August 26, 2024 4:20 PM >>>>> *To:* AnimalFarm Microwave Users Group mailto:af@af.afmug.com >>>>> *Subject:* Re: [AFMUG] fiber patch cables >>>>> >>>>> >>>>> >>>>> People say you need a launch cable but our cheap china OTDRs have no >>>>> issues seeing the connector at the end of the patch cable and stuff >>>>> beyond. I bought a big launch cable back in the day and never use it >>>>> anymore. >>>>> >>>>> >>>>> >>>>> Might be different with AE? >>>>> >>>>> >>>>> >>>>> On Mon, Aug 26, 2024 at 5:16 PM <ch...@go-mtc.com> wrote: >>>>> >>>>> Only minimum length I know of is the OTDR dead zone. If that is a >>>>> problem you purposely lengthen the cable with a launch cable. >>>>> >>>>> >>>>> >>>>> *From:* Josh Luthman >>>>> >>>>> *Sent:* Monday, August 26, 2024 1:59 PM >>>>> >>>>> *To:* AnimalFarm Microwave Users Group >>>>> >>>>> *Subject:* Re: [AFMUG] fiber patch cables >>>>> >>>>> >>>>> >>>>> Reddit is wrong. Gasp. >>>>> >>>>> >>>>> >>>>> Connectors are loss, there is more loss in either one of the >>>>> connectors than there is the single mode glass. >>>>> >>>>> >>>>> >>>>> Between a switch/router in a rack what I see all the time is long >>>>> (like 5/10/15 feet) cables and then put the slack in a loop along the >>>>> posts. >>>>> >>>>> >>>>> >>>>> On Mon, Aug 26, 2024 at 1:19 PM TJ Trout <t...@voltbb.com> wrote: >>>>> >>>>> Patchbox makes some great products, their fiber system is pretty slick >>>>> but expensive. >>>>> >>>>> >>>>> >>>>> Cable length is irrelevant it's optical budget / Rx signal strength. >>>>> Normally on 2-20k LR optics you are ok with any length cable, 40km+ needs >>>>> a >>>>> pad on short spans. (Attenuator) >>>>> >>>>> >>>>> >>>>> On Mon, Aug 26, 2024, 8:29 AM Ken Hohhof <khoh...@kwom.com> wrote: >>>>> >>>>> Is there a minimum length for a single mode fiber patch cable? >>>>> >>>>> >>>>> >>>>> I have been using 1 meter cables and they are almost always too long, >>>>> I’m talking about going between routers and switches in a rack, stuff like >>>>> that. I see that FS sells 0.5 meter cables, but I saw somewhere like >>>>> maybe >>>>> on Reddit someone claiming there was a minimum length. Given SM fiber and >>>>> LR optics, I don’t see how 0.5 or 1.0 meter would be different they are >>>>> both essentially zero length. >>>>> >>>>> >>>>> >>>>> Probably there’s some kind of cable tray or cable management solution >>>>> I could be using but I’ve never liked such things. >>>>> >>>>> -- >>>>> 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 >>>>> >>>>> >>>>> -- >>>>> 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 >>> -- >>> 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 >
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