We use 3GIS and document the sequentials (footage in/footage out) and then tack on 50 or 26 feet for slack (midspan, butt).
On Tue, Aug 27, 2024 at 3:55 PM <dmmoff...@gmail.com> wrote: > Yeah, I was gonna say, the OTDR might give you a perfect fiber distance, > but accounting for the built-in twist and the slack loops complicates > matters. > > > > > > *From:* AF <af-boun...@af.afmug.com> *On Behalf Of *ch...@go-mtc.com > *Sent:* Tuesday, August 27, 2024 3:47 PM > *To:* AnimalFarm Microwave Users Group <af@af.afmug.com> > *Subject:* Re: [AFMUG] fiber patch cables > > > > 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 <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 > <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 >
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