[time-nuts] Z3805A cooling requirements?

Erno Peres ernieperes at aol.com
Thu Dec 20 05:32:51 UTC 2012

Hi Said,

just additional question:  did the DC current increased when you started to blow air????????
You should run this test / blowing air / minimum 24 hrs.....or longer....!

Rgds Ernie.

-----Original Message-----
From: SAIDJACK <SAIDJACK at aol.com>
To: time-nuts <time-nuts at febo.com>
Sent: Thu, Dec 20, 2012 3:57 am
Subject: Re: [time-nuts] Z3805A cooling requirements?

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 
ithin  <1E-011 of 10MHz. This is a free-running 10811.

ompare that to the plot of the OCXO I had sent out some hours ago when it  
as running stable inside the foil - there was almost no average frequency  
hange between the two tests.

f the heaters had an issue keeping average crystal temperature stable,  
hen the frequency would have changed from the first plot to the last plot  I 
ould 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 
CB  which are very sensitive to the airlfow. Consider that this unit and 
t's PCB  was designed to live inside the 53132A (very close to the fan) that 
 am now  using as an air source. One thing this tells me: the fan in the 
ounter could be  disabled and it would improve the units stability, if one 
eeps an eye on  internal counter temperature.


n a message dated 12/19/2012 18:42:08 Pacific Standard Time,  
ctast at hotmail.com writes:
I think  the data shows that the heaters were losing ground, which would 
xplain the  steadily falling temp of the SC cut quartz. 
Thomas  Knox

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