..."junk GPSDO"... . Are you sure of that statement ?
The Cal Lab where I retired from had one of those "junk GPSDO's"
that they used. The only difference between theirs and mine (that
I built) was the 3 orders of magnitude difference in price !!

73, Dick, W1KSZ

-----Original Message-----

Richard W. Solomon wrote:

He said, [a] "junk GPSDO that I salvaged from telco equipment."

A poor choice of words, perhaps, but I think the intention may be that
the telco took it out of service for some reason and "junked" it. Not
necessarily an adjective denoting quality. More than 90 % of my
high-tech equipment is "junk".

Rex skrev:

We can be happy that telcos etc. work on a system thinking. While they
shift systems they can't handle little details like re-use of GPSDOs
even thought they would still do a good job even for the new system.

Cheers,
Magnus

I wonder if companies don't junk equipment because "electrolytic capacitors
last years not decades" Does this  make sense?

Ed
----- Original Message -----
From: "Rex" rexa@sonic.net
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Saturday, December 20, 2008 5:42 PM
Subject: Re: [time-nuts] Thunderbolt accuracy...??

Edwin B. Walker skrev:

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.

Cheers,
Magnus

I do not think so.  Most telephone company stuff is engineered to last
20+ years - it takes them a few years to recoup there investments cost
wise, and the electronics are usually close to mil specs.

Probably what happens, is they engineer a whole new system and all the
old systems , racks and all go.

Brian KD4FM

Edwin B. Walker wrote:

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

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

Lux, James P skrev:

Indeed. When running such a large network, having a consistent network
management system is crutial. The network management needs to know all
key boxes in the system, be able to control them, be able to take alarms
from them and be able to provide good information to the team doing the
24x7 hours of network operation. These people cost good hours and must
be able to take actions to ensure the network functionality. Large set
of diversity is a problem in such cases. Designing network management
software that makes the two boxes act and behave in the same fasion,
making the manuals for the support team etc. becomes more expensive. To
support that telcos spend alot of effort to ensure there is standards
and multiple vendors for the same box-role to ensure that not a single
vendor can skirt them up or dry up.

Indeed.

One should recall that for a telco, the actual equipment cost is only a
part of the cost. Operational costs, maintenance cost and installations
costs includes so much more.

So gear being phased out from a telco may have no value for them but may
not be without value outside of their framework.

However, not phasing out equipment in time to keep consistency can also
bite back. One telco for instance had their complete network failed as
their GPS receivers (same model thoughout) did not support a certain PRN
number, and as long as it was not overhead they would work, but fail as
it came up again.

Let's just say that the customers where not impressed and happy about
it, they had to make a very quick (and hence more expensive) buy-up and
replacement.

Another aspect may be that you want to shift them out before they die on
you and in a way that kills you more than the loss of the machine...
loss of data. Loss of access to data is annoying but can painstaking and
critical in itself, however usually that spreads out a bit. Loosing
critical data and not being able to get it back is worse.
Being able to support the set of applications needed and upgrading OS
and applications is an issue. In just about three years machines seems
small and weak, but can still work on for a while. In 5 years another
upgrade becomes troublesome. At the same time the actual hardware cost
as gone down. Upgrading to a OK machine has become much less a hardware
issue than the cost of managing it.

Developing and revising test rigs comes at a fairly high cost. Being
able to support the same command-set to ease drop-in-replacements is one
way to achieve things. For a production line setup, being able to swap
in instruments to handle scheduled calibrations should also be
considered. As a source of instrument dry up, this could lead to stalls
in the production. In the end, it could mean the death of that product.
With dry up it can mean that the instrument support has been dropped for
instance. Being able to keep it calibrated could be an issue. Loosing
calibration due to loss of battery power is another issue.

Certainly. Let's not complain or whine about it. We are winners on this.
Most of the time.

Cheers,
Magnus