[time-nuts] Z3805A cooling requirements?

Said Jackson saidjack at aol.com
Thu Dec 20 16:46:49 UTC 2012


Bob,

The ADEV plot was done after the unit had fully settled to it's new location in front of the 53132A fan.

The Tsc5125A instrument has a limit of 9 minutes to plot the frequency drift for some reason, so I can only show you the last 9 minutes.

The transient due to the new temperature was long gone when I started this ~20 min ADEV plot.

Bye,
Said

Sent from my iPad

On Dec 20, 2012, at 4:36, Bob Camp <lists at rtty.us> wrote:

> Hi
> 
> 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.
> 
> Bob
> 
> 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.
>> 
>> 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
>> 
>> 
>> 
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.



More information about the time-nuts mailing list