[time-nuts] questions about oscilloquartz 10MHz module

[Bob kb8tq]

Hi

The bigger issue is: Was the “ST” version done as a low cost approach that just
happened to be in the 8663 footprint? If so, the only way to know what it does / 
what it is would be to find the elusive spec sheet. 

Bob

> On Feb 2, 2020, at 5:47 PM, Magnus Danielson <magnus at rubidium.se> wrote:
> 
> Hi Nigel,
> 
> I was about to make a similar comment. The 8663 is for sure limited by
> it's size. Actually, for being Oscilloquartz they are by far not the
> best or the worst, but kind of mid-range. I have OSA 8712 here, and the
> even smaller one. Then there is the OSA 8666/8667 and well, I guess the
> OSA 8600/8607 does not need introduction. I do not have the full OSA
> range of oscillators for sure, but a fair sampling of it.
> 
> I think we should look at the 8663 for what it intends to be, a
> mid-range OCXO to address some of the telecom market needs.
> 
> Cheers,
> Magnus
> 
> On 2020-02-02 23:37, gandalfg8--- via time-nuts wrote:
>> I don't have access to the full copy of the quoted reference, so don't know whether or not specific part numbers are quoted, but did note from the abstract the comment.....
>> "To allow the assembly on a board of 4TE width, the height of the OCXO is limited to 19 mm"
>> This I would suggest could again point to the 8863, which is specified as having a maximum height of 19mm, rather than to the 8663 which is specified as having a maximum height of 25mm, perhaps to allow for some physical thermal insulation?
>> Nigel GM8PZR
>> 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)
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