[time-nuts] HP OCXO warmup graphs

[Richard (Rick) Karlquist]

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