[time-nuts] Thunderbolt cooling vs heating for stability

Bob Camp lists at rtty.us
Tue Jan 18 17:41:12 UTC 2011


There's pretty much nothing in a TBolt that wears out. The heat rise on the
parts on the pc board is modest and the only heated part is the OCXO.
Cooling down the OCXO actually increases the stress on it (more heater power
pulled => more stress on the heater). 

Obviously you can get it to hot. The OCXO does have an upper temperature
limit. I don't think that extreme measures are needed to keep it at a
rational temperature. Simple fans and boxes seem to be working pretty well
for people. Any setup that results in sub 60C temperatures at the OCXO is
likely to have very little impact on reliability or performance. 

The more important question is how you package it to reduce gradients. If
you use the internal sensor, it's location is a bit sub-optimal for tracking
the OCXO. You could put all sorts of sensors throughout the package. An
easier thing to watch is the correlation between external temperature and
EFC voltage. As long as EFC correlates (positive or negative) with outside
temperature, you have room for improvement. 


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Pete Lancashire
Sent: Tuesday, January 18, 2011 12:16 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Thunderbolt cooling vs heating for stability

Been getting ready to build a box for the t'bolt and instead of it all
getting hotter to maintain a stable temp
is the idea of cooling with a Peltier cooler, or a mix of a Peltier
and a heater ?

Extending life time is the major concern


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