[time-nuts] Bad batch of HP10811's

Jeroen Bastemeijer J.Bastemeijer at TUDelft.nl
Tue Feb 20 10:35:14 EST 2007

Dear Bruce, Time-Nuts,

Sorry for the "silence" it was a long weekend. I checked the oscillator, 
the serial number was: 1528A10107

If I'm correct this means it was manufactured in week 28 of 1975.

A pity that the cold frequency-offset is nowhere metioned, except for 
the HP-Journal article.

Best regards, Jeroen

Dr Bruce Griffiths wrote:

>Jeroen Bastemeijer wrote:
>>Dear Time-nuts,
>>New info on an old subject:
>>I opened the counter (5345A) to check what kind of oscillator was 
>>inside. It was a 10544A instead of a 10811A!!!
>>I checked for a datasheet of the 10544 but I couldn't find it. Luckily I 
>>ran across an article in HP Journal. See the quote below:
>>Warmup. The 10811A/B Oscillator cuts the 10544/B/C
>>warmup time specification in half: 10 minutes for the
>>10811A/B compared to 20 minutes for the 10544A/B/C Oscillator.
>>Warmup time is defined as the time between oscillator
>>oven turn-on and the time when the output frequency
>>is within 0.05 Hz of the operating frequency, In portable
>>instruments, where battery weight must be minimized, low
>>power and quick warmup are crucial. Since the instrument
>>warmup time is likely to be much shorter than the oscillator
>>warmup time, the latter usually dominates. A side benefit of
>>the 10811A/B is that its frequency just after oven turn-on is
>>only 100 Hz low compared to 1 kHz low for the 1054aA/B/C.
>>This allows faster lock-in for instruments using phaselocked
>>Bottom line: The 10544 gives a higher offset at switch-on compared to 
>>the 10811.
>>Only thing to do now is find a datasheet to verify it with real numbers, 
>>as my oscillator was 1700 Hz off (compared to 1 kHz in the article) and 
>>Didiers' oscillator was 200Hz off (compared to 100 Hz in the article).  
>>Is there a link to the 10544 datasheet somewhere out there???
>>Have a nice weekend, Jeroen
>There are at least 2 versions of the 10544A. After the initial 
>production models modifications were made to improve the phase noise specs.
>The oscillator, oven controller and oven supply volatage specifications 
>also changed after this modification.
>I have a set of datasheets  dated:  1 October 1972, July 75, July 1976.
>There is no specification on the datasheet for the frequency offset at 
>startup with a cold oven.
>Any idea when your oscillator was manufactured?
>time-nuts mailing list
>time-nuts at febo.com

Ing. Jeroen Bastemeijer

Delft University of Technology
Department of Electrical Engineering
Electronic Instrumentation Laboratory
Mekelweg 4, Room 13.090
2628 CD Delft
The Netherlands

Phone: +
Fax: +
E-mail: J.Bastemeijer at TUDelft.nl

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