[time-nuts] HP 106B quartz frequency standard...the story so far

[Steve Rooke]

2009/8/7 Chuck Harris <cfharris at erols.com>:
> If I recall correctly, the HP quartz oscillator manuals say that you must
> allow
> at least 72 hours of burn in after shipment from the factory, and 72 hours
> between
> frequency adjustments.
>
> Double oven quartz oscillators are dodgy things.  The Sulzer 2.5C and HP
> 107's that live
> in my shop have an interesting characteristic:  They age upward in
> frequency, and I
> make the appropriate adjustments every few days.  But if I break power for
> even an instant,
> the crystals pop down in frequency to about where they were back when they
> were last
> started...  And it takes them months to get back to where they were before
> the power quit.

I have seen this too and wondered what is going on here. Maybe some
day I will collect data from startup and then cycle the power to see
if the next set of data corresponds in some fashion to the original
aging.

Cheers,
Steve

>
> -Chuck Harris
>
> Mark Sims wrote:
>>
>> The first question to ask is how long had the unit been inactive and how
>> long has it been powered up?  I have noticed
>> on several 5370 counters that the oscillators took several (4-6 weeks) to
>> stabilize after I received the units.  I am
>> pretty sure that the units had been inactive for quite a while and were
>> not recently removed from operation.
>>
>> I had them connected to a Tbolt or cesium oscillator.  I would set them
>> each morning to a few counts above 10 MHz.
>> By the next morning the reading was below 10 MHz.  It took between 4 and
>> six weeks for the units to stop drifting.
>> Interestingly,  the 10544 oscillators drift much less than the 10811's
>>  and all the oscillators drifted in the same
>> direction.
>>
>> Before doing any serious study of your 106B,  I would plug it in,  leave
>> it on,  and let it cook for a couple of
>> months.
>>
>> ----------------------------------------
>>
>>
>> _________________________________________________________________ Windows
>> Live™: Keep your life in sync.
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-- 
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.