[time-nuts] questions about oscilloquartz 10MHz module

[Bob kb8tq]

Hi

The HP10811 is a single oven. It has been around for a *long* time. 
It is spec’d to do 2.5 ppb over 0 to 70C. Indeed they typically exceed
this spec. HP was a bit conservative on their numbers. 

Several versions of the 8663 are not spec’d as tightly over temperature
as the 10811. The main reason to put up with the added complexity 
of a double oven is to improve temperature performance. There is no
other advantage to using one. Indeed there are a number of disadvantages.

It is unclear to me why would would add “troubles” of a double oven if
the normal benefits were not forthcoming ….

Bob

> On Feb 2, 2020, at 1:03 PM, Attila Kinali <attila at kinali.ch> wrote:
> 
> On Sat, 1 Feb 2020 21:08:42 -0500
> Bob kb8tq <kb8tq at n1k.org> wrote:
> 
>> are representative, the 8663’s don’t quite get to that level. The typical 
>> spec unit is at 1 to 4 ppb over 0 to 70.  That’s
>> reasonable performance for a modern single oven. I very much doubt they 
>> built a true double oven simply to hit
>> a single oven spec.
> 
> 
> I don't know what your definition of a "true double oven" is, but
> the 8663 definitely uses two ovens. You can find its construction in [1].
> The basic design is that the crystal is mounted on a copper plate, which
> becomes the inner oven, that is placed in a hermetically sealed package
> that doubles as outer oven. All together is than mounted in the outer
> package. 
> 
> I guess the "low" performance of the double oven comes from the low
> thermal mass of the innver oven. That said, Mark did some measurements
> with the Star4 GPSDO (uses an 8663) and attested it superp holdover
> performance.
> 
> 			Attila Kinali
> 
> [1] "A new kind of view for a Double oven Crystal Oscillator"
> by Lefebvre, Weber, Aubry, 2007
> https://doi.org/10.1109/FREQ.2007.4319182
> (can be also found in the EFTF 2007 proceedings)
> 
> 
> -- 
> <JaberWorky>	The bad part of Zurich is where the degenerates
>                throw DARK chocolate at you.
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.