[time-nuts] 10811 serial numbers

Dave Carlson dgcarlson at sprynet.com
Wed Jun 1 01:59:10 EDT 2005

A clarification:

The 4-digit prefix preceding the "A" or following the "US" in newer units is
indeed based on 1960 and a 28xx refers to 1988. However it is the year/week
of the most recent engineering change documented. The last 4 or 5 digits are
a sequential number that is unaffected by the serial prefix. Therefore a
2850A or US2850 prefix does not necessarily mean that it was manufactured in
the 50th week of 1988. It does means that it could not have been
manufactured earlier than that date. The only way to know the upper boundary
is to know the next serial prefix assigned to the next engineering change.
Usually service manuals provided this information in the backdating and
change sheets, but for non-field-repairable oscillators this information was
not readily available.

The changeover to the unusual 4-digit code given in this thread of messages
is not the result of the HP/Agilent spin-off. Agilent continued to use the
prefix/suffix nomenclature for its oscillators after its operation as a
separate company.

I can't say where that strange "A03912" number came from, except that it may
have been a separate asset number added to that oscillator by the previous
owner or that as a result of a previous repair a new label was generated as
a replacement and the prefix was not considered relevant.

I also know of no tamper-proof labels used on the 10811 series oscillators.

Dave Carlson

----- Original Message ----- 
From: "John Miles" <jmiles at pop.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: May 26, 2005 11:13 AM
Subject: RE: [time-nuts] 10811 serial numbers

> BTW, does anyone know if the 10811-series oscillators had any 'tamper
> resistant' label of any form, such that if one was missing, you could
> reasonably assume someone has taken it apart at some time?

None of them I have seen has anything like that.

-- john KE5FX

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