We’ve had a lot of fiber installs in the ROW around here (including for a Meta datacenter), almost all buried, combination of directional boring and trenching but I haven’t seen anyone doing direct burial. It’s all in conduit. One county it’s something like 4 inch and I was told the county requires that size. Not sure if conduit and handholes and blown fiber are just the preferred method of construction to make repairs easier, or if it’s a govt requirement to bury stuff in the ROW.
From: AF <af-boun...@af.afmug.com> On Behalf Of Josh Luthman Sent: Thursday, August 29, 2024 12:47 PM To: AnimalFarm Microwave Users Group <af@af.afmug.com> Subject: Re: [AFMUG] fiber patch cables >Sometimes just one strand That sucks! So you have a HH every 20k/40k feet with the butt splice? Nothing in between? On Thu, Aug 29, 2024 at 1:42 PM <ch...@go-mtc.com <mailto:ch...@go-mtc.com> > wrote: Gophers will kill one fiber at a time. Sometimes just one strand, sometimes they will eat through the whole cable. Steel armor and all. Direct bury across the desert, there is no advantage to hand holes. Since you are not blowing you cannot install slack loops. So the HH is at the splice point. When you have damage you dig it back and install two HH with slack loops. I don’t build direct bury any more. But some do. From: Josh Luthman Sent: Thursday, August 29, 2024 11:20 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] fiber patch cables When the gophers hit, do they get the entire cable or just a healthy bite of the cable. I'm wondering if you could somehow see the strength of a tone down the armor? How far apart are your HH? We try to keep it 1320 or 2640 feet at most but we are doing FTTH. On Thu, Aug 29, 2024 at 1:17 PM <ch...@go-mtc.com <mailto:ch...@go-mtc.com> > wrote: Yes, if it is a strike you don’t even need the OTDR. Just drive the route and stop where they are digging. Sometimes splices go bad and normally the OTDR indicates a distance very close to a splice point so that is easy too. Gophers, never easy. From: Ken Hohhof Sent: Thursday, August 29, 2024 11:06 AM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] fiber patch cables Sounds like gophers are a lot worse than somebody digging in the wrong spot, because once you are close you can just look for the above ground evidence like a hole or an excavator with yellow vest people standing around. What were the critters than Bill Murray was at war with in Caddyshack, were those gophers? Dumb movie, but iconic I guess. From: AF <af-boun...@af.afmug.com <mailto:af-boun...@af.afmug.com> > On Behalf Of ch...@go-mtc.com <mailto:ch...@go-mtc.com> Sent: Thursday, August 29, 2024 11:43 AM To: AnimalFarm Microwave Users Group <af@af.afmug.com <mailto:af@af.afmug.com> > Subject: Re: [AFMUG] fiber patch cables Index of refraction (IOR) differs from reel to reel. If you need accurate distance measurements you have to enter a precise index of refraction, and the IOR can vary with distance as well. The internal timebase drifts. Clock errors and stability cause accuracy issues. Pulse width and sample interval adds precision errors. Longer distances need wider pulses so you lose precision. So with a loss of both precision and accuracy that is proportional to distances being shot, you are never going to walk right up and dig up the correct spot. Bottom line, long cables, gopher faults, you will spend lots of time digging along the line to find it. From: Josh Luthman Sent: Thursday, August 29, 2024 10:22 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] fiber patch cables 1.01x 20,300 foot cable reel is 20,500 of glass On Thu, Aug 29, 2024 at 9:01 AM <dmmoff...@gmail.com <mailto:dmmoff...@gmail.com> > wrote: That and fiber distance is not equal to cable distance because of the twist built into the buffer tubes. From: AF <af-boun...@af.afmug.com <mailto:af-boun...@af.afmug.com> > On Behalf Of ch...@go-mtc.com <mailto:ch...@go-mtc.com> Sent: Wednesday, August 28, 2024 5:05 PM To: AnimalFarm Microwave Users Group <af@af.afmug.com <mailto:af@af.afmug.com> > Subject: Re: [AFMUG] fiber patch cables Good point, with direct bury the sequentials are frequently rubbed off. From: castarritt Sent: Wednesday, August 28, 2024 2:42 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] fiber patch cables Yeah, with direct bury and no handhole for miles, you are in a tough spot. If the footage marker on the cable you dig up is still there, you could go off that instead of guessing or cutting. On Wed, Aug 28, 2024 at 2:58 PM <ch...@go-mtc.com <mailto:ch...@go-mtc.com> > wrote: 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 <mailto: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 <mailto: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 <http://www.mccowntech.com> www.microtrench.pro <http://www.microtrench.pro> www.terabitnetworks.com <http://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 <mailto: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 <mailto: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 <mailto: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 <mailto: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 <mailto: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 <mailto: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 <mailto: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 <mailto: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. 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