[time-nuts] Z3805A cooling requirements?
SAIDJACK at aol.com
SAIDJACK at aol.com
Thu Dec 20 02:56:59 UTC 2012
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.
bye,
Said
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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