Prev: SCR and snubber LTSpice simulation
Next: RayMing PCB how to choose a good PCB manufactory
From: miso on 3 Aug 2010 18:01
On Aug 2, 8:03 pm, Bob E. <besp...(a)invalid.tv> wrote:
> A friend is having a new roof put on his his 50-year-old, flat-roof home.
> This provides access to all kinds of new wiring possibilities for the
> structure.
>
> He wants to do 2xCAT6 and 2xRG-6 throughout. I'm not sure what to recommend
> re. fiber optic.
>
> Is it too soon to know how this will be an advantage to existing homes?
>
> I hear there are several FO standards (62.5 micron, 50 micron). Is there
> strong competition, or is one the clear favorite into the future?
>
> What should I recommend?
>
> Thanks.

There are companies that make data and RF bundled cable. Just a
thought.

I'm not so sure running RF is all that useful these days. I own a few
boxes that pipe video over either data cabling . Silicon Dust for TV
and a USB satellite box. But there are satellite boxes that support
data cables directly these days.
From: Josepi on 3 Aug 2010 22:47
All glass fibre optics need a large radius for the bends. 1/4" radius will
definitely break any of the corning glass products we used to build a four
city wide MAN fibre optic network.

I was warned of this bend problem early in my installation training and
thought it was bunk. I was using electrical tape boxes (about 4.5" dia.) to
store spare flexible jumper leads for usage in the field instead of making
two trips from the site to warehouse each time. It took a few months to a
few years for the fractures to show up in the glass and become problems for
customers once they achieve high bandwidths and cannot attain them, due to
data errors...fractured glass strands = reflected light and bad light
conduction.

One day a contract cross country fibre optic company we used to do all our
splices, showed me, with his laser light indicator, what happens when you
bend the stuff too sharply. Red light spills out the sides at the fractures
and you can see it right throuygh the jackets too. Most strands never
recover but still work fine, depending on tolerable light losses. We stopped
storing the flex jumpers in small round boxes from then on. Behind the
scenes I began seeing all our installed jumpers being replaced due to data
errors (light impedance)....ooops!

Check the specs and although these jacketed outdoor cables with many strands
looks tough they cannot make the sharp bends. Most specs will tell you to
use no smaller than 2-3" conduit to enforce slow turns.

Shock?
A few incidents where cables between poles were hit, one by a dumptruck, and
a pole hit in an accident (IIRC), shattered some (or all) of the strands in
50 or 100 strand aerial cables. The contractors started cutting back cable
sheaths to find the start of the good glass sections and make a splice
there. One fracture from the dumptruck with dumper up, stretched the cable
so badly before snapping, the inside the fractured strands when over 1 km in
one direction and almost 1/2 km the other, due to longitudinal mechanical
shock. The injuries are restrung back to the nearest splice box now, without
test, and it it takes a few km of new cable it is faster and cheaper. The
drivers not looking pay big time for those ones.


"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message
news:fpvg56thporsijb0aq81qges0ke0ktf7hg(a)4ax.com...
Jacketed fiber is tough. One trick is to blow it into existing
underground gas pipes, with a little parachute/umbrella sort of thing.
A quarter inch bend radius has no effect on the stuff we use.

But shock?


John


On Tue, 3 Aug 2010 14:17:27 -0400, "Josepi" <JRM.(a)easynews.com> wrote:

>Fibre needs it's own conduit. It is still fragile, limited bend radius and
>subject to shock. Secondly, it will be corning glass so thin that it bends.
>Plastic fibres have too much opacity, went out with hooped skirts and is
>limited to toys and lamps now.





From: furles on 4 Aug 2010 03:35
On 3 Aug, 18:19, Mark F <mark53...(a)gmail.com> wrote:

> Cat 6E might be for real now, so try for it instead of Cat 6.
> The cables I put in in 2004 say "CAT6E", but it certainly wasn't
> an official specification then.

Do you mean Cat. 6A? I've never heard of 6E.
From: Ross Herbert on 4 Aug 2010 04:15
On Mon, 2 Aug 2010 20:03:51 -0700, Bob E. <bespoke(a)invalid.tv> wrote:

:A friend is having a new roof put on his his 50-year-old, flat-roof home.
:This provides access to all kinds of new wiring possibilities for the
:structure.
:
:He wants to do 2xCAT6 and 2xRG-6 throughout. I'm not sure what to recommend
:re. fiber optic.
:
:Is it too soon to know how this will be an advantage to existing homes?
:
:I hear there are several FO standards (62.5 micron, 50 micron). Is there
:strong competition, or is one the clear favorite into the future?
:
:What should I recommend?
:
:Thanks.


In my opinion, no residential situation will require the extreme bandwidth of
fibre internally for the foreseeable future. Cat5e or 6 for data and RG6 for TV
distribution provides all the bandwidth capability you will ever require in your
lifetime. It will also cost a lot less...

Typical home wiring scenarios for a FTTH network can be found here
http://www.telstra.com.au/smartcommunity/assets/homecablingforvelocity_0509.pdf

Note, this is as the situation as for Australia but it won't be much different
no matter where you are.
From: Ecnerwal on 4 Aug 2010 12:33

Best and cheapest option is empty conduit (pull string optional - if the
conduit is installed correctly, a shop vac, a rag or chunk of foam and a
string should be able to install a pull string when you need one - I
just installed pull strings in 2 330 foot runs of 2" conduit this way.)
Then you only spend money on cables when you actually need cables, and
you can always yank the old cables out and replace them with the latest
thing when the latest thing comes along and you decide that you need it.
Use large radius bends, and provide access to pull boxes where needed.
Run at least one more conduit than you know what you are doing with now,
for something that comes along later.

Not limited to electrical use, either - if at some point you decide you
need compressed air in a room, you can run a compressed air hose through
a conduit, for instance. Or use them as old fashioned speaking tubes...

In multimode fiber, 50/125 is able to haul more data than 62.5/125. IMHO
the only reason to use 62.5/125 is if you already have an installed base
of 62.5/125 to maintain compatibility with. I have yet to see enough
movement in singlemode pricing and connections to see much point in
going there for anything short-haul.

I also feel that for now, plain old Cat5e copper does pretty much
everything that anyone is likely to need in a house, computer network
wise. It's far faster than any offsite connection available, and most
people don't have a lot of call for more than 1Gb/s rates around the
house itself. Its also cheap enough to use part of the 500 or 1000 foot
box for the Plain Old Telephone Service wires. Fiber is mainly of
benefit going between buildings, where its immunity to lightning induced
surges is a great benefit, and the ability to go much further than 100
meters is of use. However, if the differential in price between Cat6A
and Cat5e has come down enough, Cat6A offers possible future benefits.
It's just that paying much for "future benefits" you never use is rather
silly.

Quick shopping results, 1000 feet, not exhaustive:

Cat6A - 68 cents a foot plenum, 30 cents a foot not. (UTP version)

Cat6 - 28 cents a foot plenum, 12 cents a foot not.

Cat5e - 18 cents a foot plenum, 4 cents a foot not.

By running it in dedicated conduit, you avoid any need for plenum-rated
cable (though the cat 6 cable at some vendors was rated to a higher
speed with plenum .vs. not plenum insulation on it.)

--
Cats, coffee, chocolate...vices to live by
First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4
Prev: SCR and snubber LTSpice simulation
Next: RayMing PCB how to choose a good PCB manufactory