[time-nuts] OSA 8601

Magnus Danielson magnus at rubidium.dyndns.org
Fri Sep 18 20:46:42 UTC 2009

Fellow Time-nuts,

I have received several requests over the day for the OSA 8601 
datasheets that I was fortunate to get from Oscilloquartz. They scanned 
their archive sheets and excused themselfs for making them large.
Anyway, while it was not my intention to publish them, I asked my 
contact and he sayed OK, so I put them up on my webserver.

Here you go:

In addition there is several other sources, where one nice is

If you look at the datasheet above you realize that OSA 8600 and OSA 
8601 is really the same oscillator, which only differ in terminal 
connections. However, comparing the datasheet to the modern version at 
Oscilloquartz you see that there is quite a difference in the power 
consumption when heated, and running them side by side you can very 
easilly feel the difference. First I thought it had a broken thermo 
flask, which I had problem with on my OSA 8600, but no... it tracked up 
nicely and when I got to see the datasheet I could see this was 
expected. Phew.

But the material on the OSA 8601 is much more interesting than 4,5 W vs 
2 W. Look at the gravity sensitivity plots, they are gone in todays 
datasheet. If you look at the PTTI article you also find f^-3, f^-1 and 
white noise separated numerically, which you really don't see often 
enought. Prof. Rubiola teaches how to do this... with and without credit 
cards as assitance (in lack of rulers at hand, not to pay anything).

An interesting note in the PTTI article is about the BVA having a lower 
gravity sensitivity, an improvement by a factor of 4 (see page 6).

The PTTI article is also interesting in how it discusses time-constants 
for cesiums and hydrogen masers. You also find the baking details there, 
as well in the datasheet material I brought up.

Anyway, enjoy. I am sure someone sees something much more interesting 
fact than I did.


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