[time-nuts] Re: HP 10811A vs 10811-60111

Tom Van Baak tvb at leapsecond.com
Sat Apr 23 15:56:07 EDT 2005

The seller should give you the 10811A that you
bid on and won.

In general there is a difference between a 10811A
and a 10811-60111. The 10811A meets all the
specs on the data sheet and the 10811-60111
has relaxed specs. These -60111 are often found
in medium performance frequency counters such
as the 5328A where some of the 10811A specs
have little or no relevance.

My guess is rather than design multiple OCXO
types, HP designed one really good one and then
used the results of manufacturing performance
tests to determine which units should go to into
which products.

For example, it would be a waste to put a 10811
with well above average phase noise performance
in a frequency counter that only needs an OCXO
for a precise 1 second gate.

I suspect most other companies do the same for
high-end OCXO.

This is not to say the 10811-60111 that you have
is bad; nor that the 10811A that you should have
received is guaranteed to be better. These are old,
surplus oscillators and a lot can happen in the 20
or 30 years since they came off the manufacturing
line. I've seen some -60111 that test really well
and some 10811A that are in really bad shape.

If you're a bottom feeder in the surplus oscillator
market like the rest of us the only way to know
the performance is to test what you get for the
few parameters you're interested in. A few eBay
sellers do performance tests (such as accuracy
or drift rate) but most sell as-is.


----- Original Message -----
From: "David Kirkby" <david.kirkby at onetel.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Saturday, April 23, 2005 09:38
Subject: Re: AW: [time-nuts] HP 10811A vs 10811-60111

> Thanks for that.
> It does seem the specification of the 10811-60111 is poorer than the
> 10811A, as the formers time domain stability at 1s is twice as bad
> (10^-11) compared to that of the 10188A (5x10^-12), and just about every
> other parameter is "not specified" on the 10811-60111.
> It is particularly annoying when I has some suspicions it was not an
> 10811A, so asked the seller
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7505853855
> and he confirmed it was, and then said I could have an 10811-60111 if I
> wanted for the same price. I made it clear I did not want it, so he
> sends me it anyway!
> I sent him a mail saying:
> "I have sent you payment for this. Please ensure it is the HP10811A and
> not the HP10811-60111, which you said in an email you also had"
> So he sends me an HP10811-60111 anyway!
> Dave Kirkby
> Hubert v. Bonhorst wrote:
> > Sorry for page flipped. Attached pdf is for 10811-60111
> > Best regards
> > Hubert
> > DB7ME
> >
> > -----Ursprüngliche Nachricht-----
> > Von: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] Im
> > Auftrag von David Kirkby
> > Gesendet: Samstag, 23. April 2005 16:32
> > An: Discussion of precise time and frequency measurement
> > Betreff: [time-nuts] HP 10811A vs 10811-60111
> >
> > Can anyone tell me the difference between the two above oscillators? I
> > have the manual for the 97page manual (page 2 is upside down), but it
> > does not mention the latter.
> >
> > However, I think I have seen a small couple of page document somewhere
> > which listed the 10811-60111 as having no specification for phase noise,
> > and so therefore not an ideal choice for a low phase noise oscillator.
> > One might as well start with something that is specified for a low phase
> > noise.
> >
> > I can't however now find the exact spec of the 10811-60111. Can anyone
> > give me it?
> >
> > I won an auction for a 10811A on eBay and the seller said I could have a
> > 10811-60111 for the same price if I wanted it too. I said no, I wanted
> > the 10811A, but he has sent me the  10811-60111 instead.
> >
> > Is the 10811-60111 inferior? How does it differ from the 10811A?
> >
> >
> >
> > ------------------------------------------------------------------------
> >
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> > time-nuts at febo.com
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> --
> Dr. David Kirkby,

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