Crossing driveways and roads are easier with conduit all the way. Lots less
figure 8s. I don’t direct bury anymore.
From: Chris Fabien
Sent: Thursday, August 29, 2024 7:46 PM
To: AnimalFarm Microwave Users Group
Subject: Re: [AFMUG] fiber patch cables
We do a lot of direct bury, including at time up to 144F. Every so often I get
ashamed of myself and design a project using conduit for the larger county
fiber sections. Most of those, I have ran into various problems with pulling or
blowing the fiber, causing additional re-work or troubleshooting time. So it's
more material cost, additional work steps (placing cable) and more chace for
problems requiring troubleshooting. We've almost never had issues with
installation damage during plowing cable. The conduit does offer some
protection against critters, around here we have ground hogs which like to dig
into ditch banks, every spring we get a handful of cuts from that, usually they
only seem to damage areas where we ran 12F flat drop as mainline. That's a
pretty quick and inexpensive repair.
On Thu, Aug 29, 2024 at 4:54 PM <ch...@go-mtc.com> wrote:
Are you using double or triple armor cable?
From: Josh Luthman
Sent: Thursday, August 29, 2024 1:43 PM
To: AnimalFarm Microwave Users Group
Subject: Re: [AFMUG] fiber patch cables
We are something like 80% direct bury. We pay for it ourselves. There are
use cases for both.
Our repair kit is: two handholes, a little bit of fiber, and a pair of splice
cases. Like $1000. This is much cheaper than say $1/foot pipe for a million
feet (which of course does not guarantee you will not have damage).
On Thu, Aug 29, 2024 at 2:11 PM Ken Hohhof <khoh...@kwom.com> wrote:
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> 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> 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> On Behalf Of ch...@go-mtc.com
Sent: Thursday, August 29, 2024 11:43 AM
To: AnimalFarm Microwave Users Group <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> 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> On Behalf Of ch...@go-mtc.com
Sent: Wednesday, August 28, 2024 5:05 PM
To: AnimalFarm Microwave Users Group <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> 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> 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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