[time-nuts] Morion MV89A position

[Charles Steinmetz]

Paul wrote:

>Can you mention the size of the aluminum box you are using to add 
>thermal capacitance?

It depends on the size of the oscillator -- as a general rule, I'd 
leave at least 3-4 cm of air space on all 6 sides of the 
oscillator.  The cast aluminum boxes I use have wall thicknesses from 
1.6 mm to 4 mm.

Warren pointed out that the MV89 has a double oven and said that this 
makes added thermal capacitance unnecessary.  He seems to have had 
better luck with MV89s than I have.  I did not find that the three I 
tried had significantly less sensitivity to fast ambient temperature 
changes than a number of single-oven oscillators in my 
collection.  In my experience, and from the many posts to this list 
and elsewhere, it is obvious that the quality of brand new MV89s 
varies all over the place and, additionally, that many of the ones 
available used on the surplus market are broken.

Best regards,

Charles