[time-nuts] HP OCXO warmup graphs

[Bob Camp]

Hi

The conjecture has always been that all of the 5334B’s with 10544’s were a field 
swap out. Why would you do such a thing? That’s never been explained. One 
*might* wonder if the fact that the 5334B sells for about the price of a 10811 and
few would notice a (lower value) 10544 is involved ….

Bob



> On Apr 24, 2016, at 12:28 AM, Richard (Rick) Karlquist <richard at karlquist.com> wrote:
> 
> 
> 
> On 4/23/2016 6:27 PM, Bob Camp wrote:
>> Hi
>> 
>> The 5334 spanned the era when the 10811 was being introduced. I’ve never been
>> able to sort out exactly *what* was in each version as shipped and what got swapped
>> around by various techs over the years. I always *thought* the 10811 was
>> standard for the 5334B version. There are a lot of examples running around
>> with earlier 10544 OCXO’s ...
>> 
>> If only the project manager for the 5334B was here on the list …. :)
>> 
> 
> Well, here I am :-).  The 5334B standard oscillator (not the OCXO) was
> the same as the 5334A standard oscillator.  Which was IIRC an
> inexpensive crystal with an oscillator circuit using ECL line
> receivers.  I simply continued using it because I didn't have time to redesign everything.  An ECL line receiver is not a low phase noise
> design and has an adverse contribution to tempco.  OTOH, it is fool
> proof.  The only optional oscillator ever available from the factory
> was the 10811, which was well established by 1987, and the 10544 was
> long gone.  10811's are guaranteed to work in any 10544 socket, mainly
> because they don't draw any more warmup power than a 47 ohm resistor.
> 10811 sockets are not guaranteed to be compatible with 10544
> oscillators.  However, they are certainly mechanically compatible.
> It's entirely possible that a 10544 might work in a 5334B, but the
> factory never shipped such a configuration.  Where would they
> get 10544's?
> 
> Rick Karlquist N6RK
> Project Manager HP 5334B
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