When you are out in the desert tracking direct bury fiber, only handholes are 
splice points.... good luck. 
If the closest hand hole is 2 miles away from the area of the fault, good luck. 
 You will wheel it off, read the sequential, then wheel it off again, dig 
again.  Not find the damage.  Then you have the choice to cut and shoot it 
again or just start exposing cable.  Flip a coin to choose which way to start 
digging and start digging.  Have dug for hundreds of feed looking for damage 
and sometimes it is very hard to see.  Sometimes a gopher will just eat into 
the side of a cable a little bit.  

You can strip it and have someone put a visible light on it if  you are not too 
far away for that to work.  That can tell you if you are on the CO side of the 
fault.  There are also those bendy fiber detectors that can help with that too. 
 Hopefully you find it close enough that you can put a handhole near where  you 
stripped it.  Always takes two handholes or peds to fix.  And LOTS of digging.  


From: castarritt 
Sent: Wednesday, August 28, 2024 1:49 PM
To: AnimalFarm Microwave Users Group 
Subject: Re: [AFMUG] fiber patch cables

Shouldn't you be able to look at the distance to fault from the last splice, 
look up the cable footage marker going into that splice closure (go check it if 
you didn't document that when it was built), check footage marker at closest 
handhole, and then wheel it off from there?

On Wed, Aug 28, 2024 at 2:42 PM <ch...@go-mtc.com> wrote:

  So on a 15 mile shot with a problem somewhere in the middle, you think you 
can wheel it off and dig it up and find it?
  One shot, from the end.  Walk right to the problem?



  From: Josh Luthman 
  Sent: Wednesday, August 28, 2024 1:07 PM
  To: AnimalFarm Microwave Users Group 
  Subject: Re: [AFMUG] fiber patch cables

  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. 

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