Hi There are a bunch of cheap little USB thermometers out there ($10 or so). If you plug one into the back of your PC you can get a "guess" at what the room is doing. Just as you found with the power supply and fan - it's only a guess. Between that data and LH's EFC plot you should have some pretty good information on just how much the temperature control is helping.
Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Achim Vollhardt Sent: Wednesday, January 26, 2011 3:12 AM To: [email protected] Subject: [time-nuts] Temperature stability for Thunderbolt: results After some tweaking of the temperature controlled fan setup (not always to the better), I finally settled on a setup with great results. - Peak-peak variations in stable environments are down to 0.02K. - opening window for few minutes disturbs only 0.03K down. - TBolt sits now nice and stable at 36 degC. Summarizing the important points (and please if somebody wants to add/correct, feel free!): - Using Lady Heather's temperature controller helps A LOT. - Using a too small fan results in too small control range. Large temperature disturbances cannot be compensated. - Direction of flow DOES make a difference. First attempt blew the air from the (warmer) power supply to the TBolt.. which make you kind of wondering why the temperature shoots up while the fan is running 100%. - I minimized the thermal mass *between* the fan and the TBolt. It is still in his own case, but no passive shielding around. Slows down the control loop and seems to make things worse. Some thermal mass around the fan control loop might be a different story. - Once the temperature has settled, 'ka4' optimizes the controller parameters. Another improvement in response speed and temperature residuals. A big thank you to Warren and Mark for implementing this feature (sorry if I forgot somebody) and all others who helped in this list. I think this feature is a must-have for all TBolt setups out there.. 73s Achim, DH2VA _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
