That hasn't been my experience, but at the same time we're not 25 mile shots - it's maybe 15 max.
On Wed, Aug 28, 2024 at 11:43 AM <ch...@go-mtc.com> wrote: > I also use EXFOs and they will read to the meter, but if you have a fiber > cut out 25 miles, I will bet good money that when you dig up the spot where > your OTDR says the fault is, you will be off by 100 feet or more if you did > not do a test from the nearest splice point. In reality it will be off by > thousands of feet. > > Best Regards, > Chuck McCown > > McCown Technology Corporation > 8401 N Commerce Dr > Lake Point, Utah 84074 > 801-250-9503 Office > 435-830-4306 Cell > www.mccowntech.com > www.microtrench.pro > www.terabitnetworks.com > > *From:* Ryan Ray > *Sent:* Tuesday, August 27, 2024 9:58 PM > *To:* AnimalFarm Microwave Users Group > *Subject:* Re: [AFMUG] fiber patch cables > > 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 >> > ------------------------------ > -- > 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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