microducts

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1

Hi

I am planing a new FTTH outside plant deployment. We are going to use microducts but which system is the best? I see many resources describing the options available but few if any will take a stance on which one to choose.

Some of the choices are:

1) Ducts with larger fixed tubes for direct burial 12/8 mm. Typically 7 ducts in a larger tube.
2) Ducts with smaller fixed tubes 5/3,5 mm. Typically 24 small tubes with one larger centre tube for backbone.
3) Ducts for direct burial arranged in a stripe side by side instead of in a tube. 12/8 mm ducts. Makes it easier to access the tubes and avoids problems with tubes of different length on the drum.

And many more variations.

I am planing to deploy in an area with the average distance between houses of 10 meters (actually 20 meters but we can serve both sides of the road from one walkway, so that makes it 10 meters average).

I want to support a low level of initial uptake of just 10%. The problem is that most sources assume that I am planing for anything between 100% and 50%. I do expect that we will get more customers than just 10%, but the solution might become too expensive, if I have to pay all costs upfront years before I have any hope of that many customers.

Some people say just put a lot of plastic down because it is so cheap. But it really isn't. I need to put down the correct amount of tubes because tubes are everything but cheap. I also need a system that is easy and quick to work with because labour is very expensive (but also very skilled) around here.

I would appreciate any pointers to articles about this subject.

Regards,

Baldur

2

I can provide you some advice from a local person in my area that is doing this, while homes aren’t of such a nice identity of 10 meters, they place a pedestal that has capacity for 96 count splice trays at every 3rd home. You can use something like a flat drop cable to be buried later as that connection. They may also drill up to the home or use a maxi or mini-sneaker type device to directly place the duct in the ground from that pedestal.

The bonus of this type of solution is in the winter months where the ground is frozen you can often leave this cable on the ground to be buried at a later date. I helped a local WISP turn up their first fiber link in the past two weeks and this was the strategy they took.

- Jared

3

I doubt any such data exists, but I wonder how many fiber miles and customers WISPs turned up in the past year as compared to some high-profile goalpost... Google Fiber or Verizon FiOS or AT&T Gigawhatever or... Obviously not 1:1, but WISPs as a whole compared to the titans.

4

Hi.

ducts from a cabinet to each home, and put in for 100% when doing the digging, the cost for the duct is low, so it's a bad idea to not do it right away.
You do not have to leave duct to reach all the way into the customers home, just leave it at the customers premise in the ground (don't forget to add a dust cap so that you do not get in moisture and/or dirt into the duct).

We have blown 800 meters of EBFU in a 7/3.5 mm DB duct, so as long as you don't have lots of curves (or atleast not sharp ones and make good duct splices (which is not hard)) then you can go a long distance.

How many cabinets you need depends on the cost of subscriber ducts/fiber vs. cabinet cust.
We have had cases where we could do 100% uptake with just one cabinet, but it was 25% more expensive that just add another cabinet and put a 14/10 ducts with 96 fiber betweeen them.

Another recommendation is to use 14/10 ducts from the CO and between the cabinets.
Put in more than one so you can expand or use to go to the next area or CO.

Example:
CO > Cabinet 1 > Cabinet 2 > Cabinet 3 > Cabinet 4

Each cabinet in this case can have up to 48 subscribers.
Start with a 192 fiber (which is available for the 14/10 ducts) between CO and cabinet 1.
Go with 144 fiber from cabinet 1 to cabinet 2.
Go with 96 fiber from cabinet 2 to cabinet 3.
Go with 48 fiber from cabinet 3 to cabinet 4.

You can also go with for example a 192 fiber all the way, and if you need to expand, just blow in a new fiber (in another 14/10 duct) between the CO and cabinet 1 and splice them into the rest of the fibers between cabinet 1 and cabinet 2.

There is alot of different designs, but it's much cheaper to put in a cable of extra ducts day 1 than to dig up everything to put in another duct later.

Here is some prices for reference (from distributors in Sweden, prices may differ and project pricing apply from your manufacturer):
DB1 - 7/3.5 0.16 Euro/m
DB4 - 7/3.5 0.82 Euro/m
DB7 - 7/3.5 1.28 Euro/m
DB12 - 7/3.5 2.06 Euro/m
DB1 - 14/10 0.33 Euro/m
DB2 - 14/10 1.05 Euro/m
DB4 - 14/10 1.85 Euro/m
DB7 - 14/10 2.94 Euro/m
24x SM Microfiber for 14/10 0.78 Euro/m
48x SM Microfiber for 14/10 1.15 Euro/m
72x SM Microfiber for 14/10 1.49 Euro/m
96x SM Microfiber for 14/10 1.89 Euro/m
144x SM Microfiber for 14/10 2.76 Euro/m
192x SM Microfiber for 14/10 3.56 Euro/m
EBFU 2x SM for 7/3.5 0.166 Euro/m
EBFU 4x SM for 7/3.5 0.194 Euro/m
EBFU 8x SM for 7/3.5 0.353 Euro/m
EBFU 12x SM for 7/3.5 0.454 Euro/m

In Sweden most providers use this kind of material for their FTTH projects, but small providers to the incumbents.
The old way of using 32 or 40 mm ducts is mostly used for long backbone links or where you use bigger fibertrunks (384, 480, 960, 1280 fibers (most often ribbon fiber)).

Hope it helps, and if you have any questions, just ask.