[time-nuts] Z3805A cooling requirements?
lists at rtty.us
Thu Dec 20 12:36:56 UTC 2012
Did I miss part of the data?
The plot I got shows about 9 minutes. Temperature step stress takes a *long* time to settle out.
On Dec 19, 2012, at 9:56 PM, SAIDJACK at aol.com wrote:
> Not sure about that, if you look at the frequency plot after ~20 minutes in
> moving air the frequency was still extremely close to 10.000000MHz.. to
> within <1E-011 of 10MHz. This is a free-running 10811.
> Compare that to the plot of the OCXO I had sent out some hours ago when it
> was running stable inside the foil - there was almost no average frequency
> change between the two tests.
> If the heaters had an issue keeping average crystal temperature stable,
> then the frequency would have changed from the first plot to the last plot I
> would think. In my opinion the airflow is just adding a huge bunch of heater
> control loop noise to the output stability, or there are components on the
> PCB which are very sensitive to the airlfow. Consider that this unit and
> it's PCB was designed to live inside the 53132A (very close to the fan) that
> I am now using as an air source. One thing this tells me: the fan in the
> counter could be disabled and it would improve the units stability, if one
> keeps an eye on internal counter temperature.
> In a message dated 12/19/2012 18:42:08 Pacific Standard Time,
> actast at hotmail.com writes:
> I think the data shows that the heaters were losing ground, which would
> explain the steadily falling temp of the SC cut quartz.
> Thomas Knox
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