[time-nuts] How to accurately measure an oscillator's temperature.

sams10 at comcast.net sams10 at comcast.net
Thu Apr 24 03:35:56 UTC 2014

I'm unsure what temperature you wish to measure, but, assumng the OCXO has a proportional oven control, the input current is a good measure of the oc 
scillators ambient temp. 
Sam Shniper 

----- Original Message -----

From: "Chris Albertson" <albertson.chris at gmail.com> 
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com> 
Sent: Wednesday, April 23, 2014 10:37:29 PM 
Subject: [time-nuts] How to accurately measure an oscillator's temperature. 

I have both an OCXO and an FE-5680 Rb oscillator and I'd like to track 
their temperatures. 

What is the best why to measure?   Maybe each has a different best method 

The OCXO is just a small steel can.  Is measuring the steel can temperature 
the best why to go.  Epoxy some kind of sensor to it? 

The Rb is mounded to a large heat sink and there is a fan.  I want to 
control the fan so as to keep the Rb temperature constant. 

In both cases I tried using TMP36 three terminal sensors and just got 
noise.  The reported temperature was up and down more than 2C.    The fan 
controller just chases noise. 

BTW the fan based temperature control is effective.  The FE5680 gets very 
warm in it's box but if I give the 12V fan even 8 volts the heat sink 
quickly cools.  I want to throttle the fan to keep the Rb at constant 
temperature but the temperature data I'm getting is not very good. 

The problem I think is that any sensor I have is on the outside of the 
oscillator and is effected by cooling air   What are others doing?   What's 
the best kind of sensor. 


Chris Albertson 
Redondo Beach, California 
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