[LINK] The market for wireless [WAS: Work on Next Generation Wireless in Canberra]

David Boxall david.boxall at hunterlink.net.au
Mon Nov 29 16:14:52 AEDT 2010

On 29/11/2010 9:55 AM, Richard Chirgwin wrote:
> On 29/11/10 9:33 AM, Jan Whitaker wrote:
>> ...
>> Has anyone seen the life of network data for the NBN business plan?
>> Has it been released yet for those details? I know they've said the
>> network end equipment will handle the upgrade requirements, but I'm
>> wondering what time frame they're thinking for the whole thing? 20
>> yrs? 50? How long has the copper network been installed? I know it
>> was starting to degrade in some places.
> Not for the NBN business plan, but having done some research for an
> article back in September, I can tell you that the accepted
> *depreciation* life of a fibre network is 30 years.
> The source for this is a company called Technology Futures Inc, whose
> data seems generally accepted by the investment community.
> This suggests to me that the fibre is expected to be in-service for more
> than 30 years, since you don't have something that's being replaced
> before it's been depreciated off the books. And this, in turn, is in
> line with other research I've seen - in one case, a fibre that had gone
> through ten years of freezing, heating, flooding and mud in Oregon
> showed zero measurable degradation in its optical performance.
I heard a mention of at least 60 years service life. On Link, I think.
> Yes, the copper is degrading where it's old. Some of the copper is as
> much as 50 years old, although by now (due to progressive replacement)
> it's mostly newer than that. There's all sorts of mechanisms in place to
> try and protect it against degradation - putting the wires inside
> pressurised cables etc - but age is catching up with the copper. As far
> as I know, the relative age of different bits of the copper plant is not
> public knowledge, nor does Telstra separately report the full cost of
> maintaining the copper.
> ...
In my area, the copper had been ploughed directly into the ground (no 
ducting) about 40 years before it was replaced (according to the 
linesmen overseeing the replacement). Some of the cables reportedly fell 
apart when disinterred. I didn't know that could happen.

Bottom line: fibre will probably outlast copper.  It's actually cheaper 
overall, as well.

David Boxall                    |  The more that wise people learn
                                |  The more they come to appreciate
http://david.boxall.id.au       |  How much they don't know.

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