Terminating Fibre Optic cables

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raytaylor

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#88328 13-Aug-2011 23:00

Hi all,

Todays project:
On top of a mountain I have a microwave radio broadband transmitter, but i want to link it up to another transmitter on another knoll up the mountain and extend coverage into another valley below.

This involves an ethernet link of 480m - no problem for me - typically I would use a VDSL bridge, but there will be 110v AC power running in the same duct in the trench.

I am mainly concerned with the 110v untwisted cables inducting energy into the twisted pair cat5. A parallel electric fence up the mountain does this to another line that i have 110v running 50m and the fence prevents a homeplug bridge from working over it.

I have never tested any DSL running parallel to AC power over such a distance and no one can confirm to me if it will work so I figured its probably better to go with fibre.

So

Now I know where to get the rolls of fibreoptic cable from - ideal electrical can order it in for me, but I dont know what I need to crimp (or equiv) the ends on. I know you can get kits but not really sure what to ask for, or what the tools I need would be called. They dont really deal with very much fibre at the local ideal branch so i want to specify what to order rather than let them tell me.

Of course if anyone here can say VDSL will work running parallel to a 110 or 240v cable for 500m then that would be awesome. The cables are running inside a tube the size of a garden hose.

Ray Taylor

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#506122 13-Aug-2011 23:14

It's not trivial mate, you need a splicing machine and be trained on how to use it.

My suggestion would be to order, if the distance is 480m a 500m cable that is pre-terminated so all you have to do is plug each end into your SFP. It will be expensive but definitely cheaper than any other option. Going multimode will also be slightly cheaper I would imagine, especially with the termination equipment (although this won't be the expensive part). I've got 2x spare SFPs and a spare media converter if you want it (free as I have no need for it anymore).

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Zeon

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#506123 13-Aug-2011 23:15

And yes I imagine running power right next to cat5e is going to cause issues. Have you thought about shielded cat5e?

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raytaylor

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#506147 14-Aug-2011 01:40

Zeon: And yes I imagine running power right next to cat5e is going to cause issues. Have you thought about shielded cat5e?

No i didnt think of it - good suggestion though.

As i understand, all i would have to do is connect the shield to an earth at each end.
If thats the case it may be a problem. Its all limestone up the mountain so to get a good earth, you need to drop two or 3 long grounding rods, and surround them with graphite? i think is the stuff they use up there.

So i have seen in the past on youtube some videos of some terminating kits that come with special micro stones, alcohols and a mini microscope thingy that you use to check that you have smoothed the end of the fibre properly. The kit looks like it might be worth $50 all up - but i dont know what its called. I think I also saw a video of a scotch splicing joiner that easily rejoins a broken fibre almost like cutting it and then inserting the fibres into a little joiner clip and then locking them in.

Is anything like that avaliable here? Im sure I must be able to do it without a fusion splicer or some expensive training course. Just wanna figure out what tools i need to put some ends on a bit of glass.

The reason I want to do this myself is so I dont have to rely on the local fibre networking guy as he would cost a fortune to get him to come up the mountain and repair a cable, or even just to make up a cable for me. And i potentially have many more similar projects where I will need to make up different lengths of fibre, so rather than continue relying on little DSL links, i might as well have a go at fibre.

If i cant rejoin a broken cable, then my plan would be to keep a roll in the garage, and use a draw wire to pull a replacment through then re terminate it up there as needed.

Thanks for the offer on the converters. I would have to pay for them - but im going to hold off on taking it up until i know what im doing.

Ray Taylor

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cyril7

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#506163 14-Aug-2011 07:55

Hi Ray, rural DSL experience has shown that fence noise does not seem to pose much of an issue, close mains also not a big issue dont forget that DSL does not use any spectrum below 25kHz and deliberately high pass filters any LF rubbish out. Also any high frequency rubbish that may be on the power line (ie switch mode power supply hash) will not travel far along the poor mains line therefore reduces its chances of coupling, and when it does it then has the CMRR of the cat5e to deal with. I dont recommend going to shielded for this.

Exacly how far apart is this new cat5e and the main cable, and what is the construction of the mains cable, just TPS or double sheathed, or neutral screened? What kind of load is on the main feed,

You can purchase pre termintated fibre it comes with special end cap socks to help you pull it through your conduit, talk to your local wholesaler about it. Obviously all you require is OM3 for a 450m run, but I would give your VDSL a go first.

Cyril

raytaylor

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#506240 14-Aug-2011 13:24

cyril7: Hi Ray, rural DSL experience has shown that fence noise does not seem to pose much of an issue, close mains also not a big issue dont forget that DSL does not use any spectrum below 25kHz and deliberately high pass filters any LF rubbish out. Also any high frequency rubbish that may be on the power line (ie switch mode power supply hash) will not travel far along the poor mains line therefore reduces its chances of coupling, and when it does it then has the CMRR of the cat5e to deal with. I dont recommend going to shielded for this.

Exacly how far apart is this new cat5e and the main cable, and what is the construction of the mains cable, just TPS or double sheathed, or neutral screened? What kind of load is on the main feed,

You can purchase pre termintated fibre it comes with special end cap socks to help you pull it through your conduit, talk to your local wholesaler about it. Obviously all you require is OM3 for a 450m run, but I would give your VDSL a go first.

Cyril

The mains cable will be TPS, the cat5 would be in the same hose so they are pressed up against each other.
There will be about 0.5amps running down the 110v cable alongside it. For my low voltage applications such as this where I need to send power somewhere, i use an isolated 110v supply and it goes to a standard 4-way power board at the far end. The radios and ethernet switch at the far end just use 100-250v switchmode power supplies and the voltage is usually around 105v by the time it gets there.

I know rural fences dont cause much issues - because they are at the bottom of the telephone pole, and even when the poles are shared, the telephone is usually a couple of metres below the power, but these will be pressed up against each other. If you reckon that is still okay, then I'll go with the VDSL

Ray Taylor

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chevrolux

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#506268 14-Aug-2011 14:39

Hey mate,
Fibre splicing -
When we cable schools the spec that all fibre must be fusion spliced which means we get in some one to do it as a fusion splicer is $20k +.
When we run fibre for 'normal' clients (not the anal ministry of education) we use 3M hand termination kits. You need a decent cleaving tool to cut the fibre and thats where the cost is. The 3M kits is $1800. Not really worth it if you are doing it once. and it takes a bit to get a good joint. We have a fluke dtx cable scanner with fibre heads. (16k for the scanner and then another 13k for the fibre attachments). So we can test the splice after we do it. if you have no means of testing the splice then I wouldnt bother. But we can get a >0.1dB loss with a manual splice. So it's a good method for us because we use the gear alot and already had the fibre otdr to test splices.
Its not super cheap to get someone to do fusion splicing but everything will be taken care of. Possibly about $400 to get a 4-core fibre terminated ready to plug in to your gear. You lay the fibre and they will come and splice it.

why do the cable have to be squashed together? I have zero experience with vdsl as they havent blessed us with a roll out down here in palmy yet. But I do lay alot of telecom service leads out in paddocks with a big whopper 400V power cable next to it. We direct bury a 2-pair lead in the same trench as the power cable with about 100mm vertical seperation and have never had a problem with power induction. The only time have had an induction problem was when there was a joint pillar right next to a 11kv transformer. I dont thin you will be dealing with this much power lol. In terms of running a cat 5. I think you will be hard pressed to find shielded, underground cat5/cat6. I have run shielded cat 6 and underground cat 6. But never seen a shielded/underground combo. And please dont be like a sparky and just say she'll be right and put internal cable underground because it WILL not last.

So basically what im saying after all that woffling is lay your own fiber in the trench and pay someone to come and fusion splice it. It's a tried and trued method. we know it works and you wont have to worry.

On another note, have you got a trade account at ideal? If not get in contact with your sparky and get them to orde the fiber for you as they will get a much better rate than someone off the street. We order most of our fiber direct from 3M or from Stewarts electrical (who are also known as Radcliffe or J. A. Russel).

John2010

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#506270 14-Aug-2011 14:44

raytaylor:

...Of course if anyone here can say VDSL will work running parallel to a 110 or 240v cable for 500m then that would be awesome. The cables are running inside a tube the size of a garden hose.

Data is not my field but I do understand tranmission lines (mainly rf though), and have no idea of the cost of fibre vs Cat5 so really just throwing this in the pot.

I would assume DC would be no problem at all laid close along side in the same duct. Would need DC power supply one end and inverter back to AC at the other. Keeping in mind ohmic loss if one did 120v DC I would expect that you could do that for less copper cost than 110v AC (as earth conductor dumped) assuming same ampacity and maybe at 60v would not be much more than for 110VAC cable. If as I think you have inferred your equipment at the destination end is DC then instead of an invertor just a DC-DC converter (or convertors if equipment not all one voltage).

The hardware will be at industrial equipment not domestic prices but as under 100W may not be too shocking. 120VDC, 60VDC, etc power supplies and 120VDC, 60v, etc input inverters and DC-DC converters are readily available in NZ. Might have to think about mix and match a bit to allow for volt drop over the half kilometre.

If you do go to AC laid with the Cat5 and you end up with a problem, then a fallback recovery position might be converting to DC along the lines above.

As I say, not my field so fibre might be as cheap as chips and I may have missed something else, in which case the above is rubbish

chevrolux

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#506299 14-Aug-2011 15:17

Oh and just another note, why woud you have to get some one to fix a broken cable? If it's laid properly there shouldnt be an issue ;)

oxnsox

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#506305 14-Aug-2011 15:22

If you need advice on fibre you could try here http://www.actechnologies.co.nz/?
they're generally pretty helpful and would make your cable up for you if required.

Otherwise what others have said

raytaylor

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#506310 14-Aug-2011 15:27

chevrolux: Oh and just another note, why woud you have to get some one to fix a broken cable? If it's laid properly there shouldnt be an issue ;)

Rabbits i guess. Not really sure.
Also because of the ground conditions, like 30m of rocks sticking out, the area cant be trenched so the cable will be attached to a fence.

okay so i have been sufficently scared away from fibre.

Good old trusty VDSL it is.

Ray Taylor

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jjnz1

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#506313 14-Aug-2011 15:32

The easiest solution would be OM3 fiber, terminated using a hand kit as mentioned above. Most data outlets hire these out for minimal cost so you don't need to buy one @$1800.

Once you get good at cutting and polishing the fiber, a connection can be done in a few minutes. Also, ask for SC connectors. The Leviton brand of connectors is good, easy and fast too.

If you need guidance, I can give you a slideshow on how you perform a fiber termination using SC connectors. really quite easy.

cheers.

jjnz1

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#506315 14-Aug-2011 15:34

raytaylor:
chevrolux: Oh and just another note, why woud you have to get some one to fix a broken cable? If it's laid properly there shouldnt be an issue ;)

Rabbits i guess. Not really sure.
Also because of the ground conditions, like 30m of rocks sticking out, the area cant be trenched so the cable will be attached to a fence.

okay so i have been sufficently scared away from fibre.

Good old trusty VDSL it is.

OM3 fiber has a few (6 or 8) cores in it, and you only need 2 of them for a Gigabit connection. Plus, if you get general cables (which the ministry of edu spec) the sheathing is very durable. I would be willing to bet the OM3 would be more durable than EXT Cat5e cable.

jjnz1

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#506317 14-Aug-2011 15:37

Broken Fiber is easy to fix. Just as easy at locating the fault as Cat5/6.

One way is to use a RED laser pen on one end of the fiber and follow it until you can't see the fiber core glow red.

raytaylor

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#506326 14-Aug-2011 16:18

Okay I will go to ideal electrical tomorrow and see what they have avaliable.
Yes I do have a trade account with them.

If I were to go with VDSL, this is my plan

Ray Taylor

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chevrolux

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#506327 14-Aug-2011 16:33

Well if you clip the cable directly to the fence then yes animals will chew it. That will happen to any bare cable. Run a 4 core fibre (cheap as. About $2/m) in conduit and have a solid connection you wont have to worry about. Outdoor cat5/ cat6 is expensive and you still need to put it in conduit.

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