Bert: Something to be said about "no moving parts".Bill-w7kxb
> From: [email protected] > Date: Sat, 17 Sep 2011 21:22:30 -0400 > To: [email protected] > Subject: [time-nuts] temperature control > > Recent comments on dewier flasks bring me back to test I conducted last > year using a nice flask that I tested extensively using the guts of a 10811 > as a constant heat source. What I found and reported was that the ambient > inside changed as much as .4 C with 8 C changes on the outside. The tests > ended when it fell off the pedestal that I mounted on my balcony in order to > take advantage of the large overnight changes. Since then I have focused on > temperature control by fan cooling. Shopping for small fin heat sinks I ran > across a VGA cooling assembly at our favorite supply site 370537089468 for > a total of $5.92. At that price I said what the heck. It came in 4 days > and I mounted it on the back of a FRS. After 4 hours without cooling, the > back plate was 59.7 C with an ambient of 29.2. the fan assembly without fan > running was actually already cooling the back plate, because without it > mounted, the temperature was 62 C. 6 minutes after powering up the 12 V 80 > mA > fan, temperature had dropped to 45 C and 30 minutes after power up the back > plate is 40.6 C again with 29.2 ambient. The fan is very quiet and it is > amazing what can be done with a small amount of moving air. This fan with a > single op amp will be able to hold the back plate within .1 C at 45 C. > Eventually all my time/frequency units will have some kind of moving air > temp. > control. Lower temp. will also extend life. > Now my dilemma is whether to use my original design with an array of small > heat sinks with the fan off the side not part of the Rb or stay with this > super simple design. > Bert Kehren Miami > _______________________________________________ > 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.
