[time-nuts] Looking for datasheet for Oscilloquartz 8602

Magnus Danielson magnus at rubidium.dyndns.org
Tue May 28 19:59:12 EDT 2013

On 05/28/2013 07:55 PM, Attila Kinali wrote:
> On Tue, 28 May 2013 09:27:55 +0200
> Magnus Danielson<magnus at rubidium.dyndns.org>  wrote:
>>> Hmm.. IIRC AT cut oscillators have the "problem" of frequency jumps
>>> on slight temperature changes. Using an AT cut oscillator thus kind
>>> of defeats the effort of doing a BVA.
>> Frequency jumps isn't a particular feature of AT cut, but rather to
>> cleanness of the crystal and mechanical stresses. The BVA strategy aims
>> to reduce systematic shift, it is then baked out to remove residues that
>> is known to cause issues. There is a good article on it amongst the PTTI
>> papers.
> Can you give a little more hints on which paper you mean?


See also

>> Also, it's an oven within a dewar flask, so temperature
>> conditions is pretty stable. The AT-cut BVA is far from the same thing
>> that a typical TTL-can AT-cut is. There seems to be an overbeleif in the
>> cut and not look at all the other things that needs to come together to
>> make a great oscillator.
> Juup. I just went back to Vig's tutorial and read up what he wrote.
> Misremembering things is not a good thing...
> But then, he explicitly writes that SC cut gives a higher stability
> over AT cut due to lower temperature dependence and less dips.

That is true, but your discreditation of AT-cut was simply way off the 
mark, so I wanted to bring it into context. There is a difference, but 
it is not as huge as it sounded like. I like to think about it as such 
that you better have done much of your homework in form of good 
oscillator and oven before considering spending money on going from 
AT-cut to SC-cut, but it does give that extra performance if you need 
it. The OSA 8600 shows just how far you can take AT-cut.

>> That is overpriced. An OSA 8602 should have about the same price as OSA
>> 8600, whatever the going price of that is.
> I haven't explicitly asked for a price of the 8600, as it isn't sold anymore.
> But the price of a new 8607 (their only BVA they still sell, with SC cut
> crystall and all bells and whistles) is a mere ten percent higher then
> the initial price of what he tries to sell the 8602 for.
> So i wouldnt say the 8602 is overpriced, but rather it's horribly
> overpriced.


If it where the going rate for a OSA 8602, I would make a small fortune 
from what's in the lab and be able to upgrade the living conditions for 
the sake of a better lab.


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