[time-nuts] Thunderbolt accuracy...??

Lux, James P james.p.lux at jpl.nasa.gov
Sun Dec 21 01:07:07 UTC 2008




On 12/20/08 4:44 PM, "Magnus Danielson" <magnus at rubidium.dyndns.org> wrote:

> Edwin B. Walker skrev:
>> I wonder if companies don't junk equipment because "electrolytic capacitors
>> last years not decades" Does this  make sense?
>
> No. Details like that does not comes into play. If the quality of the
> gear does not match the specs, the manufacturer gets a serious problems
> so they choose components accordingly. They kick the manufacturer around
> or they choose another if worse comes to worse. Shifting out systems is
> a much bigger thing. It is about being able to provide the needed
> services, ensuring the revenue stream. Shifting out old systems can also
> release frequency spectrum for new more efficient services. This may be
> at the control of the spectrum authority.
>
> So issues like poor capacitors does not really come up. Telco runs quite
> a different ship than consumer PCs. Way different.
>

Even if the basic function is sound, in a large operation, there's value to
having a limited number of different kinds of equipment around.  You have
smaller training costs, interoperability is easier, etc.  Say you have 5000
cell sites, each with a widget that's a few years old, and now you're adding
another 5000 new sites, and the old widget's not available.  It might
actually be easier and cheaper in a lifecycle cost sense to buy 10,000 new
widgets and scrap/junk the 5000 old ones.  Your maintenance manual only
needs to cover one kind of widget, your depots only have to stock 1 kind of
spare, etc.

Furthermore, the "book value" of the widgets being scrapped might be zero
(having taken accelerated depreciation of 3 years, for instance), so from a
corporate standpoint, selling them for cheap is a good thing.


You'll see this in the desktop PC market for large companies, where the cost
to support multiple hardware configurations is substantial, and where
there's a fairly standard 3 year amortization cycle.  At some point, keeping
that 5 year old PC working just isn't worth it. (Oh, only Bob knows how to
fix that one, so you won't get your computer fixed today, because Bob's on
another call or on vacation, sorry, key employee doing mission critical job,
you're out of luck.)

Even for test equipment, there's good reasons to cycle through new gear in a
fairly short time. Especially if you're changing test configurations a lot,
you want to encourage "model number independence" and not depend on
peculiarities of a particular instrument, otherwise you wind up with
specialized test sets with 20-25 year old signal generators (I'm looking at
YOU, you old HP 8663s) that can't be repaired, and because nobody has been
following along, using something new is a major jump, rather than a small
update. (And you find out that Agilent Exxxx models have very different
operating peculiarities from their predecessors with similar model #s, even
if they do work better by all rational evaluations.).

To those tinkering at home, though, this cycling through is great.. If
you're willing to fix it yourself, and maybe have a hangar queen or princess
for parts, or you don't need ALL the functions to work (never needed that
knob anyway..), then you too get really nice gear to work with. (and,
besides there's something really satisfying about that orange glow of the
Nixies... It impresses people who see your garage, because its redolent of
Atomic Age science fiction movies of the 60s and 70s.)

Jim








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