[time-nuts] Rb cooling

EWKehren at aol.com EWKehren at aol.com
Sun Jul 17 21:03:34 UTC 2011


I use on several Rb's a small 5 X 5 X 1 cm Nidec 60 mA fan with a linear  
temp regulator. I can not hear it and it is mounted on the outside back  
plate of the chassis  with the Rb  on the other side of  the back plate. In one 
case I have the fan mounted with four rubber grommets  inserted in the 
chassis with screws through their center in an other case I have  a Rb vibration 
mounted with its back plate with heat sink protruding through the  back. It 
is amazing how much cooling such a small fan produces and I have not  been 
able to detect any vibration by attaching a cheep Xtal Osc. to the Rb  
assembly.  
On my FRS unit which I would call my portable unit that runs off a 12 V  
battery the typical fan current is about 37 mA with a 45 C back plate.
Bert Kehren
 
 
In a message dated 7/17/2011 2:46:27 P.M. Eastern Daylight Time,  
w1ksz at earthlink.net writes:

If I use  a Muffin Fan to cool the Rb (both are mounted in the same box, 
in close  proximity to each other), will the noise and/or vibration affect 
the  stability of the Rb oscillator ?

Thanks, Dick,  W1KSZ





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