Original GPON specs had a timing limitation of 20 km.
From: AF <[email protected]> On Behalf Of Josh Luthman Sent: Tuesday, August 19, 2025 6:31 AM To: AnimalFarm Microwave Users Group <[email protected]> Subject: Re: [AFMUG] how is underground FTTH done? Class C optics are rated for 60km or 42mi. That's a hell of a distance when you're only doing 1:32. We did 1:2 and 1:32 on the sixteenth PON port until we built more to justify another OLT. On Mon, Aug 18, 2025 at 6:13 PM Chuck McCown <[email protected] <mailto:[email protected]> > wrote: When you work out a 32:1 GPON, the timing distance limitations are exhausted before you run out of light. Splits are a 3 dB loss. A good splice will be .02dB. So don’t worry about splices. From: AF [mailto:[email protected] <mailto:[email protected]> ] On Behalf Of Dev Sent: Monday, August 18, 2025 9:56 AM To: AnimalFarm Microwave Users Group <[email protected] <mailto:[email protected]> > Subject: Re: [AFMUG] how is underground FTTH done? The thing with PON is that every time the light hits a splitter it loses a bit of strength, so you sort of have to plan to use a little hotter SFP in your OLT sometimes. Luckily, those are getting way cheaper nowadays, so it’s not the end of the world, but you do have to plan for that. Plus, each splice you do cuts down the signal a bit more. Fusion splicers only lose a tiny bit, but a physical connector can lose a bunch more, like the equivalent of a mile or more of distance, and a piece of crud on an uncleaned connector can lose 5 miles distance, so make sure you clean them with those cheap cleaner tools. On Aug 18, 2025, at 8:39 AM, Josh Luthman <[email protected] <mailto:[email protected]> > wrote: Splitters are waaay small. Smaller than a standard house key. What you are looking at is an MST terminal, looks like 8 ports. There can be a splitter inside of that yes. You can have the MST with 8 fibers splice to another 8 fibers or you can have what is in your picture have 1 fiber in, split 1x8, and then have 8 ports out for the installers to simply plug in to. If that MST is a 1x8, you can have a 1x4 before it, between the MST and OLT. That makes for OLT -> 1x4 splitter -> 1x8 splitter/MST. That is still a 1x32 split. On Mon, Aug 18, 2025 at 11:34 AM Ken Hohhof <[email protected] <mailto:[email protected]> > wrote: I thought PON used like 16:1 or 32:1 splitters, and in this photo, I assumed that’s what the black boxes were. From: AF <[email protected] <mailto:[email protected]> > On Behalf Of Josh Luthman Sent: Monday, August 18, 2025 10:16 AM To: AnimalFarm Microwave Users Group <[email protected] <mailto:[email protected]> > Subject: Re: [AFMUG] how is underground FTTH done? Don't assume that about aerial. That's not how it works. Don't think about it in terms of taps. Generally speaking, installations are PON. What we do is design the fiber so we can hook up 100% of homes. We assign a color to every house. The first thing to think about is that you have to access the individual strand out of the cable, be it 12/24/48/144/etc. That is done with a SpliceCase or you splice on an MST for an ez mode plug. At Imagine we only splice - no connectors, no MST, no plugs, etc. Second thing is that when there's a cable up and down the road, you just need access to it through the case/MST from the house. This can be from the house to the handhole (concrete box in the ground) or you can run it from the house to the handhole through some 1.25" duct to the next handhole where there is one case. I can show you what it looks like if you don't get it yet. On Mon, Aug 18, 2025 at 11:11 AM Ken Hohhof <[email protected] <mailto:[email protected]> > wrote: The fiber train left without me, so maybe someone here can help me understand how the physical installation is typically done. I’ve seen aerial fiber and it’s pretty straightforward, I see splitters up on poles maybe at each intersection, and to hook up a customer, they run a drop wire from the nearest splitter to the house. If take rate is better than expected or a new house is built, worst case I assume they just add a splitter. But I also see FTTH deployments going in where they are boring for duct in the ROW and putting a little handhole in front of every house. How does this work? Are they using taps instead of splitters? If not, when they get a customer install order, do they pull his drop cable through all the handholes to a splitter? That doesn’t seem feasible. Are they dedicating a strand to each house and pulling the main cable out each time and splicing to that strand? And what if they estimate the take rate wrong, or a new house is built? There’s probably a simple explanation and once someone enlightens me it will be a Duh! moment. -- AF mailing list [email protected] <mailto:[email protected]> http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list [email protected] <mailto:[email protected]> http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list [email protected] <mailto:[email protected]> http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list [email protected] <mailto:[email protected]> http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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